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Feb 11, 2010, 11:43 PM
GFBurke's Avatar
Ok. Got the 3 pieces cut out. Two EPP one Depron.
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Feb 12, 2010, 09:58 AM
SG Talon... Super Genius.
Whoa... what a sec. How do you get your woman to cut out your planes??? All mine does is complain about the mess i make in the living room when I do it while watching TV!!!

She does run an occasional camcorder though so i shouldn't complain.

Looking pretty nice. Remember to keep it light!

You are planning to split that Elevator for an elevon right? I would have left the center section attached to the wing area to keep a nice "keel" to lay your vertical fuse on it.
Feb 12, 2010, 11:45 AM
GFBurke's Avatar
hehe. thanks.
na, no verticals here.
Riteway coming soon. A bit heavy and overpowered is what I'm shooting for.
Feb 14, 2010, 05:44 PM
If it flys,I can crash it
cptdragn's Avatar
I was thinking that one way to both stiffen the wings and yet keep it lite would be to use flat carbon fiber strips along the outside of each wing. That way, you'd have no up and down flex but they would still give side to side flex in a knife edge crash.
Feb 14, 2010, 06:05 PM
flyd7's Avatar

tristing on front end

hey ive used this method before .... try using c/f flat stock ,its3/8ths x 16th thick, hope that helps
Feb 21, 2010, 03:30 PM
GFBurke's Avatar
Ok. All three pieces togther, CF spars, adding control surfaces, then adding some 30m90 and weave. Trying to make the arms heavier...
Feb 21, 2010, 10:45 PM
In the 20' glider range
anti-gravity's Avatar
Coming along nicely Jamie. Be sure to tell me the maiden day, have to see this.
Do you plan to just hand launch it?
Feb 22, 2010, 03:32 PM
GFBurke's Avatar
Ideas on CG. Just brain storming. Diggs came up with idea #1, Lucien came up with idea #2.
Leaning to idea #1. Run them as one 3s 2000mAh lipo. Having two motors is just more complicated... maybe..
Feb 22, 2010, 06:19 PM
3DHS 'native'
going4speed's Avatar
My 'engineering' gut tells me the cg will be further back than that. What we commonly refer to as cg is really the center of lift. Also two 1000 'MAH' packs would be a huge amount of weight.

With the 2 batteries that may be the center of gravity but I think the center of lift is what is going to really matter on this 'plane'

This may be a plane that needs a gyro to remain stable or even flyable.

Have you thought about running perhaps a Kfm4 airfoil or the like behind the prop?

Originally Posted by GFBurke
Ideas on CG. Just brain storming. Diggs came up with idea #1, Lucien came up with idea #2.
Leaning to idea #1. Run them as one 3s 2000mAh lipo. Having two motors is just more complicated... maybe..
Last edited by going4speed; Feb 22, 2010 at 06:29 PM.
Feb 22, 2010, 06:39 PM
GFBurke's Avatar
ahh that's a good idea.

Well, that whole section that is 'missing' will be lift as well. I'm placing in some clear/thin plastic poster, that will make it so there is no "hole". It will be like an oval UFO on the air. And I've seen "oval UFO" style planes setup as delta that fly just fine. Like... that Surfboard dude. But clear in the center.

Yeah, those packs might be too large.. but it's just the idea. I'll do hand tosses once I get servos in.
Feb 22, 2010, 08:28 PM
I am the BBQ Ninja
Willmsy's Avatar
Looks like you should make a half scale chuck glider.
Feb 23, 2010, 10:11 AM
SG Talon... Super Genius.
Best scale for testing is 12":1'

I always found that it is easiest to play around with the CG by tossing my planes into tall weeds/hay fields. I have a very convenient one about 100' from my garage door.

I usually do it before i put any hardware on. Just tape the control surfaces in place. Usually nice and light and you can really play around with the cg.

If you are going to enclose the open area you need to look at this thing like a Pizza Box Flyer. Your CG is going to be at about 15-20% from the leading edge.

I am nearly certain that you are going to need some kind of vertical fins too. THe raider does have some vertical to it. I would make a vertical fin that looks like the center section and start there. Check out the Klingon Bird of Prey thread. We spent a lot of time getting that guy to fly, it was very unstable with the first few tries. By doing a minor redesign it flies great. If you are not holding a picture up to it 95% of people would never even notice, and 100% of everyone will just think it is totally awesome!
Feb 23, 2010, 10:36 AM
GFBurke's Avatar
O sure, that sounds great! I'll do a vertical on top to start with.
Thanks for the help!
Feb 23, 2010, 12:06 PM
GFBurke's Avatar
when I said "no verticals" , I meant for stiffening. But yes, I'll need a couple fins there or there. I'll toss her in some tall weeds soon.
Feb 24, 2010, 12:11 PM
Innov8tive's Avatar

SGTalon is correct about CG placement on a "Piza Box" type model. I built one called the Hoot several years ago, and started with the CG at 20%. It was severely pitch sensitive, so I moved the CG up to about 15% and it was a completely different model. A lot of flying wing designs like the old Scimitar series had the CG around 12% of the chord.

Always remember that a nose heavy plane may fly sluggish, but a tail heavy plane will only fly once!


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