> - anybody know what kind of constant-speed prop, if any, would work on a > C-90 engine?
The first place to look for information like this is in the aircraft Type Certificate Data Sheet. You can get a copy on line from the FAA web site. That said, there are two props that fit your description that are reasonably available. They are the Beech Roby controllable prop and the Koppers Aeromatic. The Beech prop is adjustable via a crank that looks like it came from the driver's window of a 1936 Packard. The Aeromatic is a "constant speed" prop in that pitch is controlled by counterweights attached to the blade hub. Both of these props are mechanical marvels and if in good shape, the ideal gift for the aircraft owner who has to have the ultimate oddity. Both props have wooden blades secured to metal hubs by the aircraft equivalent of lag screws. Both hubs are the subject of some concern about failure of the said attachment, and both are light on support. It is possible that at some point there would be no good way to maintain them in an airworthy state. Lastly, typically, to install one of these on a C90 requires different blades than the C75-C85, so, unless it has the correct blades for your setup (see TCDS again) it won't do you any good. > - would it be worth it for performance? > Who cares? It'll be so cool, no one will care. Actually, with the Beech prop and the C90, you may be elegable for 5 minutes of 95 take off hp at 2675 rpm. Takeoff and climb should be considerably better with either prop. Cruise will be similar with the Beech. You'll probably find your self cruising at a higher RPM (and lower manifold pressure) with the Aeromatic. John
<<attachment: winmail.dat>>
