How to Build a Wild Wing

Wild Wing on picnic table

We have reached a peak in our pursuit of the perfect combat plane.

The perfect candidate can float slowly in the air, then zip forward, up or down for a lightning strike or getaway. It can loop in a heartbeat and speed straight to a target. It laughs at wind and spins in a tight victory roll after bashing an opponent.

Our quest has taken us through Mini SpeedWings, Boomers and hacked Wild Wings. We’ve looked at other wings, too, including HyperFleas and even Strykers.

The Great Meadow is our laboratory and we’ve had altogether too much fun conducting this research.

Speed Doesn’t Kill. One of our earliest combat discoveries was that speed is not your friend. A fast plane overshoots its target.

You want to confine your flying to a small volume of air in front of you. As you reduce the volume of the combat arena, you increase the chance of contact. For more excitement, increase the number of combatants in that small arena. :-)

So you want to fly slow. You want a light plane because

  • Light planes fly slow
  • Light planes crash light
  • Light planes fly long

We Want It All. In addition, our dream combat vehicle is

  • Cheap
  • Durable
  • Easy to Build
  • Easy to Repair
  • Powerful
  • Acrobatic
  • Responsive
  • Accurate
  • Slow
  • Fast

The winner? A hacked Wild Wing, not the first hack or the second, but maybe the third or fourth.

The Wild Wing is a $20 35-inch wing kit sold by Hobby People. [Update: as of November, 2008, Hobby People is out of Wild Wings. As of March, 2009, Mike Bowns has developed a replacement that flies even better.]

Butch’s Boomer. We were pointed to the Wild Wing by the Boomer, an agile slow-flyer which has proven excellent for combat. It’s based on a cut-down Wild Wing, with numerous added parts, including a boom, nose and elevator.

The Boomer has inspired regular combat sessions in Livermore and is the focus of a lively discussion on RC Groups led by Butch, who conceived and designed the twin-boom wing with aelerons and elevator.

Rear view of Wild Wing in flightBut the Boomer is injury-prone. Its elevator is mounted on two fragile booms. Its nose breaks quicker than a clumsy boxer’s. Its big prop pops the motor off its mount during a hard landing.

Dave North pioneered our Wild Wing variations. He started by mounting the motor in the middle, then moved it aft and experimented with horizontal stabilizers, various size elevons and different vertical stabilizers. He cut the wing down, tinkered with various motor and prop combinations and one day walked out of his lab with a perfect little warrior.

Close Combat. Since that fine day, several of us have copied his ideas. The result is intense close-quarters combat with lots of contact but very little damage.

If you’d like to join the fun, this is what you need:

  • Wild Wing kit
  • 9 or 10 amp speed control
  • 2800 kV outrunner motor turning a GWS 5×4.3 propeller
  • 2S 730mah battery, or smaller
  • 2 micro servos
  • 9mm EPP sheet
  • 6mm Depron sheet
  • Control horns & control rods
  • Goop and/or Canopy Glue
  • Hinging Tape (Blenderm or 3M)

Rare Bird. First, a few words about the motor. Unfortunately, efficient 2800 Kv outrunners are nonexistent.

Dave will make you a motor in exchange for two hexTronik 16-gram Brushless Outrunners from Hobby City. If you want to buy a motor online, here are Dave’s recommendations: “Only two that I know of might be suitable, and both are inferior. The Little Screamer Park Jet is 2800 Kv and will more or less turn a 5043 about right. The 24-gram Hextronic 3000Kv is okay for 5030 props and marginal for 5043 (might stress the ESC depending). Neither is quite right. Efficiency is unsatisfactory in both motors. Other than those two ‘efforts,’ it’s a completely unaddressed market.”

Flying time with a 730mah 2S LiPo and an efficient motor is about 12 minutes, though I generally limit my flights to 10 minutes so I don’t bash the battery. (And I fly some batteries that are 2+ years old.)

Bigger Prop. Alternatively, you can use a different motor turning a larger prop. If so, you’ll need to adjust the following measurements, which assume a 5-inch propeller.

First, slice the wood strips off the trailing edge of the Wild Wing. You don’t need them.

Mark the center line of the Wild Wing.

Cut the wing on both sides 2.125 inches from the center line, leaving approximately 6 inches of foam between the two vertical stab slots.

Front view of Wild Wing in flightKitchen Knife. To cut the foam, mark the lines with a pencil, then score the cut with a couple of passes using a fresh sharp razor and a straight edge. To finish the cut and keep it straight, sneak into the kitchen and insert a carving knife or chef’s knife into the razor cut, then slice. It’s surprisingly easy.

Mate the two halves and check the fit. Sand as necessary to achieve a smooth join.

Battery Compartment. At this point, Dave carves out a neat pocket for the battery. I didn’t think ahead, so later I used a soldering gun with some heavy gauge copper wire to burn a slightly messier pocket for the battery.

Glue the wing halves together using Goop, Uhu Creativ or Canopy Glue, set them on wax paper on a flat surface with weights and let dry overnight.

The rest is straightforward. Refer to the photos and captions and feel free to ask for details if you need additional information.

Notes
Inset the motor mount about 0.5 inch so you don’t have to add nose weight. Update: Inset the motor mount at least 1 inch to avoid a tail-heavy plane. If it turns out nose-heavy, you can add spacers to the firewall to extend the motor rearward.

Replace the stock elevons with larger elevons cut from 6mm Depron (mine are 2.5 x 12 inches, a rectangle with one short side angled in a few degrees to clear the elevon, plus rounded corners) and replace the vertical stabilizers with lighter ones cut from 6mm EPP. Here’s a printable PDF pattern for the vertical stabilizer. Don’t try to glue the vertical stabs into the slots: glue them on top of the slots.

We hinged the elevons using Blenderm, a wonderfully sticky tape which seems immune to UV radiation. Use Blenderm on both sides of the elevons. You’ll find Blenderm at some local R/C dealers, or look for it online. Set the elevons for big throws.

Update: Initially, I installed very lightweight servos, but after stripping gears multiple times I’ve replaced them with heavier models. I seal the servos with clear tape, then Goop them into the servo cutouts.

Dash of Color. I painted the elevons and vertical stabs with orange acrylic paint using an air brush. A bit of color will help you identify your warship in the heat of combat.

Protect the nose and the leading edge with filament tape — the front takes a lot of abuse in combat.

Aim for AUW (including battery, of course) of less than 7 ounces. My wing is 6.5 ounces. Dave’s is a bit lighter.

Gaining Momentum. So far, Dave, Frank D and I are flying these small WWs. Mike Nadler’s working on his and I expect to see many more quite soon.

They mix perfectly with other small wings — Mini SpeedWings, HyperFleas and, of course, Boomers — but they’re the most agile combatants in the air: Monkeys vs. Cats.

Safety Note
If you’re building a plane for combat, keep it light and don’t add hard reinforcements such as carbon fiber rods on the leading edge of the wing. These add weight and create an unnecessary hazard for your opponents. All you need is a bit of tape on the leading edge.

If you want to get a suitable Wild Wing motor from Dave North, send me an email and I’ll put you in touch with him.

Here’s an article by Mike Bowns on how to build a Wild Wing, with lots of pictures.

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17 Responses to “How to Build a Wild Wing”

  1. Dave says:

    I do have a couple of not-yet-wound motors on my desk, so I can probably crank out a something if need be. Not everyone wants to order from Hong Kong.

    Also, if you know you’re starting a build and tell me ahead of time I can put in an order. Probably take two weeks to get here and a couple of days to unwind/wind/check/solder. (Unwinding is the worst of it. Chinese mfgs have a weird fixation on slopping glue all over motors. I have no idea why, but the Middle Kingdom Knows Best).

    You’ll also need a prop adapter, so I’ll toss one in for $25 total. The motor mount comes with the motor. This deal is a public service _only_ for people who are building wildwings to fly in the Baylands Airwar Running Fight.

    Come to think of it, that’s actually cheaper than trading for two motors because of UH/HC/HK shipping costs… well, if you want to toss in a miniEZconnect or something else, that would be fine too. Or not.

    Dave

  2. Dave says:

    About the “scoop”:

    Not necessary, but a nice touch. Gives some ESC cooling instead of just sealiing it into the bottom pouch.

    The easiest way to make it is to cut some EPP strips — not very big — and glue them to the bottom of the wing, forming two ridges.

    Then just glue another piece to the top of those ridges to form the scoop. Trim off the excess. Round to taste.

    Note: Gluing to the formed surfaces of the Wild Wing requires a pretty good glue. It’s surprisingly resistant to stuff like Canopy Glue (which works great on interior joins). So far Goop and UHU Creativ have proven to work. Any contact-type cement should be good, including GWS glue. I have found Epoxy works, but not as well. You’ll have to ask Mike about Hot Melt Glue.

  3. Dave says:

    Tentatively, for someone adventurous who wants to cheap out, the FC 2805 2840 Kv motor from hobbycity unitedhobbyking might actually work out. The numbers posted indicate it could be a little weak and it’s certainly heavier, but it sure is cheap. I’ve tested it previously and it had very poor efficiency at higher power levels. However, with a 5×4.3 GWS 2S it would be idling at full throttle .. for a motor of its mass (26+ grams).

    Numbers indicate it’s possible a rewind would make it work fairly well. I may have to run the experiment. But I think it would be adequate as shipped (if you get lucky and it’s a good wind. Odds are maybe 50/50. Get two?)

  4. Dave says:

    MOTOR NEWS

    First, the Hextronic 24-gram 3000 Kv model from Hobby City is acceptable with a 5030 prop. It’s a $10 motor (plus about $1.50 shipping when you order two). It will not be as strong as the motors we’re using, but if you want cheap and dirty, the test results were fine. I metered three with (as expected) three different results. One was quite good, the other two not bad. Efficiency varied up to four points and power by over 1/2 ounce top-to-bottom. But even bottom would do the job. So that’s something to consider.

    How do they compare? Produces about the same thrust as the motors we’re using, with about the same power input. But: since it’s using the 5030 rather than the 5043 prop, it goes about 12mph slower. This translates to a shorter but less dramatic runup for attack moves. During 90 percent of the flight, it means nothing.

    ALSO:

    I have experimented some more with using the 24-gram motors to rewind and got a perfectly reasonable result — about on par with the smaller 16-gram we currently run. (Actually a shade more power and efficiency, but you have to carry an extra 8 grams, so it’s really close to a wash).

    This means now there are two usable rewind options that are quite strong, and at least one motor you can get right off the shelf that will do an adequate job at a very low cost.

    Oh yeah, I did test the 3000 Kv with a 5043. Efficiency went through the floor and amps were unacceptably high: over 12. That would require a bigger battery and (maybe) ESC, driving the weight up enough to nullify any gain from running the higher-pitch prop. So forget that.

  5. petej says:

    In building a couple more Wild Wings, I discovered an effective way to smoothly join the two wing halves. I slather on a thin coating of Goop, press the wing parts together and wiggle them a bit to distribute the Goop evenly on both halves, then I insert the jaws of a woodworking clamp into the two servo cutouts and tighten to compress the two halves together. Weight the edges of the wings to keep them straight and let sit for at least 12 hours. At that point, you can use your fingers to roll the excess not-quite-solid Goop off of the joint.

  6. Dave says:

    Update on the 2805 motor from United Hobbies: I’ve tested one and it’s not very good. But it was incorrectly wound. So the problem here is, you have a good chance of getting one like this (with 15 turns on 8 teeth and 14 turns on four teeth). Results:

    Stock 15T Delta Kv 22321/7.97 = 2800 Io: 2.08
    15381 rpm @ 7.29v/10.58a 307 grams 10.8 oz 58.2% Efficient

    Hey, almost 11 oz thrust. Great, huh? Well, no. Contrast to my latest wind:

    GWS 5043 DD SOC 2S
    16753 rpm @ 7.41v/9.77a 364 grams 12.8 oz/thrust 79.7% Efficient

    Note the amps and efficiency. That’s how much worse this particular Emax is. Pete has another on order and perhaps I’ll get a chance to do a “stock” test on it.

  7. Dave says:

    Good news:

    The Hextronic 24-gram 3000Kv motor is workable with the GWS 4540 prop. Not as good as a rewound version with the 5043 prop, but not too bad. The smaller prop blade is something of a bonus. I test flew this setup this morning and can pronounce it “adequate.” Definitely not “a dog.”

    Bad news (sort of):

    Tested four more Emax 2805s. One was DOA; shorted out. Two were okay (not horrible) and one borderline. This is completely consistent with the first estimate that about half of the production motors are useless. However, the two that worked okay are tolerable … but not as good as the setup mentioned above.

  8. Larry says:

    One additional tip…
    After cutting the center section out of the wing, I recommend you trace the wing root airfoil onto the vertical stabilizer pattern.

    The most recent Wild Wing kit I got from Hobby People has significant reflex in the airfoil (also noticeably more washout at the tips). Maybe they shipped me a boogie board by mistake…

  9. Restie says:

    Do you suggest using any of the CF rods that come with the kit? And do you use the filament tape to add some support to the overall wing?

  10. petej says:

    We don’t use the carbon fiber rods or filament tape for support or rigidity. These wings aren’t subject to huge G forces and we’d rather keep them light. But we often use filament tape on the leading edge for protection against prop strikes.

  11. Brian says:

    Where to get 9mm EPP sheet?

  12. petej says:

    Brian — I ordered EPP sheets online. You can also use Depron or other kinds of foam, as long as the foam is not too heavy.

  13. brian says:

    Dave,

    Got a spare motor that I can purchase?

    Brian

  14. Dave says:

    Brian, an email is on its way with a scary long explanation of your options. But if it drives you nuts, just say “pick one for me” and I’ll have at it.

    Dave

  15. Larry says:

    Go like a bat-out-of–hell!!!

    If you wish to build a blindingly quick Wild Wing, here are some tips…

    The old adage about building your airplane light still holds. My observation is that if you can achieve an AUW of 5.5 oz, you are rewarded with a quick, highly maneuverable wing (even if you don’t have the hottest motor out there). In order to accomplish this goal, you do need to wary of weight during each step of the fitting out and build process. Here are some suggestions (I do admit a couple of these may be contrary to the “cheap fun” spirit of combat wings…):

    1. Abandon all of the kit’s hardware.

    2. Don’t use wing spars. If you feel compelled to, try a pair of 20” long .5mm carbon rods top and bottom, just forward of your motor mount.

    3. Use glue sparingly. Take care to achieve a perfect mechanical fit prior to gluing. UHU glue seems to be lighter than epoxy or goop.

    4. Use paint sparingly. The Tamiya TS spray paints are much lighter than the garden variety Rustoleums.

    5. Use 6mm EPP for the fins.

    6. Use a 12-16 gram motor.

    7. Go for the lightest possible ESC.
    The 6 gram Castle Phoenix 10 is good.
    If you know your motor’s current draw with a GWS 5043 prop, you may be able to get by with a 4 gram Castle Thunderbird 6.
    After your wing is completed, trim any excess length from your ESC’s motor leads.
    Don’t use bullet connectors larger than 2mm.
    Make sure to provide adequate airflow for your ESC.

    8. Use 4-6 gram servos as well as very light weight control rods, EZ connectors, and elevon horns.

    9. Use the lightest possible receiver. For 72 Mhz, the 4 gram Castle Berg 4L is hard to beat. For Spectrum 2.4 Ghz, the 2 gram AR6300 Nanolite receiver along with JST connector servos (Blue Bird BMS-303JST) should work great.

    10. Keep weight in mind when shopping for Lipos. The 15C Thunder Power 2S 730 mAh is a common choice (34 grams). Depending upon your motor’s current draw, consider using a 25C Dualsky 2S 450 (28g), or 15C Thunder Power 2S 480 (23g).

    11. Plan ahead to get the CG to come out ~7 inches from the leading edge so you can avoid adding ballast later. Do a mock up by taping all of the main components to the wing and checking CG prior to actually mounting your {motor, ESC, receiver, servos, Lipo}.
    It seems most of us inset our motors about 2 inches forward of the trailing edge.
    You might consider abandoning the factory servo pockets and cutting new ones just forward of the old location.

    12. I recommend to mechanically set up your elevons for +- 1.25” throw, but tone it down to 50% via the dual rate or ATV menus prior to maiden flight. You can adjust later per your individual flying style. You will find these lower flying weight wings are far more resistant to tip stalls.

    There you have it. Though I’m occasionally complemented on my flying skills, the reality is…..it’s the building skills that make me look good.

    Cheers,

    -Larry

  16. Larry says:

    Go like a bat-out-of-hell…<>
    I should emphasize that a stiff wing (use of thin carbon spars) is also a requirement for high performance. Though I first added spars to an existing wild wing hoping to provide some immunity against collision-induced catastrophic wing separations, I immediately noticed an improvement in my wing’s ability to execute abrupt, high G maneuvers – - to the extent that you can eject the battery or dislocate the prop!

    I have been using a pair of .5mm carbon rod spars top and bottom. Use a single pass of an X-acto knife with ruler to cut a *very* shallow slot in the EPP, about 20” long, maybe half an inch forward of the motor mount. Lightly coat the spars with a flexible epoxy (West Marine G-Flex) or other suitable glue, then separate the wing skin a bit with one hand while gently pressing the spar into the slot with the other. Work slowly and use light finger pressure as these delicate carbon rods snap way too easy with rough handling. Let dry overnight then fasten your seatbelt!

    Cheers,

    -Larry

  17. hey everyone
    I love the wild wing delta planes, have been flying them for over a year and have come up with my own method of cutting the wing, i usually cut really deep to balance out the CG because if you want a fast wing, you will be using heavier motor and battery, so a little screamer will not cut it, in any case, cutting deep gives many advantages, here are 3 of my wild wings, i will soon have step by step instructions as well on how i build them hopefully this week.
    http://www.skyhighhobby.com/about/wild-wing-build

    thanks