pitts pilot

Is the spar on the yak supposed to be a constant thickness from root to tip?Mine looks like a banana when viewed from the side. Also the thickness tapers on one end and not the other.Out of flustration and knowing that if one wing panel was thicker at the tip than the other the plane would fly a little off I cut a new spar of constant thickness then followed the instructions again.

pitts pilot

I just found out that the spar is 3mm thinner at the tip. So, to make a new one up does the taper start at the middle and taper 1.5 to the tip on each side?

89ram

i would take it back and get a different one if it looks like a banana and has an uneven taper.

jvigani

The spar material is made from strip stock bought from a balsa supplier and should be the same thickness along its length. The caps are 1/8 x 1/2 and the vertical web is 3/16 x 1/2. The pieces are normally checked for reasonable straightness before they are packed. A small bend in the pieces is usually not a problem as the spar will come out straight when it is glued together. If the pieces are tapered or severely bent Paul will replace them.

Spiccoli

The Yak wing spar should be relatively straight. Balsa is cheap. Go to your LHS and buy some balsa pieces that are relatively straight. Build your spar against a straight edge and insure that the pieces are straight as you glue them together. It's really easy to do.

grn2806

The spar stock with mine was warped and rather than replace it I went ahead and built the spar against a straight edge like the instructions show. when I removed the spar from the building board it still had a considerable amount of warp in it. I then sprayed the entire spar with water and taped it to my straight edge which is a 4 foot aluminum level. I let the spar dry over night and it came out almost perfect. Just one extra step and the problem is solved.
Doug