3 1/2 is what you want. I found out about it when I went to mount my cowl. Then I saw where someone else posted it on the boards. Also

The ply that they used for the firewall is garbage. I put together the plane late last winter and it sat waiting for spring. Spring came and I gave the plane a good once over and found that the firewall was bowed out from the weight of the motor. Also the washers that I used for right thrust were being driven into the wood so my right thrust kept on changing. Last Friday I got sick of messing with it and cut off the old firewall and put in a good piece of ply.

Be aware this thing needs a good 3 degrees of right thrust. I had about 2 degrees to start off with and then had to add some more.

The landing gear plate is a weak point. They (Lanier) say to use wood screws to put the gear on. I didn't I used #8 blind nuts. On a really easy landing the gear just folded underneath it. Same thing happened to another guy in our club that has the edge. I replaced the gear plate with good 1/4 inch 5 layer birch ply and haven't had a problem since.

Check your tail. The spar in mine was sloppy loose I used epoxy to get rid of the slop. Email me if you want the how to's.

Watch your wings. After I flew this weekend I found that the phenolic tube in one of my wings was totally free floating. It wasn't a hard fix but I hate to think of what would have happened if I was a 3D flier.

I guess that is about it. Other then those few thing it is a great flying plane.

Michael