Hello,
I am in the process of building a T.C.O.W. Super Cub and cannot decide to go with a 0-320 built up or a stock 0-360. Any suggestions?
Thanks.

How much money you got?

The key to a really nice flying Cub is keeping the weight low. A very light Cub is a pure delight to fly, and performance is great.

Add more weight, and more horsepower, and you can perhaps equal the takeoff performance of a lighter airplane, but you'll never make it fly like a light plane would.

My recommendation is: Keep it light!! Note that ALL the O-320 engines are about 10 pounds lighter than any of the 360's. That's ten pounds right off the nose. Oh, and by the way, every 360 equipped airplane I've met actually weighs a LOT more than ten pounds more than any 320 equipped airplane.

Go with the 320, tune it, do whatever, but KEEP THE PLANE LIGHT.

That is the key to success, Grasshopper...

MTV

Damn Mike you spoiled my whole plan.

I think a turbo charged 0-320 would be the ticket.

Welcome.

It's a good idea to keep the plane light, no doubt, but upping the output of an engine beyond what it is designed for has its own set of trade offs.

To get more power at the prop you will need to increase torque or RPM. By doing either you create higher forces on all the parts in the load path. All those parts were designed with a maximum load in mind, and then the stresses were calculated and fatigue life was estimated. Any additional loads will cause the fatigue life to be shortened. There is always a safety factor so you can push the engine a certain amount above its design point without creating a major safety issue, but you probably will have more of a problem than normal meeting TBO. If you go too far then catastrophic failures start to become more likely.

Assuming you increase the power within reasonable limits, I would think you would start seeing the typical O-320 problems sooner than normal. For instance, compressions might be low and oil consumption might be high for an engine of comparable age. Bearings and cams are sensitive to loads and would probably suffer the worst.

Just my thoughts, for what little they are worth.

So, what wings did you use? The D&E Aircraft ones or something else? I've been threatening to start a super cub project for a while now, and I'd love to see pictures and a description of mods you've made.

Hi 96,

A local friend is nearing completion on his Smith and has chosen the ECI O-340. (177 hp) I will be taking a closer look at this combination when I go down that road. It shares cyls with an O-320, but has a longer stroke. As I understand it this crank can be used in a narrow deck O-320, but I am not certain they (ECI) will sell just the crank.
BTW... this is not the same engine as the orphaned Lyc. O-340...

another option...

Take care, Rob

Chevy,

I agree with the polished and ported O-320 B2B (160+ hp) thoughts. Having helped build a Smith with the O-360 we ended up at 1355 pounds!!

There is another Smith on the field here with a new O-340 and they've been having some cooling issues with it. That said it makes GREAT power and the airplane is much lighter than the O-360 powered examples of the breed.

I like a rodded O-320 with the thrustline mod as the best choice.

Brad

ECI sells a stroker upgrade kit for standard 0320s . Crank, rods and pistons.

Wow , thanks for all the feedback. It sounds like the 0-320 tuned would be the ticket . The kit is very good quality but the instructions , or lack of, makes thing harder to assemble . Thanks to some friends that have worked on Cubs before I am plooding along.Turbine Cubs staff are great to work with on any help needed. Wayne at TCOW is developing manuals and videos on the build. Thanks for your help .