RC Airplanes | Gliders | Helicopters
WHO, WHAT, WHERE MONSTER PLANES 2013
J-3 CUB 450
FLY A CLASSIC WIN $10,000
WITH THE DRONE SOCIAL IMPACT AWARD RC-SF.COM
• Do Pro-Looking Trim Colors • Build Cockpit Door Latches • Swordfish Biplane Bomb
JANUARY 2014
USA & CANADA $6.49
HOW TO
TABLE OF CONTENTS Pitch Angle or Angle of Incidence
DEPARTMENTS
10 LEADING EDGE 14 HOT PRODUCTS
Tip Path Plane Angle of Attack
Relative Wind
96 ADVERTISERS’ INDEX 97 MYSTERY AIRPLANE EVENT
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MONSTER PLANES 2013 WE TAKE YOU INSIDE THIS EVENT TO SEE THE ACTION AND BIG, MONSTERSIZE AIRPLANES. By Bess Byers
Pitch Attitude
LEARN ABOUT TIP PATH PLANE AND RELATIVE WIND WITH RESPECT TO HELICOPTER DESIGN AND ENGINEERING.
PG 72 BUILD
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FAIREY SWORDFISH LEARN HOW EASY IT IS TO FABRICATE A WORKING TOPEDO FOR YOUR NEXT FLOAT AIRPLANE. By Bob Zychal
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ADDING TRIM COLORS
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OUR MODEL BUILDING PRO SHOWS YOU HOW TO ADD COLOR TO MAKE ANY MODEL TRULY YOURS. By Jeff Troy
BUILD A DOOR LATCH THIS STEP-BY-STEP REPORT EXPLAINS HOW TO ADD A WORKING DOOR LOCK TO YOUR MODEL’S COCKPIT. By Rob Caso
HOW TO
PG 26
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GET COMPLETE CONTROL OF AN AIRPLANE ON THE RUNWAY WITH A SET OF BRAKES. By Tom Wolf
The “Flip-Out“
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RC SPORT FLYER . JANUARY 2014
BRAKE CONTROL
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AEROBATICS PART 10 THIS MONTH DANIEL EXPLAINS HOW TO DO THE FLIP-OUT AND KNIFE-WALL MANEUVERS. By Daniel Holman
JANUARY 2014
COLUMN
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E-POWER
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BUILD A DRONE AND WIN!
WHEN CURRENT FLOWS IN ELECTRIC MOTOR SYSTEMS THEY GENERATE HEAT. LEARN HOW AND WHY THEY DO. By Andrew Gibbs
READ THIS ARTICLE TO DISCOVER HOW YOU MAY BE ABLE TO WIN $10,000 DESIGNING AND BUILDING A DRONE. By Lucidity
DISCOVER HOW YOU COULD WIN $10,000 DESIGNING AND BUILDING A DDRONE..
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HELICOPTERS 101, PART 2 DAVE EXPLAINS TO YOU THAT A HELICOPTER IS REALLY A BUNCH OF PARTS WORKING IN TIGHT FORMATION. By Dave Phelps
PG 66 88
PG 80
E-FLITE J-3 CUB 450 TAKE A HOP AROUND THE PATCH IN OUR REVIEW TO SEE WHY THIS J-3 IS SPECIAL. By Dan Deckert
PG 88 REVIEW
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AEROWORKS GT TRAINER INSIDE AND OUT, THIS NEW MODEL IS MUCH MORE THAN A TRAINER, AS WE DETAIL HERE. By Richard Kuns RC-SF.COM
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HOT PRODUCTS Specifications
AEROWORKS TRAINER GT QUICK BUILD ARF
Wingspan Wing area Length Cowl width Spinner Weight Engine Radio
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ew from AeroWorks comes the 20- to 30-cc Trainer GT. It is designed for gas-powered engines, and for the firsttime pilot wanting to learn to fly. It is also pointed at pilots that want a larger and more versatile sport airplane that can be used as a trainer, but one suitable for sport and fun-fly flying. This new trainer is also for the seasoned pilot who wants something different to fly. Now, too, you can take your son or daughter to the RC airfield and let them fly RC with you. Add the drop module and the Trainer GT is perfect for bombing candy at your club’s next event. Features • Strong, lightweight construction • Two-piece wing • Semi-symmetrical wing airfoil • Aluminum wing tube • Large, beveled control surfaces for maximum throws • Pre-hinged surfaces w/ pin hinges • One servo per wing • Ultracote® covered /w extra • Reinforced landing gear mounting area • Painted and pre-mounted 7075 aluminum landing gear • High quality SAE hardware package • Adjustable pushrods w/ centering nut • Pull-pull hardware • 4-40 ball Links • Pre-mounted fiberglass cowl w/ templates • Quick-release top hatch • Pre installed and fuel-proof firewall • Laser-cut engine mounting templates • Designed for DLE-20 and DLE-30 engines • Custom choke bracket and linkage for DLE-20 • Pre assembled gas fuel tank • CG Buddy included • Decal set • 8 to 10 hours assembly • Detailed instructions on CD Optional Accessories • Wheel pants • Candy drop Price $449.95
RC SPORT FLYER . JANUARY 2014
Great Planes P.O. Box 9021 Champaign, IL 61821 Phone: 800-637-7660 greatplanes.com
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he new Great Planes Escapade MX is designed to combine classic sport engineering with the pilot features you’ve come to expect from Great Planes. It builds fast, and it flies even faster. It uses commonplace components, and its bright trim scheme is as eye-catching as it is unique. You can even choose between the option of glow or electric power. It is an airplane that let’s you have a sport airplane that’s a break from the common place. Features • Fast, easy glue-free assembly • Choose glow or electric power • Two-piece wing simplifies assembly and transport #GPMA1202 $139.99
AeroWorks 4903 Nome Street Denver, CO 80239 Phone: 303-371-4222 aero-works.net
Distributor
GREAT PLANES ESCAPADE
Price
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Distributor
88 in. 1320 in.2 74 in. overall 6.25 in. 3 in. 11 to 13 lb 20- to 30-cc 6-channel min
Specifications Wingspan Wing area Weight Wing loading Length Engine Motor ESC Battery Radio Servos
52 in. (1,320 mm) 449 in. (29 dm.) 5 – 5.5 lb (2270 – 2490 g) 26 – 28 oz/ft2 (79 - 85 g/dm2) 45 in. (1145 mm) 2-stroke .46 – .55 42-60-480 Kv outrunner 60 amp 14.8-volt 3350-mAh LiPo 4-channel 4–5
AIRBORNE MODELS 1/4-SCALE HALL CHEROKEE II
A
Specifications Wingspan Wing area RTF Weight Length Radio
130.7 in. (3320 mm) 1190 in.2 (76.8 sq dm2) 8.3 Ib (3780 g) 64.5 in. (1637 mm) 5-channel w/ 7 standard servos
Distributor Airborne Models 4749-K Bennett Dr Livermore, CA 94551 Phone: 925-371-0922 airborne-models.com
irborne Model’s all new 1/4-scale Hall Cherokee ARF is based on Dave Smith’s plan that was published in Quiet Flyer magazine (prior to RC Sport Flyer). The model’s wood construction captures the nostalgia of the original full-scale glider, which was a home-built glider designed by Stan Hall. The model replicates the structure of the full-scale glider almost identically. This model is the perfect fit for any pilot that is hungering for a chance to participate in aero-towing. However, it is at home thermal soaring or even slope soaring in light wind conditions. The model’s light wing loading makes it easy to soar, even in weak thermal lift conditions. Airborne Models has priced this glider for nearly any glider pilot’s budget at only $499.99, plus standard size servos. Watch for an in-depth report on the Hall Cherokee II in an upcoming issue of this magazine. Features • High-quality wood structure • ToughLon™ covering material • Two-piece wing • Aluminum Joiner • Bolt-on horizontal stabilizer • Finished canopy • Quick servos installations • Servo-operated tow release installed • Wing bag included • Optional fiberglass scratch guard Price $499.99
ESTES PROTO X
Distributor Great Planes P.O. Box 9021 Champaign, IL 61821 Phone: 800-637-7660 greatplanes.com
T
ake a look at the new Proto X from Estes, the brand name you know and trust. The Estes Proto X is super-small, it’s also one of the world’s lightest quadcopters. The Proto X is tiny, ideal for indoor flying—and it weighs less than one half ounce. Bright, built-in LEDs make it easy to see the Proto X in low-light conditions. A 2.4-GHz radio not only allows for interference free flight, but it makes it easy for multiple Proto X helis to fly at once in the same environment. A 3.7-volt 100-mAh LiPo battery, USB charge cord and spare rotor blades are included in this Estes ready-to-fly package. All you need to add are two AAA type batteries and you’ll be set and ready to start flying. Price
#ESTE4606 $39.99 RC-SF.COM
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EVENT HOW TO
THEY’RE BIG, BEAUTIFUL AND POWERFUL MONSTERS!
MONSTER BY Bess Byers
R
C Pilots from all over the world know Monster Planes USA is about flying big, expensive, exciting and fun-tofly airplanes. Some enter Monster Planes USA to compete for Best Jet, Best Multi-Engine, Best Military, Best WWI, Best WWII, etc. The reality is, though, every pilot that registers at Monster Planes wins. That’s because this AMA sanctioned event is a huge fun fly, where like-minded aviation enthusiasts come together for a weekend of fun and relaxed monster airplane flying. It is an event that has been copied around the U.S., but not really duplicated. After all, how can you duplicate an event that takes
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place in the heart of Florida, where the sun shines from morning till night. Monster Planes USA 2013 was, and has been, held in Lakeland, FL for a number of years now. This time it was hosted from October 24 thru 26. The RC airfield adjoins Lakeland Linder airfield. It is a gorgeous site, with close-cut grass and plenty of room for the modelers’ pit areas, as well as several vendors. The event is hosted by Frank Tiano—a legend in the hobby industry—and by ZAP® Glue. You’ll want to check out the list of other sponsors as well. They’re the ones that make this event happen from
year to year by supporting Paradise Field and the events hosted at this oneof-a-kind airfield. This year’s event had 78 pilots registered. They came mostly from the U.S., but one pilot came from Western Canada, Dave Collis, attended. He made the longest drive to Lakeland, traveling 3500 miles from Pitt Meadows, British Columbia—seven days down and seven days back! Ali Machinchy also traveled a significant distance to fly at Monster
Planes by coming from the United Kingdom. Other pilots were mostly from the Florida, Georgia and the surrounding areas, with a few down from the upper states. The thing about Monster Planes USA 2013, as I saw it, was pilots came to fly—they weren’t there to show and crow. Nope, they were there to log airtime on their airplanes. As such, Frank tells me there were 238 flight logged over this threeday event. Among the airplanes flown were fixed-wing WWI, WWII, civilian, etc., plus there were some turbine-powered models and a few helicopters. Nearly every model I saw was detailed to the nth degree—let me tell you my dad would have been jealous. Then too, you would have been impressed by the piloting. If you saw any of our Facebook posts, you know many of the models
flown and shown at Monster Planes were not for the faint-of-heart pilot. Rather, most of the pilots that flew their models were extremely skilled, knowing how to get their monsters up and down in stellar fashion. When you consider many of the models took a few hundred hours, if not a thousand, to build, with some costing upwards of $20,000 to complete, it is impressive to see them flying down the runway just inches off the grass, and doing so in knife-edge flight. All in all, I had a very enjoyable time at Paradise Field, reporting on this event for RC-SF. You will too, that is if you opt to attend the event in 2014. I’ve looked at my calendar and it appears the 2014 event will be scheduled for October 23, 24 and 25. I’d say start planning now to attend this event. If you are from my
generation (20 years plus) consider being there. I intend to, and; I’d really like to see you flying your scale airplanes, jets and helicopters there. Dad tells me turbine-powered scale helicopters are extremely impressive flyers, so I’d like to see one of you flying one. I’ll be shooting lots of photos, getting video and posting to Facebook, Twitter and Instagram. I want to photograph your models and make you famous—or at least in our minds anyway. Now enjoy the photos from this year’s Monster Planes USA. Also, watch for more photos on our website rc-sf.com, and on Facebook. I’ll be posting them as soon as this magazine goes to print. For more information on Monster Planes 2014 point your browser at franktiano.com.
PLANES 2013
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BUILD
FAIREY SWORDFISH
HOW TO ADD A DROPPABLE, MOTORIZED TORPEDO TO THIS FISH
BY Bob Zychal
I finished my Swordfish in Royal Navy colors using Rustoleum paint. It works well and is definitely waterproof, as the airplane testifies.
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ISTORY When I first learned that the great battleship Bismarck was crippled by an attack of Fairey Swordfish biplanes, I became interested in building the model. Although the Bismarck wasn’t actually sunk by them, their torpedoes disabled the ship’s rudders such that the Royal Navy could then catch and finish her off. The success of this biplane against such a formidable target proved the versatility of the little aircraft affectionately called Stringbag for all of the various armaments hung from it during the war.
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In searching for a Swordfish model I came across Rob Caso’s design and kit, which was featured in the May ‘05 issue of Model Airplane News. However, since my airplane building experience is limited, I preferred to purchase the kit to save building time. BUILDING & MODIFICATIONS Rob’s short kit was very easy to build because it includes laser-cut parts, which also have slots in their outer edges for alignment of ribs and braces. Consequently, within two weeks my Swordfish was framed and ready for covering. It was then
that I decided to add additional scale features, including a domed center section and wing braces. The domed center-wing section was formed by adding two extra 1/16-in. balsa sheets on top and sanding them down to the edges to create the dome. To hollow out the underside I taped sandpaper to a round waste basket and slid the section back and forth over it until the concave depth was achieved in the wood. Also, because the bottom ribs were exposed at this point in the build, I opted to cover them with a sheet of 1/32-in. plywood as a way
I’m shown here with my modified Swordfish biplane. I fly my models with the members of Simsbury RC Club in Connecticut.
Initial water trials showed that the bow splash interfered with the propeller, which was later solved by adding spray rails to the floats. RC-SF.COM
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BUILD
TRIM COLORS
MAKE IT YOURS! LAY ON SOME COLOR AND A UNIQUE SCHEME BY Jeff Troy
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ow I covered my 108-in. Dallaire Sportster with natural, white fabric was my December 2013 RC Sport Flyer article. At the close of that installment, I promised you the red and blue trim colors would soon be added, along with the possibility of a little yellow thrown into the mix. That time is now. I’m trimming my Dallaire with colored fabric. If you have ever
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tried to iron plastic film over plastic film, you’re already aware that one non-porous surface over another non-porous surface can only result in blisters and bubbles. These are caused by the trapped air between the non-porous surfaces. There is no way to prevent them. Fabric is a different story. ADHESION Although the Coverite fabric I’m
using is coated with adhesive on the back, the top side of the fabric’s weave has more than enough depth to act as an escape route for any air between the layers. The end result is that you can iron fabric over fabric without fear of excessive blistering or bubbling. The word “excessive” is used because you must still be prudent about the way the fabric is applied. Sealing one, two or even three edges is a good way to do it.
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Trim colors add character to a model, but how will you know where to apply them? The best way is to draw sketches of different color schemes, eventually settling on the one you like best. Pleasing colors and good visibility must be considered in your scheme.
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Use Balsarite, Balsaloc, or a similar product to coat surfaces where trim pieces will be applied.
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Iron temperature is critical for attaching trim pieces. It must be hot enough to activate the adhesive, but cool enough to keep the trim from shrinking and distorting.
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Familiarize yourself with the process by attaching the smallest trim piece to the smallest model component: in this case, the blue trim on the base of the Dallaire Sportster’s vertical fin.
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Wrap the trim around the edges of the components, seal them and trim away the excess material.
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The Dallaire’s fuselage is a sizable affair, but the technique for trimming it is the same as it is for the smaller components. Always work the iron gently when sealing along a color-change line.
You can work most of the air out from the fourth edge before you seal it. Doing so ensures the best possible trim work, with little to no bubbling.
Selecting the correct iron temperature for applying the fabric trim colors is critical. The iron must be hot enough to activate
the adhesive, but it positively must not cause the trim to shrink and distort. Because the adhesive will have only minimal grab at such RC-SF.COM
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BUILD
COCKPIT DOOR LATCH CLOSE THE DOOR BEHIND YOURSELF, WILL YA? BY Rob Caso
O
ftentimes, scale details take longer to design in my mind than they take to build. In the case of my 66-in. wingspan Tiger Moth, late in the build I decided to make the cockpit doors functional and needed a way to keep them reliably closed when in flight. I made the doors from fiberglass using my “quickie mold” process described more thoroughly in the October issue of RC-SF, hinged with a couple of Robart 1/2-A pin hinges. This aspect of the process was a mere sideshow to the main event— designing and fabricating the latch mechanism. Even though my Moth
The components of the latch, the most important of which is the 3/4-in spring. You should roughen the aluminum for better adhesion.
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is almost 1/5 scale, a look at some drawings showed that the latch—a long box tube with retractable pins at each end—was a scant 3/16-in. or so in overall width, or about an inch on the full scale, which seemed about right. Although I could find no drawings or photos of the internal mechanism, it all had to work in a fairly confined environment and with everything situated inside a long, thin tube. After conjuring a number of design ideas, why not simply design it using an educated guess as to what was on the real airplane? Spring loaded tubes seemed like they would work on the model and it would
make sense that the prototype had them also. I knew I was in business when my junk drawer yielded a couple of firm, 1/4 inch long by 3/32-in. diameter compression springs from Reid Tool and the rest of the materials came from my tube and rod supply. The theory behind the design is that two opposed, sliding 1/16-in. diameter pins would each ride in sections of aluminum 3/32-in. diameter tubes. The aluminum tubes are in turn mounted to plywood pads on a ply plate, the pads being needed for clearance for the sliding mechanism and spring. The 1/16-in. diameter
pins are actually tube stock and the key to the system is the 0.030-in. wire rod that is soldered inside one pin assembly, but is left free to slide in and out of the other, with the spring in the middle. The 0.030-in. wire rod keeps the opposing tubes and pins in alignment, while also trapping the spring and keeping it centered. The outer ends of the 1/16-in. diameter pins protrude beyond the ends of the aluminum tubes, slotting into holes in the edge of the cockpit, thus keeping the door closed. Brass bushings on either side of the spring, and soldered to the sliding pins, keep everything together. A further scale wrinkle here is the two vertical posts that are soldered to each of the sliding pin’s
The completed latch is only about 3 inches long on my model. CA glue only the aluminum tubes to the plywood plate.
bushings, and which provide the pilot (or you) the means of retracting the pins to open the door. Once the internal mechanism was fabricated, it was a simple matter to box it all in
with either plywood or plastic sheet, leaving a slot for the vertical posts. Keep in mind that the total combined travel of the sliding pins cannot be less than their total exposed lengths at the ends of the mechanism. If they are, the pins will not retract completely, although this is an easy fix. While this mechanism is about as small as I could humanly make it, the design could easily be scaled up by simply substituting the components in the drawing with larger telescoping sections of rod and tube. I needed two of these and
The completed latch is affixed to the fiberglass cockpit door. Corresponding tubes should be let into the cockpit sides on the fuselage.
You will simply squeeze the door latch release levers to open the door. The tube lock pins will then retract for the cockpit’s tubes.
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photo by Greg Wolf
HOW TO
BRAKE CONTROL GIVE YOUR MODEL RUNWAY DIRECTIONAL CONTROL
BY Tom Wolf
H
ave you struggled to maintain runway heading during takeoff when flying an airplane with conventional landing gear (also known as a “tail dragger”)? A swing on takeoff can be the result of P-factor, engine torque, or crosswind conditions. A more significant factor for multi-engine airplanes is uneven engine transition from low to full throttle, which results in a
that airplane headed down the runway during takeoff. Most takeoff attempts resulted in aborts because the airplane was headed off the side of the runway long before it had reached flying airspeed. A particularly frustrating aspect was that it could swing either left or right; there was no consistent pattern. The Mosquito is notorious for poor ground handling on takeoff because the relatively small vertical tail and rudder are located on the aircraft’s centerline, out of the propeller’s blast. Until flying speed is reached, the rudder has almost no control authority. During a normal takeoff, the tail comes up almost immediately, effectively negating any tail-wheel steering long before the rudder is effective. SOLUTION After months of frustration, I found a solution that has been very effective and trouble free for the 20 years I have been flying this airplane. The solution to this problem involves something that full-scale airplanes use: Differential braking of the wheels on the main landing
photo by Kelly Collin
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significant swing towards the weaker engine. Any of these conditions is difficult to manage during the initial part of the takeoff roll when the tail gets light but there is little airspeed to provide good rudder control authority. About 20 years ago I built an 1/8-scale DeHavilland Mosquito, and while it flew great once it was airborne, I just could not keep
RC SPORT FLYER . JANUARY 2014
This braking system utilizes a simple torsion spring and a bronze brake bushing. The torsion spring is a slip fit onto
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The brake bushing’s pin engages a hole drilled in the side of the wheel hub.
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the brake bushing. Braking action is achieved when one leg of the spring is deflected while the other leg is held stationary.
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This is the brake bushing I fabricated for my 1/5-scale Mosquito. The pin engages a hole in the side of the wheel hub and the bushing rotates on the axle together with the wheel.
gear to provide directional control. I cannot take credit for the idea of trying this on my Mosquito: After witnessing my continued frustration, Tom Protheroe, a fellow member of the Santa Barbara Radio Control Modelers, suggested I try adding brakes that are slaved to the rudder.
After a few weeks of considering how to implement them, I built a simple brake system connected to pull-strings that ran to the rudder servo. The resulting improvement in directional control was simply
The brake system shown utilizes two dedicated servos to operate the brakes, which is the configuration that was used for my 1/5-scale Mosquito. Smaller aircraft can use only one servo to operate both brakes, as was the case for my 1/8-scale Mosquito.
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BRAKE SERVOS: BOTH ARE CONNECTED TO RUDDER CHANNEL WITH “Y” HARNESSES RIGHT RUDDER
RIGHT RUDDER .032 DIA SULLIVAN FLEX CABLE PUSHROD PRODUCT NO. S507 MONFILAMENT FISHING LINE
TORSION SPRING
BRAKE ACTIVATE
BRAKE BUSHING THIS END FIXED
LEFT MAIN WHEEL DIRECTION OF ROTATION
RIGHT MAIN WHEEL
BRAKE SYSTEM SCHEMATIC RC-SF.COM
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HOW TO
Gabriel Altuz and I are shown here as we prepare to fly a formation aerobatics demonstration flight at the Wenatchee, Washington’s Huckfest. We are tight competitors, but also the best of friends!
AEROBATICS PART 10 YOU’LL FLIP OUT WHEN YOU DO A KNIFE-EDGE WALL BY Daniel Holman
A
significant step to becoming an expert aerobatic pilot is learning and knowing your airplane’s handling characteristics so well that you aren’t afraid to try new maneuvers. Building confidence as a pilot is necessary, and it will help you even with the basics. Often crashes are the result of the pilot losing his or her nerve during a maneuver, which then results in a fatal mistake. However, once you reach the skill level of knowing exactly what is going to happen to your model with each control input it is much
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easier to remain calm and collected during a maneuver—even when your airplane appears to be in a bad situation. Without knowing your airplane’s handling inside and out, would you ever think to burying full down elevator control when flying it in a low knife-edge pass? Or what about a maneuver that requires you to give an up-elevator input from low inverted flight? These examples sound scary to do, but are standard procedure for most professional aerobatic pilots. In this issue, I will break down,
and explain, two more extreme aerobatic maneuvers that demand you know your airplane well! FLIP-OUT The first aerobatic maneuver I pioneered is called the Flip-Out. I learned this maneuver near the beginning of 2010. I used it in the Extreme Flight Championship as well as the Pacific Coast Freestyle Championship later that year. It was met with much surprise at both events and is now used by many extreme aerobatic pilots.
Let’s take a look at what is required to do this maneuver. The Flip-Out is entered from inverted flight and is basically half of an extremely deep positive snap. During this snap, the airplane makes a 90-degree heading change while it is stalled. The airplane exits the maneuver upright, having made an almost instant right-angle turn. As with the Vortex maneuver, that I detailed in the December 2013 issue, the Flip-Out is all about timing. This maneuver can be entered from any airspeed, but is easiest to perfect when done from a slow to moderate entry airspeed. Performing the Flip-Out from a fast entry speed is very exciting, but much more difficult. Also, this is a fairly torquesensitive maneuver and can be performed much cleaner from right to left, with a left snap. Now let’s break the maneuver down and talk about the control inputs. From inverted flight, I open the throttle to about 75 percent to ensure that lots of air is flowing over the control surfaces. Immediately after opening the throttle, I input approximately 30 degrees of upelevator control, along with around
25 degrees of left aileron. At the same time, I bump full left rudder for a split second and then neutralize it as soon as the airplane stalls and begins to rotate. Once the airplane has rolled 90 degrees and turned approximately 45 degrees, I input almost full right rudder and relax the up-elevator input. Also at this point, I start to neutralize the aileron input so that I reach neutral once the airplane has rolled 180 degrees. Once the wings are level, I am holding almost full right rudder along with 75 percent throttle while making small
Although the Flip-Out maneuver is very daunting at first, it can be performed as low as my model is being flown here. This is a perfect entry to this maneuver, with a slow airspeed, wings level and a very slight positive angle of attack.
Performing the Knife-Edge Wall from high speeds is a real show stopper. As long as the airplane’s entry is perfect, this maneuver can be performed safely with minimal altitude. Just make sure your airplane can handle the resulting G-forces!
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COLUMN HOW TO
This view of the Komet shows you its unusual WWII Alexander Lippisch design, which featured it being a rocket-powered airplane. The elevons are in the 10 degrees up position for level flight.
E-POWER
POWER IS HEAT—THE HOW AND WHY OF IT BY Andrew Gibbs
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n this installment I start to explain motor efficiency. First, let’s look at an inspirational model.
Full-scale pilot and modeler, Rick Morris shows us his Me163 Komet. This small model gets a lot of interest from other modelers at the airfield. It has also given Rick much piloting pleasure. The model is shown here with its original, fixed-pitch, non-folding propeller. The bungee’s hook can be seen on the Komet’s belly. The wheels are a scale detail that Rick uses for display only.
The absence of formers makes positioning equipment easy. Foam rubber in front of the battery maximizes its chance of survival in the event of a hard landing.
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ME163 KOMET Recently, I met Rick Morris at a model event. He is a retired pilot. We talked about flying models and fullscale airplanes. He also showed me his Me163 Komet. Rick’s Komet is based on a vintage glider by English modeler Keith Humber, which Keith designed for slope soaring. However, Rick installed an electric power system in his model. He has also changed the airfoil section and altered the
The Komet is positioned on its launch ramp, ready to be bungee launched. The motor is started only after the model has cleared the ramp and become airborne.
The Me163 Komet sits in a menacing stance ready to chase down the enemy, and hoping that it made a kill before it ran out of rocket power. The propeller is not noticeable in flight.
Rick’s model was retrofitted with a folding propeller because the nonfolder kept breaking on landings. The cowl is cut down from a Brian Taylor part.
This is the release mechanism that Rick uses with his bungee launching. When you step down on the pedal it pushes the string of the peg and release the bungee. I like the warning!
fuselage construction considerably. Rick chose a NACA 2312 semisymmetrical section, which is 14% thick at the wing root. It uses a 16% thick airfoil that closely resembles a Clarke Y section at the wing tip, with four degrees of washout. This, plus the fact the tip has a relatively thick section as compared to the root results in very safe stalling characteristics. Rick says the model has no defined stall as such, but comes down flat “like a pancake” if the airspeed goes low enough. The fuselage design is also altered. The original design used formers. Rick’s model has none,
The Me163 Komet is positioned on the ramp and ready for launch. Once the release pedal is pressed, the bungee will accelerate the model to flying speed, after which the motor is started.
being of monocoque construction. Consequently, the RC gear and power system were positioned in the fuselage as needed. The power system consists of a Hacker A30-12M and a 3S 2100-mAh LiPo battery, which provides fiveminute flights. The 8x6 propeller is of the folding type. FLIGHT TESTING Flight testing was flown in a coat of green primer over the undercoat. The test flights were undertaken without the power system installed as a way to reduce weight, and thus the chance of damage. The model
was bungee launched and flown over long grass. This gave Rick the opportunity to find the model’s best center of gravity position, and to determine elevon control throws. A setting of around 10 degrees up elevon is required for level flight. IN FLIGHT The model is bungee launched. Rick’s technique is to hold full up elevator for launch, easing off once the model gains airspeed. Rick has devised launch ramp that is noteworthy because it takes up very little space to store and transport. I’ve include several pictures of this system so you can copy it.
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COLUMN
BUILD A DRONE HELP YOUR COMMUNITY WIN $10,000 IN COLD, HARD CASH BY Lucidity, Roswell Flight Test Crew The Drone Social Impact Award seeks to inspire and recognize individuals and groups doing beneficial and humanitarian work with home-made drone aircraft.
The video can be seen on the front page of the organization’s website:
www.bansheereeksnp.org
Scenic Banshee Reeks Nature Preserve in Loudoun County, Virginia, was the location of one community service project conducted by the D.C. Area Drone User Group (DC DUG), which could serve as an example for a possible entry in the Drone Social Impact Award. Group members used their systems to capture aerial footage of the area and created a promotional video, which they then provided free of charge to the Friends of Banshee Reeks.
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ere at the Roswell Flight Test Crew, we’ve found some kindred spirits among the fast-growing membership of the Drone User Group Network (DUGN) and most especially its founder, Timothy Reuter. Like us, Timothy believes that First-Person View (FPV) technology and automated flight systems will transform the economy and save
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lives—and, owing to a quirk of fate, hobbyists have a unique and profound role to play in making that happen. The Federal Aviation Administration (FAA) has been caught flat-footed by the drone revolution that has emerged over the past few years. As a result, they have clamped down on all commercial operations until 2015 at the earliest,
which has effectively locked the big corporations out of the domestic industry. However, RC enthusiasts are permitted to fly drones under FAA Advisory Circular 91-57. It’s as if following the invention of the cell phone, AT&T and Verizon and all the rest of them had to sit on the sidelines and only ham radio operators were allowed to play around with this new technology.
This is a moment that is almost unprecedented in human history— and, like us, Timothy decided he wanted to be a part of it. He wants you to be a part of it, too, and he’s got $10,000 on the line to prove it. TALK = CHEAP According to Timothy, awarding a prize for demonstrating the positive uses of hobbyist drones is a natural continuation of what he’s already doing in the hobby. “For the past year, we’ve been constantly thinking about how to expand the impact of our work with drones. We want to make the world a better place with flying robot technology,” he told me. “I started by founding a group in my own community, the Washington, D.C., Area Drone Users Group (DC DUG), and then I went on from there to establish a nationwide alliance of similar groups, which is the Drone User Group Network. “The next logical step was to offer a prize for people to demonstrate beneficial social impacts of this technology, to start building up a catalog of cases studies to show what is possible.” Timothy explained that he was inspired by the original Ansari X Prize, which was awarded to Burt Rutan’s Scaled Composite in 2004 for conducting two sub-orbital flights in a reusable spacecraft within a two-
week period. “I was also inspired by the ‘Grand Challenges’ that are being offered by different agencies of the federal government to The primary video capture platform used to produce the video was a Mikrokopter-based octocopter, which is owned encourage technological by Nils Granholm. innovation,” Timothy said. “The United States Agency for International Development, for example, has one that is looking at how to “But the fact is that we’re living in prevent atrocities and crimes against amazing times when you can get humanity, and NASA has one looking useful results for a couple of hundred for ways to achieve sense-and-avoid bucks.” capability with Unmanned Aircraft To be considered for the award, Systems (UAS) operating in the the project must be accomplished National Air Space.” using a drone that costs less than His hope is to get people to move $3,000. Entries must include a beyond tinkering with their aircraft written overview of the cost, and to finding practical applications for finalists will be contacted to provide them. a detailed financial breakdown of the “There are a lot of people active in platform that they are using, so hang this community right now, including on to those receipts. me, who are very much in love with “We included the $3,000 limit the technology—I want to get them for three reasons,” said Timothy. thinking about how they can use it to “First of all, we want these projects solve real-world problems,” he said. to be something achievable by “I hear people talking all the time an individual or a small group. about these great ideas. My goal is Second, we wanted the prize to be to get them to stop talking and start proportional to the amount spent doing.” on equipment, and third, I think that putting a constraint on resources RESULTS = $10,000 forces people to think outside the “In many people’s minds, drones box.” are only for governments and large Timothy said he is leaving the corporations,” Timothy explained. term “social impact” vague for a RC-SF.COM
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COLUMN HOW TO
HELICOPTERS 101,PART 2 A HELICOPTER IS NOTHING MORE THAN A WHOLE BUNCH OF PARTS FLYING IN TIGHT FORMATION, EACH ONE YEARNING TO BE FREE. BY Dave Phelps Tip Path Plane and the Rotor Disk
Rotor Disk
Tip Path Plane
The tip path plane is the flat plane formed by the tips of the rotor blades as they travel around the circle. The orientation of the tip path plane is controlled by the cyclic control and is used to control the helicopter both laterally and longitudinally. The rotor disk is the term used to describe the disk formed by the entire rotating rotor system.
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ast month, we discussed basic aerodynamics as they apply to airplanes and helicopters alike. This month we’re going to focus on helicopters. For the sake of simplicity, our discussion will be concerned with one specific type of helicopter; one with a conventional two-blade single rotor system that turns clockwise when viewed from above, with collective pitch and a single variable pitch tail rotor. There are many other types of helicopters available to the modeler and when it’s appropriate, we will mention specific factors as they apply to variations on the conventional helicopter.
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It’s probably best at this point to define some commonly used terms. Let’s start with the “tip path plane,” which is the plane formed by the tips of the rotor blades as they travel around the circle. The circle formed by the tips is often referred to as the “rotor disk”. When the rotor system is lifting, the blades don’t form a flat disk, they form more of a shallow cone. The angle formed between the blades and a perfectly flat disk is called the coning angle. While this may seem to be a distinction without a difference, it does have an effect, however small, on the aerodynamics of the rotor
system. So it’s a distinction worth knowing. Coning angle, like so many other seemingly insignificant factors affecting helicopter flight is one of those things that can work alone to produce a very minimal effect, in opposition to other forces, which effectively cancel each other out, or it can be one of several factors working in unison to create a much more significant overall effect. We will expand on its importance and effects in future installments. WHICH PITCH IS WHICH? The term “pitch” will be used a lot
Coning Angle
Coning Angle Coning Angle
The coning angle is the angle formed by the rotor blades in reference to the tip path plane. When the blades are under load, they form a shallow cone rather than a flat disk. The amount of coning is determined by the weight and distribution of the weight of the rotor blades, the load that the rotor system is supporting and the rotational speed of the blades. Centrifugal force keeps the coning angle from becoming too acute.
as we proceed. For our purposes, it actually has two different meanings. It is used to describe one of the three axes of motion (pitch, roll and yaw) and in this context refers to the nose up or down orientation of the aircraft relative to the horizon or its attitude (not to be confused with the term used in the teacher’s notes section on a report card, which in my case usually indicated a need for major adjustment). When used in the context of rotor blades, pitch refers to the angle of incidence, which is the angle formed by the chord-line of the rotor blade in reference to the tip path plane. (Which pitch is which? Just be glad we don’t have to tune rotor blades like a piano or coat them with pine tar to make them stick. Either one would be confusing, and I’d need a beer first). The words pitch and angle of attack are sometimes used interchangeably. While this is more or less accepted practice, it’s not always entirely accurate so an understanding of the difference is beneficial (crucial in the case of a standardization check ride). When used in the context of rotor blades, pitch refers to a mechanical measurement, while angle of attack, as we learned last month, is an aerodynamic measurement. Only in a no-wind, stable and motionless
Tip Path Plane Rotor Blade
hover would pitch and angle of attack seem to be more or less the same. But even then they really aren’t, as we’ll see later. OF STICKS AND LEVERS There are four controls that the pilot of a helicopter uses: cyclic pitch, collective pitch, throttle and anti-torque. Cyclic pitch controls the pitch and roll orientation of the tip path plane, while anti-torque controls yaw, or heading (nose left and right, like the rudder of an airplane). Collective pitch and throttle combine to control the overall lift, or the total force the rotor system produces. If we envision the rotor system as a simple fan, collective pitch controls how much air the fan blows while cyclic pitch controls the direction it is blowing. Throttle is used to control the rotational speed of the rotor system and anti-torque is used to control the yaw axis and to counter the rotation of the fuselage caused by the torque applied to the rotor system. When the radio is set up in Mode 2 (the most commonly used mode in the U.S.) the right stick controls cyclic pitch and the left stick controls collective pitch, throttle and anti-torque. A term that is often used to refer to the combined effect of engine torque and lift as a control function
Coning Angle
is “power”. You will sometimes hear the collective stick referred to as the power lever (pronounced powah leevah), especially by those in the UK. This is actually a very accurate description, probably more accurate than the term “collective stick” used by us rebellious colonists. You will also sometimes hear a Brit refer to the cyclic stick as the “pole”. I’ll let you use your imagination to fill in the blanks about my reaction to the request of an RAF helicopter pilot with whom I traded nickel rides in our respective aircraft (his was a Westland Lynx, mine a Bell AH-1S Cobra), when he asked me, “Can I hold your pole, mate?” I think I got more ride for the taxpayer’s nickel though. The pole and lever in that Lynx are bolted to an absolutely amazing machine. The Cobra is no slouch when it comes to brute horsepower and agility, but in air-to-air combat, because it can operate at zero or even negative G’s, the Lynx wins pretty much every time. That is unless the Snake is flown in a wholly “Un-British” (read that sneaky) manner. In other words, if you want to get a decent bead on a Lynx, you gotta cheat. Hold my pole, indeed. THE RIGHT STICK - CYCLIC The cyclic stick controls the pitch and consequently the angle RC-SF.COM
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REVIEW HOW TO
GT TRAINER
IT’S MORE THAN A TRAINER, AND IT’S 30-CC GAS POWERED BY Richard Kuns
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hile attending the annual Weak Signals show in Toledo, Ohio last year, I was surprised to see a large trainer airplane in the Aeroworks booth. I was so because Aeroworks is known for its excellent selection of aerobatic airplanes, and more recently for several superb scale model offerings. Aeroworks’ new, giant trainer/ sport airplane, however, caught my attention at the show. It is designed
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for power from either a DLE-20 or 30 gas-powered engine. After studying it in their booth and reading the specifications, I was eager to assemble one and fly it. I wanted to see how much of Aeroworks’ aerobatic tradition had found its way into this attractive trainer/sport airplane. KIT CONTENTS • Fuselage
• • • • • • • • • • • •
Right & left wing Horizontal stabilizer w/ elevator Vertical stabilizer w/ rudder Windshield w/ mounting screws Front & rear side windows Cowl w/ mounting screws Aluminum wing tube Nose wheel steering pushrod Throttle/choke Linkage Pre-drilled nylon engine mount 3.5-in. wheels & axle set Nose wheel strut w/mount
RC-SF.COM
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REVIEW HOW TO
J-3 CUB 450
THE 25-SIZE’S LITTLE BROTHER THAT HAS BIG BOY CHARACTER BY Dan Deckert
My new E-flite® J-3 Cub 450 sits on the ramp at the RC airfield, waiting for its maiden flight. This model is the little brother to my 25-size E-flite J-3 Cub.
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hen I saw the new E-flite J-3 Cub 450 , it was a have-to-have airplane for me. Its 51-inch wingspan isn’t much smaller than its big brother, the E-flite 25-size J-3, which sports a 62-inch wingspan. Even so, it just had the right feel in terms of size to meet my Piper Cub obsession. Because I already have the E-flite 25-size J-3 Cub, the decision to own this new 450 model was an easy one to make. A huge bonus is the fact this is an airplane that is balsa built, with factory done covering, rather than some of molded foam models that are often commonly seen at the RC airfield. Then too, E-flite almost-ready-to-fly (ARF) kits are easy to assembly. So, I knew the J-3
Cub 450 wouldn’t disappoint me in terms of quality of build, fit and finish and certainly in terms of flight performance. KIT CONTENTS First, and importantly, the J-3 Cub 450 comes well packaged with each part being individually wrapped, bagged and separated. My kit arrived with no damage. The covering did, however, require some ironing to remove a few small wrinkles in places. Otherwise, my E-flite J-3 Cub 450 ’s airframe was beautifully covered in plastic film. Also, you’ll see almost immediately, upon opening the box, that the J-3 will require little time and effort to assemble and ready for flight.
• Scale design lines • Laser-cut balsa and plywood construction • Factory-built airframe • Hangar 9® UltraCote® covering • Ready-to-mount a motor • Struts and jury struts • Pre-painted fiberglass cowling w/ engine details • Cross-brace and instrument panel cockpit detail • Internal servo mounting for scale integrity • Pre-cut clear plastic windshield • Pre-formed side windows • Authentic Cub wheels and finished wire landing gear • Battery hatch w/ magnetic latch • Steerable tailwheel • Hardware package n decalscal set RC-SF.COM
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