What is some good air foil for a .90 size plane of wibg chord 16 inches and span 63" ?

I designed this plane as my inspiration for Epsilon .... need suggestions on airfoil ...


Thanks People .... Waiting for ur comments and suggestions ...

USMAN.

Naca 64-012A This is what I am going to use in my pattern project. Check Your PM's.

Honestly, a lot of people may tell you different, but airfoil really doesn't matter TOO much on a pattern plane. A good rule of thumb is 10-12% for a 2 meter, fully symetrical. Some smaller designs have thicker wings, some as high as 20% or higher. That's a bit much if you ask me. For a 90 sized plane I'd stay around 12-14% with about a 2:1 aspect ratio. Sweep is personal preference, I like my tips 1"-2" swept forward from a straight trailing edge. The leading edges need to be a little sharp to break into a snap cleanly, you don't want the plane to have a 15 deg AOA to stall. Remember, the AMA rules say a 2mm radius minimum. That's actually fairly sharp.

Other than that, just play with it. I believe you'll find wing and stab placement and fuse side area more critical than the actual airfoil. SOme very nice top end pattern planes have REALLY wierd airfoils and don't fly remarkably different than a straight up Symetrical 10% airfoil. If they tell you different, they are usually trying to sell you something.

Designing a pattern plane is a LOT of trial and error. Small changes have a dramatic effect on the way a plane locks on or couples, especially with rudder input. I believe you'll find that the actual airfoil is one of the least important design parameters you have to worry about.

-Mike

Also remember the sweep of the leading edge especially has an effect on effective dihedral. Just remember to take that into consideration....

-Mike

Did you want to use a Laminer or Non-Laminer Airfoil section ?

__________
Schpankme

"No matter what happens, somebody will find a way to take it too seriously."

That NACA airfoil is close.....with the maximum width about 34% back. Looks a little fat for my taste, I prefer 10% but 12 would probably be better on a 90 size.

-Mike

I agree to Mike,

In pattern like we fly today symetrical airfoils just don´t make the difference as long they are the same category, i.e. laminar or non-laminar.
The usually have similar delta alfa/cL and stalls and the same maximum cL. What makes them really differ is they behaviour in the near stalll. We do want a sharp stalling airfoil.
Also, we must be in mind that a the root and the tip airfoils are flying at dissimilar Reynolds number (i.e. the relative viscosity of the air) and the behaviour change as Reynolds number change.
More importantly is the wing platform and the correct positioning and dimensioning of the stab and rudder
One thing to experiment with is the use of symetrical reflex airfoils. By using them we could design very small stabs (10% of the wing area) and expect a very predictive airplane in the pitch axis (I think).
A great program to tinker with is the Profili 2. In it you can design, modify or just use the more than 1000 airfoils from the library. Also there is a implementation of the aerodynamic Eppler program that you could use if to visualize the polars and help you chose your airfoils

Dr. Wladimir

Airfoil Problem Solved.
I've decided to simply use a 12 % with a 2:1 aspect

When i was reading through the replies ... I came across the stabilizer placement thing.
Indeed it is the most important thing. DO you guys think that my plane's stabalizer is in the right place ? It is a bit below the thrust line ...I've seen some planes that have it below the thrust line and these planes suffer pitching in knife edge .... but there are planes that still have it below and do perfect in knife edge.


UBY.

I would make the fuselage without the lightening holes above the stabilizer, that way you make it easier to move it up later on, if you find that the model pitches towards the canopy. I do not know any other way to tell than by trial and error, apart from looking at other models that are tracking well. Too many unknowns that are affecting the flight performance.
Magne