Constant speed effect

[greeny]

DUC, a French propeller manufacturer claims its (fixed pitch) SWIRL propeller provided a "constant speed effect".
Has anyone ever heard of that, ever tried it and knows if and/or how it works?

http://www.duc-helices.com/anglais/swirl.htm

[banaari]

Hi Peter,
yes it is feasible, and it does work. Prince propellers http://www.princeaircraft.com do essentially the same thing, and achieve about four inches of pitch change, take-off to cruise. The page labelled "About Us" has a more detailed write up. The prop has to be designed to match the aircraft's operating speed envelope, as well as just the engine... so ordering one involves something of an involved discussion.

cheers,
John

[RayAR3]

That is an interesting prop. Sort of a "wing warping" prop. Looks like the Wright Brothers are still influencing us.

There is another option as well:

The blades would have to be installed for a pusher configuration, but the Beech-Roby propellor is a true variable pitch prop that needs no special equipment. The pitch is changed automatically internally in the hub to make the prop pitch maximize climb, cruise, etc. Essentially, it is the perfect prop, and was a factory option on many aircraft years ago.

The Beech-Roby, or Aeromatic http://www.aeromatic.com/ prop could be a neat addition to a high-performace gyro without the costly weight of an actual constant speed prop.