Anybody using these?
http://www.ramoser.de/home_e/varioprop_e/varioprop_e.html

Looks like a neat idea to me: get a prop hub and a spinner, and then you can put on prop blades in the length you want. Adjust pitch to what you need.

Some sizes available left handed too.

Also 3, 4, and 5 blade hubs and spinners.

That might be too many moving parts for me Has it been installed in a plane?

I have noticed that F3A people have played with contra props, to improve tracking, I guess.

Might be a bit hard on the bearings during a square corner!

Bill,
You dog! I looked for one of those critters for eons and look at the deal you got!
They were only for sale domestically in Japan and to selected competitors worldwide. The grey market skirted that, though. They were not intended to be run at anything over 11,000 RPM (set to 10-1/2" pitch) but noise cheaters (like the entire Italian pattern team in '83) used them to skirt the noise test at high pitch and then flew at reduced pitch and high RPM. Yeah, they blew up that way too! I worked as the timer on one of the two flightlines at that Worlds, and I distinctly remember one of the Mexican team members using such a grey market item on a flight where he was on the hairy edge running over the time limit. He landed flat and fast at maybe 1/2 throttle to get back to the runway quickly, threw the prop into flat/reverse and then revved the engine. It only rolled an 1/8 of a mile that way!

When E-Pattern was first being seriously discussed after the high-current nickel metal hydrides first happened, a few of us theorized that running the motor (brushed back then!) at full voltage and varying the pitch to control power delivery would be a good idea.

Thanks for shaking a few cobwebs loose!
Dean Pappas

in flight variable-pitch prop unit

Pretty interesting. That's for sure.

Doesn't sound like something a mere mortal like me should really play with, though.

The modular and slightly adjustable approach of Varioprop, on the other hand.... Even I might manage to keep it working.

Pertti