Hey

After flying and practising with some smaller f3a planes, (kyosho sonic, extreme flight vanquish) and since I enjoy building/experimenting. I have for some time now been thinking about designing and building my own f3a plane. I Figured I'd keep it simple for easy modification/testing so it will be a traditional full balsa construction and most importantly I aim at making the motor, wing and stab incidences fully adjustable.

I think I have most do's and dont's figured out, But I do not want to simply copy an existing f3a plane and do some cosmetic changes. Instead I want to understand what exactly a v-shaped stabilizer does, what exactly creates the need for a canalizer and so on.

So I turn to you guys for the things I can't figure out myself

1, Probably something basic but I just can't understand it. Why do all modern f3a designs have much more fuselage side area obove the wing compared to below the wing line? Surely it can't be just a cosmetic decision to put a big canopy above the wing. Afterall you won't see a bubble canopy on an competitive f5b plane.
I understand why the prop position has to be above the wingline (and connected to this, why you don't have the ailerons span all the way inwards to the fuselage) and this creates assymetry of the fuselage but many modern design f3a planes don't even seem to try and compensate with a taller belly.
Even if you in knife edge have an equal amount of of side fuselage area on both sides of the prop line, the wing will create some serious weight on one side and this in my head equals the need for a bigger belly area.

2, All the f3a type planes that I've flown have a tendency to want to turn into the wind. Wich means constant compensating to keep them aligned in the box. I realize a CG further back helps this. And I also realize you can't get rid of this effect completly without making the plane track poorly aswell. But has someone out there found a way to minimize this effect? Without removing the fin? What was the solution? A lower and longer fin perhaps? Better balance between front fuselage side area and fin area? Perhaps someone has flown a plane that had very little of this tendency, if so what plane was that? (so I can study the lines and try and figure this out)

Hoping someone out there has the patience to try and explain these things!

Cheers
Radek J

Not trying to bash you, but a SEARCH on this forum would yield good results...here is a good thread on the subject:

http://www.rcuniverse.com/forum/m_25..._1/key_/tm.htm

Ppljr, thanks for the answer, and I know you mean well.

I have done alot of searching and reading on this forum regarding Airplane design. There are many threads and articles on sorting out pitch and roll coupling, these touch the wing-placement question. And I have found explanations on how to remedy the "non axial rolling" (don't know the word for it) a low or high wing plane gets. But have found no reason as to why designers place the wing so low in the first place. In one thread someone linked to a video file where Chip Hyde supposedly explains why he prefers low wing placement. But the link was dead and I can't seem to find that video by searching elsewhere either, I think it had the answer I was looking for.

I'm sure someone can point to a thread that answers my questions, and since I have failed finding that thread myself. Please do.

Radek J

Well, I do know about the canalizer. The propeller blows the air around the fuselage in a clockwise motion (known as the spiraling slipstream). The canalizer helps straighten out some of this rotating turbulent air, thus allowing the tail to become more effective.