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May 11, 2014, 08:25 AM
Planes are for trix
tiretrax's Avatar
Thread OP

Build your own Flytrap $17 Acrobatic Slope Wing

The FLYTRAP 48" Uber cheap RC Combat and Acrobatic Flying Wing Glider
*Updated 7/13/18

24", 36" and 48" build plans shown below (this main build log is for the 48"er)
Let's keep this intro, short!
What is a Flytrap?
She's a super fast building and fantastic performing slope glider and a good platform for a motorized pusher RC Wing.
My favorite flying wing so far (I have built about 30 of these suckers to date)

She has fantastic, symmetrical like, inverted flight and no to TIP STALLS !

The secret is the new KFH (Kline Fogleman HYBRID) Airfoil (similar to a KFm2 style 'foil but with a twist).
Normal KFM2, KFM3 and KFM4 'foils didn't quit get it 'dun for gliders.
Thanks to Dick Kline for his support and inspiration....

The Flytrap is made from FFF (fan fold blue foam) and can be made from Depron and dollar tree foam as well, and will for sure look much nicer too.

How to build:
Use what I am calling , the KFH airfoil for this build and she will amaze you!
Build to plan if possible.
(Note: I will redo the video and post it with better instructions)
Gather these super hi-tech building materials;
- razor blade
- dual temp hot glue gun set to low
- roll of clear 3m or scotch packing tape
- steel ruler, ideally 36'er
- your wife's (or husbands) clothing iron, or better yet, mono-coat iron
-high end marking device like those used for writing on paper.
-some kind of poker (that's what she said, ha) to make a hole in your elevons for zip tie control horn

Ok, we all know how to build on the cheap, but let's get to the 'nutz of it,
How much do I need to fork out to build this "Ugly Betty"?
And what equipment do I to run?

Approx total cost to build the flytrap Glider (no spar needed, BONUS):
-Fan fold blue foam, dollar tree foam or other = $2
-9gram HXT900 servos (2) = $6.50
-Zip tie horns (2) = almost free
-0.039' Metal wire linkages = $0.50
-Hot glue = pennies
-zippy LiFe 6.6v 700mAh Rx pack = $5
-HK orange Rx, lemon rx or other receiver= $7
-Razor blade = near "0"
-Cool paint scheme = priceless!
TOTAL = about $20 give or take a few coffees...

- 48" wingspan
- 3" elevens
- 15" root chord
- 6" tip chord
- 15" sweep from nose
- 50% step with control surfaces included
- root step length is 9"
- tip step is 4.5"
- CG = 9.375 from nose
- zip tie control horns
- wire or wire and carbon linkages
- chord thickness 1/2" at step
- AUW as flown about 8-9 oz and can be up to 13+ without a problem.
- wing area approx 630 sq in

Original plans are in the second post, courtesy of Ken
There are 36" and 24" flytrap plans in the pics below.
(use 3mm depron for the 24" with target AUW of about 3oz)

POWER TRAP option:
Same build as above but ad pusher motor!
I use the 24gram Hextronic 1300-1500kv outrunner for a light build, 10amp esc, 700-950mah 3 cell lipo, 8x4 prop.

Bonus traits to the flytrap;
-no tip stall
-no death spiral
-no washout in wing tips needed
-no hotwire cutting
-no monokote needed
-no new stuff required
-no spar needed!
-easy to fly as a trainer too

Negative traits to the flytrap;
- she ain't the prettiest
- your friends might be mad at how much you paid for it
- girls won't be flocking over to say hi, well one did, she's in the first pic

-no expo needed
-throws 100%

VINTAGE Footage found by Rich! More Carnage
Another day of carnage at Daves Beach in Carlsbad back in the day 3_22_2014 (6 min 4 sec)

More Carnage part 2
Another day of carnage at Daves Beach in Carlsbad back in the day 3_22_2014 Part 2. (3 min 31 sec)

(0 min 49 sec)

Special thanks to Tony65x65, Viking60, jackerbes, gold guy, gpw, JGAF, kbstingwing, vtdiy, dz1sfb, Dickeroo (Dick Kline) of course, and anyone else that I may have stole ideas from to make this wing a reality. Thanks for all your inspirations and thanks to the rest of you here on RC groups that have given so many great ideas away to those of us in need! Special thanks to Ray Nemovi and Rich Gorsuch for the handy iphone work.
Last edited by tiretrax; Sep 17, 2020 at 10:32 AM. Reason: Added photos
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May 11, 2014, 09:31 AM
Ken's CAD Models
dz1sfb's Avatar
How much distance from the centerline to the aileron root? Looks to be about 3.5".


I took some liberties by interpolation.

Plan update with CG and a few odd dimensions corrected.
Last edited by dz1sfb; May 12, 2014 at 06:04 PM. Reason: plan updated
May 11, 2014, 09:58 AM
Ken's CAD Models
dz1sfb's Avatar
Wing area checks to 630.7855 sq. in.

May 11, 2014, 10:03 AM
Registered User
fearfactorfred's Avatar
Pretty awesome! I like it! Congratulations!

Looks light. Curious how much it weighs?
May 11, 2014, 12:24 PM
flyin' fool
goldguy's Avatar
Looks like a winner. Add weed whacker line to the LE for combat.
May 11, 2014, 12:35 PM
Closed Account
I flew it for a couple hours yesterday. Best foam board slope wing out there.
May 11, 2014, 02:07 PM
Slope Samurai Bushido
kbstingwing's Avatar
that's a nice foam board wing Troy, looks like a lot of fun.
May 11, 2014, 02:20 PM
Registered User
Dickeroo's Avatar

The Revert was terrific. The Swifter even better. But the FlyTrap takes a step up to a whole new level. And your approach to making a sharper leading edge is brilliant thinking.

~ Dick
May 11, 2014, 05:33 PM
Ken's CAD Models
dz1sfb's Avatar
Got a Flytrap scratched out today if you could call it that. Maybe more like my interpretation.

AUW with a 750 mAh 2s battery is 250g as pictured.

May 11, 2014, 06:12 PM
Planes are for trix
tiretrax's Avatar
Thread OP
Wow I step out for a few hours and you guys go crazy.

Thanks Fred, goldguy, Kevin, Dick and Justin.
Justin- would you mind if I posted some footage of you flying this thing? You really had some impressive lines and brought it to life.

Ken, holy schnikies you really knocked that out fast. Thanks so much for posting the drawing. The elevons are 3" so that makes the root chord 18" and the step chord ends up at 9" and tip step chord is 4.5". I was a little concerned at first since my best results thus far where at 40% but 50 is the magic number. Any further back and the step might start to interfere with the control surfaces.

One important thing is the CG. It's perfect at 9-3/8" (9.3875) to maybe 9.5"

I cut the battery hole through both plies and hot glued a small piece of 2mm coroplast on the bottom to lower the battery. I needed the nose weight anyway so this balanced it perfectly.

Goldguy - weed wackier line on the LE would be the ticket.

Ken - Your build is so nice in white. It looks like you nailed it and I'm sure this can be tweaked a lot of directions and still work well.

I have to say so far that I have flown most of the wings that have been made to date and by far my all time favorite is the kato. The kato light is absolutely incredible even though it's built very light with small servos, they can't be easily knocked out of the sky. Their recovery is incredible and for combat, that to me is truly the most important trait. And there is no better inverted flying wing out there. Hats off to Kevin for that design and to Justin's build techniques for creating a truly acrobatic wing.

The Flytrap lfills in yet another gap with ease of build and price. It's getting really hard to get wing cores these days and this might help to keep the flying wing going strong.

So enough of my ridiculously long posts.
Ken - send me a close up of your LE. I will try to get a few more photos added today. Working off the iPad and I feel a little handicapped
May 11, 2014, 06:20 PM
Planes are for trix
tiretrax's Avatar
Thread OP
Originally Posted by dz1sfb
How much distance from the centerline to the aileron root? Looks to be about 3.5".


I took some liberties by interpolation.
Spot on Ken, this the official plan. I wouldn't change a thing. Now I don't have to open autocad, YES!!!

And the distance from the centerline is exactly 3.5. Man you got some skillz.
May 11, 2014, 06:40 PM
Closed Account
Go for it just play some cool music with it
May 11, 2014, 06:48 PM
Planes are for trix
tiretrax's Avatar
Thread OP
Hmm that's the hard part, there's no cool music that's free anymore. But I got a pretty good clip of you that almost is better with a little background chatter than some royalty free techno

I'm gonna post it. I can ad music later if it sux. Haha.
May 11, 2014, 07:10 PM
Ken's CAD Models
dz1sfb's Avatar
Originally Posted by tiretrax
Ken - send me a close up of your LE. I will try to get a few more photos added today. Working off the iPad and I feel a little handicapped
Here is what I believe you're looking for. I used the video you posted of construction as a guide to the airfoil. Beveled the inside edges of the leading edges back .5". Taped and pulled over. Used hot glue on all edges. Pressed the tips flat together. This was done to get a more consistent airfoil from left to right.

May 11, 2014, 07:13 PM
Planes are for trix
tiretrax's Avatar
Thread OP
Ken that is beautiful. Better than mine for sure. It should fly even better. Check out the second video I just added to first post of Justin bangin sticks

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