RC Airplanes | Gliders | Helicopters
HANGAR 9® MERIDIAN FLIGHT TEST
LARGE-SCALE
ANTARES
SAILPLANE BUILD REPORT
AND
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Cutting to the Bat Bone The Drone Underground Engine Telemetry Made Easy Prototypical Building Lost Foam Molding Aerobatics Part 12
GET REAL! LEARN TO FLY THE INEXPENSIVE WAY
MARCH 2014
USA & CANADA $6.49
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TABLE OF CONTENTS DEPARTMENTS
SEE HOW THE MAIDEN FLIGHT OF THE DALLAIRE SPORTSTER WENT FOR OUR BUILDER.
10 LEADING EDGE 12 HOT PRODUCTS 96 ADS’ INDEX 97 MYSTERY PLANE
PG 32
BUILD
20 6.6-METER ANTARES LEARN HOW RICK BUILDS A LARGESCALE SAILPLANE THAT’S DESIGNED FOR GPS RACING. By Rick Shelby
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Aerobatic Figures
PG 52
PROTOTYPICAL BUILDING OUR EXPERT DETAILS HOW HE USES THE THINKING MAN’S APPROACH TO DESIGN. By Rob Caso
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HOW TO
BONE 40 BAT MULTIROTOR
DALLAIRE SPORTSTER JEFF FINISHES HIS BUILD PROJECT, AND MAKES THE MAIDEN FLIGHT OF A NEW AIRPLANE. By Jeff Troy
PG 46 6
RC SPORT FLYER . MARCH 2014
THIS THREE-MOTOR MULTIROTOR IS A SUPERB FPV MACHINE. JAMES SHOWS YOU WHY. By James VanWinkle
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LOST-FOAM PARTS MAKING YOU GET THE RIGHT DIRECTIONS IN THIS ARTICLE ABOUT HOW TO MAKE ONE-OFF PARTS. By Tom Wolf
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LEARNING THE ARESTI SEE WHY LEARNING THE ARESTI MANEUVERS WILL POLISH YOUR PILOTING SKILLS. By Daniel Holman
3-VIEW
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GERMAN DORNIER DO 27 AN AIRPLANE DESIGN THAT WORKED FOR THE MILITARY AND FOR CIVILIAN USE. By Wil Byers
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MARCH 2014
COLUMN
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ENGINE TELEMETRY LEARN HOW TO LISTEN TO WHAT YOUR MODEL’S ENGINE SAYS. By Pete Bergstrom
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THE DRONE UNDERGROUND FPV PILOTS AND AMATEUR DRONE ENTHUSIASTS ARE NOW BANDING TOGETHER. SEE WHERE AND WHY. By Lucidity
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PG 40
ELETRIC MOTOR POWER GET THE DOPE ON HOW MAGNETIC ATTRACTIONS MAKE MOTORS WORK. By Andrew Gibbs
101 76 HELIS PART 4 DAVE GIVES YOU THE INSIDE SCOOP ON HOW GROUND EFFECT AND ROTOR DESIGN AFFECT PERFORMANCE. By Dave Phelps
PG 60 DISCOVER WHY THIS LITTLE BAT CUTS TO THE BONE WHEN IT COMES TO BEING A GREAT FPV PLATFORM.
REVIEW
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HANGAR 9 MERIDIAN WE FLY A 10-CC GAS-POWERED AIRPLANE THAT YOU’LL WANT IN YOUR HANGAR. By RC-SF Staff
PG 90
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90 REALFLIGHT VERSION 7 CHECK OUT HOW RF7 DELIVERS TRUETO-LIFE FLIGHT PHYSICS AND 3D FLYING SITES. By RC-SF Staff
PG 82
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HOT PRODUCTS E-FLITE CARBON-Z® YAK 54 3X BNF BASIC & PNP
E
-flite’s new Carbon-Z Yak 54 3X airplane is an evolution of materials and technology. Improvements give this model a definitive edge in performance over the ground breaking original, which begins with the latest in Carbon-Z construction. The airframe features strength enhancements to increase durability and to withstand aggressive 3D maneuvers. The new Carbon-Z Yak 54 3X delivers a 3D precision airplane for you that is ready to fly in the length of time it takes to charge its battery pack. Features • Improved Carbon-Z® structure w/ lightweight CA hinges • AS3X® system delivers optimal precision and agility • Spektrum™ AR635 6-channel AS3X Sport receiver • High-output, 25-size, 1000 Kv brushless motor system
• E-flite® 60-amp Pro Switch-Mode BEC Brushless ESC V2 • Digital high-speed, metal-gear mini servos • CA hinged control surfaces w/ control links installed • Plug-in wings and stabilizers • Cockpit details, pilot figure and tinted canopy • Multiple access hatches w/ magnetic and mechanical latches • E-flite 2800-mAh 14.4-volt 4S 30C LiPo battery Price $379.99 & $299.99 (EFL10550 & EFL10575)
Specifications Wingspan Wing loading Wing area Length Weight
48.0 in. (1220 mm) 13.8 oz/ft2 525 in.2 (34.0 dm2) 48.5 in. (1230 mm) 3.75–3.80 lb (1.70–1.73 Kg)
Distributor HORIZON HOBBY 4105 Fieldstone Road Champaign, IL 61822 Phone: 217-352-1913 horizonhobby.com
ESPRIT MODEL JETI HICOPTER MULTIROTOR BRUSHLESS ESCs
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sprit has just announced their new Jeti HiCopter line of speed controllers. These units are designed for controlling and regulating brushless motors that are typically used for multirotor aircraft. Each speed controller is factory programmed with settings optimized for use with multirotor stabilization systems. HiCopter controllers accept a control signal with a frequency of up to 500 Hz. This allows accurate response times to rpm changes required by the control/ stabilization unit. The throttle signal is optically isolated from the flight battery in all HiCopter speed controllers. HiCopter speed controllers do not require or allow any programming changes. The propeller brakes come turned off, the cutoff voltage is pre-set to the lowest possible level (depending on type)
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Distributor Esprit Model 1240 Clearmont St NE, Unit 12 Palm Bay, FL 32905 Phone: 321-729-4287 espritmodel.com
and the motor timing is set automatically by the speed controller. Changing motor rotation is as simple as swapping two of the power leads. twitter.com/rcsportflyer
EAGLE TREE SYSTEMS VECTOR FPV CONTROLLER
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agle Tree Systems announces their new Vector FPV Controller. Their Vector has all the features FPV pilots are looking for to outfit their airplane, helicopter, glider or multirotors, This new unit comes in one small, lightweight package. Features • Built-in OSD w/ color graphics and customizable screens • World class fixed wing and multirotor flight controller w/ GPS modes and RTH • Simple setup, out-of-the-box operation, with no PC required for most features • Compatible: PCM, SPPM and S.BUSTM receiver support, w/ four types of RSSI
• Expandable w/ additional sensors, accessories, and internet firmware updates • Flexible: fly w/ or w/o FPV equipment • Reduced wiring: innovative wire harness w/ power distribution simplifies hookup • Current sensor with quiet and efficient filtered 12V and 5V power supply unit supports up to 6S packs • Built-in altimeter, IMU and magnetic compass sensors Price: $279.99
Distributor EAGLE TREE SYSTEMS 4957 Lakemont Blvd SE, Suite C-4 Bellevue, WA 98006 Phone: 425-614-0450 eagletreesystems.com
Distributor
Specifications
HORIZON HOBBY 4105 Fieldstone Road Champaign, IL 61822 Phone: 217-352-1913 horizonhobby.com
Type Fuel Displacement Bore Stroke Cylinder type Cylinders Plug Type Weight total Engine weight Muffler weight Ignition weight Muffler threads Propeller range Rpm range Oil Muffler
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EVOLUTION 62-CC GAS ENGINE W/ SUREFIRE EFI
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iant-scale, multi-engine airplane enthusiasts and aerobatics pilots looking for a great single-cylinder gas engine that’s reliable and easy to use are going to like the Evolution 62GXi with SureFire™ electronic fuel injection. This new engine is simple to setup and maintain. EFI is a Horizon Hobby innovation that means giant-scale enthusiasts will never have to touch a needle-valve to get their facebook.com/rcsportflyer
• model’s engine started. And, this engine will deliver many hours of reliable performance. Features • First gas-powered engine with electronic fuel injection for outstanding performance • No needle valves—SureFire electronic fuel injection technology combines finetuned software and sensors to give the engine the perfect fuel flow • Compact electronic ignition and SureFire EFI systems run on one 7.4-
• • • • •
2-stroke Airplane Gasoline—87+ octane 62 cc (3.8 cu in) 1.80 in (46.0 mm) 1.50 in (37.0 mm) Ringed Single CM-6 66.6 oz (1888 g) 53.8 oz (1525 g) 8.2 oz (233 g) 4.6 oz (130 g) 5 mm 22x8 – 24x10 1000 – 8000 Synthetic 40:1 Inverted wrap-around
volt LiPo power to save weight and simplify installation as well as giving easy starts, superior reliability and run times Lightweight rigid construction with a low-profile rear intake for smoother running Purpose-built for giant-scale model aircraft Common muffler mount fits a variety of available exhausts Shares the overall dimensions and mounting pattern of other U.S. engine manufacturers Dual ball-bearing equipped, cantilevered crankshaft Common 4-bolt propeller mounting pattern found on other U.S. engines Supplied w/ muffler, spark plug fuel tubing and filter clunk.
Price
$579.99 (EVOE62GXI)
RC-SF.COM
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BUILD 6.6-METER ANTARES HIGH QUALITY BUILD MAKES FOR HIGH PERFORMANCE RACING
BY Rick Shelby / Wil Byers
T
he new Antares is a Jeri Baudis sailplane that was purpose designed and built for the new GPS racing circuit that is beginning to grow worldwide. Jeri Baudis is known for his years of producing some of the best F3B models in the world. As such, Baudis wanted to push the outside of the performance envelope with the Antares design, to create a racing machine that was unequaled. The Antares sports a 6.6-meter (260-in.), double-carbon wing. As you would expect of a machine such as this one, all the parts of the sailplane were built in CNCmachined molds as a way to get the tightest airfoil tolerances on all the flight surfaces, as well as to create an accurate-to-scale fusealge—even the spars were CNC milled! Note the Antares won the first GPS Triangle race Jiri entered. The Antares is mostly factory built: with gauges, seat belts, canopy
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mounted, and with landing gear and tow release installed. The wing comes with four servos built in, with rotary drives systems in place, so there are no external horns. It is one clean machine. The SoaringUSA.com package even includes the servo leads, wing bags and servo frames. This 33-percent scale sailplane is an absolute, dedicated racing machine that soars like an F3B airplane. However, step on the “gas” and this sailplane will turn into an allout lift-over-drag hotrod racer. You’ll be able to go for the gold by turning in the most laps around the course in a 30-minute working window. Talk about fun!
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Build Having scored on the Antares at the AMA’s annual convention in Ontario, California, I needed to figure out how I was going to get it built and ready for the flying season. This is no small task for me anymore because I’m always busy with work projects and just trying finish review airplanes. Fortunately, Soaring USA’s Bob Breaux tipped me off that Rick Shelby is one of the best builders around. He told me that if Rick had the time in his work and build schedule he would probably gladly build the model for me. Next Bob took it upon himself to introduce me to Rick. So it was that, after some a bit of negotiation, Rick offered to finish the build on the model. What was required were a few servos, the making up of the wiring
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harnesses, gluing in a few servo trays, installing the servos in the empennage and then doing a set up of the radio system. What I got when I took delivery of this model was a machine that is ready to race, including the addition of ballast weight and a GPS system. I want to share with you through a photo pictorial how this model is built, and how Rick installed the hardware. It isn’t often that we show a build like the Antares’ but I think you’ll learn much about what is
The canopy hold-open stay, screws into the bulkhead at the front of the cockpit opening. It was removed from the front bulkhead and the screws were reversed so that they could be accessed.
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The hold-open stay’s screw hold needed to be reversed so that it could be removed in the event I’d need to get into the front of the fuselage to do maintenance work. RC-SF.COM
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BUILD PROTOTYPICAL BUILDING USE THE THINKING MAN’S APPROACH TO DESIGN
I
t’s probably safe to say not many of us have access to a lot of expensive equipment to test exactly how a certain design or component will perform under stress or load. This makes me somewhat of an “eyeball engineer.” And, one
of the biggest challenges in scale model aircraft design is determining “how strong is strong enough.” Certainly, an option is to overbuild everything, but then you’re bumping up against another constraint called wing loading. Too heavy is
BY Robert J. Caso
no good either and this game has the potential to become an endless spiral of more weight needing more power, which translates into more weight, which, well, you get the idea. We’re not alone in this dilemma as there are numerous stories of full-
Up
Down
Net Lifting Force % More Lift
% Less Lift
Net Lifting Force Fulcrum
Main Strut
Figure 1 Fi-156 Storch Front View
The Storch’s net lifting load travels from the outer wing panels, down each main strut and then underneath the fuselage to pick it up.
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Lift Flying Wire
Lifting force transfer
Figure 2 WWI Biplane Wing scale designs that have gone down the same path to the point where the prototypes were either too complicated or too heavy. So, what do you do to optimize a design to get it close to being just right—putting the structure—and therefore the weight, only where you are going to need it? Without the ability to test, how do you know? Study, research and educated guessing are the short answers, the first two components of which are closely related. To avoid reinventing the wheel, I like to study and critique other models (plans) of the same or similar aircraft and I also take a very close look at the full-scale design. The logic here is that designers of each had to solve the same problems that I am trying to solve. Since I am somewhat of a student of the Fieseler Storch, let’s take a look at this airplane from both perspectives to determine why was it built the way it was, with the ultimate goal of determining how a model should be built. At first blush, it’s easy to see the airplane had giant control surfaces and some fairly significant gaps between these and its fixed surfaces. facebook.com/rcsportflyer
Next, there’s a ton of stuff hanging off the thing: wing and tail struts, a huge shock absorbing landing gear (LG), a gawky, flat plate canopy and all manner of bumps and equipment on the skin. Read a bit further and you’ll note the Storch was built for STOL, which is why it also had a high lift, high aspect ratio wing, leading edge slats and a powerful engine. So, since it never was intended to go fast, it wasn’t built for such. Big control surface gaps? Who cares? The surfaces will never go fast enough to flutter. But they were big so as to move a lot of air at low airspeeds. So, in model airplane land, all this is key—design the model for certain flight parameters and then stick to them when you fly it. The Storch never did snap rolls, loops, inverted flight nor flew very fast—and neither should yours. If a model is built prototypically, it may fall apart under such stress. Studying model designs of this and other airplanes can be fraught with issues. Just because a previous design may have been successful, does not mean that its structure has been optimized. I have seen designs of Storchs having carbon
Lift WWI wings generally have two sets of flying and landing wires to prevent twisting—the main spar in each keeps the wings straight and true under load.
fiber tubes going through the cockpit to each wing, overbuilt wing roots and strutting in the wrong place compared to the prototype. Back to the real one, its wing-to-fuselage connections consists of a hinge at the trailing edge for the folding wing mechanism and a large locking pin on the leading edge. That’s it. A friend of mine who has a full-scale Storch says that you can walk up to it and shake the wing root up and down with your hand! How can this be? What about all the flight loads? The short answer is that there aren’t any. Take a look at the wing (Figure 1), noting where the main struts are positioned and you will find that about 58 percent of the wing’s area is outboard of the struts and 42 percent is inboard. This means that more lift is being generated outboard than inboard and, with the strut so positioned, a net down force is being applied to the root when the airplane is flying. The structure at the root is doing almost nothing other than preventing the wing from yawing and keeping it located it on the fuselage—it’s the main strut that is doing all the work. So, and here comes the educated RC-SF.COM
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HOW TO This is the kit for the Bat Bone, along with some parts I plan to use like the AFRO® ESCs and the Turnigy® motors.
BATBONE
AN EASY-TO-BUILD MULTIROTOR MACHINE BY James VanWinkle
H
aving a multirotor (MR) in my hangar has been high on my list of wants for several years. I was, however, unsure as to how to set one up, including what size is best or how many rotors must power it. You’ve likely had these questions too. After much research I settled on a tricopter for a couple of basic
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reasons: their increased agility as compared to quadcopters, and there are fewer parts to fail. A tricopter does require a servo for the tail, but it requires one less motor and electronic speed controller (ESC). It really comes down to personal preference though, and the sky is the limit for the number of rotors—it is not uncommon to see any number
from three to eight or more. Next I had to determine which frame to use. This is where the Bat Bone entered my hangar. BAT BONE I am completely hooked on the flitetest.com videos, primarily due to the great personalities. Also, their raw video styling is such that they are not twitter.com/rcsportflyer
The landing skids are made of a flexible plastic called Delrin®, which allows them to take a lot of the load during hard landings. They are attached to the wooden booms via screws.
afraid to show boom microphones or cameras. They focus purely on the RC hobby and are willing to explore many avenues of flight, keeping the required experience level around the beginner to average skill levels. They rarely venturing into territory that requires expert building or flying skills. I watch all of their videos, no matter the model, just to witness their on-screen magic. Their creativity is amazing. Then, when their discussions turned to MRs, I became even more interested. One of the models they created is called the Bat Bone. It is a tricopter frame with a design that stows the wiring and placement of electronics out of sight. And, I think it just facebook.com/rcsportflyer
looks cool too. It is constructed of a fiberglass board material with wooden arms and Delrin® landing skids. They offer a battery tray that suspends the battery under the frame via wire, which lessens the vibration when cameras such as the GoPro® are mounted to the MR’s tray. Another nice feature of this tricopter is that its arms are foldable, making the Bat Bone easy to transport as compared to other MRs. Note there is a lot more to a successful MR than just picking a frame or brand of motor or ESC. You need a good control system for stable flight. While there are many good systems to pick from, one is a definite standout in my mind. It is the
ArduPilot from 3DRobotics®. I bought one for use in my foam airplane—just to try it out. It has many additional stability options from that of other systems. Plus it includes some nice extras such as Return-To-Home (RTH) capability in case of transmitter signal loss, or an emergency. Also included is an autoland feature. The most impressive, however, is the ability to establish way points using a mission planner. The control system is based on the Arduino system, which is a type of opensource micro-controller, meaning it can be custom programmed to perform many user-defined tasks. Consequently, the ArduPilot was my choice to guide my tricopter. (There will be more about this system in an upcoming issue RC-SF, as it warrants its own more in-depth article.) ASSEMBLY Putting the frame together is quite simple. If you need help, there are videos online at Flitetest showing the step-by-step procedures. Assembly RC-SF.COM
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HOW TO
LOST-FOAM
AN QUICK WAY TO FABRICATE FIBERGLASS PARTS – PART I BY Tom Wolf
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To start the shaping process, a foam block is clamped between the plywood templates, using the larger of the two front templates.
RC SPORT FLYER . MARCH 2014
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Preliminary shaping produces a cylinder of foam between the two template disks.
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Photo by JJ Cavins
F
uselages and other aircraft parts fabricated from fiberglass provide high strength, excellent surface finish and have few limitations on finished shape. The conventional method for fabrication of fiberglass parts is a multi-step process that requires fabricating a pattern (or plug) that mimics all of the outer details of the desired final part, fabricating a female mold from the pattern and then using the mold to lay up the fiberglass part. The fabrication of the plug and mold is labor-intensive, but is justified if multiple parts are planned for fabrication. However, for a one-off situation, there is another approach that cuts out much of the labor, reducing the process essentially to
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The larger front template is replaced by a smaller one in preparation for shaping the leading edge of the cowl.
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4
To make the cowls for the Boeing 314, templates were fabricated from 1/4-in. plywood. A 1/4-20 threaded rod was used to clamp the foam between the template disks.
the equivalent of what is required to fabricate the pattern in the conventional process. This two-part article will describe the process of making cowls, fuselages, nacelles and other similar parts by fabricating a foam part and then applying fiberglass to the exterior of the foam. After the fiberglass has been applied, the foam is removed from the interior of most parts. However, for fuselages the foam may be left in place except for the areas where the radio or other gear is to be installed. By leaving the
The leading edge radius is shaped with a small sanding block to blend down to the smaller front template.
RC-SF.COM
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HOW TO
AEROBATICS PART 12 THE ARESTI
BY Daniel Holman
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f there is one thing I have endeavored to stress in my columns, it is that practicing precision aerobatics is absolutely the best way to sharpen your piloting skills. For some pilots, practicing precision aerobatics is very enjoyable. For others, it can get tedious and boring. When the latter is the case, most pilot’s lose interest due to a lack of purpose and motivation. That because it is easy to kick back, jam the radio’s control sticks around and have fun doing what you know. If you’ve found yourself in this situation, but still have the desire to become a better pilot, my advice would be to get involved in International Miniature Aerobatic Club (IMAC). Even when competing at the basic level, the competition is stimulating and challenging. Importantly, IMAC lets you get together with other guys who enjoy good-natured competition. It will also motivate and push you to be the best pilot possible. Then too, gleaning knowledge and experience from other pilots is invaluable to your success. In the next couple parts of this series, I will explain the finer points of precision aerobatics competition, the maneuvers and how judging works. I’ll also cover some airplane/ programming setup tricks. THE ARESTI Designed by Spanish aviator Colonel Jose Luis Aresti Aguirre, the Aresti catalog enumerates the aerobatic maneuvers flown
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It was a beautiful evening at the Pacific Coast IMAC and Freestyle Championship in Molalla, Oregon. The camaraderie is always awesome at this event. The friendly competition helps motivate pilots to improve their skills and be the best possible pilot!
in International Aerobatic Club (IAC) and other precision aerobatic competitions. This catalog has been adopted by radio control (RC) airplane pilots around the world and is the standard for IMAC and pattern competitions. It is crucial you have a good understanding of the Aresti maneuvers and how to read them before your first IMAC contest. Here are the main maneuvers and the primary points on which they are judged: AEROBATIC FIGURES Every aerobatic sequence has a structure. It is a framework of figures
to be drawn in the sky from which different rolls, point rolls, snap rolls, spins, etc., are flown on. The basic class of IMAC does not include any snap rolls, and only has a few partial or full rolls. This is because mastery of figure-drawing is the foundation for precision aerobatics competition. With each class progression, more and more snap rolls, point rolls, spins, stalls, etc. are added to increase the complexity. Even in the Unlimited class, points for geometry are high. So, it is best to start working on geometry from the start. Each maneuver is drawn on the Aresti sequence sheet so that routine twitter.com/rcsportflyer
Aerobatic Figures
is understandable and easy to follow for the pilot’s caller. Each maneuver diagram starts with a black dot and ends with a vertical black line that Ts the figure. The diagram between the marks is considered one maneuver. The maneuver is judged deductively, with a perfect score being ten. The black line used to draw the figure represents a wings level, upright line or positive-G (G = force of gravity) loading radius. Similarly, a red dotted line represents a wings level, inverted line or a negative-G loading radius— down elevator condition. As I wrote previously, establishing
Loops
a clearly-defined flight box is very important. All maneuvers should be the same height and use the base line of the box. Cross-box maneuvers flown on the Z axis should have top and base lines with the same altitudes as those flown on the regular, close base line. The ends of the flight box should be clearly defined as well. For the most part, maneuvers are either placed in the center of, or on either end of the flight box. Their positions are clearly marked by the location of the maneuver diagram on your Aresti sheet. Maneuvers placed on
either end of the flight box should all reach the same point at the ends of the flight box. For instance, if you fly a Split-S turn-around maneuver at one end of the flight box so the airplane is 1,000 feet to your right at the farthest point of the maneuver, a shark-tooth on that end of the field should also reach, but not exceed the 1,000 foot distance mark as well. Both of these maneuvers should also reach the same altitude at their highest point and share the same base line. Another very significant aspect of performing Aresti figures concerns the radiuses. All radiuses (pitch changes) that are drawn as corners should be equal and all radiuses drawn as circles/semicircles should be equal. That means all the radiuses on any square-loop, shark-tooth, etc., should be equal, while all loops, Split-S and Immelmann turns, cuban-eights, and like maneuvers should all have equal radii. Keep in mind that the radii on these maneuvers is more gentle than those of the previous list. Simply put, all maneuvers should be proportional to each other. Now, here are some common figures you will see flown on an IMAC sequence: LOOPS The loop must be flown as close as possible to perfectly round while holding the wings level. A loop is generally placed in the center of the flight box and should be sized so the top of the maneuver touches your top line. Variations of this maneuver include the inside-out loop (a red dotted line figure to indicate the airplane has negative-G loading), the square loop and the diamond loop. These can be positive or negative. Unless otherwise indicated, looping figures must be flown so they are equal in height. In the advanced IMAC classes, integrated rolls and snaps are usually present in the maneuver. I’ll cover those later. Although technically not in the loop family, maneuvers like figure-9s, tear-drops and like maneuvers are judged in much the same way for their equal radii, placement, size and wind correction.
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RC-SF.COM
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COLUMN HOW TO
ENGINE TELEMETRY INE ENGUMN COL
LISTENING TO WHAT YOUR AIRPLANE’S MOTOR HAS TO SAY. BY Pete Bergstrom
W
ouldn’t you like to know if you are treating that costly piece of machinery on the front of your airplane correctly? This month we are going to take a look at one of the basic engine diagnostic tool in the form of telemetry. Gone are the days of relying on the local engine guru (the guy with enough experience that he can just look at your model’s engine and it starts to act right… he’s the ‘Engine Whisperer’) to get a top performing and reliable power setup. Now we have tools to diagnose your model’s engine performance on the ground and in the air. IN-AIR RPM AND CYLINDER HEAD TEMP Using just two bits of information you can learn much about what your engine is doing and how well it is performing or operating in the air: rpm and cylinder-head temperature. For this article I’ll be using Spektrum® Telemetry gear because it’s what I have, but other systems will work well too. Just mimic what I am showing you how to do. Rpm There is hardly anything handier to have than a telemetry driven rpm readout, either on your transmitter or on a handheld readout device. There are three different ways to obtain the rpm readout, depending upon your
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model’s engine type and installation preferences: 1. Optical sensor through the propeller: This works exactly the same as your handheld tachometer in that if itt senses the shadow of the propeller passing in front of the optical sensor. The readout system requires that you enter into its memory how many blades the propeller has so it can correctly display the rpm. This requires mounting the sensor to a part of the airframe (usually the cowl), and such that it points in the direction of the propeller. 2. Hall Effect sensor (magnet) pickup: This works by activating the Hall effect sensor (essentially a magnetic switch) every time a magnet passes the sensor. You can either mount a magnet in the drive washer of your engine and then mount the sensor adjacent to this on the crankcase, or you can utilize the Spektrum Telemetry rpm sensor and pickup (SPMA9569) and mount this in the backplate of your engine where it uses the passing of the steel crankpin on the engine’s crankshaft to activate the sensor. 3. Tachometer from electronic ignition: This last system is the simplest if the engine is gaspowered, with an electronic ignition that has a tachometer
Spektrum TM1000 Aircraft Telemetry Module (SPM9548) with rpm sensor and bracket (SPMA9569) on the right, and the temperature sensor (SPMA9571) on the left.
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Spektrum rpm sensor and bracket mounted in the back of an Evolution 60NX engine.
output lead built in. The ignition unit then sends a signal to the sensor each time the ignition unit fires the spark plug. It is a surefire way of getting an accurate readout. Separate handheld tachometer units are available for many of these ignitions. EvolutionŽ Engines provides an Ignition Telemetry Adapter (EVOA107) that plugs into the tach output of all RCExl style ignition systems, and into the Spektrum TM1000 Aircraft Telemetry Module. For other telemetry systems you may have to make your own adapter cable. CYLINDER HEAD TEMP This is excellent information for help in fine tuning the needle valve settings on an engine to deliver the most reliable in-air operation. It also aids in evaluating the cooling effects (or lack) of an airplane’s cowl installation. For temperature information to be reliable you must establish sensor mounting standards that provide consistent and meaningful measurements. The two commonly available sensors are: 1. Inline thermistor: This sensor gets mounted in the center of a length of wire, with a connector for the telemetry module. This facebook.com/rcsportflyer
wire (like the Spektrum Aircraft Telemetry Sensor (SPMA9571)) has an overall length of about 12 inches. It will easily reach from the engine compartment of most installations back to the telemetry module. 2. Thermistor in a ring connector: In this case the thermistor is in a ring configuration with a telemetry connector at the other end of the wire. This is generally meant to mount to the engine either under a spark plug or to a mounting bolt somewhere on the case.
Using either of the above choices requires thought as to the mounting process. I’ve found that the most reliable and repeatable information is gotten by mounting the thermistor as close as possible to the glow or spark plug. This is the hottest point on an engine. So, if RC-SF.COM
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COLUMN HOW TO
THE DRONE UNDERGROUND FPV PILOTS AND AMATEUR DRONE ENTHUSIASTS ARE BANDING TOGETHER
BY Lucidity In local coffee houses and city parks, lonely FPV pilots and amateur drone enthusiasts are banding together to share the hobby that they love—and to shape the future of a movement that will change the world.
The members of Team Grey Goose: Kevin Vertucio, Leif Jensen, Steve Cohen, Mike Chidlovsky—also lead the New York City Drone User Group (NYCDUG).
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twitter.com/rcsportflyer
Chad Frazer joined the North Tex as Drone User Group (NTDUG), and eventually stepped up to help lead the organization, after struggling to master the intricacies of FPV flying on his own.
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he first FPV pilots were solitary creatures. They sat hunched over their work benches, attempting to decipher badly translated manuals for Chinese video transmitters intended for use in wireless security systems—hoping that their labors might one day afford them a glimpse of the world from above. If they communicated with each other at all, it was through furtive messages exchanged on the fringes of RC flying forums. However, it was impossible that this situation would endure—at least according to the Greek philosopher Aristotle. More than 2,000 years ago, he wrote that: “Man is by nature a social animal... Anyone who either cannot lead the common life or is so self-sufficient as not to need to, and therefore does not partake of society, is either a beast or a god.” Being neither beasts nor gods, it was inevitable that a series of chance encounters, friend-of-a-friend connections and online contacts would bring these solitary creatures together. At first, they formed small, local communities that have since grown together into a nationwide movement. If you want to see the future— or better still, be a part of it—the chances are there is a friendly group of people meeting somewhere nearby in the next few weeks who will be glad to have you along. THE DRONES TAKE MANHATTAN Steve Cohen, who heads the facebook.com/rcsportflyer
An X8 flying wing built by Chad Frazer for the specific purpose of assisting in search and rescue missions. Notice the bright, high-contrast paint scheme to aid in visual detection of the aircraft.
New York City Drone User Group (NYCDUG), recalled how he first met some other amateur drone enthusiasts in his community. “It all came about very organically,” he said. “After trying several flight controllers over six months, I’d begun to get involved with the OpenPilot community. We quickly realized that about five or six of us lived within an hour’s drive of each other, so we decided to meet up. We continued getting together, and this was about the same time Team BlackSheep’s antics were getting some negative feedback— leading a group of guys in Chicago to call themselves ‘Team White Llama.’ We jokingly called ourselves ‘Team Grey Goose’ and the name stuck.” Then, at the Drone and Aerial Robotics Conference (DARC) held in October last year at New York University, he met Timothy Reuter, who heads an umbrella group called the Drone User Group Network (DUGN). “He told me about a group called NYC Flying Robots. It had a fairly large membership—about 400 people, or so—but it hadn’t actually done anything in terms of meet-ups, build-ins or social events for more than a year,” Cohen said. “The interesting thing was the membership was continuing to grow, in spite of the lack of activity. That said to us there was clearly a demand for this type of community
here in the area.” Cohen took over the leadership of NYC Flying Robots and re-launched it as NYCDUG. “It’s still pretty informal at this point,” he explained. “We have a MeetUp.com group that is rapidly closing in on 500 members. People can join at no cost.” About 1,500 miles away, in Dallas, Texas, Chad Frazer still remembers how difficult it was to get started as an amateur drone builder and pilot working all alone. “I had toiled for almost a year trying to learn this stuff,” he said. “I felt so isolated, even with the DIYDrones.com community at my fingertips, no one on the forums seemed to be in the Dallas area. “It was so lonely! It got frustrating, too—and there was only so much of this hobby that my wife could take!” Frazer eventually stumbled across the North Texas Drone User Group. After the organization’s former leader had to step aside to deal with unrelated issues in his personal life, Frazer teamed up with Romeo Espana and Tony White to keep the club together. “Now, for me, it’s about sharing as much knowledge as I can,” said Frazer. “Networking is a type of power in itself. The more people who join the club, the more buddies I have that I can go flying with, the better job we can do resisting any bad reputation that drones have.” It was that same sense of isolation that led Scott Edwards to start RC-SF.COM
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COLUMN HOW TO
HELICOPTERS 101,PART 4 GROUND EFFECT AND ROTOR HEAD DESIGN BY Dave Phelps OUT-OF-GROUND-EFFECT HOVER
This is a review of our last installment. This illustration shows airflow in an out-of-ground-effect hover. Induced flow caused by the airflow moving downward reduces the angle of attack, meaning more power is used to keep it flying. Rotor tip vortices form around the tips of the blades and remain behind for several revolutions. This creates a lot of turbulence around the tips of the blades, which interferes greatly with their ability to produce lift.
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ast month I wrote about airflow during out-of-ground-effect (OGE) hover. I explained induced flow and rotor tip vortices, and their combined effect on the efficiency of the rotor system. This month, I will detail what happens when we hover within one-rotor diameter of the ground. GROUND EFFECT Ground effect is a condition of improved rotor system efficiency due to an interruption of the airflow pattern. It is more pronounced the closer the helicopter is to the ground. Increased efficiency of the
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rotor system while operating in ground effect is due to two distinctly different causes. The first of these is the reduction of the velocity of the induced flow. As the air is being pumped downwards, the induced flow is slowed by the change in direction of the airflow caused by the ground. The result of the slower induced flow is an increase in angle of attack due to the reduced angle between the relative wind and the direction of rotation. In order to maintain that altitude, the pilot lowers the blades’ collective, resulting in a reduced pitch angle and a corresponding
reduction in the angle of attack. Lift is always perpendicular to relative wind, so when the pitch angle and the angle of attack are reduced, the lift vector becomes more vertical. Because of the more vertical the lift vector, induced drag is reduced so less power is needed to produce the lift necessary to maintain a hover. The second reason for the increased efficiency in ground effect is the reduction of rotor tip vortices. The closer the rotor system is operated to the ground, the more the airflow is directed outward as opposed to downward, which has the effect of restricting vortex twitter.com/rcsportflyer
IN-GROUND-EFFECT HOVER
When the helicopter is hovering near the ground, the induced flow is slowed due to the change in direction it must make when it hits the ground. The slower induced flow compared to an out-of-ground-effect condition reduces the angle of attack. Another byproduct of the change in direction of the airflow is that the tip vortices are much smaller and pushed away from the rotor disk more quickly. The result of these two phenomenons is that rotor system efficiency is increased.
generation. There is simply less room for them to form. The vortices that are formed are moved away from the rotor disk more quickly as they are pushed out by the outward movement of the air. The smaller vortices create less turbulence and affect a smaller portion of the rotor disk. It just so happens that the affected portion is also the outermost portion of the disk, the part with the highest airspeed, which is the part that produces the most lift. Ground effect increases rotor system efficiency up to a height of about one rotor diameter. At a rotor height of one-half-rotor diameter, lift is increased by about seven percent. At heights above one rotor diameter, the increase in rotor system efficiency is small and decreases to zero at about one-and-a-quarterrotor diameter. Ground effect is affected by the type of surface. A smooth paved surface will provide the highest level of efficiency at a given altitude. The rougher the ground, the less the rotor tip vortices are affected. An uneven surface also does not slow the induced flow as efficiently, so a partial loss of ground effect efficiency can be noticed when hovering over grass, coarse gravel or even water. You’ve likely noticed this when you’ve been taking off or landing your RC helicopter. facebook.com/rcsportflyer
ROTOR HEAD DESIGN In future installments, we will discuss why the tips of the rotor blades need to be allowed to move vertically and in some cases fore and aft. For now we will refer to the movement of the blades relative to the rotor head vertically as flapping and fore and aft movement of the blade tips relative to the feathering shaft, or the horizontal centerline of the hub as lead and lag. Rigid Rotor System There are three basic types of rotor head design. The first and least common is the rigid rotor system. As the name implies, the blades are rigidly attached to the hub and main shaft, so the only mechanical motion provided for the rotor blades is feathering. Any vertical motion of the blade tips, caused by flapping or tipping of the rotor disk relative to the main shaft and fuselage is achieved by flexing the blades. There is also no provision for lead and lag. This type of rotor system would seem to be the best as it makes the fuselage and the rotor disk operate as a single unit. It is certainly the most responsive. But like just about everything relating to helicopters, it’s not that simple. This type of head design requires the blades be very flexible, light and at the same time, extremely strong. The flexing puts
tremendous loads on the blades and the resulting need for light weight, flexibility and strength puts demands on designers and manufacturers that are usually too costly to overcome. The light weight of the blades also has a negative effect on autorotation. When it comes to helicopter design, nothing happens in a vacuum. Semi-Rigid Rotor The second type of rotor system design is called the semi-rigid rotor. This design features two rotor blades rigidly attached to the hub similar to a rigid system, but the hub is not rigidly attached to the main shaft. It is suspended using trunnion bearings that allow the entire rotor system to move independently of the rest of the helicopter, in a sort of teeter totter arrangement. Flapping is achieved through the trunnion bearings. There are no provisions for lead and lag with the semi-rigid design. The advantages to the semi-rigid system include its simplicity and its low cost to manufacture and maintain. The main drawback to this design especially for RC helicopters is it cannot be allowed to operate at a lower aerodynamic loading than about one half positive (+0.5) G. With the semi-rigid system, the fuselage hangs below the rotor system and is free to move, much like a pendulum. RC-SF.COM
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REVIEW HOW TO
MERIDIAN
DISCOVER A NEW EVOLUTION WITH THIS 10-CC LOW-WINGER BY RC-SF Staff
This low-pass for the camera person shows off the attractive color scheme and nice design lines of this low-wing gas-powered airplane.
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hen it comes to a nonscale airplane that has attractive scale-like good looks you won’t find a better airplane than the Hangar 9® Meridian. If it were any better looking you’d roll down the window and give a whistle. That’s because this very affordable airplane has it all! It is a low-wing monoplane, that embraces ailerons, flaps, rudder, elevator and
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throttle control. It is an almostready-to-fly (ARF), so it doesn’t take long to assemble and make ready to fly. And it is powered by an Evolution® 10-cc gasoline-powered engine that turns an Evolution 13x6 propeller. Combine its good looks and power with Spektrum radio gear and you’ll know why we think this is an unbeatable sport airplane combination.
It is truly a exceptional sport airplane that can be flown by experienced pilots, or by novices as an airplane to hone their piloting skills. We found it to be very well mannered in terms of handling and performance. The addition of flaps on this model makes for an aircraft that is easy to take off and to land— and it does so without any flight handling to cause pilot alarm. twitter.com/rcsportflyer
Hangar 9 provides a very complete kit, less the servos, engine, radio gear and batteries. You can get everything you need at horizonhobby.com.
In this photo we’re making a full flap slow pass down the runway. Notice the wide gear stance of this tricycle landing gear type airplane. It makes for excellent ground handling.
FEATURES • Almost ready to fly • Two-piece wing w/ aluminum joiner tube • Tricycle landing gear w/ gear attached to fuselage • Spacious hatch for access to radio gear and EP battery • Pre-painted fiberglass cowl and wheel pants • Pilot figure and instrument panel facebook.com/rcsportflyer
factory installed • Flaps for expanded flight envelope • UltraCote® covering NEEDED • Evolution® 10-cc gas-powered engine • 8-mm muffler extension • Evolution 13x6 propeller • 900-mAh 3-cell LiPo battery • 1100-mAh 6.6-volt 5C LiFe
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battery pack Spektrum® 3-wire switch harness Spektrum DX6 transmitter AR7010 7-channel receiver Spektrum charge switch (7) A6060 digital servos 9-in. & 3-in. extensions Medium / thin CA Thread locker 15-/30-minute epoxy J-B Weld / ZapGoo RC-SF.COM
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REVIEW HOW TO
REALFLIGHT 7
GET REAL! REALFLIGHT IS THE INEXPENSIVE WAY TO LEARN TO FLY BY Wil Byers
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We got RealFlight 7 with its InterLink Elite controller. The controller is made by Futaba. Alternately, you can use your transmitter.
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t pretty much goes without saying that beginners crash their airplanes disproportionately to others. It is also obvious to everyone that it is almost always due to a lack of practice and understanding what is happening to the airplane in its myriad modes of flight. This is where RealFlight must come into the play. RealFlight lets you practice flying RC aircraft, but without the fear of risking hundreds if not thousands of dollars in aircraft hardware and time spent building. Then too, God knows it has been a difficult winter in the U.S. from the north to south. When you fly RealFlight, the weather conditions don’t much matter, except that you’ll need computer power. twitter.com/rcsportflyer
RealFlight 7 includes some multi rotor machines as well. I found the multirotors to be very nibble flyers. Note too that you can use your brand of transmitter rather than the InterLink unit, which means you can fly the simulator and still get the feel of your transmitter in your hands, which I think is extremely important if you really want to transition from the simulator to RC aircraft. FREE INCREMENTAL UPDATES Don’t worry about keeping RealFlight 7 up to date. You’ll get onscreen prompts to install the updates as they are made available by Knife Edge Software. It is easy and quick to do—again, you’ll just a click of the radio button in the software. RealFlight 7 comes on CD. You’ll also get two adapter cords for connection to your transmitter rather than InterLink Elite.
INSTALLATION You’ll discover that the installation of RealFlight 7 is ‘stupid’ easy. I installed it on a on Mini-Mac that I have at home. It runs a 2.66-GHz Intel® Core 2 Duo processor. The Mac has four gigabytes of DDR3 RAM, and a NVIDIA GeForce 320M 256-MB graphics card. It also has two 500 gigabyte hard drives. Note, the Mac is running windows under a BootCamp® installation. Once I had Windows® 7 installed on the Mac, I booted the machine up in Windows. The installation of RealFlight 7 from then on was an absolute “no-brainer.” All you’ll need to do is plug in the RealFlight 7 installation CD (my Mini-Mac
EEN SCRHOT S
uses a USB connected external CD drive), click the install icon for the Knife Edge Software’s RealFlight 7 program and the installation program will do the rest for you. You’ll need to register both the software and the controller, but the on-screen prompts will step you through the process. Once the software is up and running you’ll be ready to start flying your simulator. 40 FLYING SITES PHOTOFIELDS AND 3D SITES Mega Packs offer 36 additional airplane and 47 helicopters for RealFlight, so you will likely find the type of airplanes you want to fly. There are five Expansion Packs too.
One of the scenarios lets you do some pylon racing. Here I’ve picked a vintage Bulldog because I wanted to experience the nostalgia of flying a Golden Age airplane—FUN!
facebook.com/rcsportflyer
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DOWNLOADS You will not run out of airplanes to fly either. Knife Edge Software makes download available FREE from their forums. There you will find user-generate aircraft files, which includes 1,000 plus additional aircraft and flying sites. knifeedge.com/ forums/downloads.php. You’ll likely find some aircraft that are used by some of the best pilots in the world. In so doing, you can learn about their aircrafts’ control setups and power systems. This makes RealFlight a simulator that is truly a learning tool. MULTIPLAYER RealFlight 7 incorporates the Multiplayer feature that was introduced a few revisions ago. When you use it with an internet connection, the flight possibilities become virtually unlimited. In
Here you see that I’m flying this Curtis biplane in a one of the many 3D realistic environments. I’ve also turned on the smoke just for kicks. RC-SF.COM
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