ORIGINAL: Pull Up Now!



You are running into the same problem that many people do who want to buy an Evolution radial. The displacements, size, and HP do not easily fit available models out there. Choose wrong, and you can waste $500 on a kit in no time. For fitting, most companies don't give adequate info on the cowl size to be sure a radial will fit. For the Husky, after watching TBM's video to make sure they didn't mention the cowl diameter, I ended up scaling a drawing in Autocad to get the approx. cowl diameter. See the picture below. From that, I found the cowl is 10.2% of the wingspan, which yields 9.69'' diameter. But that's theoretically the OD of the cowl. I subtracted 1/32'' for each cowl wall and came up with a base number of 9.625'' diameter for the inside.

So that means either the 35 or 77cc Evolution would physcially fit. But the cowl is a little tapered, so the question is ''HOW TAPERED''? The only way to know for sure is to contact TBM by phone and get exact measurements of the cowl. The larger engine has, at the cowl widest point, 7/16'' clearance per side. Taper the cowl down and that clearance disappears pretty quickly.

But before you do that, examine horsepower because that will eliminate both engines. The 77 is 197 watts/lbs, WAY too much power unless you buy the floats. And the 335cc is too little power, at 98 watts/lb. The GP Stearman was a bit better match than the Husky.

To accomplish the work you're attempting, and from the questions you're asking Skypup, you need to equip yourself with the necessary tools and knowledge to answer many of these questions yourself. If you private message me and I'll help you get started.