Van's Air Force
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Dynacam
- Thread starter Denase
- Start date
Nothing at all against a discussion on Dynacam - a Spammer posted the identical message on about a dozen different alternative threads, and we (a couple of moderators) cleaned things up. I invited the individual to start a new, single thread on the topic if he wished.
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John Clark
Well Known Member
Posting from Mubai
I read the post (s) before they were deleted. I will be gentle and say that they failed the initial "smell test." If it was a legit posting the technique was very heavy handed. In the words of DCat22, sigh.
John Clark ATP, CFI
FAA FAAST Team Member
EAA Flight Advisor
RV8 N18U "Sunshine"
KSBA
I read the post (s) before they were deleted. I will be gentle and say that they failed the initial "smell test." If it was a legit posting the technique was very heavy handed. In the words of DCat22, sigh.
John Clark ATP, CFI
FAA FAAST Team Member
EAA Flight Advisor
RV8 N18U "Sunshine"
KSBA
I've been involved with the Dynacam engine for a while. I first sow one run in 1980. Don't know the exact status of the company but had a message very recently from one of the founders. There was some stock thing where another group got control and tried to make a stock market killing and then the rights to the engine got tied up. Apparently there is something still happening.
I've followed them for years, too. A company called "Axial Vector" (http://www.axialvectorenergy.com/) bought the technology, and they are producing the engines as part of a genset.
Dynacam was a very interesting concept because you got a lot of hp/weight and a low cross-section. However, apparently the motor prefers to spin at a LOWER rpm than what we typically want for GA, and also creates excessive vibration for our uses.
Given that you would need a gearbox to step UP the rpms, there no longer seems to be any real advantage to the Dynacam design (the motor tends to be too long for existing cowls) for flight, unless you want to use their Diesel variant and burn Jet A.
Dynacam was a very interesting concept because you got a lot of hp/weight and a low cross-section. However, apparently the motor prefers to spin at a LOWER rpm than what we typically want for GA, and also creates excessive vibration for our uses.
Given that you would need a gearbox to step UP the rpms, there no longer seems to be any real advantage to the Dynacam design (the motor tends to be too long for existing cowls) for flight, unless you want to use their Diesel variant and burn Jet A.
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?
Toobuilder
Well Known Member
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.
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.
Mike S
Senior Curmudgeon
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.
John Clark
Well Known Member
Two issues...
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
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
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.
Yeah, Rob, that was back when I had more money than sense. Now I have less of both!
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.
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!
Toobuilder
Well Known Member
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.
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.
Right! And adding more blades is another!
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)
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)
flyboy1963
Well Known Member
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!
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!
