Can you clarify for me how you will change pitch? The IVO
twists the tip, which is effectively wing warping. Does your
design rotate the entire blade in the hub like typical
constant speed props, or use some other method to change
pitch?

Thanks,

Charlie

Charlie
The IVO does use wing warping.  That is not suitable for a full range of pitch change.

Our design (read Hamilton Standards design) twists the whole blade. By twisting the
whole blade you have a full range of pitch including feathering if desired.
Their prop is forged aluminum, and has a flange on the end and a split cone and ball
bearings are loaded onto the blade shank. The balls ride on the split flange ( an
inner race) and the outer race is installed in the hub. There is an amount of play in
the bearings, and centrificul force tracks the blades. (the bearings retain the blade)

We will use a tapered roller bearing in the same manner, and we can do this because
the blade has a steel shaft embedded in the blade with a tee end.  The other end is
threaded and slips through the bearing inner race, a cam and lever is keyed to the
shaft inside the hub.  A castellated nut and cotter retains the whole assembly in the
hub. A shaft with a grooved ring runs through the Prop shaft. The end of the shaft
with the grove runs on the cam bearings and the other end has a ball bearing mounted
in a sleeve shaft so the sleeve shaft can be mounted stationary and is pulled in and
out to change the blade pitch.
The outboard portion of the hub containes a seal to stop dust and water.
The blade planform can be most any thing desired. It has a negative twist so the
higher speed end section developes the same amount of lift as the rest of the main
blade.
We will have some drawings hopefully sometime next week, this week was filled up last
week, so don't have the time right now.
Royce

 
The AirCraft Rotary Engine NewsLetter.              Powered by Linux.
ACRE NL web site.
http://home.earthlink.net/~rotaryeng/            http://www.linux.org