Had previously thought I would use a big bore 4-cyl like the 390 or 409 but now am leaning toward the O-540 for my custom 4-seat bush plane design. Offerings from whirlwind like the 80" STOL constant speed don't quite seem enough blade. Do they offer anything longer? It's hard to tell from their site.

MT of course is an option, but they are quite expensive(I think around $15k?). Just looking for other options if anyone knows of alternatives.

You might want to look into the IVO propeller line. The Magnum may work.

http://www.ivoprop.com/

SkylaneSam wrote:You might want to look into the IVO propeller line. The Magnum may work.

http://www.ivoprop.com/

Thanks for the link, but I don't think those are quite in the same class as MT or Whirlwind. Even the Magnum is geared toward heavy light sport if I'm not mistaken. My requirements are for a hydraulic constant speed for pulling a 2500 lb machine.

Did I read somewhere that Macauley is going to introduce composite blades?

The site says that the magnum series supports up to 700 hp, which is probably a bit more then you have.

cstolaircraft wrote:The site says that the magnum series supports up to 700 hp, which is probably a bit more then you have.

That's not really the point.

IVO will not sell you a prop for a lycoming. I had this discussion with them for my O-320. Due to vibration amd cracking issues they informed me they won't do it. So you can scratch that thought.
MT would be great, but I agree, pricey. If Macauley would start composite blades that would be great. A little competition never hurts.

A1Skinner wrote: If Macauley would start composite blades that would be great. A little competition never hurts.

I think they are already experimenting with composites for some of their fixed pitch models. Hopefully it proves to be a good experience for them.