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Old Jul 24, 2008, 07:15 AM
gpw
“There’s no place like Foam”
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United States, LA, New Orleans
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A-12 Simple KF Delta...

After making out the grocery list last night , we folded the paper into a cute little delta, added a paper clip and began glide testing off the second floor balcony... and it flew...Encouraged , we decided to go for a bigger version ...And with a KF airfoil... Here's a pic I found on the net... Plans will be up soon ...More simple Fun...
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Last edited by gpw; Jul 07, 2011 at 06:44 PM.
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Old Jul 24, 2008, 07:41 AM
Look outside the Square
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Gosford, Australia
Joined Jan 2006
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Mmmmmmmm...............

B x
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Old Jul 24, 2008, 09:07 AM
I'm not flying backwards!
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Oshawa, Canada
Joined Sep 2004
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Neat project Glen. I wonder if yaw will rear its head on this one as the A-12 doesn't have the long aft swept wingtips of the B-2.

I thought you might be able to use this pic.

Tony
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Old Jul 24, 2008, 09:24 AM
gpw
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Box, Ton' , I was thinking of changing the elevon placement to move the working surfaces as close as possible to the tips ... The glide tests of the paper model proved surprisingly straight and stable ...
The KF should help a bit, plus the possibility of a "slight" dihedral angle just for "insurance"
DISCLAIMER:.....I Must state that I'm NOT making a scale model, 3D model ,Trainer, Speed record breaker,or "demon roller", in any sense of the word... just another strange Simple flying thingie' to challenge our ennui...It's one of those things where if we can get it to fly well, others can take it as far as they want..."scale-wise"... It would be very easy to hot-wire out some EPS cores for a Big A-12...easy to sand a block of foam into a canopy , or pull one from a 2 liter bottle ...perhaps with retracts ...Plenty of potential , but we'll start real simple ...
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Old Jul 24, 2008, 09:37 AM
gpw
“There’s no place like Foam”
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OK, here goes...just to start...
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Old Jul 24, 2008, 09:55 AM
I'm not flying backwards!
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Oshawa, Canada
Joined Sep 2004
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Oh yeah. You got me inspired! I'm thinking 48", KFm3 (for stiffness) with drag wedges at the tips and a BP21 in tractor config...mmmm.....
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Old Jul 24, 2008, 10:07 AM
gpw
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Ton', ya' know with a fixed point hot-wire , we could easily make a Fat(thick airfoil) one any size we want(I'd love to hot-wire out a "real" KF section for model testing)...and oh yeah, drag tips !!!!! Cool eh !!!
48" seems about perfect for FFF sheet , and a great vehicle for KFm3 (that's the thick 3 layer one , right?)
I was thinking of making one out of EPP, just in case... hahahaha Pusher with c-20 motor ...tryin ' to keep it light ,to fly around the house ,outside(not in the house)
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Old Jul 24, 2008, 10:10 AM
I'm not flying backwards!
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Oshawa, Canada
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I was thinking something like this.

Tony
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Old Jul 24, 2008, 12:28 PM
Trying to defy gravity...
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USA, NY, East Northport
Joined Dec 2003
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Kind of looks like a Pibros to me:

http://rc-soar.com/pibros/

I've built a couple of them...indestructable and a panic to fly.

http://www.rcgroups.com/forums/showthread.php?t=256084

Jimsky
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Old Jul 24, 2008, 01:41 PM
gpw
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Jsky, yeah , all this has been done before , just another name ,another place ...Whatever you call it, we still call it FUN!!!
Ton' looks Great to me Dude!!!
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Old Jul 25, 2008, 01:52 PM
gpw
“There’s no place like Foam”
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United States, LA, New Orleans
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I keep thinking a canopy would really make it nice and distinguish it from "other" delta imitators , but a profile canopy would only add to the area forward of the CG... may have to massage' or carve and sand out some foam into a nice shaped and rounded canopy , that seems to have little effect on the yaw...that and a few sharpie panel lines...we noticed Jasta's formed canopies for the B2 caused no ill effects...
Now about a light trike gear with tiny wheels ...that would really make it cool for indoors..or on the street by the house too...
For an easy to project the wing area /wing loading , just imagine a Square , say 10"X10".. that's 100sq.in.cut the square on a diagonal point to point , flip and tape , and you have a 100sq.in. A-12...Right...??? So to get a good flying A-12 at say about 8-9 oz.(or the weight of your gear +33% foam wt.) just project how many squares you need and do it...
for example ... At 8 oz. AUW , a 400 sq.in. square will give you a 2.8 oz./sq.ft wing loading ... pretty light , should fly good and slow too...thats a 20"X 20" square , just a PBF size really, or a 40" WS A-12...EASY!!!
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Old Jul 25, 2008, 11:05 PM
I'm not flying backwards!
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Oshawa, Canada
Joined Sep 2004
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Here's V2. Went to a KFm2 for simplicity. I share your concerns about the canopy are forward but it's so distinctive, I thought schmaybe fins were the lesser of the evils. Your thoughts?

Tony
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Old Jul 25, 2008, 11:33 PM
CNC Cutter
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United States, IN, Indianapolis
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What Jimos said !!!
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Old Jul 26, 2008, 07:38 AM
I'm not flying backwards!
Tony65x55's Avatar
Oshawa, Canada
Joined Sep 2004
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Quote:
Originally Posted by birdofplay
What Jimos said !!!
Yeah, the wing planform is identical to the Pibros. It's probably where McDonnell Douglas and General Dynamics got the idea from (lol)

Tony
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Old Jul 26, 2008, 07:45 AM
gpw
“There’s no place like Foam”
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United States, LA, New Orleans
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I think they get their ideas from folding bar napkins at happy hour...
Fins ...we don't need no stinkin' fins ...
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