RC Airplanes | Gliders | Helicopters
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POLARON EX, IT’S HOTT
Mike McConville Designed Sbach 342 60 ARF
26 New Products AMA Trade Show 2014 Making Lost Foam Fuselages Putting Aresti Sequences Together Flying Surface Molds Made Easy APRIL 2014
USA & CANADA $6.49
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RC-SF.COM
Fly This Scale Airplane Anyway You Like!
TABLE OF CONTENTS DEPARTMENTS
10 LEADING EDGE 12 HOT PRODUCTS 96 ADS’ INDEX 97 MYSTERY PLANE
LEARN AN SIMPLE STEP-BY-STEP METHOD FOR MAKING COMPOSITE FUSELAGES — IT’S EASY!
PG 44
BUILD
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2014 AMA CONVENTION TAKE A TOUR OF THE ANNUAL ONTARIO, CA TRADE SHOW TO SEE THE WINNING MODELS. By Pete Bergstrom
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SURFACES MOLDS DISCOVER HOW EASY IT IS TO CREATE ACCURATETO-SCALE SURFACE MOLDS. By Rob Caso
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HOW TO
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LOST-FOAM FABRICATION LEARN THE EASY AND INEXPENSIVE WAY TO MAKE COMPOSITE FUSELAGES. By Tom Wolf
OUR PROFESSIONAL PILOT SHOWS YOU HOW TO ASSEMBLE ARESTI SEQUENCES INTO A ROUTINE. By Daniel Holman
LEARN WHAT IT TAKES TO PUT ARESTI SEQUENCES TOGETHER.
PG 50
SUPER SPORTSTER 60 GET A BUILDER’S SECRETS TO MAKING YOUR MODEL’S WING JOINTS STRONG. By Jeff Troy
PG 32 ROB SHOWS YOU HOW TO MAKE SURFACES MOLDS FOR YOUR NEXT SCALE PROJECT. 6
50 AEROBATICS PART 13
RC SPORT FLYER . APRIL 2014
3-VIEW
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CESSNA 185 SKYWAGON SEE HANS-JÜRGEN’S DOCUMENTATION OF THIS LIGHT UTILITY AIRPLANE IN HIS 3-VIEW DRAWINGS. By Hans-Jürgen Fischer
APRIL 2014
COLUMN
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COMPARTMENT SEALING
DISCOVER WHY YOU SHOULD BUY THIS FUN, MICRO QUADCOPTER.
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PETE DETAILS HOW TO SEAL YOUR MODEL’S ENGINE COMPARTMENT. By Pete Bergstrom
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MICRO MULTIROTOR
ELETRIC MOTOR POWER TAKE AN INSIDE LOOK AT BRUSHED MOTORS AND AN E-POWERED MODEL. By Andrew Gibbs
101 76 HELIS PART 5
IF YOU’RE LOOKING FOR A LITTLE FUN, YOU’LL WANT TO READ OUR REPORT ON THIS MICRO QUADCOPTER. By Lucidity
PG 72
GET AN EXCELLENT EXPLANATION OF TRANSLATING TENDENCY AND HOVERING ATTITUDE. By Dave Phelps
GRAUPNER’S NEW POLARON IS A “STAND-UP” CHARGER THAT IS NOT BOWING TO ITS COMPETITION.
REVIEWS
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ESPRIT STANDBOX THIS NEW MODEL AIRPLANE STAND WILL SAVE YOUR AIRCRAFT FROM DENTS AND DINGS. By Staff
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GRAUPNER / SJ POLARON EX A CHARGER THAT MAKES BATTERY MAINTENANCE AS EASY AS TAPPING A LCD SCREEN. By Staff
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PG 90 SKYLAR TUCKER, OUR COVER MODEL, SHOWS OFF THE BEAUTIFUL DESIGN LINES OF HANGAR 9’s NEW SBACH 342 60 ARF. facebook.com/rcsportflyer
9 90 HANGAR SBACH 342 60 READ THIS REVIEW TO SEE HOW EASY THIS NEW MIKE McCONVILLE DESIGN IS TO BUILD. By Wil Byers RC-SF.COM
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HOT PRODUCTS AIRBORNE MODELS TWO-PIN EZ CONNECTOR W/ PULLER
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ow you can stop fighting your airplane’s power system’s connectors to get them apart with Airborne Models’ new 2-pin EZ connectors, with puller. It will revolutionize the way you disconnect your airplane’s power system. With the new 2-Pin EZ Connector, with Puller, you’ll stop tearing your airplane’s up trying to get the battery pack disconnected from the speed controller. No longer will you fight the connector to get it apart after a flight or a charge cycle. Instead, you’ll use the EZ Connector’s puller to get the connectors apart easily and without the worry of ripping the battery out of the airplane, or worse, when the plug finally snaps apart. Only with Airborne Model’s puller system can you quickly and easily separate the male connector from the female connector, without having to yank on the connect with all your might. Then too, the 2-Pin EZ Connector’s are gold plated for the lowest possible circuit
resistance at the connector. As such, you’ll get the full potential of the batteries power delivered to the electronic speed controller. Price
$7.99 (KP0011213)
Specifications Max Current Plating Connectors Puller
40 amps Gold Three per pack One per pack
Distributor Airborne Models 2403 Research Drive Livermore, CA 94550 Phone: 925-371-0922 airborne-models.com
BLADE 300 V HELICOPTER
B
lade’s new 300 CFX helicopter is more than a mere upgrade of the popular 300 X. It adds carbon fiber and aluminum parts, and is now equipped with the same ground breaking servo geometry used on the Blade 700 X Pro Series helicopter. The Blade 300 CFX uses the same servo geometry as the Blade 700 X Pro Series helicopter. It virtually eliminates mechanical inefficiency by keeping swashplate links near vertical throughout their range of motion. The result is flawless cyclic and collective response that feels almost telekinetic. This is a helicopter to consider for the warm summer weather headed your way. Features • Carbon fiber main frame • Optimized servo geometry • 245-mm carbon fiber main blades • CNC aluminum head • Integrated bearing block servo mounts
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Specifications Type Collective pitch flybarless electric helicopter Main rotor 21.7 in. (550 mm) diameter Tail rotor 5.5 in. (140 mm) diameter Weight 18.0 oz (510 g) Length 20.1 in (510 mm) Main gear ratio 12.72 Motor 4500 Kv outrunner Kit BNF Basic Control system 120-degree CCPM Rotor blade 245 mm length Experience Expert Level Assembly No Required
• 11-tooth pinion gear • Spektrum™ AR7200BX Flybarless control • E-flite® 320H 4500 Kv brushless outrunner • E-flite 25-amp brushless heli ESC • E-flite DS76 digital cyclic servos • E-flite DS76T tail servo Price
$399.99 (BLH4650)
Distributor HORIZON HOBBY 4105 Fieldstone Road Champaign, IL 61822 Phone: 217-352-1913 horizonhobby.com
Specifications
DLE DLE-61 GAS ENGINE
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ore power at lighter weight. Innovation is the key to excellence. The new DLE-61 engine is upgraded to make it lighter weight and to give it more power. They’ve added innovations like a magnesium alloy crankcase, improved crankshaft bearings, and a better design for the piston/cylinder fit. The DLE-61 weighs just under four pounds and delivers over six horsepower. A special airplane type carburetor, muffler, standoffs and electronic ignition are included in the package. It’s a solid 60-cc-size engine. Features • Efficient, lightweight design for high power-to-weight ratio • Lightweight piston for fast acceleration. • Excellent compression and low vibration
Displacement Bore Stroke Weight Engine Muffler Ignition Module Output Propellers
61.0 cc (3.7 cu in) 1.85 in. (47 mm) 1.38 in. (35 mm) 3.65 lb (1655 g) 2.8 lb (1273 g) 3.9 oz (110 g) 3.9 oz (110 g) 6 hp @ 7500 rpm 22 x 10, 23 x 8, 23 x 10, 24 x 8
Distributor Great Planes P.O. Box 9021 Champaign, IL 61821 Phone: 800-637-7660 greatplanes.com
• Increased piston/cylinder contact area • CNC-machined parts • Enlarged crankshaft bearings • Two petal reed valve • Muffler included for optimized power • Electronic ignition Price
$449.99 (DLEG0061)
SPEKTRUM DX6 TRANSMITTER
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he new DX6 has been designed from the ground up to deliver more than you would ever expect from a 6-channel transmitter, especially in its price range. This very affordable transmitter gives you an abundance of programming features for airplanes, helicopters and sailplanes. You also get other extras like voice alerts, a wireless trainer link and enough internal memory for up to 250 models. Features • Ergonomically designed case w/ comfortable rubber grips • Stores 250 models in memory, expandable by SD card or PC • Direct System Menu Access — no need to power off to access menus • Includes voice alerts and wireless trainer out of the box • Supports Air/Heli/Sailplane model types
Specifications Channels Modulation Band Receiver Model memory Modes Transmitter Battery
6 DSM2/DSMX 2.4 GHz AR610 included 250 User Selectable 1 – 4 4 AA batteries (Included)
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Distributor HORIZON HOBBY 4105 Fieldstone Road Champaign, IL 61822 Phone: 217-352-1913 horizonhobby.com
• Easy to use AirWare software • Smooth, precise four-bearing gimbals • AR610 6-channel full-range receiver included • Programming capability for most sailplanes — supports 4 wing and 3 tail types • Supports the most Spektrum Telemetry sensors • Includes 4 AA Alkaline batteries, optional Lithium Ion battery w/ charger • 5 programmable mixes — mixes are selectable to be normal or 7-point curve mixes • Dual aileron, elevon, and V-tail differential • 7 aircraft wing types and 5 tail types • 7 swashplate types • 7-point throttle (air and heli) and pitch curves (heli) • Intuitive SimpleScroll™ programming interface • Advanced DSMX® technology (DSM2® compatible) • SD card slot for updating firmware • Bind mode activation from the menu Price
$229.99 (SPM6700) RC-SF.COM
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EVENT HOW TO
2014 AMA SHOW LET’S GO, ONTARIO, CA. IT’S HOME TO THE SHOW!
BY Pete Bergstrom
ANTELOPE VALLEY SOARING CLUB
The Antelope Valley Soaring Club displayed at AMA 2014. They were there with their full-scale sailplane as way to promote their activities. Their booth included a simulator for those wanting to try their hands at this aspect of our sport.
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he annual pilgrimage to Ontario, CA for the AMA Show is not only the start to the RC trade Show season but also a welcome destination for those of us who live in the more northern and colder climates. This year’s show was held over the weekend of January 10 – 12, 2014. It featured a host of speakers on the main stage, including Jeff Skiles, whom gave a report about his experience as the copilot on the “Miracle on the Hudson.” This January 15th marked the 5th anniversary of the ditching
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of the US Airways Airbus Flight 1549 in the New York City waterway. His talk about his experiences in the copilot seat was engaging and very informative, describing the event during and after the ditching. At AMA Show there are also many opportunities for demonstration pilots to fly in the indoor spaces, typically showing off helicopters, foam airplanes and the new rage in RC, quadcopters. A lot of stories and information are shared amongst the enthusiasts too. AMA Show has a number of rooms that provide for
the swap meet, demonstration areas and there even individual classrooms. For those of you that have not attended the AMA Show it is an event that truly underscores the meaningfulness of the Academy of Model Aeronautics. It is why the AMA’s membership continues to grow and why we all share in the benefits it provides. AMA Show 2014 was how it all came together this year. You should plan to attend in 2015. You’ll have fun if you do!
BEECHCRAFT STAGGERWING, JIM MARKHAM Byron Originals Beechcraft Staggerwing by Jim Markham featured lots of extra detailing both in the front and rear of the engine compartment, as well as a superbly done aircraft interior. This is a beautiful rendition of a Jerry Bates 1/5.5-scale Douglas SBD-5 Dauntless. It is intended for Top Gun competition — built by Frank Harris and piloted by Kyle Goodwine in 2014. The airplane features a Saito FG-57T twin-cylinder, 4-stroke gas-powered engine, with Spektrum DX18 control.
DAUNTLESS, FRANK HARRIS
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RC-SF.COM
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BUILD
This is a basic jig-built stabilizer and elevator framework. A skin is being made only for the stab since the elevator was covered with fabric.
FLYING SURFACES MOLDS WORKING WITH STICKY STUFF — PART I
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il (editor) posted a few photos of my new 120-in. wingspan Lysander project on the RC-SF Facebook page a few weeks ago. However, I have really just started the model. The airplane is a lot more complicated to build than it looks (aren’t they all?), and so I decided to start with what I thought was the relatively simpler area, the empennage. Early into the design, I felt that making a molded glass skin for the stabilizer would be a good idea since the underlying structure would be
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laser cut and built on a jig. As such, the framework came out straight and true. Although, this particular aspect of the model was complicated by the need to have two separate halves for the stabilizer, which is in keeping with the real airplane. Each stabilizer on the actual airplane was a mirror image of the other, and it was adjustable in flight to maintain landing and takeoff trim. Thus the need for two separate sections as the stabilizers are visibly separate from the fuselage, being connected aft by their pivoting structure.
BY Robert J Caso My reasons for wanting to make glass skins therefore were as follows: 1. I felt a fiberglass skin would be lighter weight 2. I would only have to make a mold for one side 3. The mold could incorporate the needed detail of the skin’s surface 4. I have never done this before. The conventional way to replicate scale surface detail is to build a sheeted structure, which is then glassed, primed, filled and detailed. As with any scale model, reducing tail
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Foam blocks are epoxied to the skeleton framework top and bottom to fill in the open structure of the plug.
2 weight is a constant battle, with an ounce out back having to be offset by three to four ounces up front. The sum total therefore adds up to four or five ounces to the model overall. My thinking under item number one was that I will be using fiberglass only for the skin, so I could recruit that for both the monocoque structure and the surface detail. This would eliminate the balsa skin, as well as all the materials it soaks up during finishing. Whether it will in practice be actually lighter weight remains to be seen, and we will both be waiting together since this is an involved process. Items two and three are rather obvious benefits, but the benefits of at least number three will be largely offset by the time it takes to make the molds, which are contemplated to be in two halves. I always try to learn something new with each model I make, so number four for me was the proverbial no brainer, as I have never done a mold for a flying surface. Again, whether I actually come up with something usable however, remains to be seen. As a side note, I will not use this process for the vertical fin since, thankfully, there is only one on this airplane. Here, I will be employing the traditional balsa/glassing/ priming/filling/detailing regimen. Between you and I, I have never done much of this either. To further complicate my life, I am considering skinning the fin instead with G-10 facebook.com/rcsportflyer
Add the blocks first to one side, cut them off close to the outline and then add the blocks to the other side.
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Looks better now with the blocks cut in to match the plug’s profile — now it is on to sanding to the shape of the formers.
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HOW TO
LOST-FOAM
AN EASY WAY TO FABRICATE FIBERGLASS PARTS – PART II
BY Tom Wolf
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ast month I introduced the lost foam fabrication technique for making fiberglass parts. Required materials, tools and equipment, some basic fabrication considerations and techniques for fabricating fiberglass cowls, wheel pants and similar parts were discussed. Now,I’ll expand the discussion to cover some additional techniques associated with fabricating fiberglass fuselages and engine nacelles using the lostfoam technique. As I showed you last month, it is quite an easy way to make inexpensive parts for your airplane and glider designs. So...
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FABRICATION: FUSELAGES & NACELLES Fabrication of fuselages or engine nacelles is an extension of the process described last month. Shaping a foam blank for a fuselages or engine nacelle utilizes many of the same procedures that were required for cowls and wheel pants. However, incorporating wing and stabilizer mounting provisions, engine firewalls, landing gear mounts and other structural members requires additional planning and adds some extra fabrication complexity. In most cases it is advantageous to add structural members prior to
applying the fiberglass. This results in an integrated bond between the structural item and the outer fiberglass skin, which is created as a part of the process of applying the fiberglass. Some structural items, such as servo mounting provisions, and hatch or canopy frames, are most easily installed in the fuselage after fiberglass application is complete and the foam has been removed. The following discussion will walk you through some of the more common structural inserts and provides guidance for introduction into the fuselage construction. For fuselages with plug-in wings,
Photo by Peter Richner
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Step one for fuselage fabrication is to mark the profile of the fuselage onto the foam blank. You can do this with a pattern and a black SharpieÂŽ pen.
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The profile is shaped by rough cutting with a hot wire or a saw and then finishing with a large sanding block, making sure the top and bottom surfaces are perpendicular to the sides. RC-SF.COM
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HOW TO
AEROBATICS PART 13 IT’S ALL ABOUT PUTTING SEQUENCES TOGETHER BY Daniel Holman
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ast month I started to explain how to read the Aresti catalogue, focusing on the basic aerobatic figures and how they are drawn. In this issue, I’ll pick up where I left off, now explaining the main, point and snap rolls, plus spins. I’m going to show you how they are written, and how to interpret the Aresti symbols. Some of this may seem a bit tedious at first, but with a little practice it’ll become natural. Note that Aresti provides the foundation for International Miniature Aerobatic Club (IMAC) competitions, as well as precision aerobatic flying.
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ROLLS
It will hone your piloting skills by learning the Aresti catalogue. It will also give you an overall understanding of how IMAC sequences are assembled, which will then let you become an even better 3D pilot.
About a month ago I took my Extreme Flight 104-in. wingspan Extra 300 to a local hay field to fly. It was nice to enjoy a calm evening and a beautiful sunset, with Mt. Hood as the backdrop for this photo.
Let’s start with the basic roll and its variations. It is a full roll, followed by various roll combinations. The first couple of diagrams are selfexplanatory, but the latter are a little more complex. The first thing to note is that when more than one roll is drawn in succession, with a line right above and almost connecting the arrows, the rolls are done consecutively
IMAC contests are more fun than you can possibly know. There’s a great atmosphere at each one. This picture was taken by Jerry Smith at the Georgia Model Aviators IMAC contest that happens near Atlanta, GA. facebook.com/rcsportflyer
without hesitation. However, when the rolls are not connected and are drawn with oppositefacing arrows, the rolls are separate. Although the line segment between each roll is short, opposite-direction rolls should always have a hesitation in between, just long enough to clearly display to the judges the pilot has established the line, and that the airplane’s wings show accurate angles: 0, 90, 180, 270 or 360 degrees. Keep in mind that with the exception of the hesitations in an 8-point roll, there is no maneuver in IMAC that leaves the
airplane’s wings at any angle other than zero or a multiple of 90 degrees. Also the rolls in the accompanying diagram for a full roll always means one full roll. The symbol for the half roll on the other hand indicates a half roll unless otherwise specified. If there is a one-quarter or three-quarters fraction shown next to the symbol, that is what the pilot must fly. All rolls should be coordinated with elevator and rudder inputs to maintain a perfect heading. RC-SF.COM
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3-VIEW
T
here is probably no other airplane company that has ever served more general aviation pilots, as well as commercial pilots, than the Cessna Aircraft Company. Their designs have stood the test of time because they are functional, durable and purpose built Importantly, they are affordable for pilots to own and maintain — not quite like the Model T Ford, but not astronomically expensive. The Cessna 185 pretty much stands above the rest in terms of it being an outstanding light utility aircraft. The 185 is also known as the Skywagon. It is a singleengine, six-seat, aircraft that first flew as a prototype in July 1960. The first production model was
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introduced during the month of March 1961 — 53 years ago! To date over 4400 185s have been built. The 185 is distinctive in that it is a high-wing, conventional landing geared airplane that sports a tail wheel. However, many have been fitted with floats, which makes it an excellent airplane for bush pilots and those that want to get in to back country lakes. Bush pilots have also equipped the 185 with skis. It has been modified in multiple ways, including an enlarged belly for cargo, etc. Note that the Cessna 185 is much like the 180, however, it is features a strengthened fuselage, a larger vertical fin and a 300 hp (224 kW) Continental IO-520-D engine.
SPECIFICATIONS
CESSNA 185 SKYWAGON
BY Hans-Jürgen Fischer
Wingspan : 35 ft 10 in. (10.92 m) Length : 25 ft 9 in. (7.85 m) Height : 7 ft 9 in. (2.36 m) Wing area : 174 ft2 (16.2 m2) Empty weight : 1,748 lb (793 kg) Gross weight : 3,350 lb (1,520 kg) Powerplant : 1 Continental IO-520-D 300 hp (220 kW) Propellers : 2-bladed constant speed, 6 ft 10 in (2.08 m) diameter Maximum speed : 155 Kts (178 mph / 287 kph) Cruise speed : 145 Kts (167 mph; 269 kph) Stall speed : 49 Kts (56 mph; 91 kph) Range : 720 nmi (1,333 km) Service ceiling : 17,150 ft (5,230 m) Rate of climb : 1,010 ft/min (5.1 m/s)
Cessna 185 Skywagon 0
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3m
Zeichnung
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COLUMN HOW TO
ENGINES II ENGINE COMPARTMENT SEALING
BY Pete Bergstrom
W
hether you are scratch building from plans, building from a box full of raw wood pieces, or assembling an ARF airplane, you must finish and seal the structure against spilled raw fuel and/or the exhaust residue and unburnt oil. In the former instances, this task undoubtedly falls to the builder, but in the latter cases sometimes the ARF manufacturer has done this for you. No matter, it is up
to you, the owner of the aircraft, to determine the quality of the seal work. I suggest if you want a long lasting aircraft, that the small amount of time expended to do a good job of sealing the structure and glue joints will reward you handsomely with an easier to clean, easier to maintain and ultimately, an easier to operate airplane. Sealing the engine and fuel tank
This is the ZAP® Finishing Resin I like. It’s odorless, clear, non-brittle, easy to sand, works on fiberglass/wood/foam and cures in three hours.
compartment entails using some sort of a fuel proof sealer to seal the grain and pores of the wood structure. The areas we are particularly interested in are the engine mounting/firewall area, the inside of the cowl (if wood), the inside area of any fuselage parts surrounding the engine mounting, and the fuel tank compartment, complete with its surrounding structure that might be subject to raw fuel — if a small leak were to develop in the fuel lines or tank. You should consider sealing the entire lower part of the fuselage from
West Systems Epoxy is great because it has a low viscosity, typically it has 30- to 45-minute working times and you can sand it when it has cured. Also when it cures it does not have an amine blush.
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are dowel pins and sockets that secure the forward part of the wing to fuselage, and when it is fuel soaked it will compromise the airframe’s strength and durability. The best time to fuelproof an airplane is when the structure is open to you, which is obviously during your build or assembly. If you are scratch/kit building it can be easier to seal the individual pieces of wood as the building progresses. Doing so will result in a fuel-proof surface as you go rather than trying to do it once the airplane is
front to back to protect the structure in the event of a catastrophic tank failure — the type of failure where the fuel is running out the tail wheel area, while you unknowingly continue to pump fuel into a tank after the stopper has failed. If you haven’t done this, or witnessed it, you will if you stick around the hobby long enough. The fuel tank and its tubing attachments seem to be a favorite place for Murphy to hang out. Further away from the engine compartment but no less important is the wing saddle area for onepiece wings, especially in a lowwing airplane where the exhaust constantly runs past the joints. It is where the residue likes to collect at the leading edge of the wing and the fuselage joint. Sealing this area can be critical because most often there facebook.com/rcsportflyer
assembled, which often makes for cramped work quarters. At any rate, I suggest it is easier, in fact necessary, to sand, seal and protect these areas before any final finishing materials or paint goes on the model. What follows is my process for protecting my aircraft. I’ve found that my fuel-proofing processes make my models durable and long lasting. I think the process is well worth the effort you’ll need to expend. TOOLS AND MATERIALS What is the best sealer, in my opinion? For all the areas I’ve mentioned, a good two-part epoxy is by far the best and most durable finish for sealing surfaces. I use two brands exclusively on my airplanes: Z-Poxy® Finishing Resin from ZAP® Glue and West Systems Epoxy, with their #207 Special Clear Hardener. These two products are both easy to mix, easy to use, are the right viscosity for brushing, and they provide a reasonable working time. Both of these epoxy systems work well for applying cloth (fiberglass or carbon fiber), in addition to their use as a sealing agent. While it is more expensive to purchase initially, I suggest you consider picking up the West Systems epoxy if you do a lot of building. It has a long shelf life, and I’ve found it to work well for different model types. On a side note my first introduction to West Systems Epoxy was in the 1980’s when I was laying
These are my cut-down and ready-to-use chip brushes. You want to secure the bristles to the ferrule with some CA glue—works great.
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COLUMN HOW TO
The Astro Hog’s covering scheme was derived from all the left over bits of film that Trevor needed to use up!
E-POWER VII IT ALL ROTATES AROUND THE WINDINGS
BY Andrew Gibbs
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his month’s inspirational model is an Astro Hog by Trevor Hewson. We’ll get right to it; and, we’ll also have a look at the way in which electric motors work. ASTRO HOG Trevor Hewson is a guy who has been enjoying building and flying electric-powered models for many years. Trevor is also an accomplished modeler. So, it is that we feature his classic design, the Astro Hog. The Astro Hog is well known, and is very much a classic model airplane design. The model was designed by
This view of Trevor’s fine Astro Hog shows you why it has been such a successful kit. This really is a classic American design.
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flaps, and of course to convert the model to electric power. These changes, although significant, have not in my view spoiled the model — the vintage character of the original design still shines through its upgrades. The flaps are a significant modification, and are relatively simple to install. When installed in a model with a low wing loading like this one, the benefits are perhaps less than they might be with a more highly loaded airplane. Even so, there is no denying they provide an additional degree of slow-flight performance, and in my view are very worthwhile addition to almost any model. The flaps are driven by a single servo, centrally mounted in the wing root. The servo drives a torque rod, which connects to both flaps. The flaps of the Astro Hog are seen here lowered to around 45 degrees, which is the position used for landing.
POWER SYSTEM ANALYSIS The model is powered by a HiModel 4120 outrunner motor. This motor has a Kv (rpm per volt) of 660. Trevor chose a 5S LiPo battery as the model’s power source. LiPos have a nominal voltage of 3.7 volts per cell, or 18.5 volts. (5 x 3.7 = 18.5 volts) The maximum voltage of a charged 5-cell LiPo battery is 21.0 volts (5 x 4.2 = 21.0 volts). However, under load, the battery voltage will be less, perhaps as little as 3.3 volts per cell. The actual load-voltage depends on factors such as the current demand, Super neat servo installation. the state of charge of the battery, the Trevor has elected to use snakes battery temperature and its internal for the rudder and elevator control of this model.
The flaps of the Astro Hog are shown in their take-off position, which is about 15 degrees.
Fred Dunn of California. Fred first flew his prototype Astro Hog in 1957 (a time when electric-powered airplanes were not in the forefront of the hobby). The Astro Hog was kitted by Berkeley in 1958. The design quickly became very popular, even sweeping the Academy of Model Aeronautics (AMA) National Championships — first thru fourth places. It is considered by many to be the first successful RC aerobatic model. Later on, Sig acquired the rights to Berkeley the kits, after Berkeley stopped trading. The design continues to be available today in kit form from Sig Manufacturing. The plan is also easily, and legally, available online. It is how Trevor got started on building his. In common with Sig’s kit, he made a few changes to the original design; these include a reduction of the wing dihedral and changing the stabilizer to a highmount position. Trevor also chose to fit his model with a pair of simple facebook.com/rcsportflyer
Trevor spent a bit of extra time on the Astro Hog’s cockpit area. A little simple detailing makes for a more scale appearance. RC-SF.COM
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COLUMN PHOTOS BY Ginny Sanford
HOW TO
HELICOPTERS 101,PART 5 TRANSLATING TENDENCY AND FUSELAGE HOVERING ATTITUDE
BY Dave Phelps “Like all novices we began with the helicopter but soon saw it had no future and dropped it. The helicopter does, with great labor, only what the balloon does without labor, and is no more fitted than the balloon for rapid horizontal flight. If its engine stops, it must fall with deathly violence, for it can neither float like a balloon nor glide like an airplane. The helicopter is much easier to design than an airplane, but it is worthless when done.” - Wilbur Wright
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guess asking the guys that invented the wind tunnel, the modern propeller and fixed wing roll control to invent the swashplate, tail rotor and three axis gyros too, might have been asking a little too much. Last month we talked about air flow during a hover and rotor head design. We covered the three basic types of rotor systems; the rigid rotor, the semi-rigid rotor and the
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fully articulated rotor system. This month we’re going to look at how the most common type of model helicopter rotor system, a hybrid of the semi-rigid and fully articulated systems when combined with the tail rotor, affects and is affected by fuselage hovering attitude. TORQUE AND TRANSLATING TENDENCY Newton’s law of action and
reaction causes the fuselage of a helicopter to tend to rotate in the opposite direction of the main rotor. This effect is called torque and must be counteracted before flight is possible. In helicopters equipped with tandem or coaxial rotor systems, the rotors turn in opposite directions, which neutralizes torque. Heading control is achieved by changing the ratio of collective pitch or speed of the two rotors from a
PHOTOS BY Ginny Sanford
Headed to the club after a tough day at the office.
My Eflite® UH-1 Huey hovers in a very scale-like attitude, tail low, with one skid hanging a little lower than the other. The only real difference in its appearance is that the full-scale UH-1 hovers left side low. The factors that cause the RC Huey and the full-scale UH-1 to have similar hovering attitude characteristics are quite different in the two birds, however.
PHOTOS BY Ginny Sanford
The Eflite UH-1 Huey is built on the Blade SR airframe, so it has many of the same flight characteristics. The scale detailing on the UH-1M fuselage is really quite remarkable, right down to the FM homing antennae on the tail boom and the inverted airfoil on the horizontal stabilizer. It has seen a lot of stick time and is starting to show its age. You may notice that it is missing its rocket pods and mini-guns. The guns went missing in action a long time ago making it a scale model of a full-size flying cargo van.
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direct 1:1, causing an unbalance in torque produced by each rotor, which in turn causes the fuselage to turn in the same direction as the lower powered rotor. For single main rotor helicopters using a fuselage-mounted engine or motor, torque is a direct result of the work/resistance relationship of the main rotor. Therefore, torque is concentrated at the center of the rotor disk. Torque results from the power applied to the rotor by the engine and drivetrain, meaning that any change in power output creates a corresponding change in torque. In most single rotor RC helicopters, torque is compensated for by the use of a variable pitch antitorque tail rotor located at the end of the tail boom. The tail rotor is driven
by the main rotor drive system at a constant ratio and produces thrust in a horizontal direction in opposition to the torque developed by the main rotor. Because torque changes any time a power change is made and fuselage yaw attitude is also affected by aerodynamic forces unrelated to torque and power settings, it is necessary to adjust the thrust of the tail rotor almost constantly. Fortunately for us, most of this task is usually accomplished by a gyro. When a heading-hold gyro is installed, there is very little input required of the pilot other than pointing the nose in the desired direction. When a rate referenced gyro is used, transmitter mixing is usually also used that slaves tail rotor pitch to the throttle channel so more thrust is created as the throttle setting increases. More control input from the pilot is generally needed with this type of gyro, but it is still a lot less than needed when there is no gyro at all. Many people, myself included, prefer the feel of a rate referenced gyro. For me and the type of flying I do, more scale than 3D, it’s better and easier to fly a helicopter that seeks to stay in proper aerodynamic trim than it is to have the nose always locked in the same direction. From what I can tell, many folks prefer the equipment with which they learned to fly. But I’m not going back to a four-channel AM airplane radio and no gyro, no matter how much I think I miss “the good ol’ days”. It is important to note that the tail rotor gets its rotational power from the same powerplant that the main RC-SF.COM
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REVIEW HOW TO
STANDBOX
DESIGNED TO SAVE YOUR MODELS FROM HARM BY Staff
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sprit Model’s new, flexible StandBox™ systems makes quick work of finding a place to store, transport and carry your airplanes. It is the perfect solution to getting models moved around the shop and airfield, and it does so without damaging your airplanes. What makes StandBox a standout is that it is extremely lightweight, yet durable because it is made of dense foam rubber. The foam is purposed designed to hold your model well, but it is flexible too, which means you won’t damage your airplane getting it in and out of StandBox. Then too, Esprit Model’s StandBox system is modular. It is system that will hold one, two or even three airplanes because the modules
simply lock together, one on top of the other. How cool is that? GREAT FOR TRANSPORT StandBox makes airplane transportation to and from the RC airfield safer. It doesn’t matter whether you are taking your models in a car’s trunk, a truck bed or van. The StandBox will keep it protected against abrasion and dings because the foam rubber is soft enough to absorb the bumps and bruises that often happen in transit. StandBox works great for getting your model onto the airfield too because its easy-to-attach carrying straps, let you pick it up and go. It will even work well as a model stand for tuning on a bench.
IN YOUR SHOP Esprit’s StandBox lets you get your airplanes’ hangar organized. Now you can stack them so they are out of harms way. Due to StandBox’s dovetail joints and clips, you can assemble a stand of StandBox carriers up to a maximum height of five feet. We found they simply pop together. What you’ll like is you can configure StandBox in a variety of ways, such that they will hold almost any airplane you have in your inventory. StandBox uses dovetailed, locking joints that makes them simple to snap together or reconfigure… So, stop wasting space in your shop and get your airplanes store neatly in StandBox. FLEXIBILITY We also found that StandBox can be modified quickly and easily by cutting the foam parts as shown in the instructions — they are printed on the back of the box. The instructions explain how to reconfigure StandBox such that you can make them fit nearly any airplane. Note too that StandBox are designed to use an interlocking system that is easy to snap together, but that will not easily
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Final Print size: 6’ x 3’
come apart, so your model will remain safe and secure in the stands. Additionally, what we found to be a very nice feature of our StandBox was that you need not glue the parts together with epoxy or cyanoacrylate glue. Just snap the parts together and your are ready to start carrying your models or storing them as needed.
they are a great buy. Compared to a wooden stand, that can damage your model, they seem to be an excellent buy. Moreover, we found them to be very easy to assemble and set up for our shop models. StandBox gets “two airplane thumbs up” from us!
FEATURES (4) Foam Support Ends (Blue) (4) Foam Bars (Yellow) (1) Neck Strap (2) Carrying Straps (1) Shovel (10) Clips Price $39.00
DISTRIBUTOR
RIGHT PRICE Considering that StandBox sells for only $39 at EspritModel.com,
Esprit Model 1240 Clearmont St NE, Unit 12 Palm Bay, FL 32905 Phone: 321-729-4287 Espritmodel.com
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REVIEW HOW TO
POLARON EX THIS IS A STAND-UP CHARGER IT’S NOT BOWING DOWN TO ANY BY Staff
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he Graupner Company, Kirchheim unter Teck, was founded 84 years ago. Graupner has been and is known the world over as a leader in the RC industry, providing modelers absolutely top quality gear. In 2013 Graupner was sold. It continues in the business of building RC products that excel in quality and functionality. The new Polaron EX charger is an example of just one of the many products that are now being sold in the U.S. by OpenHobby.com. It is, without question, a top-of-the-line charger that is feature rich — being built for the RC enthusiasts who want a charger that is easy to use, yet one that provides functions and features fit for professional pilots. From the moment we removed the charger from its foam-lined packaging we knew the new Polaron was a charger built to extremely high engineering standards. Little did we know the functions and features built into this new charger were pretty much second to none. What you get in the Graupner Polaron is a charger designed to stand upright on your workbench, with an extendable leg that slides out from the side to give it additional stability when necessary, which also functions as a dock with optional Polaron power supply (S2012), or is suitable to an 11 – 28-volt DC power source. The case for our test unit is painted blue, however, it is also available in black, silver, red and orange. There are two charge ports
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Skylar Tucker is showing off the great design lines of the Polaron AC/DC charger. As you can see it is the only charger now on the market that will stand proud on your workbench.
The Polaron EX comes in black, silver, red and orange. The unit has its ports well laid out on the front, right side and back. You’ll find the base lets it stand on your workbench solidly.
on the front, marked CH1 and CH2. These ports are also have associated balancing ports, plus each has a port for a temperature sensor — the charger comes with two. At the top front is the 3.0-inch color thin-filmtransistor (TFT) liquid crystal display (LCD) screen and specialized touch keypad. On the right upper side of the charger is the 12-volt DC output port, plus there is a 5-volt USB port. On the lower right side toward the front is one of the cooling fans — another is located on the back of the charger. Located on the back of the charger, at its bottom is the receptacle for the 100 – 240 AC three-prong power cord. Just above the AC receptacle is a 12- to 15-volt DC input. You’ll like how the TFT LCD display works. The unit comes with a plastic stylus. The stylus stores in the right, upper side of the case, so you can keep it with the charger. Once you power the unit, the LCD display becomes your interface to the features and functions of the Polaron. You simply use the stylus to navigate between different menus, which we’ll explain in the photos. The TFT screen is very sensitive to the stylus, so even a light tap lets you navigate between menus easily — no need to press hard, just a touch will do it. This unit gets its power from facebook.com/rcsportflyer
You’ll get a 5-volt USB port, a motor sensor, servo test port and external module. There is a stylus that fits nicely in its case, and our unit has a 12- to 15-volt DC input on the back.
either an AC input or a DC input, so you can take it to the RC airfield as well as use it on your workbench at home. Our Polaron pumps out 120 watts on 12- to 15-volts operation, or 60 watts out on 120 to 240volt operation per side — that is 240 watts if you combine both output ports. We found navigation between menus to be extremely intuitive. The charger nearly tells you what step to take in order to charge a battery of your choice: NiCd, NiMH / 1~14 cells / channel, LiPo, LiFe, LiIon / 1~7 cells / channel and Pb / 1~12 cells (2 volts /cell) / channel. The menus at the Home screen include: Profile, Charge, Discharge, Cycle, Balance, Data, Misc and User Set. Not surprisingly, these menus are where you set up what Here is how your Polaron will ship. Notice, everything is packed in foam rubber. It will come in a cardboard box, with another cardboard box around it. Ours arrived in perfect condition. RC-SF.COM
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REVIEW HOW TO
SBACH 342 60 ARF
MIKE McCONVILLE’S Sbach DELIVERS 3D AND PRECISION AEROBATICS
BY Wil Byers
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he design impetus for Mike McConville’s design of his Hangar 9 Sbach 342 comes by way of the fullscale airplane. The full-scale version was designed and built by the German company XtremeAir GmbH of Hecklingen. Their Sbach 342 is a high performance two-seat aerobatic and touring monoplane. It was designed by Philipp Steinbach along with Albert Mylius. The full-scale Sbach 342 is a composite structure, low-wing monoplane that sits atop a fixed landing gear. The 342 is powered by a 315 hp (235 kW) Lycoming AEIO-580-B1A piston-powered engine that turns a threebladed propeller. The XA42 received its certification from the FAA in November 2012.
Our cover model, Skylar Tucker is shown here with our new Hangar 9 Sbach 342 60-size ARF. She and the airplane make for a very attractive combination, as we’re sure you’ll agree.
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The inspiration for the Mike McConville designed Sbach 342 came from this fullscale airplane. Hangar 9’s model delivers 3D performance, which the full-scale does not.
MODEL My thoughts on Hangar 9’s Sbach 342 60 ARF is that it has very svelte, sexy design lines. It sports generously-sized control surfaces, with power to spare from its Power 60 outrunner and the 6S LiPo pack. With the summer months near, I wanted an airplane that would be fun to fly, as well as capturing the attentions of my fellow RC club members. When I considered that the 60size Sbach 342 is made from very lightweight balsa and plywood, is covered in UltraCote®, has a painted
You will get a very complete and high quality kit from Hangar 9. It even includes fiberglass wheel pants and a complete hardware package, so it assembles quickly.
Hangar 9 recommends you use the Castle Creations Pheonix Edge 100 electronic speed control to run the E-flite Power 60 motor. The Edge 100 is an outstanding ESC!
fiberglass cowl and wheel pants, plus a set of plug-in wings, I was pretty much hooked on having one. Additionally, Hangar 9 says its large control surfaces, when driven by the high-voltage-powered servos, deliver precision maneuverability and 3D capability. It, therefore, wasn’t long before a generously-sized shipping box arrived at my office. It arrived undamaged too! The remainder of the parts I had ordered from Hangar 9 came in two additional boxes, also without any shipping damage having been incurred by UPS. FEATURES • Mike McConville designed • Airframe delivers giant-scale flight feel and control response. • Lightweight laser-cut balsa and
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