View Poll Results: Elevon Location?
Outer most part of the Wing? 17 50.00%
Next Angle in from the outer most part? 17 50.00%
Voters: 34. You may not vote on this poll

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Mar 01, 2012, 07:14 PM
Registered Misuser
Vince77's Avatar
Unless you're shooting for a high roll rate, I can't imagine the need to get them out on the wingtips. But then again, getting a flat design on it's edge at all is risky unless you have a high roll rate to make it all the way over.

Oh, and you don't look nearly as hard core as your avatar would lead us to believe...
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Mar 02, 2012, 05:27 PM
Flying Models for 55 Years
Sixter's Avatar
gpw has a nice B2 design, it's very simple to build and it flies very well. It has a 39.5" wingspan and that will eat up one 24" x 48" sheet of FFF. It has been built with the prop in the front, in a slot and hanging off the rear. Wingspan's from 14.5" to 10'. Check it out https://www.rcgroups.com/forums/show...t=simple+b2+gp

Bobby
Mar 02, 2012, 06:11 PM
Home of "Golf Cart Flying"
pecanpatch's Avatar
Its too small and too simple Bobby. Josh is wanting this 74" wingspan version. Is he re-inventing the wheel? Maybe, but we are drawing on the wing experience we got from here.

https://www.rcgroups.com/forums/show....php?t=1551613
Latest blog entry: My Slow-Boat build log.
Mar 02, 2012, 06:14 PM
Flying Models for 55 Years
Sixter's Avatar
Josh Here you go, Big 80" ws and Twin Powered, built by Hepdog Here (Post # 462) -->
https://www.rcgroups.com/forums/show...t=twin&page=31

Bobby
Mar 02, 2012, 06:18 PM
Registered Plan-a-holic
Hepdog's Avatar
HEY! You beat me to it ...(thanks!)

I did pretty much what you are trying a few years back. Flew alright. I had elevons on both the outer wing and inner wing and also used differential thrust.

You can read all about it in the links or ask any questions you want - I think I remember most of it....

I did more B2 work here:

https://www.rcgroups.com/forums/showthread.php?t=777001

It's got some other planes in there but lots of good B2 stuff like CofG and flight characteristics.

I have some U-tube vids here:

B2 montage.wmv (5 min 12 sec)
Mar 02, 2012, 06:29 PM
Home of "Golf Cart Flying"
pecanpatch's Avatar
Thanks guys... with all due respect
It looks like yall are just building them flat and maybe adding a KF airfoil.

That's not Josh's intent at all!

again,
https://www.rcgroups.com/forums/show....php?t=1551613

Latest blog entry: My Slow-Boat build log.
Mar 02, 2012, 06:35 PM
Flying Models for 55 Years
Sixter's Avatar
I thought it had too be Flat to be a Stealth aricraft The one Josh is holding looked flat to me !
My mistake.

Bobby
Last edited by Sixter; Mar 02, 2012 at 07:01 PM.
Mar 02, 2012, 06:52 PM
Registered Plan-a-holic
Hepdog's Avatar
Oh you want an airfoil - that's not really simple at all

The deal with the KF type wing is that it's pretty critical to making a B2 fly without vertical tails OR some form of "duckerons" or "ruddervators" or what ever you want to call them. The KF also keeps a simple sheet of bluecore from flopping around like a fish. At 74" that is going to be a BIG problem. My big B2 had an actual airfoil and there was NO way it would fly without the tip ruddervators open or some verticals installed!

Every airplane needs some form of directional control and the KF step provides that via drag on the wingtips. If you look at GPW's thread he experimented with wedges on the wing tips and that seemed to work okay. I suppose you could try an actual airfoil wing and permanent open "duckerons" or a wedge out on the wing tips. The problem with an actual airfoil is that its so smooth aerodynamically - the KF solves that problem rather well.

I just went through my vid collection from the 80" test bed and found notes that indicated the differential thrust was good for turning but not for stability - too slow a response.
Mar 02, 2012, 07:04 PM
PecanPatch's Son
Jmurdock's Avatar
It will have an airfoil. It will also have 6mm Carbon fiber rods inside the leading edge. And it will be filled with Expand-a-foam. I have flown a wing a similiar size without rudders and was happy with the Control. The real B-2 isn't flat, it has an airfoil. My B-2 doesn't have to be undetectable by radar.

https://www.rcgroups.com/forums/show....php?t=1551613
https://www.rcgroups.com/forums/show....php?t=1551613
https://www.rcgroups.com/forums/show....php?t=1551613
https://www.rcgroups.com/forums/show....php?t=1551613

It may turn out to be a bad idea, In which case I'll start over, or cut in Duckerons, or scrap it and use the electronics on my next Brilliant idea.
Mar 02, 2012, 07:07 PM
Home of "Golf Cart Flying"
pecanpatch's Avatar
For me, if the plane just doesn't have enough stability, I would put some small lexan vertical fins on it and call it a day.
Latest blog entry: My Slow-Boat build log.
Mar 02, 2012, 07:10 PM
Home of "Golf Cart Flying"
pecanpatch's Avatar
HepDog! That is a brillaint effort in that video u posted. wow. a lot of work though.
I think what jmurdock wants is something in between that and the KF one shown earlier. But dang fold it over simple construction.
Latest blog entry: My Slow-Boat build log.
Mar 02, 2012, 08:29 PM
Registered User
rajazo's Avatar
impresive plane Hepdog!!

good luck with your finless B2 , Jmurdock, I will follow your progress
Mar 03, 2012, 05:09 AM
gpw
gpw
“There’s no place like Foam”
gpw's Avatar
The split flaps worked very well on my B2’s ... Simple !!! Effective ... Used them on my A-12 too ... they fly as if they had fins ...
Mar 03, 2012, 01:00 PM
Registered Plan-a-holic
Hepdog's Avatar
I read the thread for the wing and I like that construction technique You honestly might be on to something here.

Since all my big B2 flights were done with the clamshells at least 1/4 open for stability, you could probably just make them non-movable in that position and use differential thrust for the rest - should work fine. Please more pics as you go and of course video when the day comes
Mar 03, 2012, 05:32 PM
PecanPatch's Son
Jmurdock's Avatar
Cool! Got some of the needed parts for this build today at Perry swapmeet. Had a blast there with everybody. Still need to order some things online. Hopefully I'll have updated pictures soon.


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