Frankenstein simple soarer

[Buck Harding]

first off, greetings ladies & gents, nice ta meet-cha.

second this isnt so much a whole simple soarer i'm going to be trying to build here. i'm looking for deader than dead simple cause i want this to be the plane i care the least about, teach relatives how to fly a little maybe or just tow it up with my dad & goof off, make attempts at a smoking hole award at the local field...

the fuselage will likely be made out of cardboard tube, its free and easy for me to get through my job, we get 60" brake lines shipped in em. decently light with respectable strength for the application too. and the tail probably isn't going to match up terribly well to original plans either.

i do like the wing from the simple soarer except for the poly-dihedral. this is where i want second opinions, i'm thinking i might be able to get away with a flat wing with ailerons. i realize this might not be so great for the first time flyers i'm considering (possibly building 2 wings, one flat and one not) but i do like the simplicity, ease of construction and what i believe may be some additional efficiency from not spilling additional air off the wingtips with that dihedral (also considering wiglets, but that's between me and the thermals).

what do you guys think, poly-dihedral, necessity for a soarer or can i get away without it?

 

[rcspaceflight]

what do you guys think, poly-dihedral, necessity for a soarer or can i get away without it?

I think it would be necessary. I'm unsure if you're looking for a pure glider, something with a motor to get you up high and then glide around, or something that is flown like a plane without any glider characteristics.

If you want it to be any form of a glider then you'd be better of with poly-dihedral. Any corrections you make to the ailerons is going to produce drag and you're going to slow down and lose lift. Poly-dihedral will do a much better job at keeping the plane level then any human could. Which would give you maximum lift and the least amount of drag.

 

[rcspaceflight]

But if you want a really, really simple easy to build wing, you could make wings like I made for a glider like plane: http://www.flitetest.com/articles/simple-v-tail-version-2

Probably the easiest wings to make and you don't need the wing tips to be angled as much as I have them. Because the wing is flat bottom and the wing tips are undercambered, you get extra lift from the undercambering which acts like poly-dihedral even without an angle.

 

[Buck Harding]

...Any corrections you make to the ailerons is going to produce drag and you're going to slow down and lose lift...

superb point, i didn't consider the drag involved.

...Poly-dihedral will do a much better job at keeping the plane level then any human could. Which would give you maximum lift and the least amount of drag.

and i was really hoping nobody would mention that. but also a good point i was worried about.

the purpose of this plane is both a learning platform/quick flight sample for new flyers as well as a tow-up glider for me to sample that aspect of the hobby a little more than my dead-stick experience.

i think the plan is going to reshape a bit.

a dihedral or poly-dihedral is back in the picture, ailerons are out.
i'm liking the V-tail, never worked with that before, thinking it might have a slight advantage over vertical/horizontal stabilizers as far as drag goes.
and still thinking strictly glider but a motor may be an option in the future.

sound advice rcspaceflight, i appreciate it.

 

[xuzme720]

Put a folding prop with a modest motor on it for the best compromise. There's plenty of lift with that wing, just keep the system light and she'll do both well, climb and glide.

 

[rcspaceflight]

i'm liking the V-tail, never worked with that before, thinking it might have a slight advantage over vertical/horizontal stabilizers as far as drag goes.

Actually, V-tails create more drag. At least that's my understanding. It's because whether you're using elevator or rudder, the two control surfaces of a V-tail have to counter act each other. Like for left rudder, one control surface moves up and left, the other moves down and left. The up and down forces counter act each other so you get a net force of left. The counter action creates a force that is wasted in excess drag.

But it's one of those things that with the small scale of a RC glider, it may not be that noticeable and it's not worth completely avoiding a V-tail just because of that. If you like the look of a V-tail, or you want the tail up and out of the way to avoid the tail catching when towing the plane, then certainly go with the V-tail.

I went with 90 degrees between the two surfaces of the V-tail, but you're supposed to go with 100 degrees or 110 degrees. The farther apart, the more elevator you have, the closer they are, the more rudder. But again, it doesn't really matter and may not be that noticeable.