Bird Shaped Thermal Floater (prototype!)

[CactusJackSlade]

Here is a shape I'm working on... hope it flys!

Wanted something that looked more bird like. It has a thick thermal foil and a flat hinged tail like a bird. I may opt for a V tail later... or even tail-less...

Here is what I have so far... a couple more nights and it should be flying... or floundering! :D

Oh, I moved all my foamie stuff from my http://www.hobiehawk.com page to my NEW Foam In Fusion website. You can check it all out here - step by step photos:

http://www.foaminfusion.com/EppTechHawk.html

Enjoy?...

CJS

[FlyingPig]

Beautiful :)
How is your control ? You might want to see the link below for reference.

http://pbs-saf.virage.com/cgi-bin/visearch?user=pbs-saf&template=template.html&squery=Flying+Free

(select the first one -- Is it a bird ? -- )

FlyingPig

[Jack Hyde]

The plane looks very nice. I would guess that with no vertical stab it may be unstable in yaw (like a boomerang) and without dihedral or ailerons it mayl be unstable in roll. You have fwd sweep, producing negative effective dihedral, at the root where most of the lift is generated. That effect is reduced by the rear sweep at the tips. I would start with about 10 deg dihedral and a v-tail then reduce dihedral a bit at a time if that was desired for asthetics.

[CactusJackSlade]

I actually haven't put the ailerons or flaps on yet... (watch for it in the next step of the photos) it will be a full house ship, with the exception of a rudder.

Really it started out as a flying wing, but I put elevator control on it do I could use crow mixing for tight landing spots...

Oh, also I plan winglets for a bit of yaw stability...

CJS

[CactusJackSlade]

Jack Hyde,

Yes, you are correct about the forward swept wings producing negative effect dihedral... Question: wouldn't the rearward swept outer panel couteract this to some degree?

I was aware of the negative effect of dihedral in a forward swept wing... I guess I was assuming a positive effect with a rearward swept wing?.... what do you think?

CJS

[Jack Hyde]

I don't know the quantitative stuff required to tell if the rearward sweep of the outer panel offsets the forward sweep of the inner panel. A lot of birds like that wing plan.

[ajroahkni]

I think birds do it w/ a gullwing

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[BMatthews]

I tried a few small gliders like this myself back in my teens. They were little 6 to 8 inch span models made from 1/32 wings and a bit of 1/8 sheet for a fuselage. Mine were full flying wings with no tail and IIRC I didn't use any fin. I also seem to remember that they flew decently. Stable enough in straight ahead test glides but not able to take any sort of launch and recover in any meaningful way to normal gliding. Mine hade more taper out at the tips to better resemble the bird wingtips.

The forward sweep being in near the fuselage doesn't have as much leverage to work with as the outer swept back tips do so it stands to reason that the outer sweep will be dominant.

But making your own little all sheet test models couldn't hurt. You're definetly out on the slippery plank of new ground with this one.

Good luck and kudos for trying something so different.

[CactusJackSlade]

Well,

About all I have to do is cover it... I'm considering not covering it and just getting it in the air in case I have to do some mod's that way I don't waste my time re-covering it...

Anyway, I'll let you know how it goes!

CJS

[AirBornOne]

Traitor ;)
Looks good CJS.
What, a Minimoa isn't good enough?
Anxious for flight photos.
Jay.

[CactusJackSlade]

No test flight today...

wind was hooting 30-35 with gusts 50-55 and a peak gust in town of over 60... so maybe tomorrow!

CJS