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01-22-2011, 12:26 PM
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Join Date: Aug 2007
Location: S21, Oregon
Posts: 161
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Ask and ye shall recieve......
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Kelly
RV-7 empennage done, wings done, fuselage to QB stage.
1973 Maule M4-220C flying
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01-22-2011, 01:55 PM
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Join Date: Mar 2009
Location: Van Nuys, CA
Posts: 62
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Dynacam
There's a discussion about this engine on homebuiltairplanes.com . The axial engines group mentioned on a post above with a web site is the group that got control of Dynacam but they are just blowing smoke now, so I'm told. The discussion on homebuiltairplanes is connected to the original people. They are wondering what anyone has to say about the engine, good or bad.
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01-22-2011, 01:55 PM
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Join Date: May 2005
Location: Santa Barbara, CA
Posts: 1,324
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Two issues...
Quote:
Originally Posted by Toobuilder
Second, the engine operates at 2000 RPM, which is far from "too slow" for propellers. It's better, in fact than the 2500-2700 range we use now. Noise goes down, and efficiency goes way up with a big, slow turning propeller.
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The Dynacam design does have a low output RPM, but there is a catch, the piston speed is quite high, due to the "ratio" between the pistons and the output shaft. At 2000 RPM, the piston speed is the same as turning a Lycoming 4500 RPM. As Mike said, the propeller problem can be addressed, but the easy way is with diameter and that could get interesting. I used to fly a turboprop that a max prop RPM of 1600, but the props were over 10 feet in diameter. Might pose a problem on the ground in an RV airframe.
John Clark ATP, CFI
FAA FAAST Team Member
EAA Flight Advisor
RV8 N18U "Sunshine"
KSBA
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01-22-2011, 11:23 PM
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Join Date: Oct 2009
Location: Victoria, BC, Canada
Posts: 3,932
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Quote:
Originally Posted by elippse
But I have a little plastic model that I bought from the company for $16.00 that sits on my dining-room table and is a great conversation piece. You can twirl the shaft and watch all 12 of those little pistons go back and forth twice per rev! 'Wonder what I can get for it on E-bay?
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You *bought* one of those? Ouch. The company sent our flying club a *box* of 30 models, complete with brochures, for free, about 5 years ago. I think half of them are still in the back of the office at our clubhouse. Neat model, though.
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Rob Prior
1996 RV-6 "Tweety" C-FRBP (formerly N196RV)
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01-23-2011, 10:12 AM
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Join Date: Dec 2006
Location: Arroyo Grande, CA
Posts: 938
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Quote:
Originally Posted by Snowflake
You *bought* one of those? Ouch. The company sent our flying club a *box* of 30 models, complete with brochures, for free, about 5 years ago. I think half of them are still in the back of the office at our clubhouse. Neat model, though.
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Yeah, Rob, that was back when I had more money than sense. Now I have less of both!
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01-23-2011, 07:46 PM
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Join Date: Dec 2006
Location: Atlanta, GA
Posts: 1,231
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Quote:
Originally Posted by Toobuilder
OK, there are some people putting out feelers to get production started once again on the Dynacam, and in the ensuing discussions, it is universally agreed that the engine operates without any perceptible vibration.
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Do you have some links to anyone who has conducted tests? I was very excited about this engine many years back, but read several reports about vibration being an issue.
Quote:
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Second, the engine operates at 2000 RPM, which is far from "too slow" for propellers. It's better, in fact than the 2500-2700 range we use now. Noise goes down, and efficiency goes way up with a big, slow turning propeller.
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All fine and good if you have a plane that can swing a big prop, not so convenient if you have a little plane.
Weight and balance will be an issue too, with the motor being so long. Well, anything is possible and I hope it works out!
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01-24-2011, 04:38 PM
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Join Date: Jul 2009
Location: Mojave
Posts: 4,652
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The hyperlink in my first post goes to the thread on the Homebuilt Airplanes forum. Several people in that discussion seem to have first hand knowledge of the engine.
As to big props on little airplanes, there is more than one way to reduce the "wing loading" of an airfoil. Increasing the span (diameter) is just one choice.
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WARNING! Incorrect design and/or fabrication of aircraft and/or components may result in injury or death. Information presented in this post is based on my own experience - Reader has sole responsibility for determining accuracy or suitability for use.
Michael Robinson
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Harmon Rocket II -SDS EFI
RV-8 - SDS CPI
1940 Taylorcraft BL-65
1984 L39C
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01-24-2011, 05:38 PM
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Join Date: Dec 2006
Location: Arroyo Grande, CA
Posts: 938
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Quote:
Originally Posted by Toobuilder
The hyperlink in my first post goes to the thread on the Homebuilt Airplanes forum. Several people in that discussion seem to have first hand knowledge of the engine.
As to big props on little airplanes, there is more than one way to reduce the "wing loading" of an airfoil. Increasing the span (diameter) is just one choice.
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Right! And adding more blades is another!
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02-07-2011, 05:27 AM
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Join Date: Jan 2008
Location: Wisconsin
Posts: 40
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There is a gentleman on the homebuilthelp forum who insists that the RV'ers have summarily dismissed the engine.
Since I've noticed homebuilders of all sorts (RV and otherwise) to be resistant to pigeonholing, I'm dubious of the claim. Then again, if all of you RV'rs have decided to now only make your decisions collectively, I stand corrected (that's a tongue in cheek comment, BTW) 
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02-07-2011, 03:28 PM
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Join Date: Oct 2008
Location: Lake Country, B.C. Canada
Posts: 2,416
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the holy grail...again
Ah don't we all love that 'new' engine that is 'just on the horizon'.....welll, maybe our kids hover cars will be powered by a dynaCam.
sounds a lot like the K-cycle started by some prof at University in Manitoba.
...I thought I'd hear they were using it to power some types of torpedo's?...but of course, that has kind of a low TBO, and ample coolant at hand! 
Perhaps the proliferation of small cnc production capability will have a positive effect on these types of operations. Too bad the so often fall into the hands of stock promoters and lose their focus.....one reason why a success story like Scaled Composites is so rare....from homebuilts to space ships....gotta love that!
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Perry Y.
RV-9a - SOLD!....
Lake Country, BC
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