[Dennis Pedersen]

I am getting ready to cut new wing cores for a Giles G202 I started to build many years back. The plane was all framed up and the cores for the wings and stab where cut. I finished up the stab and elevators but never finished the wing. The project stopped and I cannot remember why, but it is time to finish it. I plane on attending a few IMAC events with it and so I have been looking at different airfoils. I made up template patterns of a S8035 14% airfoil which has a bit more forward high point and a little thicker front to the wing. The plane is based on the old Midwest 27% G202 kit which has a 72" span and around 970sq" of wing. It will have a 3W24 for power. Does any one know much about my possible airfoil choice or a better option with an explanation. Hoping for a final max weight of 11.5 pounds, hopefully less. Thanks for any advice.

[kip51035]

The 14% airfoil will allow the aircraft to gain a lot of speed when pointed down hill. You will have to match the CofG with the average high point on the wing. If by thicker front section you mean a more rounded leading edge. This will allow for a better slow speed and less chance of tip stall on high "G" manoeuvres.

[agl892]

I think you would be fine. Very close to a NACA 00 series, which is a solid performer in pattern planes, although some prefer the highpoint a littler further aft.

I think whats more important is the relationship between tip thickness and root thickness, and what you want to achieve from it. ie: good snap performance while sacrificing some tip stall at low speed, or the other way around.

A few years back F3A was going with 12-13% roots and 14-15% tips, but as snaps became more and more integrated into the sequences, and more complicated as well flight speeds slowed down a bit that has changed to thicker roots 13-14-15% and thinner tips ~12%.

Some things to consider for sure.

Chad

[Dennis Pedersen]

Thanks Chad, what are your thoughts on leading edge profile for the wing. I know many of the new planes have a reasonably sharp LE shape. I have heard so many different opinions on this but new real explanation. Thanks

[Dennis Pedersen]

Well one wing is in the bag. Decided to just finish the cores I had cut many years back. Made up some skins and we shall see how she fly's.

[agl892]

Hi Dennis,

A sharp LE is used mainly to help the wing to snap better, supposed to get the wing to initiate a stall a little easier. The consequence of that is usually a little more pitch sensitivity.

When I build my own pattern models I usually just match the LE profile to the airfoil by eye as best as I can, I have not ever felt any issue flying wise with that approach.

Chad

[Dennis Pedersen]

Thanks Chad, that is basically how I have done it also so I will stick with the tried and true. I have one wing s leading and trailing edge all planes and block sanded into the profile of the wing. I will get the second to match then finish the nose of the leading edges. I will post some pictures when I am done. Thanks