RE: DLE55 & 3-Blade Prop
I have run several DLE55's with a 3-blade Mejzlik 21X12 and that works great provided you are using a canister for exhaust. This is what I use on my Composite ARF Yak55SP 2.1m with a DLE55. However, with an inverted wraparound muffler the engine is markedly less efficient, and you would be much better off for instance with a Mejzlik 2-blade 22X10. This is what I use on my TF GS P-47 with a DLE55. If you really want to go with a 3-blade, I would recommend a 21X12 or a 21X11.5N Mejzlik to a Biela. Bielas are quite heavy propellers.