I have ordered the plans for a 54" wingspan Shoestring.

Question #1. The plans call for .40's size 2 stroke engine. What size of 4 stroke would be good in its place ? (70-90)

Question #2. Where can I get a cowl?

Queston #3. Has anyone else built this model from RCM plans?

I have been told that those plans are just about like a Goldberg Shoestring. I would not waste my time putting a 4 stroke in it. Keep it light, put a Hot .46 two stroke and you will love it. If you add the weight of a 4 stroke, it will be a dog and not worth it. It is a great flying plane. Keep it light and it will do anything. If you have to go a 4 stroke, use a saito 56. That would work out ok and it would fly well, not as fast but not bad. Hope that helps.

thanks, I already have a OS 46fx.

That is what I use. It will rock.