RE: VQ P-61 CONTRUCTION
Yeah, clearance in the cowl is a big factor in engine selection for this plane. I was thinking big Saitos at first. But the biggest Saito that would fit correctly would be a 100 and it would stick out almost as much as the YS. The YS 110 is a bunch stronger than the Saito, using straight pipes eliminates the muffler problem, and a pair of un-muffled 110's should sound really cool!
If you want everything inside the cowl then it looks like the 2-stroke 91 or equivalent is just about the only way to go. But based on earlier postings the 91 won't handle a 4-blade prop. I don't know if Sam P ever actually tried them in the air though.
Reliability was also a huge factor in my selection. Unlike most of you guys that are working on the 'Widow I've only flown R/C for a few years, and I know that my model building ability is way ahead of my flying ability. I've yet to build a plane that I couldn't get up and down in one piece, but I want to be as sure as possible that I will have enough flight time to get to know this one well before facing the first engine flameout with it! My experience with YS's is that they are more reliable than the Saitos or big 2-strokes, and this is a big plus for me.
I'm gonna go and fly the second 110 some more today, and while I am at it I'll get some thrust readings with the 2-blade and 4-blade props. I already put the digital fishing scale in the flight box.
Walt