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Old Jan 02, 2013, 01:50 PM
wbuttry
sikeston mo
Joined Apr 2009
361 Posts
Discussion
quick question

Hey guys i got a 48 inch epp flying wing i wanna bunge launch it off the catapult. And i'm trying to determine where is the best place to put the wood plate and and launch peg at. Some say the cg and others say toeward the leading edge .Your thoughts would be very helpful thank you in advance for your help...
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Old Jan 02, 2013, 02:04 PM
the flying is good
dephela's Avatar
USA, CT, Hamden
Joined Oct 2002
2,056 Posts
Definitely towards the LE!
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Old Jan 02, 2013, 02:11 PM
Registered User
LI, New York, USA
Joined Mar 2003
24,011 Posts
Depends on what kind of a launch you want.

If you want a zip launch, low and fast where you turn speed into altitude, then you place it near the nose. This is common for slope gliders.

If you want a higher, slower launch, like a regular sailplane launch, then you put it near the CG.

On my Zagi 3C slope glider flying wing I put a plate with a blind nut near the front, under the battery and another near the CG under the receiver.

I pick the launch based on where I put the hook.
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Old Jan 02, 2013, 02:53 PM
wbuttry
sikeston mo
Joined Apr 2009
361 Posts
exactly what i got it is a zagi i think the nose is where i would really need to put it aeajr that i thinkis also the best spot i want a zoom launch dephela that cinches it nose is where it goesthen thank you guys for your input.....
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Old Jan 02, 2013, 03:10 PM
Ninja Master
BigSwede's Avatar
United States, CA, Thousand Oaks
Joined Feb 2007
1,766 Posts
Don't put the hook right on the nose. You'll end up launching your plane right into whatever your bungee is anchored to. I've done quite a bit of bungee launching wings, and the best spot I found is about halfway between the LE and CG. It will zoom your plane clear of any obstacles on the ground. Great fun.
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Old Jan 02, 2013, 04:17 PM
ahh crap! crunch..
atmosteve's Avatar
Australia, QLD, Fraser Island
Joined Nov 2007
3,870 Posts
^ I'll confirm what Big Swede has said, after playing around myself over the years with a few types of chevron combat wing type foamies. It also depends a little how you like to balance your wing and the aileron reflex you give it, but a hook point halfway between the nose and cg point is the very best place to start when you are trying this for the first time. Then you can tune it from there to your liking and best results.
At best only half listen to advice you get off the internet.
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Old Jan 02, 2013, 04:20 PM
Registered User
LI, New York, USA
Joined Mar 2003
24,011 Posts
My forward attachment point is about 1 1/2 to 2 inches back from the point of the nose. It launches low and fast. As they said, don't actually put it in the nose or it won't climb at all.
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Old Jan 02, 2013, 09:22 PM
wbuttry
sikeston mo
Joined Apr 2009
361 Posts
1 1/2 to 2 inches got it do you think i need to re inforce the wing a tad bit it isnt gonna be a full power launch at all here is what i wanna do
RiteWing TL 50 Bungee Launch (2 min 5 sec)
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Old Jan 02, 2013, 10:26 PM
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LI, New York, USA
Joined Mar 2003
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In the photos below you will see two compartments along the center of the wing.

The forward one is where the battery goes. Under the battery is a piece of 1/16" ply that is the size of the entire battery area. Through that I placed a blind nut that finishes flush with the bottom of the foam. Then another pice of 1/16" ply on top and then the battery.

Behind that is the receiver area, over the CG. Same arrangement there with the blind nut a bit forward of the CG.

I can screw the hook into either blind nug and the top ply prevents it from screwing in far enough to touch the batter or the receiver.

Blind nut puts pressure on the ply which spreads it out over the foam. Never had a problem.
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Old Jan 02, 2013, 10:32 PM
wbuttry
sikeston mo
Joined Apr 2009
361 Posts
i'm gonna give it a try looks like it will work fine do i need to reenforce the plane any for that type of launch?
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Old Jan 02, 2013, 10:40 PM
Registered User
LI, New York, USA
Joined Mar 2003
24,011 Posts
Not really. Just make sure the foam under those compartments is solidly attached. If it was cut out, glue it back. Then cover that area with reinforced tape overlapping onto the surrounding foam by at least an inch. Then put on your normal tape or heat shrink covering. Then go fly!
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Old Jan 03, 2013, 12:38 AM
Will fly for food
davidjensen's Avatar
Bellevue WA,
Joined Dec 2003
6,631 Posts
We did this many times and kept pushing the limits of the foam wings. We kept adding more and more rubber and getting insane speeds until the wings fluttered so bad you thought the ship was going to explode. So what do you do then? Take a WW Raider and cover it entirely in extreme tape. Yep flutter that to. Last year a friend fluttered a raider covered in 10mm new stuff while DS'ing a ridge. TOO MUCH FUN
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Old Jan 03, 2013, 04:29 AM
Registered User
LI, New York, USA
Joined Mar 2003
24,011 Posts
Next you cover it with glass or carbon and you no longer have a foam wing but a composite wing.
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