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Electric Stunt => Gettin all AMP'ed up! => Topic started by: PerttiMe on October 23, 2009, 07:18:43 AM
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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.
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:-)
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That might be too many moving parts for me :o Has it been installed in a plane?
I have noticed that F3A people have played with contra props, to improve tracking, I guess.
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not yet
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Might be a bit hard on the bearings during a square corner!
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PerttiMe, here's a thread I started a couple years ago on an in flight variable-pitch prop unit the rc pattern guys were using many years ago. Not exactly the same theme you're presenting but kind of interesting.
http://www.rcuniverse.com/forum/m_4900751/anchors_4902571/mpage_1/key_/anchor/tm.htm#4902571
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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
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I figured if anybody here would appreciate this thing it would be you Dean. Near as I can tell this one was built for Tony Bonetti. All the clues point to that. He was active and one of the top fliers 30 years ago, he used Webras, he lived in Las Vegas during that time etc.. And the clincher, his initials are on the one-page instructions.
What was a little disturbing to ponder though was why would a sharp guy like Tony want to put an item like this in hock? Maybe he just got tired of kicking it around his workshop. Bill
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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