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June 2012

CONTACT! ISSUE 104.5 PAGE 1 Issue #104.5

PO BOX 1382 Hanford CA 93232-1382 United States of America 559-584-3306

Volume 18 Number 4 June 2012

Issue #104.5 MISSION CONTACT! Magazine is published bi-monthly by Aeronautics Education Enterprises (AEE), established in 1990 as a nonprofit corporation, to promote aeronautical education. CONTACT! promotes the experimental development, expansion and exchange of aeronautical concepts, information, and experience. In this corporate age of task specialization many individuals have chosen to seek fresh, unencumbered avenues in the pursuit of improvements in aircraft and powerplants. In so doing, they have revitalized the progress of aeronautical design, particularly in the general aviation area. Flight efficiency improvements, in terms of operating costs as well as airframe drag, have come from these efforts. We fully expect that such individual efforts will continue and that they will provide additional incentives for the advancement of aeronautics. EDITORIAL POLICY CONTACT! pages are open to the publication of these individual efforts. Views expressed are exclusively those of the individual authors. Experimenters are encouraged to submit articles and photos of their work. Materials submitted to CONTACT! are welcomed and will become the property of AEE/CONTACT! unless other arrangements are made. Every effort will be made to balance articles reporting on commercial developments. Commercial advertising is not accepted. All rights with respect to reproduction, are reserved. Nothing whole or in part may be reproduced without the permission of the publisher. SUBSCRIPTIONS Six issue subscription in U.S. funds is $20.00 for USA, $24.00 for Canada and Mexico, $32.00 for overseas air orders. CONTACT! is mailed to U.S. addresses at nonprofit organization rates mid January, March, May, July, September and November. Please allow time for processing and delivery of first issue from time of order. ADDRESS CHANGES / RENEWALS The last line of your label contains the number of your last issue. Please check label for correctness. This magazine does not forward. Please notify us of your date of address change consistent with our bimonthly mailing dates to avoid missing any issues. COPYRIGHT 2012 BY AEE, Inc.

Several years ago we published multiple articles by or about the late Paul Lipps and his remarkable work with propeller efficiency and nearly every issue with his work in it sold out. With the demand for these back issues being so high, I felt it was a better use of our resources to print a special compilation issue than it would have been to reprint the individual issues that contain the material sought. The special Paul Lipps issue was numbered 88.5, as it came out after issue 88 but before issue 89. So along those same lines, the issues in which we’ve published Revmaster Aviation’s engine articles have been in such great demand that it’s become necessary to do the same with this issue. So other than some slight editing to these reprinted articles, the only thing in this issue that might be considered “new” to a loyal CONTACT! Magazine subscriber is the “Motor Glider To Paraguay” article, on page 24, and this editorial.

EAA Founder Paul Poberezny once told me that if you've not read it before, then it's new to you. With that in mind, please enjoy this retrospective issue.

UPDATES TO THE R-3000 The R-3000 is an engineering marvel. It’s a ground-up redesign of the venerable Volkswagen Beetle engine that so many companies have used as the basis of their aircraft engine conversion business, yet it only shares a few dimensions and the cam bearings with the stock VW engine. Although only a few prototypes have been created from the original 10 raw castings, all but two have gone into race cars. Now some may say that racing equipment doesn’t properly compare with aviation use, but when a turbocharger is installed and 600 reliable horsepower is pumped through it, and it holds up race after race, that speaks volumes to the ability to handle 110 hp for hundreds of hours on end. Continued on page 23


Revmaster R-3000 Engine.— 15 years in the making, this new engine is about to hit the market and take the 100 hp engine genre by storm. By John P Moyle


Meet Joe Horvath.— A brief sidebar on Joe and his background with the VW engine By John P Moyle


RevFlow: Innovations and improvements.— Descriptions and details of the inner-workings of the RevFlow variable-jet, injector carburetor. By Joe Horvath


Revmaster R-2300 Conversion.— The fine people at Revmaster Aviation have done it again, increasing the bore and stroke of their renown R-2100 to up the horsepower safely.


Motor Glider To Paraguay, 8,000 Miles Behind A TurboRevmaster.— Jack Lambie tells his tale of an epic 8,000 mile flight from Southern California to Asuncion, Paraguay, to deliver a newly hatched motor glider, powered by a turbo-normalized 80 hp Revmaster R-2100DT that includes an aluminum constant-speed prop. Reprinted from the March 1981 issue of EAA’s Sport Aviation Magazine.

On the cover: 85 horsepower, 2332 cc Revmaster R-2300


Photo courtesy of Revmaster Aviation

By John P Moyle Photos by Pat Panzera There is something new and very exciting happening at the Hesperia airport (L26) located in Hesperia, California. A completely new, experimental aircraft engine has been designed and is being manufactured. It’s in the highly desirable 100+ horsepower class, which should fit into a large segment of experimental aircraft including many Light Sport Aircraft category candidates.

A BIT OF HISTORY Revmaster Aviation is best known in the experimental aircraft community as a major producer of air-cooled Volkswagen automobile engine conversions. To date, Revmaster has converted and delivered over three thousand of these engines. Many light aircraft, such as the Rand Robinson KR series and other popular designs, were conceived with engines like these in mind. A turbocharged version of an early model Revmaster engine, complete with a constant-speed propeller, powered Ken Rand’s original KR-2 at speeds up to 190 mph at 14,000 feet MSL. The Revmaster R-2100, a 75 horsepower, naturally aspirated, direct drive, air-cooled, 4 cylinder boxer engine, was the fully assembled engine offered with the Q-2 kit from Quickie Aircraft Corporation. That “fast glass”,

seat, tandem wing was immensely popular during the early 1980’s and still has a healthy following even though the kit has been out of production for almost 2 decades. Its stunning good looks and outstanding performance, on such little horsepower, made it the darling of its era. In time, as is so common with experimental aviators, the owners of these sleek little planes began to desire even greater speeds. Revmaster provided a turbo-normalized 80 HP version of their 2100 c.c. engine (R-2100DT) to meet that need, as well as offering an electronicallygoverned, oil-actuated, constant-speed propeller. Finally, the movement towards Continental O-200 powerplants for the “Q” took place and the associated increased gross weight mandated a new canard with a stronger spar. The altered plane was christened the Q-200. Builders of other VW-conversion-powered aircraft designs, also seeking higher performance, seemed to follow suit. Back then, the O-200 was abundantly available in mid TBO condition at a fairly reasonable price. Those days are long past and the remaining choices for less costly engines in the O-200 class are few, with the cost figures having escalated rather dramatically. A very limited number of alternative engines are available which can provide the sought-after horsepower, in a usable form, at an affordable price.


ADDRESSING THE SITUATION Joe Horvath, founder and president of Revmaster Aviation, probably has more experience than any other individual person in the field of converting VW engines for experimental aircraft. With over 30 years in the business, the impressive volume of his production cannot be challenged. When aircraft designers and builders wanted more power from their VW-based engines, Revmaster responded; but there can be no argument that extracting greater power from small displacement engines takes its toll on component lifespan. The cylinder heads and piston crowns can reject only so much heat unless fundamental changes are made to the amount of cooling fin surface area and piston alloys, etc. Eventually, the only reliable solution becomes additional displacement, as we’ve heard it said many times, “There’s no substitute for cubic inches”. The constant demand for increased performance made Joe look hard at the Type IV Volkswagen engine as a possible conversion. This 1.7 to 2.0 liter, air-cooled, 4 cylinder boxer engine is mostly known for its use in the VW Bus (Transporter) and the Porsche 914. But there are problems with these engines which are not easy to resolve, such as the availability of serviceable cores (as well as limited after-market parts) and the cost to overhaul in general. While some of these engines have been converted independently (up to 2800 c.c.’s) and are currently flying successfully, these too have failed to gain strong acceptance from the EAA faithful. Mr. Horvath began to consider the prospect of applying his knowledge and experience to a completely new design with none of the compromises and restrictions that come with conversion from other applications such as the automotive realm.

bers, processes carried out, and the technicians involved. Mr. Horvath has properly laid all the groundwork for this engine to join the ranks of FAA (and other nations’ controlling-agencies) certified powerplants, should he choose to pursue that option in the future.

A new R-3000 crankcase attached to a traditional VW engine stand awaits final assembly.

BUILDING AN EVOLUTIONARY POWERPLANT It eventually became apparent to Mr. Horvath that he could indeed create a 3.0 liter displacement engine capable of delivering well in excess of 100 hp. He calls this development an “evolution” of his prior experience with Volkswagen based conversions, combined with his perception of what is needed in the largest segment of the current and future Experimental and Light Sport Aircraft business.


During the earlier course of creating custom parts for the R-2100 series, Revmaster Aviation had developed working relationships with foundries capable of making castings and forged metal engine components. Major casting for the all new R-3000 crankcases, accessory housings, cylinder heads, valve covers, camshafts and cylinder barrels, plus the forged parts such as the crankshafts and connecting rods, have been commissioned to these outside sources and are delivered to Revmaster for precision finish-machining. All the designs are from Joe Horvath’s shop. Each component that is being created for this engine is being handled as if it were going to be FAA certified. The “birth certificate” of individual pieces follows it through the approved procedures with careful notation of date and time, material source, batch num-

The case features a full circle of head-retention studs. One of the shortcomings previously alluded to concerning larger displacement VW conversions was the lack of adequate and well-spread clamping force from only four studs around each of the expanded bore cylinders. The R-3000 boasts a 50% improvement in this regard, with six well spaced studs surrounding the cylinder bore (see photo next page) providing more even, superior, clamping pressure. Gone should be the days of lost compression and blown heads.

Using permanent metal molds, the case is cast from aluminum alloy, although earlier versions were sand-cast from magnesium. The case halves are split vertically down the centerline, similar to Continental, Lycoming, Franklin, and yes, Volkswagen too. The left and right sides are attached to each other using 14 mm diameter 8740 steel through-bolts.

Besides the central portion of the case, unlike its predecessor, there is a top cover plate, similar to what you might find on Franklin and Corvair engines. The front of the case is furnished with a bolt-on propeller drive-


The clean-slate designed engine case that Joe developed has 2 additional bolts per cylinder bore, located at the 12 and 6 o’clock positions. extension-housing which supports the huge #4 bearing. The bottom of the case is closed with a cast oil-sump, either wet-sump or dry-sump, as specified by the customer. While a wet-sump is simplicity itself, the dry-sump model has the advantage of moving the weight of the

Fitted with an alternative “front cover” this engine can be bolted in to a traditional VW automobile.

The genius of this system lies in the interchangeable “front covers”. The casting pictured above and to the right show how this engine is fitted for aviation use. The photo at the top of the next column shows the engine fitted for automobile use by installing a different and separate “front cover”.

Photo courtesy of Revmaster Aviation

For comparison, this photo of a stock VW engine case (converted for aviation) shows the intricacies of the casting which are vital to the stock case. These specific features are replicated by Revmaster in their “front cover” designed for automobile use. The aviation “front cover” was developed with a clean slate and is 100% aviation oriented, complete with a proper bearing, and not a compromised conversion.


150 foot pounds. The prop flange provides a cadmium-plated SAE #1 prop mounting hub and features a massive #4 bearing journal surface which is carried by a B8-50 alloy aluminum bearing. This bearing is installed in the propeller shaft housing and exceeds the total bearing area of the other three main bearings combined, effectively absorbing the propeller dynamic loads. The crankshafts are all heat treated, nitrided, superground, and interfaced with the taper on the prop hub end. These cranks will handle a prop weight of up to 25 pounds, including constant-speed models. Everything about the crank is designed for the future installation of an oil-actuated, constant-speed propeller.

CONNECTING RODS Photo courtesy of Revmaster Aviation

This photo of the underside of the engine shows many details including the dry-sump oil pan.

Forged 4340 steel H-beam type connecting rods have 100% machined surfaces and utilize 3/8 inch ARP 2000 rod cap bolts. They are balance-matched

excess lubricant to the firewall (or anywhere on the airframe actually). This option may help designers and builders to have greater control over how much weight they suspend on the engine mount at what may be a long moment-arm from the center of gravity, in addition to other desirable performance features usually associated with dry-sump systems. The amount of oil carried would not be restricted by available crankcase volume if the dry-sump system were chosen.

CRANKSHAFT The crankshaft is forged from E-4340 steel alloy and is counterweighted. The stroke is 90mm. Bearings #1 and The business end of the crankshaft with the prop #2 are typical steel-backed split-type plain bearings, 60 flange removed, showing the 3º taper. mm at the inside diameter. The # 3 bearing, an aluminum ring-type thrust bearing (again 60 mm) is located nearest to the prop end (but still inside) of the crankcase. The prop end of the crank features a 3º precision locking taper and is fitted with a long prop hub/ flange which is further secured by a left-handthreaded, ¾ inch locking bolt in he The crankshaft is a 2 piece affair. Everything from the left of the cam gear shown in the phonose, torqued to to above is attached to the crank via a tapered fit and a left handed, 3/4” bolt.


CAMSHAFT The camshaft is a chilled cast-iron unit with a lobe hardness of 60 HRC. In the casting process a “chill” (a metal piece placed in the sand mold) is used. These “chills” act as quenches which remove or “wick” heat rapidly from a specific area in the mold. The rapid cooling makes the metal near the chill much harder than the surrounding material without the chill. The hardening depth goes significantly beyond any other hardening process.

into weight groups of +/- 3 grams. The rod length has a 6.0” center-to-center dimension. The “big end” carries pressure-lubed plain bearings from Ford’s Capri engine, which rotate on 54 mm polished and radiused journals. The small end (with bronze bushing) connects to full floating Chevrolet wrist-pins that are retained by spiral circlips. Splash style lubrication is effectively used to get oil into the wrist pins and piston lands via strategicallyplaced orifices in the piston interior and the rod end.

CYLINDERS, PISTONS AND CR The cylinders are centrifugally-cast iron with a bore diameter of 102.36 mm (4.03”). A 25 micro-inch crosshatch finish-hone is applied to the bore. The pistons are a forged aluminum, flat-top, off-the-shelf Chevrolet part,

and are equipped with chrome-moly rings. This flight engine is configured to produce a compression ratio of 8.9 to 1 and operates on the 100LL avgas that has become the most widely available fuel among North American flight centers and FBO’s.

The custom grind provides .520 inch of valve lift and 274º of duration. A bolt-on aluminum cam-gear runs against the billet-machined, carbon-steel, crank-gear at the front of the engine, while the cam itself turns in pressure-fed plain bearings from the Type 1 VW. Of note here: Converted VW engines suffered from having crankshaft strokes severely limited by their close proximity to the camshaft. The R-3000 has been designed to place its cam low in the case to allow for the clearance required when using its longer stroke crank. The cam also drives a 38 mm high volume oil pump that has the capability of moving 2-3 times more lubricant than the 30 mm pumps used in the R-2100. That’s potentially up to 9 gallons per minute!

LIFTERS AND VALVE SEATS One of the frequently mentioned issues that plagued the early VW conversions was the persistent (though incorrect) belief that the solid lifters in those engines were responsible for the need to adjust the valve lash every 25 hours. The truth, discovered after exhaustive research by the Revmaster technicians, is that the original valve seat material was inadequate to tolerate the heat being created in the combustion chamber once the displacement grew beyond the Volkswagen factory specifications. The hot valves had begun to lift tiny particles of metal from the seats and that erosion, (in addition to destroying the efficiently of the combustion chamber) allowed the valve to sit deeper in the head. The clearances at the rocker arm would then diminish or disappear altogether, causing some to believe that what was happening was that the valves were "stretching". Frequent valve lash adjustments (typically every 25 hours) became the common practice, even to this day with VW engines still utilizing inferior valve seat material. Other folks choose to modify the engine to accept hydraulic lifters, which takes care of the constant need to adjust the valve clearances, but does not remedy the cause of the problem occurring at the valve seats. The true solution is to use seats with a very high nickel-content alloy, which is precisely what Joe has been doing since 1985. Solid lifters work just fine and are super easy to set to the proper clearances. No additional maintenance beyond “check at annual” is required and the valve train has proven to be very durable since the improved (hardened) seats were adapted.

HEADS The all new aluminum head castings have been carefully designed with appropriate mass and significant cooling fin area to handle the heat generated therein. There are two 14 mm x 3/4" Bosch platinum-tipped spark plugs per


The day we visited Revmaster, Joe was in the process of building engines destined for the drag-strip. The photo above shows the size and shape of the combustion chamber, but what’s missing is the second set of sparkplug holes that would normally be there if this head was dedicated to aviation.

This cut-away of the head shows just how well the engine can breathe, in addition to showing just how beefy the valve seats are. chamber, one upper and one lower. Each plug has its own ignition coil mounted just inches away with a very short spark plug wire (similar to those used in modern Corvette engines). This redundant system is mated to dual, independent, fully-solid-state, electronic CDI sources. The combustion chambers are fitted with stainless steel valves, 53 mm for the intakes and 41 mm for

the exhausts. These provide the “easy breathing” and close on hardened nickel-alloy valve seats. Chrome-moly roller-rockers are used to transfer the movement of the pushrods (also chrome-moly) to the valve stems with the least possible friction. Roller-rockers also help to reduce the side loads that would otherwise wear the bronzesilicone valve guides prematurely.

INTAKE SYSTEM Dual-port intakes are positioned on top of each pair of cylinders. (See cut-away photo, upper left corner, this page) The intake manifold design will vary with the airframe and cowling requirements. For instance, a more typical aircraft updraft carb would be mounted aft beneath the engine in most installations. The cast aluminum manifolds depicted on the Revmaster photo on page 3, shows a pair of 40 mm RevFlow throttle-bodytype carbs mounted above the engine. These are an inhouse product manufactured and sold exclusively by Revmaster Aviation. The engine shown in that photo was built for an airframe that had space limitations which precluded installing the carb(s) under the engine.

EXHAUST SYSTEM Exhaust systems may vary depending on the installation limitations of specific aircraft, but the factory does offer a close-fitting, four-into-one, tuned-header which may be suitable for a wide variety of experimental designs. The Revmaster in-house dynamometer tests credit this system for about four extra horsepower over straight pipes. Either mild steel or stainless versions are available. With the head fitted to a special fixture Joe uses to test run his valve trains, we can see the detail that has gone in to the design and application of the light -weight roller-rockers.

OIL SYSTEM At the front of the engine, below the propeller shaft housing, and driven from the end of the cam, is the lubrication system source. This is another proprietary casting of the company. It includes the oil-pump cover section, the


mounting location of the spin-on, full flow, oil filter, as well as the mount for the diaphragm-type mechanical fuel pump. Besides servicing the usual oil passages for the internal engine components, pressurized oil is plumbed (via external braided hose and threaded fittings) to the propeller-shaft housing. Additional lines are routed to the oil cooler, usually mounted in a horizontal plenum positioned beneath the crankcase. Optionally, other styles and mounting locations for oil coolers can be specified by the customer. Revmaster builds their own oil pump in-house. Above is a small portion of pumps being machined. Below is a case of housings yet to be machined.

ACCESSORY CASE This accessory housing package is responsible for four items critical to the engine and aircraft operations. It contains three major operating systems: the dual alternators, the self-energized ignition source, and the electric starter, plus provides the physical mount to the airframe. The R-3000 model is nearly identical to the proven unit currently used on the R-2100 model (60 of those units are now in use) and is yet another product made exclusively by Revmaster. The three electrical sub-systems are independent, but function as an integrated unit within one compact case. Let’s look at each component separately for the sake of clarity. The precision machined alloy casting fully encloses the dual 18 ampere alternator package. Mounted to the interior face is a stationary, twelve pole stator ring. An aluminum flywheel incorporates twelve neodymium iron-boron magnets that are attached to the interior of the flywheel. These are the strongest magnets commercially available. The magnets rotate around the 8½ inch diameter stator.

During our interview with Joe Horvath of Revmaster Aviation we discussed some interesting revelations concerning one of his experiments. He is always searching for more efficient methods and new materials which might prove beneficial to the manufacture of components. One such endeavor has led him to attempt production of a unique cylinder for his air-cooled aircraft engines. The material is an aluminum silicon carbide alloy. The process requires taking a billet of this metal and extruding it into heavy wall tubing. This tubing is cut to cylinder length and precision machined to accept pistons in the bore. This is no small task since the tool normally used to bore the cylinder is very similar metal and can’t do the job. Instead, a diamond tipped device must be used. This same problem extends itself to the cutting of the cooling fins. The pistons could be run directly against the finished interior surface of this high-tech metal, but it seems that long life wouldn’t be likely unless a surface hardness

preparation is completed in the cylinder bore. Nikasil is a nickel and silicon carbide matrix coating about .0025” thick. The nickel component is very hard, but it is comparatively ductile. Dispersed through the nickel are particles of silicon carbide less than 4 microns in size. These extremely hard particles make up 4% of the coating and form a multitude of adhesion spots on which oil can collect. Besides providing a long wearing surface for the piston and rings, Nikasil also contributes to longer engine life by ensuring good cylinder lubrication. Unfortunately, the Nikasil process is an expensive one. Between the special cylinder material, the custom machining required to shape it, and the special coating, we have quadrupled the cost of the cylinder. This is a big investment to save eight or nine pounds on a set of four. The desire to reduce the weight suspended on the engine mount is strong, but at what price? We’re talking more than $200 per pound at the manufacturers’ current price. I have no doubt that Mr. Horvath will find a way to reduce the cost of this option, if there is a way. He’s got a long history of solving difficult problems. But if you are willing to pay the price, the cylinders are available. ~JPM


The aluminum accessory case shown above is very similar to the unit produced for decades by Revmaster, except the old case supported a pair of magnetos in the area that is now machined to accept the electronic ignition and alternator regulator shown below.

Inside the accessory case is an array of coils which serve as both dual ignition and dual alternators. Any movement of the flywheel sends its magnets spinning in close proximity to the stator’s. 12’ each of copper wire windings, exciting the electrons and creating electrical energy in those coil windings. There are two groups of five alternator coils, each set functioning as an independent 18 amp alternator. The current generated from these coils is sent to solid state regulators and then to the airframe’s battery and operational power buss. In the unlikely case of a failure occurring in one system, the other would remain unaffected.

IGNITION The two coils which make up the ignition power source are located 180 degrees apart at the 12 and 6 o’clock positions (see photo to the left), separating the previously mentioned five-left and five-right alternator stator coilgroups. The ignition coils are creating power whenever there is rotation of the flywheel also, but their energy is exclusively hard-wired into the CDI package. There is a triggering sensor mounted to the center area of the housing’s interior which receives a signal from a device attached to the end of the crankshaft. This component acts as the “distributor” and tells the CDI when to transmit the power to the eight mini coils which are positioned near the upper and lower spark plugs at each combustion chamber. Once the engine has been started, the battery is not necessary to operate the ignition. The ignition advance is set at a maximum 25° before top center. I would normally identify this as a fixed timing


position but, in reality, the “effective advance” behaves as if the low rpm timing is at 15° before top center. This desirable situation is created by magnetic precession in the self-energized design. Lower voltage exists in the system when the engine is turning slowly, reducing the current flow at the timing triggers. The engine likes 15° BTC for easy starting and comfortable idle. As rpm rises, so does the voltage and the ability to “snap” the timing and the advance moves quickly to its maximum setting. Experience has proven that 25° BTC, while possibly leaving a few horsepower untapped, is a smart place to limit the spark advance because it greatly reduces the opportunity for destructive detonation.


Photo courtesy of Revmaster Aviation

The aluminum flywheel features a heatshrunk steel starter ring-gear. The geared Subaru electric starter motor (pictured upper Revmaster has several R-3000 engines in a “beta” test program. right, previous page) is a compact 6 inch The one pictured above is going in a one-of-a-kind, metal Sonerai. long (installed) model, weighing 8.5 pounds. The ability to place the starter motor in the location with Experience has established a long service life for this the most surplus space can be a huge advantage. economical unit. It’s mounted in an aft cantilever style. Machined locations for the polyurethane-cushioned engine mounting bolts are located in the “corners” of the accessory case casting. With the symmetry of this design, the unit can be rotated 180º to facilitate the starter motor being positioned at either the top or bottom position. This would be a particular bonus for airframe designs such as the Zenith 601 (whose firewall angles aft at the top) and the Sonex (whose firewall rakes aft at the bottom). These significantly-slanted firewalls present unique challenges when installing engines other than those that were originally planned-for by their creators.

PERFORMANCE The R-3000 makes its highest torque, 180 ft-lbs, at 3,200 rpm and delivers approximately 110 horsepower at those revs. There is a “sweet spot” in the operation of internal combustion engines, the place where the torque curve peaks, as shown on the performance graph from the Revmaster dynamometer. This is the place where the volumetric efficiency is optimized. In this instance, by design, the performance benefits from having this situation occur at a usable prop rpm. That negates the need for a propeller speed reduction unit, retaining the preferred simplicity of direct drive to the prop. There will most likely be an even more powerful turbocharged version available soon. The new engine package is quite compact at 30” overall length (excluding the starter) and 31” wide. The weight of the R-3000 is said to be approximately 205 pounds, dry. This means that this engine is both smaller and lighter than the Continental O-200 which it is likely to replace in homebuilt aircraft. The price is expected to be thousands of dollars less than the Jabiru 3300 or the Rotax 912, and has the additional benefit of being assembled in the USA, making it less subject to the ups and downs of foreign currency exchange-rate uncertainties which has recently hurt the imported engine market.

WHAT THE FUTURE HOLDS Given the big push that the Light Sport Aircraft category is receiving, and the number of airframes which may see production as ready-to-fly planes, it wouldn’t be surprising to see a lot of interest in the R-3000 from designers currently leaning towards Rotax, Jabiru, or other factory engines in this class. Designers and manufacturers are


likely to admire the relative simplicity of the R-3000 and with the target price at $9,995, there is a large price advantage over the other choices. Many private builders of homebuilt models are also certain to look hard at this fresh and innovative offering from a well-established American company with a long track record of success.

directly via e-mail at The phone number to their facility is (760)-244-3074 Visitors are welcome at the factory; however, a phone call in advance is appreciated. The factory and offices are located adjacent to the Hesperia, California, airport (L26) runway and mail can reach them if addressed to 7146 Santa Fe Avenue East, Hesperia, California 92345

CONTACT INFORMATION For more information check the Revmaster Aviation web site: or contact the company

In the late 1950s there was a phenomenon happening in Southern California. A funny-looking little car, known affectionately as “the Bug”, had won the hearts of those living in that temperate climate. Its 36 horsepower air-cooled engine soon grew to 40 horses, and the business of rebuilding the smaller units (and converting them to the “big bore” model with a miraculous 10% improvement in motive force!) began. Joe Horvath was at the forefront of that development. He and his partners created European Motor Performance Inc. (EMPI) and Revmaster LLC. (automotive), becoming the force to reckon with if you wanted to make your Bug get up and go! I still remember EMPI’s drag racer, “Inch Pincher”, which humiliated American hot rods with regularity. The aerospace industry joined the fray when Northrop Aircraft asked Joe to produce a serviceable engine for military target drones. Before long, Revmaster Aviation was born and began marketing engines to experimental aircraft builders, too. The company built engines of nearly every conceivable displacement until it settled on the 2100 cc R-2100 series. It had become apparent that there was no significant price advantage to produce the versions with fewer cubic centimeters of displacement (1600, 1835, etc.), so Revmaster invested heavily in one well proven principle model and as a result, was able to keep the costs in check. Frequently the best solution to a problem was simply creating many of their own components in-house. When the Quickie Q-2 kit-plane came along, Revmaster was chosen to provide their R-2100 as the standard powerplant. Decades of product sales-and-service later, with more than 3,000 engines delivered, you might think Joe Horvath would be resting on his laurels. But Joe and his lovely wife Roberta still come into the office every morning and the pursuit of new and better aircraft engines has never ceased. The accompanying article discusses his commitment to bring a three-liter engine of reasonable price and rugged reliability to the experimental aircraft community. Revmaster has invested ten years of research and development into the new R-3000.

John P Moyle

Knowing that there is wisdom in a diversified customer base, and having a long interest in auto racing, Joe designed the R-3000 with the full intent of it having it be adaptable to earth-bound vehicles. A turbocharged and fuel-injected version of this engine raced at the Fontana, CA, drag strip this spring. Would you believe 700 horsepower? Okay, so it’s only for a very fast trip down the quarter mile, but you have to appreciate that this is the exact same base-engine as the flight version - so one would have to believe that the internal components are well engineered, competently manufactured, and incredibly strong. Mr. Horvath is a man with unparalleled dedication, experience and vision. His stalwart commitment to improving the product, even to the current point of creating a totally new and vastly superior powerplant, is obvious. He has placed a number of the R-3000 engines in “beta test” installations with builder/pilots of various experimental aircraft. When he’s satisfied that there are no “issues” to attend to, this design is market ready. The plan would include upgrading his manufacturing partners to include a higher level of finish work from them, and the Hesperia factory would become the final assembly facility. His remarkable ability to identify the best solution to a problem, whether it be a design issue or a manufacturing problem, may be his greatest personal asset. He has been successful in the past at bringing “outsource” manufacturers into the mix, while maintaining strict quality control, which allows his company to create the custom components for Revmaster Aviation products at reasonable prices. ~JPM


ing screw. Several throat sizes and needle configurations are available. The guillotine-slide is actuated by a wheel and leaf-spring that opens and closes to the throat-opening when the wheel is rotated via the control-arm. The slide has four flutes that guide it very precisely on several surfaces so the transition from idle to full power is without hesitation.

By Joe Horvath Twenty five years ago Revmaster engines used a throttle -body carb called the POSA, manufactured by Jim Birmingham. By most reports it was a dreadful, leaky thing that lacked an effective idle cut-off and a functional mixture control. Many operators indicated that this carb had difficulties in the “ram air” mode and the number of owners who indicate that keeping the POSA in tune a “hit or miss” adventure are legion. When Joe Horvath got tired of having to shoulder the complaints about the inadequacies of this fuel metering unit, he decided that while he knew the concept was sound, the manufacturer’s execution had been lacking. He was certain that he could improve the design and create a superior device. A fluid systems engineer was brought into the company to investigate the shortcomings of the Posa. Joe and his associates came up with solutions and a new design was created by the engineer which met these new higher criteria. The following article is from “Technical Study: RevFlow Injector Carburetor” and reprinted with the permission of the author. ~JPM TECHNICAL STUDY: REVFLOW INJECTOR CARBURETOR Revmaster has been manufacturing the RevFlow-series injector carburetor since 1981. The major components of the RevFlow are precision die-cast, not machined from-bar stock. The die casting process allows for many intricate features to be cast in, thus reducing manufacturing costs. The injector unit incorporates a once-patented variable-jet for fuel metering and a guillotineslide which controls the air flow. The two parts work in unison, thus providing the engine with the proper fuel/air mixture. The fuel-metering-needle is ground with a flat tapered side which gives it an asymmetrical shape. The needle is attached to the slide and is allowed to float so it is self-aligning when inserted into the fuel nozzle. The head of the needle is configured so it cannot rotate while in service and is spring-loaded so the fuel mixture can be fine-tuned during the initial installation via a slotted adjust-

When the slide is in the wide-open position, there are no other obstructions in the way of the air flow except for the needle, thus allowing for much greater air flow than with throttle-bodies which typically have butterfly valves. The flat side of the needle is oriented towards the engine and produces a low-pressure on the back side which in turn causes fuel to flow in relation to the air flow. This characteristic has altitude compensation benefits due to the variance in air density at higher altitudes. In order to manually control the mixture, the injector unit is equipped with a manual mixture control and idle cutoff. Besides controlling the mixture, this system will allow the fuel to be cut off at the nozzle, thus eliminating fuel leakage from the fuel line. Then, on restart, the fuel is at the nozzle for priming and starting. The unit is equipped with two control arms; one for throttle and one for mixture cutoff. They require vernier-type controls with at least 3.5" travel with solid wire ends. Cable-housings are connected to the injector body via cable housing attach-points. This eliminates any movement in the cable housing which can Continued on page 22

We currently have a RevFlow mounted under a Corvair engine attached to our test stand, exceeding our expectations. We’ve had two other carburetors on the rig in the past and the RevFlow out-performs them all.


Patrick Panzera Introduction by Tim Kern Revmaster Aviation has finished development of its latest upgraded engine and the results are in: more horsepower at any usable RPM. The new Revmaster R2300 (2332 cc) engine maintains Revmaster’s breakthrough R-2300 engine offers more horsepower at a Lower cruise Revmaster’s renowned proprie- RPM that previous versions. tary systems and parts including Revmaster has been in the engine business since 1959, its RM-049 heads that feature large fins and hemispheristarting out as a remanufacturer of the early 36 HP encal combustion chambers. It maintains the earlier R-2200 gine that was introduced in the Volkswagen beetle. In engine’s maximum 82 horsepower at only 2950 RPM 1960 the VW was upgraded to the 40 HP engine that has continuous, but offers 85 ponies for takeoff at 3350. become the cornerstone of VW flight engines. Around that same time, Revmaster developed a 2000 cc version The additional power ultimately comes from a 94 mm of the VW for the experimental aircraft market by first bore plus lengthening the stroke to 84 mm, but that’s manufacturing target drone engines for Northrop Corpooversimplifying things. “We’ve put a lot of energy into this ration. Revmaster spent about two years in this endeavor redesign,” says Joe Horvath, president and founder of before discovering thrifty and resourceful homebuilders Revmaster Aviation. “On paper it looks like just a few were using some of these drone engines in experimenminor modifications, but we’re really closer to a complete tals. With many of the installations being highly successrework of the internals: crank specification, connecting ful, Revmaster decided to go in that direction. Now with rods, pistons and cylinders are all new.” The longer well over 40 years experience in the homebuilder market stroke results in greater displacement, longer connecting and literally thousands of engines sold, Revmaster is rods yield better vibration and power characteristics, the announcing the latest addition to their successful line-up, lower cruise RPM allows the use of longer propellers, the R-2300. and the higher peak horsepower can be felt in shorter takeoffs and steeper climbs. Although the Revmaster is based on the VW engine, not much of the original engine remains. From a proprietary Strength and reliability are boosted by Revmaster’s fourcrankshaft to proprietary heads, including a modern elecmain-bearing, 4340 forged steel crankshaft (boasting tronic ignition with individual coils for each of the eight nitrided journals) that runs on huge (as compared to a sparkplugs, this is not the old shake-and-bake VW constock VW) 60 mm center main bearings. Thrust is hanversion of yesterday. It is more a purpose-built aircraft dled by the custom-installed 55 mm #3 bearing at the engine than it is an automobile engine conversion no prop end of the crank, formerly found at the other end. matter how it's measured. Fully utilizing its robust, proprietary #4 main bearing, the Revmaster crank has built-in oil-controlled variable-pitch THE CRANKSHAFT propeller capability, a feature unique in this horsepower range and exclusive to Revmaster VW conversions. UnConnecting the propeller is always the most difficult part like other VW conversions, props other than wood are of adapting an automobile engine to aviation use. Not that it's particularly difficult to physically accomplish, but usable on any Revmaster engine of any vintage.


rather that the loads imposed on the crank by the propeller are considerably different that those in an automobile. Potentially, the worst of these loads are gyroscopic in nature, although some might argue that torsional loads, especially harmonics that can be amplified by the propeller, are much worse if not a close second. Throughout the years, ever increasing displacements have multiplied the strength of the power-pulses and have amplified the propeller effects. And through trial and error, it's generally accepted throughout the VW engine community that the propeller used on a Volkswagen conversion should be wood and be as light as possible. This is not the case with the Revmaster and carbon fiber, aluminum and even variable-pitch propellers are open for consideration. Throughout the decades that experimenters have been flying behind the VW engine, there have been a number of different ways used to attach the propeller hub to the crankshaft, most of which have been to simply bolt a custom hub to the pulley end of the otherwise stock crankshaft using the same method that the generator fan belt pulley is retained. It wasn't until Revmaster cleanslated the crankshaft design to include a precision taper fit of the hub to the crank that the VW conversion crankshaft was made robust enough to handle props other than wood. This fourth bearing rivals that of any certified horizontally-opposed aircraft engine.

Just behind the steel cam drive gear is the #3 main bearing. Where this would be a normal plain bearing in a stock VW, Revmaster has machined the case to accept one of their custom thrust bearings they manufacture in house.

substantially more surface area than the original three combined. It replaces the oil slinger, the ignition timing gear and the comparatively insignificant automotive front bearing that's designed to carry only the fan belt loads. The case is line-bored to accept the new fourth bearing as well as the larger-than-stock Revmaster main bearings, and the adjacent engine case web is machined to accept the otherwise stock VW thrust bearing that normally resides at the opposite end.

Where the stock VW crank steps down twice to smaller diameters and has two keyways, one for the distributor drive gear and the other for the fan belt pulley, the Revmaster crank has been beefed-up and then precisionground for the 3 degree taper.

Other VW engine conversion companies have tried to emulate the design (a short list would include HAPI, Great Plains and now AeroVee), but none have come close to the total package Revmaster has developed. This package includes, among other things, a left-hand threaded retention bolt that tightens with vibrations (not one that’s prone to loosen) and the elimination of the stress riser inducing keyways that others still use. The total package is rounded out with the installation of the previously-mentioned fourth main bearing that has

The new, one-piece, bearing-grade aluminum alloy tubular fourth bearing is machined from a proprietary casting and is slid over the crank prior to the hub being fitted in place and the cases closed up. The bearing is held in place by essentially an interference fit between it and the case halves, locking it into place. The prop hub bolt is installed but not tightened until after the case halves are bolted together and torqued to specification. The prop hub itself is machined from a single-piece proprietary 4130 or 4310 (steel) forging that’s then heat treated for hardness to ensure the locking effect of the precision-honed 3 degree taper. The previously mentioned left handed retention bolt is 3/4-inch in diameter and is torqued to 160 lb-ft, locking the taper so securely that any form of externally applied puller will destroy the hub before it can be removed. However, through the use of carefully placed internal threads and the properly


Deep inside the steel propeller hub are a set of threads into which the drive bolt is installed. When driven in far enough, the bolt bottoms out on the nose of the crank, forcing the hub off with symmetrical loads, safely removing the hub with no damage to any of the parts involved.

sized drive-bolt, the hub can be removed and replaced numerous times with no damage to the hub, crank or bolt. When I visited Revmaster during the build of the engine for this article, the technician slid the hub into place and secured it by patting lightly with the palm of his hand. He then asked me to pull it back off, which I couldn’t do. He had to use the drive bolt to pull it back off as a demonstration of the strength of the taper fit.

THE CRANKCASE The crankcase starts life as a stock off-the-shelf Brazilian -made magnesium VW part. Although Revmaster can obtain aluminum cases, magnesium cases are far lighter and have thinner cross sections in various places. Once received at the Revmaster facility in Hesperia CA, the crankcase undergoes extensive machining to allow it’s integration with Revmaster's other components.

traveled by the piston from zero degrees to 180 degrees of crank rotation. Another way to look at it is the distance between the crank pin centerlines as measured when 180 degrees apart, so moving the pin’s centerline farther away from the crankshaft centerline increases the stroke. When the stock diameter pin is moved away from the crank centerline, as it rotates toward the cam the clearance between the rod and the case is decreased. New stroke Old stroke

Due to the relative distance between the centerlines of the crank and the cam, it's easy to see that the engine can only be "stroked" so far. This is one reason that Revmaster opted to make their own case for the larger R -3000 engine we wrote about in CONTACT! issue #82. That same case can be used for the "tweener" 2500cc engine, but Revmaster feels comfortable tweaking the stock case to the 2332cc being featured in this article. Since the global market is so unreliable, the future availability of the Brazilian magnesium cases is always in question and that's one of the many reasons Revmaster developed their own case. For now, however, it's more economical to buy the off-the-shelf case and modify it, but with their own case, Revmaster is not locked in to a sole source should it ever dry up.

New centerline Old centerline Crank main journal Old diameter New diameter

Not to scale


What Revmaster does is to not move the stock diameter pin farther away from the crank centerline, but rather to grind the stock pin smaller in diameter, removing material from the surface of the pin that’s closest to the crank centerline, resulting in the pin’s centerline being moved outward as shown in the illustration above.

As previously mentioned, the stroke is ultimately limited by the cam location, but Revmaster has found a way around that. Stroke is usually defined as the distance

There are other clearance issues such as interference between the connecting rod cap or bolts and the crank-


not so obvious. When the piston is at the bottom of the stroke, care needs to be taken to provide enough support for the piston skirt. Revmaster handles this with the custom manufacturing of cylinders with longer spigots that enter farther into the case than stock cylinders. The deeper spigots do create other interferences inside the case that have to be dealt with, but Revmaster has refined solved all of them.


case or even the opposing piston skirt. These are addressed with traditional, proven methods, but the use of proprietary connecting rods with streamlined bolt lugs goes a long way toward solving these issues. There are other issues that arise when stroking the engine, the most obvious being taking care of the compression ratio, but in this instance, there is one issue that’s

On the left is the special Revmaster cylinder designed to support the piston all the way to bottom dead center of the bored and stroked R-2300. Contrasting on the right is a stock VW cylinder. What’s not shown is the additional machining to the spigot end of the cylinder that’s necessary for clearance.

Forged 4340 steel I-beam connecting rods have 100% machined surfaces and utilize 9mm ARP 2000 rod cap bolts. They are balance-matched into weight groups of +/ - 3 grams. The “big end” carries pressure-lubed plain bearings from a General Motors application, rotating on 2” polished and radiused journals. The small end (with bronze bushing) connects to full floating VW wrist pins that are retained by spiral circlips. Splash-style lubrication is used effectively to get oil into the wrist pins and piston lands via strategically-placed orifices in the piston interior and the rod end.

CAMSHAFT The camshaft is a chilled cast-iron unit with a lobe hardness of 60 HRC. In the casting process a “chill” (a metal piece placed in the sand mold) is used. These “chills” act as quenches which remove or “wick” heat rapidly from a specific area in the mold. The rapid cooling makes the metal near the chill much harder than the surrounding material without the chill. The hardening depth goes significantly beyond any other hardening process. The custom grind of the R-2300 is not particularly noteworthy (270° duration with a .390” lift), being on par with a lift and duration for low RPM/high torque as one might suspect. It performs well between 2500 and 3400 RPM, with peak torque at 3200. Revmaster services the entire spectrum of automobile applications for the VW engine and will grind one of their camshafts for just about any profile for any application. The stock (aluminum) VW cam gear runs against the otherwise stock VW crank gear at the front of the engine, while the cam itself turns in pressure-fed plain VW bearings.

Note the substantial differences between the crank-end of the stock VW connecting rod in the foreground and those attached to the crankshaft.


CYLINDER HEADS Revmaster, through their history with EMPI, has had a big part in the creation or evolution of aftermarket VW heads. These heads are pretty much the benchmark for aftermarket high performance VW heads and aviation conversions but Revmaster has taken the evolution even further with the development of their proprietary 049 heads. With thicker sections where needed and opened air passages for better cooling, these heads are capable of dissipating the torturous heat that has otherwise peaked the VW aircraft engine at the 65-75 hp limit for sustained power.


Although a lot of parts that go into the Revmaster conversion are proprietary, they try to use off-the-shelf parts where ever they can. The pistons are high performance forged Mahle parts. Note how short the piston is and that when it’s at BDC the rings are inside the case.

One of the frequently mentioned issues that plagued early VW conversions was the persistent (though incorrect) belief that the solid lifters in those engines required adjustment of the valve lash every 25 hours. The truth, discovered after exhaustive research by the Revmaster technicians, is that the original valve seat material was inadequate to tolerate the heat created in the combustion chamber once the displacement grew beyond the Volkswagen factory specifications. The hot valves had begun to lift tiny particles of metal from the seats and that erosion, in addition to destroying the efficiency of the combustion chamber, allowed the valve to sit deeper in the head. Testing proved a loss of about 0.001" of erosion per hour. The clearances at the rocker arm would then diminish or disappear altogether, causing some to believe that what was happening was that the valves were "stretching". Frequent valve lash adjustments (typically every 25 hours) became the common practice and continue to this day on VW engines that still utilize inferior valve seat material.

The areas around the combustion chambers have been beefed up to easily accommodate 92-94 mm bores. This particular head was built for automobile use and has only one set of spark plugs.

Installing the solid lifters in the Revmaster R-2300.

Rough casting as it arrives at Revmaster Aviation.

Other folks choose to modify the engine to accept hydraulic lifters, which takes care of the need to constantly adjust the valve clearances, but does not remedy the cause of the problem occurring at the valve seats. The solution is to use stainless steel valves paired with valve seats with a very high nickel-content alloy, which is precisely what Revmaster has been doing since 1985. Solid lifters work just fine and are very easy to set to the prop-


Joe Horvath showing us the inner-workings of his high volume oil pump that includes the ability to install a spinon filter. The pump, which is driven by the camshaft, also runs an eccentric for driving the fuel pump.

er clearances. No additional maintenance beyond “check at annual” is required and the valve train has proven to be very durable since the improved hardened seats were adapted. For installations that are tightly cowled or if high power is used for extended periods and higher than normal cylinder heads temps are an issue, another anomaly may show up besides the need to constantly readjust the valves: a repeated need to tighten the head bolts. 18 lb-ft of torque on the head studs equates to .011" of stretch. As temperatures rise and the thermal expansion of the head kicks in with the aluminum expanding more than the steel stud, there could be another .004" of stretch. Since the stud lengths are not equal, the amount of stretch is not equal either and asymmetrical pressure can be concentrated on the portion of the head where it meets the cylinder. Coupled with the softening of the aluminum head as the temperatures rise and the high concentration of pressure from the point-loading of the cylinder spigot on the mating surface, the cylinders can work their way into the head and the bolts will begin to lose their torque. If the engine is continued to be pushed during these conditions, the mating surfaces of the spigot to the head can begin to leak hot combustion gases and a hole begins to be cut into the head from the concentrated stream of hot gases, like a cutting torch. To hedge against this anomaly, Revmaster developed for their earlier turbocharged models that used standard cylinders, a "power belt", which is a band of steel that's installed over the cylinder head end of the spigot, helping to maintain the cylinder’s concentricity and increases the contact area by 60 percent, reducing the point-loading enough to hinder the initial distortion of the softened aluminum. The test to see if the "fix" is needed that the lower head studs will need periodic retorquing. The R2033 however uses 94mm cylinders with sufficient wallthickness already built in to the spigot, eliminating the need for the band.

Tucked neatly under the engine is the oil cooler. Efforts have been made to allow for draining the oil without having to remove the cooler. Since the engine uses a quality oil filter, there’s no need to drop the pan and clean the screen with each oil change. Braded stainless steel hoses plumb the oil to and from the cooler.

OIL SYSTEM At the front of the engine, below the prop hub and driven from the end of the cam is the lubrication system sourceanother proprietary Revmaster casting. It includes the oil -pump cover section, the mounting location of the spinon, full flow oil filter (available at any auto parts store), as well as the mount for the optional add-on diaphragm-type mechanical fuel pump. The oil pump uses 38mm gears as opposed to the stock 30mm VW gears, and can flow nine gallons of oil per hour. Besides servicing the normal oil passages for the internal engine components, pressurized oil is also plumbed to the propeller shaft housing via external braided hose and threaded fittings. Additional lines are routed to the oil cooler, which is usually mounted in a horizontal plenum positioned beneath the crankcase. Other styles and mounting locations for oil coolers can be specified by the customer.

ACCESSORY CASE This accessory housing package accommodates four items critical to engine and aircraft operations. It contains three major operating systems: the dual alternators, the self-energized ignition source, and the electric starter, and it also provides the physical mount to the airframe. The R-2300 model is nearly identical to the proven unit currently used on the R-2100 (more than 60 of those units are now in use) and is yet another product made exclusively by Revmaster. The three electrical subsystems are independent but function as an integrated unit within one compact aluminum case. Let’s look at each component separately for the sake of clarity. The precision machined alloy casting fully encloses the dual 18 ampere alternator package. Mounted to the interior face is a stationary twelve-pole stator ring. An aluminum flywheel incorporates twelve neodymium iron-boron magnets that are attached to the interior of the flywheel. These magnets, the strongest magnets commercially available, rotate around the 8½” diameter stator.


Any movement of the flywheel sends its magnets orbiting in close proximity to the stators, with 12 feet each of copper wire windings exciting the electrons and creating electrical energy. There are two groups of five alternator coils, each set functioning as an independent 18 amp alternator. The current generated from these coils is sent to solid state regulators and then to the aircraft’s battery and operational power bus. In the unlikely case of a failure in one system, the other would remain unaffected.

With the accessory case installed, timing the ignition is next on the list.

The ignition advance is set at a maximum of 25° before top center. This would normally be identified as a fixed timing position but in reality the “effective advance” behaves as if the low RPM timing is at 15° BTC. This desirable situation is created by magnetic precession in the self-energized design. Lower voltage exists in the system

IGNITION The two coils which make up the ignition power source are located 180 degrees apart at the 12 and 6 o’clock positions (see photo above), separating the previously mentioned five-left and five-right alternator stator coilgroups. The ignition coils are also creating power whenever there is rotation of the flywheel, but their energy is dedicated exclusively to the CDI package.

The “brains” behind the brawn. Once the timing is set, the electronics are wired up and bolted in place,

The back side of the accessory case, showing the ignition trigger sensors.

A triggering sensor mounted to the center area of the housing’s interior receives a signal from a device attached to the end of the crankshaft, acting as the “distributor” and telling the CDI when to transmit the power to the eight mini coils which are positioned near the upper and lower spark plugs at each combustion chamber. Once the engine has been started, the battery is not necessary to operate the ignition.

when the engine is turning slowly, reducing the current flow at the timing triggers. The engine likes 15° BTC for easy starting and comfortable idle but as RPM rises, so does the voltage and the ability to “snap” the timing, and the advance moves quickly to its maximum setting. Experience has proven that 25° BTC, while possibly leaving a few horsepower untapped, is a smart place to limit the spark advance because it greatly reduces the possibility of destructive detonation.

STARTER The aluminum flywheel includes a steel starter ring that is heat-shrunken onto it. The geared electric starter motor is a compact 6” long model that weighs 8.5 pounds. Experience has established a long service life for this economical unit, which is mounted in an aft cantilever


style. Previously installed starters were proprietary and were designed by Molt Taylor of Mini-Imp fame. Machined locations for the polyurethane-cushioned engine mounts are located in the “corners” of the accessory case casting. With the symmetry of this design, the unit can be rotated 180º to facilitate the starter motor being positioned at either the top or bottom. This can be a particular bonus for airframe designs such as the Zenith 601, whose firewall angles aft at the top, and the Sonex, whose firewall rakes aft at the bottom. Slanted firewalls present unique challenges when installing engines other than those that were originally planned by their creators, so the ability to place the starter motor in the location with the most surplus space can be a huge advantage.

DETAILS The Revmaster R-2300 comes complete, ready to run and in fact, test run. While it’s not a kit like others offer, Revmaster will provide it as a kit if you so choose. While I was at the Revmaster facility conducting the interview and photo-shoot for this article, the entire engine was built from beginning to end (with many interruptions for questions and photos) in a little over two hours. At the peak of production back when Quickie Aircraft Corporation was ordering 100 units per month, Revmaster had a full-time staff of five engine builders knocking out 2-3 engines per day. In the big picture, absorbing the cost of building each engine right the first time, and checking by actually running it, far outweighs the headaches and problem solving with a builder who could be thousands of miles away, not to mention the damage to a company’s reputation that might come from a builder making mistakes and the product being blamed. Everything pictured in this article is included. There is nothing more for the builder to buy or supply to make the engine run except fuel to the RevFlow throttle body injector (carb) and electricity to the gear-driven starter. Airframe-specific items like the exhaust system, baffling, engine mount, and propeller are of course not sold with the engine, but in some cases are also available from Revmaster as separate items. Revmaster Aviation has a customer base that is pushing 40 years old. The name is trusted and respected throughout the aviation insurance community as an "approved" automobile conversion or alternate engine. Each engine (and most of the individual components) has a unique serial number and Revmaster has the complete records going all the way back to the raw materials. If anyone has ever considered the purchase of a 25 year old Revmaster, a quick phone call to Joe Horvath at Revmaster has probably netted the history of that engine, especially if each subsequent owner contacted Joe when they became the owner of the engine. When contrasted with a home brewed conversion with various parts collected from various vendors (some of whom may have gone out of business), it is easy to see how the insurance industry considers the engines from Revmaster to be more like certified engines than auto

conversions. This is no accident, since back in the early days the plan was to create a certified engine from the proprietary parts and since that time, all parts have been handled with the same paper trail and quality control standards as certified parts. The R-2300 and the R-3000 may still some day be FAA certified, and will most likely be ASTM compliant for use in factory-built special light sport aircraft. The Revmaster facility is as complete as a manufacturing shop can be, shy of having a foundry. From the initial drafting through the entire manufacturing process and including final assembly, testing, crating and shipping, everything is done in-house. Customer service is paramount and the people at Revmaster are prepared and available to assist the user in any way imaginable, from supplying all parts that they manufacture (including new old stock) to completely rebuilding an entire engine. Revmaster is also fully equipped for thorough testing, as evidenced by the patina on the dynamometer and the Magnaflux equipment, both of which have been in use for as long as I've been alive. Numbers published by Revmaster are well documented through actual testing, not by guessing. For the sake of time, production engines are tested outside with a test club of known performance. If the engine can't swing the club to the prescribed RPM with the anticipated manifold pressure, it doesn't leave the shop. In this way, testing can be done in under an hour rather than a full day in the test cell. The test cell is mostly reserved for specific performance research and development such as proving porting experiments after flow bench testing, intake and exhaust manifold designs, and carburetion and bore-and-stroke combinations. With the dyno, 1-3 horsepower gain or loss is easy to document and is repeatable in the controlled conditions of the cell. Those interested in the Revmaster R-2300 or any of the products they offer should feel free to contact them at their Hesperia office. Joe Horvath will be presenting forums at the upcoming COPPERSTATE EAA Regional Fly-in, KCGZ Casa Grande, Arizona October 21-23. From their website, We welcome visitors; a phone call in advance is appreciated. 760-244-3074 Revmaster Aviation 7146 Santa Fe Avenue East Hesperia, CA, 92345 (Located across the runway from Hesperia Airport)


Continued from page 13

cause erratic control problems. The wire ends of the controls are secured at the control arms with barrel clamps. The unit is mounted to the intake system by a 1-1/2” hose and two clamps. Flanged adapters can be provided on request. (The one in the Corvair engine installation photo on the page 13 shows an adapter I made to adapt the hose-clamp spigot of the RevFlow to the AeroCarb flange that is welded to the intake manifold. ~Pat)

Revmaster has a hoard of RevFlow carbs in stock. This batch of bodies is only a small part of the stock we saw at the factory. 28mm up to 42mm throat diameters are available. It seems entirely plausible that this selection would be good for 1/2 VW all the way up to 180 hp, irrespective of the engine manufacturer. Since the carb can be mounted in just about any orientation, it seems well suited for experimental aviation.

in the event multiple units are required, such as for inline engine applications, up to 4 units can be ganged on a single throttle shaft. RevFlow-injector sizes range from 28mm through, 30, 32, 34, 36, 38, 40, 42, to 44mm. An alternate-air-source assembly is recommended for most single unit installations. This assembly consists of an air filter, open on both ends, mounted onto the air-horn of the injector and held on with a clamp. The ram-air tube is clamped onto the opposite end. (The ram-air tube was omitted for our Corvair application pictured to the left~ Pat) The tube incorporates a valve that controls the ram air. When in the closed position the ram air is cut off and the engine is digesting warm filtered cowled air. The RevFlow injector is a 1-to-2 psi low-pressure injector. It will function well on gravity feed, although some applications require a fuel pump. When a fuel pump is installed, the fuel pressure should be maintained at a nominal 1.5 psi. This is best accomplished with a fuelreturn-line to the source. The return line can be restricted to achieve the 1.5 psi. For VW engine applications, Revmaster manufactures a special oil pump/fuel pump/oil filter assembly. This allows for an engine-driven fuel pump to be incorporated into certain applications. The RevFlow injector unit is floatless, therefore, it lends itself to any mounting position; horizontal, vertical, etc. The RevFlow injectors have been installed in various types of experimental aircraft over the years, with excellent service history. The unit is not type certificated (STC’d) and no such claims have been made, intentionally or otherwise.

The above photo is of an experimental version of the RevFlow we found on Joe’s desk, the day we conducted our interview. This unit has been fitted with an electronic fuel injection nozzle and a throttle position sensor. When mated with an oxygen sensor in the exhaust system and an ECU, optimal mixture can be established automatically. The real beauty of this system is that in the event of a computer malfunction or other electrical issues, if the carb is plumbed to gravity feed (in addition to the high-pressure needed by the injector) opening the fuel feed line to the carb will get the engine running again. This carb can also be fitted to most any multi-port fuel injection system, functioning as the throttle-body. If connected to gravity feed as described above, it too can act as a back-up for the MPEFI system in the event of a failure.

The original POSA carbs are still occasionally encountered; most are being used as doorstops or paperweights, it seems. I have never encountered another piece of aircraft hardware which is held in such vitriolic disrepute. There have been several other similar devices which have made it to the marketplace, including the RevFlow and the Aero Carb, which have fared far better in the court of public opinion. ~JPM


Switch On! continued from page 2

This past winter I had the pleasure of being invited to the Revmaster facility to view the unveiling of the newest Revmaster project, an alcohol-burning dragster owned by Mike Ballard and driven by Chad Blackshire. Although the long block is the same as the aviation version of the R-3000, it’s hardly recognizable it its dragster form.

As it turned out, these scoops didn’t work so well on the drag strip so they were changed to another design for a while, but have since been removed altogether in favor of a forced induction system.

Induction is handled by an electronic fuel injection system that when burning alcohol (it can also runs mogas) it’s sometimes difficult to keep the temperatures high enough when not making full-power. Every aspect of the engine’s functionality is digitally monitored and recorded, including individual EGT, CHT, MAF and manifold pressure, compiling serious loads of information that easily translates to aviation use. The business-end of the muffler.

Spent exhaust is routed through a collector that ports it through a custom, but offthe-shelf muffler, a staple in the drag racing class in which this rail runs. Although the muffler is rather wide open with only small protrusions into the exhaust stream, it does a good job of lowering the decibels without reducing a significant amount of power– if any at all . We ran the engine with and without the muffler and there was a substantial difference in ear-splitting sound. This might be one of those great cross-over technologies that could find its way into aviation— maybe something for the Rotary engine experimenters to look at. The automatic transmission is connected to a switch on the brake lever that locks the tranny into drive and reverse simultaneously. Switched on at the start line locks

the car in place with full-throttle. When the light turns green, pop the switch again and it cuts out the reverse circuit causing the car to launch. The torque converter manages the revs while locked up, keeping them at a pre-determined limit (preferably on the up side of peak-torque) until unleashed. Continued on page 32

A close-up view inside the muffler. Note the O2 sensor used to feed info the ECU.


Reprinted From the March 1981 issue of EAA’s Sport Aviation Magazine.

MOTOR GLIDER TO PARAGUAY 8,000 Miles Behind A Turbo-Revmaster By Jack Lambie Orange, CA All Photos Courtesy The Author COME ON, JOE, take a look at your Volkswagen engine. (I was getting ready for an epic flight and wanted a free service check.) Make sure it will fly to Paraguay." Joe Horvath, the developer of the engine, looked up from his latest project, the TurboCitroen and said, "Don't call it a Volkswagen. It's a Revmaster custom airplane engine. It has a solid machined crank, special pistons… heck, the only Volkswagen part we use is the case." "Okay, all the more reason for you to get some publicity. Just think, it will be the longest flight ever made with one of your engines." Joe looked at me in his relaxed way, "Look, Jack, I don't want to know about it yet. On a trip that long, too many things can go wrong that may have nothing to do with the engine. If everything turns out, you can say, 'It's a Revmaster.' "I'll have my mechanic check it, but I know that engine is good; it's only got 250 hours on it." The engine had no oil leaks but to stop a few drips, Joe's mechanic rethreaded a fitting that operated the two-position Maloof propeller and rebuilt the Posa carburetor. My airplane, is a Sportavia-Pützer RF-5B Sperber (Sparrow) motorglider (a redesign of the Fournier RF-5), originally fitted with a 1700cc Limbach VW engine. It was built in Germany in 1976. The import dealers, Phil Paul and Charlie Gynes of Aerosport, Long Beach, CA, had Joe install a 2100cc turbocharged Revmaster which improved its performance spectacularly. All their motorgliders were now being sent from Europe engineless so the Turbo-Revmasters could be installed. They had done a lot of flying with this plane in the past few years, but no one had ever seen exactly how high it would fly. On this venture I would see. We loaded the plane with a sleeping bag, the latest maps from Pan-American Navigation, hundreds of rolls of film, and checked the fuel pump, radio and inflight entertainment center- a car stereo with headset. Passports, permits and letters to flying clubs were all completed.

THE LAUNCH At 1 p.m. on April 9th, 1980, I took off. The view from the cockpit is like sitting on the front porch of the world.

Floating over the flat, green, irrigated fields of the Imperial Valley of California. The quiet Turbo-Revmaster drew the long winged RF-5B Sperber motorglider through the clear, desert air at an easy 100 mph. I radioed for clearance into Mexico and was soon gliding across the US border to Maxicali Airport for the first stop of what became a marvelous flying adventure. The one-month journey to Paraguay demonstrated to flying enthusiasts along the way that a motorglider is not only an exciting sporting machine, but a practical and economical airplane. Another purpose of this flight was to explore upcurrents along the Andes mountain range and photograph the great South American Condor soaring birds. I had departed from Chino, California, 90 minutes earlier with minimum fuel, so in Mexicali we filled the standard ten gallon tank in front, plus the 27 gallon extra tank strapped into the rear seat with 100 octane fuel to save money– only 94 cents a gallon in Mexico. "Sunset is at seven," they said when I filed my flight plan for Hermosillo.


and pushed the mixture rich. But when the tail lifted, the plane swerved to the right. Throttle off; brake on! We rolled off the runway over a small lump of paving material. The single main wheel snapped off. The beautiful motorglider fell heavily in a cloud of dust. A blade of the metal Maloof constantThe author loads his wing tip camera speed propeller prior to installing the streamlined fair- was bent, gear ing over it. doors and outriggers were broken. The wheel lay 20 feet behind wreckage, bleeding brake fluid. Jack Lambie, the RF-SB Sperber (Sparrow) and the equipment that would sustain both during the flying/gliding journey to Paraguay.

"I'll make that easily before dark; it's only three hours away," I thought. But I forgot my watch was still set on Pacific standard time (one hour earlier than Hermosillo). By the time I arrived, it was so dark the sparkling lights of the city appeared suspended in the sky because of the clear air and lack of horizon. Night visual flight rules isn’t available in Mexico, but the Commandante accepted my "wrong time" explanation of why I arrived without an IFR flight plan.

OOPS! I slept under the wing, fueled early, then taxied to the runway in the calm, hot morning. The Revmaster engine accelerated the glider quickly as I opened the throttle

WHAT HAPPENED? We found the right rudder pedal in the rear cockpit had jammed because a spare tail wheel worked its way in front of it. Spring stretch allowed steering on the ground but when the tail lifted, the jammed rudder swung the ship uncontrollably. A total disaster! It would take weeks or months to get new parts, I thought. But with the fix-anything skills and helpfulness of the Mexicans, we were ready to go again after three days. In the repair hangar, two mechanics removed the landing gear. Oscar Bianco, chief pilot for a charter service, took me, the propeller blades and broken wheel struts to his friends in Hermosillo, one of whom is an old metalworker. He repaired the shock struts and straightened the prop blade in his tiny shop. Another friend machined inserts for the broken landing gear, then welded it perfectly. While I refinished the prop blades to look like new and fiberglassed and repaired the gear doors, the mechanics reinstalled the wheel.

Down and out in Hermosillo— but not for long. Mexican mechanics lived up to their reputation of being able to repair anything and had Jack on his way in three days!

I was house guest of the charter pilot. One of the mechanics invited me to his rousing wedding party the night before I left. The Airport Commandante helped with the accident paperwork. The doctor who gave me a physical, as required by Mexican accident rules, wished me a good trip and would not accept payment. The accident was Thursday morning, yet, bravo for the Mexicans, on Sunday I was off for a test flight.


ON OUR WAY Everything worked perfectly during the five hours to Mazatlan, with wonderful thermals to 11,000 feet, then smooth air and a tailwind down the coast. That night the air traffic controllers invited me to sleep in the tower cab. Next day was an exquisite seven hours across the mountains to Acapulco. Strong lift over Guadalajara carried us to 12,000 feet but the wing shaking turbulence threatened to snap the camera off its tip mount. I maneuvered around a late afternoon storm which forced us back to the coast at Zehuatenao. With only an hour and a half fuel and 100 miles to go, I slowed to 60 mph and powerglided quietly along the beach. The elegant harbor at Acapulco slipped below and the motorglider was soon rolling along the airport's big runway with 40 minutes fuel still remaining. After a restful night on the couch in the air-conditioned "old" terminal, I took off for Tapachula at the southernmost edge of Mexico. I like to map-read and navigate by pilotage. It was too uninteresting and hazy flying along the beach so, again, I flew a straight line which carried us through tree covered mountains dotted with isolated villages. Lift under the cumulus clouds was good, but in the afternoon with cloud bases lower and mountains higher, I was forced into the calm, hazy air of the coastline near the gulf at Tehuantepec. In the gradual descent to Tapachula, smoke from agricultural fires was thick and I used the VOR to find the airport. It was 4:30 p.m., just enough time for fuel, exit formalities and go to Guatemala City before dark.

PERFORMANCE The 1600 pound motorglider seemed to accelerate slowly in the hot, humid air. The tall palm trees at the end of the runway seemed close. I let the turbo boost give 40inches of manifold pressure. The surge of power quickly pulled us into the air, but the engine protested with a loud "phumph"! I throttled back to 34-inches and circled over the field. Everything seemed normal enough so onward to Guatemala.

The author, Jack Lambie, unfolds the wings to ready the ship for take-off. The motor drive cameras were mounted in streamlined pods on the right wing tip and the top of the vertical fin. The 17 meter (56 foot) span glider folds to 36 feet for storage.

At 750 feet over the ranches of the flat, green coastal plains, I wandered between dense rainstorms that blocked my course. Gautemala City was over 5,000 feet at the end of a narrow pass. It was only 45 minutes to sunset. Could I find the Pass? Would it be clear? A return to Tapachula, Mexico, in the dark and rain would not be easy. A break in the clouds and a startling glimpse of the 13,000 foot volcano, Acatanango, glowing in the light of sunset spotted me my position. I found the pass! It was almost clear. Cool wind from the mountains pushed against the rainy, coastal air forming a convergence zone of strong lift which swept us quickly to 6,000 feet. Onto the airport for a sunset landing, with Customs and Immigration, then close the flight plan and be welcomed by Antonio Delgado of the Guatemala Aero Club. I showed films on the Gossamer human-powered airplanes (Condor and Albatross), told of the delights of motorgliding and enjoyed airplane talk in their fine clubhouse, well stocked with food and drink served by a gracious staff.

Over El Salvador, Jack flew past the 7815 ft. Volcan de Santa Ana and triggered a picture of himself and the spectacular scenery below with his wingtip camera.

The flyers here were concerned about political unrest that had overtaken Nicaragua, EI Salvador and Honduras. Armed men guarded the Aero Club, as well as their homes in town. They helped me plan a non-stop flight over the politically disorganized countries, to Panama 800 miles away.


At dawn, Antonio drove me to the Aero Club and the powerful Revmaster easily pulled the heavily loaded, long winged plane into the air over the mile-high capital city. A jaunty Great Lakes biplane flew formation with me for 20 minutes, then waved and rolled away. I was alone for the 9-1/2 hour flight south to Panama.

WEATHER The weather changed every 50 miles with a series of low pressure areas. First it was sparkling clear, then a wave lifted us to 13,000 feet south of San Salvador. Past the Gulf of Fonseca where I glided down to stay below an overcast. A shear line near Lake Nicaragua gave excellent lift then cumulus buildups over the mountains of Costa Rica. I became accustomed to three levels of clouds, low fog along the coastline, cumulus inland and big nimbus over the mountains. I was never bored and was busy navigating precisely while enjoying the varied tropical scenery.

FUEL Whenever the 10 gallon front tank used 5 gallons, I plugged in an electric fuel pump from a Honda automobile that transferred exactly one liter per minute. I could calculate fuel remaining by timing the pump run. Over politically unlandable Nicaragua the front tank had not been filled in over 39 minutes! The bubbles in the clear plastic line were moving slowly and the pump was very hot. Something was wrong! I pushed the base of the little pump out the rear cockpit vent and found and released the pinched line. The bubbles soon began rushing happily forward... whew! Costa Rica seemed especially beautiful from the air. The long day went quickly.

MOVING ON At David, a Panamanian port of entry, it was too late to buy fuel and go onto Panama City. An Air Force enlisted woman gave me a ride into town. We sat in the square watching the friendly romancing of the "foot cruisers." I felt relaxed and accomplished after the long successful flight. Later at the airport I covered myself with mosquito repellent and slept peacefully under my wing, despite loud disco music from a nearby roadhouse. Friday, in turbulent, rainy weather, it was only 2.5 hours to Panama City's EI Patia Airport. The Planeadores Panama Glider Club met me and their leader, Bob Crawford, had press and TV cameramen waiting. We removed the spare tank to give the newsmen and aviation officials rides. Three days of talks, dinner parties, and a tour of the city with the Embassy Counsel added richness to the relaxing time. I borrowed maps and advice from the local pilots, one of whom toured me over the famous canal in his Cub. Monday morning the quiet authority of the Revmaster engine swept the motorglider into the air for Medellin, Colombia. We surprised black vultures in a thermal over the hazy coast to climb into the cooler air yet still covered 93 miles the first hour.

Below were thick jungles, winding rivers. No roads, railways or air/sea rescue exists south of Panama. Hills appeared where none showed on the "unreliably surveyed" area of the map. I drifted lower to stay clear of a dark overcast. It was spooky at 750 feet with only one village of grass huts to break the wild views of trees and swamp. Rain streamed back in tiny globes along the waxed canopy. Ahead there were 11,000 foot mountain ranges. As the ground rose my horizon hazed into the rain and clouds. I turned south, and climbed through a hole to 6,600 feet in and out of “canyons and meadows" of cloud layers. This was the inter-tropical convergence where the air of the northern and southern hemispheres meet. The automatic direction finder (ADF) set to “turbo” on the Colombian/Caribbean coast had swung around and around during my wanderings to climb over the clouds and rain. If nothing appears after four hours, I would head back to Panama. Discouraged, with clouds everywhere, the plane continued climbing among the layers. Then, around the corner of a towering storm cloud, a dark peak! I flew closer and could see a hole with green farms below. The Medellin VOR began signaling. Now, heading 120 degrees between the wet cloud buildups, I see more holes. I opened the spoilers and descended to 10,000 feet ASL. A pass ahead! I swelled with joy seeing Medellin in sunshine ahead. I laughed with relief so hard I coughed in the thin air.

MEDELLIN The Albatross Club met me and helped ease entry through customs and immigration. They had radioed Panama to find my takeoff time then called the Director of "Aviation Civil" at Bogota for special permission to land at Medellin. They gave a reception and dinner, a tour of the city, and proudly showed the Eaglet gliders they were building. My talk, in English, was translated into Spanish to the large, receptive group.

ONTO CALI The next day an easy two-hour flight over many beautiful mountain estates brought us to Cali, the last port of exit from Colombia. The local pilots said, "No one ever goes straight through Pasto and Quito to Peru because of the high ground and violent turbulence." They showed me a pass to go out to the coast and said, "Be sure to stay below the overcast out there." "But the Condors are reported to be over the Andes near Pasto and Ecuador. I must go that way." I said. "Okay," one shrugged, "but don't land in Ecuador. They change the rules between flights." I agreed. Preparing for this flight I had made five telephone calls to the Ecuadorean Consulate in California. They never could determine the requirements for a landing permit.


The fuel truck driver put in 25 gallons of 100 octane. I offered him a $20.00 bill. "Okay, that's enough," he said. But thee real irony here is, the airport officials insisted on $54.00 for landing and parking fees. In early morning, with all papers stamped and tanks full, I was off for Peru.

and exciting encountering the majestic birds I had seen only in pictures. They were wary. While I'm trying to fly and photograph, the condors can dodge easily away. After 45 minutes chasing birds with the fuel-heavy, airspeedless glider, I was tense from the low level maneuvering and headed inland to find the Nasca Markings.

ONTO PERU We climbed between the thick cumulus clouds dotting the valley and headed toward the Andes. No Condors at Pasto. Into the Andes of Ecuador, the view was astonishing with green fields and cities nested over 9,000 feet. Past Quito clouds began to cover the mountain tops and spread over the valleys. I circled in rainy updrafts and squeezed through high passes with only a few hundred feet between the overcast and ground. Ahead, only the conical flanks of Mt. Chimborazo were clear of cloud. We would be trapped in the big inter-mountain valleys of Ecuador by the clouds so at Latacunga, I quickly headed west. Soaring to 14,200 feet we skimmed between clouds and mountains toward the overcast lowlands. Hours later, still at 13,000 over the dense whiteness, I saw cumulus ahead marking the beginning of the Peruvian Desert. Near the border, clouds thinned and we soared over the desert to land at Talara — Peru's northern-most point of entry — after 7-1/2 hours. The entry officials were friendly, only $20 for customs and parking plus $28 for the flight plan permit all the way to Bolivia.

JAMES BOND? Then things got bad. Three Fuerza Aero Peru Officers crossed from the military side of the airport to look at my unusual (to them) motorglider. Instantly paranoid, they thought I was the James Bond of Flying and took away all four cameras, as well as all my film. The next day they insisted I follow their Russian-built turbo-prop to Lima for further investigation. I had to use extra throttle because it would be difficult to reach Lima before dark. Fog, from the cold Humboldt current in the Pacific, gradually spread over the coast. Lima approach control said the airport was clear, but so dense was the foggy haze that even with radar vectors I didn't see anything until over the runway's flashing lights. I got my cameras back but the film was ruined. The Peruvian Department of Transportation assessed me a charge of 100,000 soles ($400.00) for a two-day permit. After three days of questions and delays, the takeoff for LaPaz, Bolivia was a relief, although the climb through intermittent fog banks relying only on the sound of the engine and sunglow was heart stopping. The gyro instruments were somehow disconnected and, during the customs and security searches, the airspeed indicator's static line had been pulled loose, rendering it inoperative. Along the coast for 150 miles and gliding down to the Isles de Chinchera, I searched for condors. Then, puttering along the sea cliffs of the Paracas Peninsula, I had a brief encounter with a condor, then another, and finally four of the giant birds soaring together. It was dramatic

ANCIENT ASTRONAUTS? After crossing an exotic desert of wind-blown sand and rock, we reached a blue-grey plateau. It was the site of the prehistoric patterns. I smiled at my navigation (guesstimation) and luck. The book "Chariot of the Gods" says that these markings could only be seen from the air and, since prehistoric Nazca Indians did not have flying machines, they must have been made by "Ancient Astronauts." True, the lines, scraped into the desert, do look like airport runways and huge drawings of the other figures such as a monkey, warrior and a condor can best be seen from the air. However, they can also be seen clearly from nearby hills so a flying device was hardly necessary. I circled and took pictures. It was late. Arequipa, Peru, should be my goal for today, but thermals were strong and I decided to climb into the Andes. Turbulence caused rapid changes in fuel pressure to the fioatless Posa carb, resulting in engine stoppage for long seconds, but the thermals were powerful and by circling tightly in the lift, we climbed higher. Deep in the spectacular snow-covered peaks, I surprised a condor and later another in a steep valley. With their superb control, they owned the air in these mountains. What if they lured me into a crash against one of these lonely cliffs and ate my carcass? But if that happened, I could think of no better way to disappear. Perhaps I would become a part of these great birds and soar with them forever. Ever higher the lift carried us and at 17,000 feet I saw EI Misti, the volcano near Arequipa, well south and behind us. A thin street of cumulus clouds beckoned. Bounding along under the lift, breathing oxygen, I could arrive at LaPaz at sunset with a few gallons of fuel in reserve. Onward to LaPaz. I relaxed to enjoy my dream experience— to cross the Andes. The brilliant scenery and invisibly clear air heightened the feeling of being in a special place. Shadows marked the mountains and incised valleys when Lake Titicaca's 12,500 foot surface appeared on the horizon, as smooth as polished slate. The clouds over Mt. Illimani and its snow covered peak were golden in the last sunrays when the long runway of the highest commercial airport in the world came in sight. The "Ayar Uchu" Glider Club members were lined up on the ramp as I climbed from the cockpit, cold and numb. After 10-1/2 hours of exhausting excitement, it was wonderful to be met with such enthusiasm and warmth by fellow pilots. Although most of the flyers had immigrated from Germany and Austria, the club took its name from


the Inca version of the myth of Icarus and Daedalus, called "Ayar Uchu." They had imported their gliders and airplanes at great expense to fly over the plains and mountains of this beautiful high country. A tow plane would be inefficient at their 12,900 feet gliderport, so they used a "TOST" winch, powered with a Ford V-8 to pull their sailplanes into the air. I gave my talk and was a guest at fellow glider pilot, Rudolpho Ortner's Tyrolean-style mansion, finished in the exotic woods of the Bolivian lowlands. Again I was aware of how we humans need one another. They enjoyed my flying visit as much as I was inspired by being with friends who also appreciated the thrill of matching oneself with the air and being creatures of flight.

ONTO SANTA CRUZ I had four days to worry about the takeoff from the 13,4000 foot high EI Alto airport because a storm was reported over the lowland jungles of my next destination, Santa Cruz, Bolivia. With only the rear tank filled to keep the nose light, we started our take-off run. My feet on the rudder pedals moved like a dancer because the wind would gust from 5 to 35 mph and change direction equally fast. After a ground-roll of 1 kilometer (3,300 feet!), the TurboRevmaster pulled us into the thin, choppy air. Good thermals and the beautifully smooth engine got us to 19,000 feet. Surprisingly, this is low because the gentle hills at 17,000 feet and the plains at 14,000 feet were only a few thousand feet below us. Past Cochabamba, the valleys began filling with cloud. I decided to continue using my remaining oxygen and stay high rather than trying to wander through misty Andean canyons. Soon the Andes were behind and we floated over the thick, white clouds. Santa Cruz was forecast "clear" but I could only get feeble replies in broken English when I tried to ask the altitude of the cloud base. Then a loud American voice called. "November 99887, come in on 123.4 and tell me what you need." "I'm from California, flying a motorglider and I need to know how much space, if any, is available below the clouds at Santa Cruz." "Okay, you've got 7,000 foot ceiling, and a strong south wind. Be sure you are over the VOR because the mountains are in the clouds." Flying over the featureless clouds, time always seems to pass slowly. My unseen new friend and I talked airplane to airplane. His name was Jack Neiman, a retired Navy pilot flying a turboprop for a mining company. "Say, I'll be back in a few hours. You can put your plane in my hangar and stay with me tonight." Sounded great! The VOR needle began to move erratically when my calculations said we should be over Santa Cruz. Gathering

my courage I pulled the lever to open the wing spoilers. With a quiet tremble of turbulence, the big glider dropped quickly into the clouds. I sat in the grey-white staring intently ahead ready to close spoilers and pull up quickly if rocks appeared ahead, then a flash of green jungle and a brown river. Suddenly, we were in a different world. Santa Cruz straight ahead, a booming oil-town in the low jungles. The dark wall of the Andes thrust into the clouds a few miles behind me. A curious, friendly crowd gathered and helped me push the plane to Jack's hangar. Soldiers ran practice maneuvers around EI Trompillo Airport. They ignored me. (Two weeks later, in Bolivia's 189th Coup, the military took over Santa Cruz.) Jack taxied up in his turboprop, parked and took me to a local bar filled with smugglers, adventurers, pilots and oil workers. He had come to Bolivia years ago to deliver a plane, married one of the beautiful girls of Santa Cruz and has been establishing his idea of paradise ever since. After dinner his wife, Natalie, served drinks while Jack helped plan the flight to Asuncion, Paraguay. The immense area of uninhabited jungle known as the Gran Chaco must be crossed. My chart stated the area was unreliably mapped so Jack marked some of the plateaus he knew that punctuated the flat, wet jungle. Surprisingly, there is little rain in the Chaco, but the melting snows of the distant Andes stagnant in the poorly drained lands resulting in impenetrable trees, thorn bushes and swamps. I stayed up late talking to their daughter, Tina, who was pioneering a thousand square mile ranch near the Brazilian border. The next morning Jack and Natalie waved goodbye after helping me through exit formalities and filling my tanks from their private supply. They were marvelous people and Santa Cruz is an intriguing city. I wish I would have stayed longer.

NEXT STOP— ASUNCION PARAGUAY The Turbo-Revmaster boosted the heavy motorglider into the tropical air with a quiet rush. I pulled up the single-wheel landing gear and was off for Asuncion 7-1/2 hours away. Within ten miles the jungle was everywhere— like a great, green ocean. A good thermal filled with beautiful hawks carried us ever higher using nature's energy. It was easy to lose direction with no landmarks but I felt secure in my little plywood cockpit with my trusted engine and compass in front. I yawned in the warm sun and checked the time. The Izozog Swamp must be below now. Fifty miles to the Paraguayan border. The VOR’s beam from Santa Cruz's EI Trompillo faded. No ADF signal from the Mennonite Colony of Filadelfia far ahead. The fuel gauge showed 5 or 6 gallons were now used of the 10 in the front tank. I plugged the electric pump into my cigarette lighter fixture on the panel. It clicked rhythmically and the bubbles in the clear plastic line showed fuel was going to the forward tank. I was feeling safe and snug high above the


unlandable tangle. How strangely exhilarating it is to be carried in an airplane over such impenetrable lands far, from our own species. Then the pump stopped! It started up for a few moments then quit again, as if to punctuate its sudden betrayal. The line was free; the pump was cool. No reason for it to stop, unless, perhaps, it had been damaged when it overheated in Nicaragua. The motorglider could probably fly to the airport at Filadelphia with the fuel remaining according to my quick calculations. But, 40 minutes later when the ADF picked up Filadelphia I saw we were east of the course. There must have been a westerly wind. Then the Cerro Leon Plateau, one of the few landmarks Jack Neiman indicated on my map, showed that we were 30 minutes late. A strong quartering headwind! There was not enough fuel to go to Filadelphia. I checked and double checked the pump... nothing. I blew in the vent pipe to pressurize the tank and bubbles began moving forward into the engine that was now set at a whispering half power, but my lungs couldn't hold the pressure high enough to push the fuel into that emptying front tank. An airstrip appeared, alone and isolated in the jungle. I squandered 7,000 feet to make an approach but found standing water and big bushes on the runway. With the long, low wings of the glider, there was little chance of landing to refuel the front tank and taking off. Nothing to do except go on until the engine stopped, then glide in the now smooth air as far as possible. I again tried blowing in the rear tank vent pipe as the ship climbed but the air was pushing back into my mouth. An idea. Why not seal the rear tank, climb, and let the pressure difference between the rear and front tank create a natural siphon? In back I had some scraps of Mylar plastic, originally used as covering for the Gossamer Albatross human-powered airplane. I pulled a piece over the refueling hole and put the cap on to make the tank airtight. I slowed to best climb speed. All praise atmospheric pressure change with altitude! The fuel bubbled forward to the nearly empty tank. By the time I reached 9,000 feet the front tank had enough fuel to easily fly to Filadelphia. I smiled in probably undeserved cleverness. It is amazing how complacent one becomes. Thirty minutes ago I could have lost the beautiful motorglider and had days or even weeks of struggle through the wilderness. Now I relaxed again and planned an automatic system like this for all airplanes to eliminate fuel pumps forever. I thought about the pump. Why had it stopped? It wasn't hot. I untaped the wires to the cigarette-lighter plug. One was disconnected. I retwisted and wrapped the joint,

After reaching Asuncion, Paraguay, Jack taught the new owners the joys of motorgliding — including aerobatics!

plugged in and the little pump again chugged to the urges of positive and negative electrons. Soon a faint spray of 100 octane splashed over the canopy. The front tank was full! Filadelphia had been established by a Mennonite religious group from the United States of America. It has a rectangular pattern unlike the ancient Spanish cities of South America. The city was truly isolated, and soon after passing, the jungle was again everywhere. In late afternoon rainbows hallowed the Sperber's shadow below us as we skimmed over scattered clouds. With the unpopulated jungle still below, Asuncion appeared, shining in the setting sun. The pilots in Asuncion welcomed me intensely and were ecstatic over the motorglider I delivered to them. It was the first true sports plane in Paraguay. I taught them to soar and operate the machine. They purchased it from the dealer in California I was delivering it for. It was sad to leave the plane. I had grown to feel as one with it, in our shared adventures over the past month.

GOING HOME A Braniff DC-8 flew me back to Los Angeles in 15 hours over the same route that had taken 85 hours in the long winged motorglider. The low rumble of the boundary layer sliding past this sleek aluminum airplane was the only sensation felt as we were carried over the curving earth a mile every six seconds. Have we lost or gained?


Some say airline flying is not travel at all. One is simply set down at another place after a number of hours, sleeping, reading, and munching cleverly packaged dinners. I disagree. I thought of contrasts as I sipped a drink and nibbled at dinner. During a fuel stop at Lima, Peru, I went into the Flight Planning Office and checked our route to Los Angeles. I was startled at the long, curving, non-stop line over the ocean. After having flown the distance over land and with many stops, in a small plane, I realized the dramatic performance of the big jets. My journey was rich and unforgettable with the intimacy of navigating and maneuvering the wood and fabric covered glider between clouds, in thermals and over mountains, deserts and jungles and the many new friends. I understood some of the feelings of Antoine De St. Exupery and Guallamet in their pioneering Andean flights. The ocean, jungles and mountains are still the same. The reliability and trust we have in our present machines is the great change.

Specifications: The RF5B Sperber (Sparrow) Wing Span

55ft 10in (17.02m)

Empty Weight

1,014lb (460kg)

Gross Weight

1,499lb (680kg)

Max Cruise Speed

118mph (190km/h)

Economy Cruise

(75mph) (120km/h)

Stall Speed

42.5mph (68km/h)

Service Ceiling

18,050ft (5,500m)


Turbocharged Revmaster

L/D at 61mph First Flight

26:1 May 1971

"Joe, that Volkswagen of yours ran perfectly." Now, as I watch the faint dawn outline the coast of Mexico, far to the East, the difference between big and small doesn't matter. I love riding the big jets, and am proud to be a member of this elegant species that can invent and control our environment in such a great machine. I appreciate how far we have come because I have intimately flown this journey and understand the concentration and flying experience it takes.

Joe winced. "I won't forget its quiet, smooth power and I'm glad my trust in your engine was well placed. It is one of the best things I ever had in the front of an airplane. You can be proud of it." "Okay," said Joe, "now you can call it..."

The jet engines were quiet as the big plane began its long descent into Los Angeles, California. The motorglider and the huge jet, as are all flying machines, are wonderful beyond imagination. I couldn't wait to tell Joe how his engine performed. He had concentrated his energies on this motor for years, and the blend of simple design and subtle refinement produced an engine in perfect harmony with any light airplane. I spent only $432.00 on gasoline in the 85 hours of flying including the expensive fill-ups in Panama and Peru. I was amazed to make 7 to 9 hour flights days in a row without adding oil. It used so little I gave away my spare cans in LaPaz, Bolivia. "Well, you made it, huh?" Joe said as I walked into his shop.

"I know, I know, it's a Turbo-Revmaster and it even sounds like a real airplane engine." I smiled and shook his hand.

The engine that made it all possible with the all metal, electronically governed, constant speed prop, invented by Horvath's long-time friend and partner, Ralph Maloof, PE. An aeronautical engineer, Ralph’s propulsion experiences date forward from the early 1940s, and include piston, turbojet, ram, and rocket engine research/design and flight testing. Joe Horvath and Ralph have been technology and business partners since the 1960s. An EAA member (#89233) since 1980, Ralph's aviation interests started before WW2, in which he served as a fighter pilot.


Switch On! continued from page 23

So how are the boys doing with the project? The above spy photo shown that they aren’t done experimenting. It appears that they’ve swiped the crank-driven supercharger from the beetle Joe Horvath had on display at the 2011 Golden West Fly-in Above is the same long-block that they raced with earlier this spring. After the forced-induction system is complete, they plan on running it with the West Coast Hot Rod Association for the remainder of the season in the “Open Comp” class where pretty much anything goes in this bracket race, save “electronic driving devices” which none of the previously mentioned electronics would be banned. They also hope to compete with the National Muscle Car Association and plan on finishing the season with them in “Super Quick,” another dial-your-own bracket category that is designed for all types of vehicles including trucks, dragsters, alterds, roadsters, and just about anything else except motorcycles. One thing that always impressed me about Revmaster Aviation is their dedication to excellence, expressed in their thoroughness and quality control. Although I’ve not been to every aircraft engine shop in the US, I do know that not many actually have a dynamometer, and many more have never even had their engines run on a dyno— with most of their numbers being a huge guess. And to a sharp eye, it’s easy to see this in their glossy brochure numbers.

But Revmaster has always been conservative with their numbers. Take for example the R-2300. Just about everyone would assume that the engine is 2300 cc’s. But with a 94mm bore and a 84mm stroke, the displacement works out to be 2332 cc’s. Now we all know that for decades the motorcycle industry has always rounded up their engine sizes, so Joe could have just as easily named the R-2300 the R-2350, but he opted to stay on the conservative side. So when we see numbers like 82 horsepower at 2950 rpm and 85 hp at 3350 rpm, not only can we believe them, but we can bet they’re conservative. I got a call from Joe the other day saying that they’re continuing dyno work. Spooling the R-2300 to higher revs nets even more horsepower with an insignificant increase in heat— thanks to the proprietary RM-049 heads that were designed to shed the heat from high horsepower applications, like the beetle shown above that has the R-3000’s 90mm stroke bottom end with the R-2300’s 94mm cylinders and heads, making it a 2490cc engine. ~Pat

The 2332cc R-2300 undergoing extensive testing in the Revmaster water brake dynamometer, with Joe Horvath standing by.


Special Issue 104.5  

The All Revmaster issue.

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