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Three New Alternative Engines

The cousin and I were talking all week about the AeroMomentum engine. Can you imagine one of those turbo 260hp's in a -10? :eek:
 
Wow. When they have a firewall forward kit ready for a -7 or -8 or -10 I'm in......

Has anybody taken delivery of one of their motors?
 
Wow. When they have a firewall forward kit ready for a -7 or -8 or -10 I'm in......

Has anybody taken delivery of one of their motors?

Be sure and research well before you purchase..... An honest aircraft motor has never been replaced by a conversion with any success. Make sure you are willing to spend the money and time needed.

............"never say never".............
 
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Be sure and research well before you purchase..... An honest aircraft motor has never been replaced by a conversion with any success. Make sure you are willing to spend the money and time needed.

Amen to that. I have taken more auto conversions out to install Lycomings than I care to remember. On the other hand, an auto conversion plane can be had for a bargain, cheap enough to put a Lycoming on and be money ahead.
 
Not true.

Be sure and research well before you purchase..... An honest aircraft motor has never been replaced by a conversion with any success. Make sure you are willing to spend the money and time needed.

I have spoken with several owners with flying conversions that work just fine. That is not to say, by any means, that the conversions are the way to go for the majority of folks. The additional time, effort, and expense to get them working is substantial.

I truly admire the people attempting to break the mold and move us into the future...getting away from the 60 year old technology that is the current norm. Those are the folks that will push progress forward, rather than remains stagnant with the status quo...

THEY put the experiment in experimental...
 
Be sure and research well before you purchase..... An honest aircraft motor has never been replaced by a conversion with any success.

The first part is good advice but "Never" is a pretty strong word...

Let's see:

Russell Sherwood's Subaru EG33 Glasair, multiple SARL wins. Routinely destroys Lyconental powered aircraft having 50-100% more displacement. 700+ hours later, still working fine.

Gordon Wardstrom's Bearhawk with Rover V8 power, 1500 hours, never touched.

Gary Spencer's LongEze with Ford V8 power, multiple race wins, 1000+ hours.

Jeff Ackland's LS powered P-85, cheaper, faster, lighter and lower fuel burn than the M-14P powered Radial Rocket. No problems to date.

PA-25 in Australia used as glider tug. LS V8 replaced the Lycoming 540 engines which were not lasting well. Huge reduction in operating costs per flight hour with considerably higher tow performance.

Bjorn Anders Subaru EZ30 turbo powered RV-7, over 600 trouble free hours to date.

I could go on.

For sure, not for everyone. Lots don't work out. Lot's do.

"Never" simply isn't accurate.
 
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I have spoken with several owners with flying conversions that work just fine. That is not to say, by any means, that the conversions are the way to go for the majority of folks. The additional time, effort, and expense to get them working is substantial.

I truly admire the people attempting to break the mold and move us into the future...getting away from the 60 year old technology that is the current norm. Those are the folks that will push progress forward, rather than remains stagnant with the status quo...

THEY put the experiment in experimental...


Amen to that!!
 
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I just posted this in the RV-12 section, where another AeroMomentum thread is going on, but thought that it might also contribute to this discussion:

Somebody posted a presentation by Mark Kettering at an EAA chapter, in case you're interested:
https://youtu.be/leQWYeHkNbw

I am really impressed by his level of experience, knowledge and openness. We also thought about other engines. After Lycoming and Conti (too heavy) and Rotax 912 (too weak), the AeroMomentum came out on top.
That they have been selling these engines for over 10 years to airboat customers, where they see lots of hours and abuse, finally sold us on them.

We therefore bought an AeroMomentum AM15 for our Zenith CH750 project, but are not flying it yet.
 
Back to the future...

I have to admit, as a three time RV builder and A&P I have always been leery of auto conversions.
Why? They were never engineered to run at 75% power for extended periods, front crankshaft bearings are not sturdy enough to handle prop loads, heavy, complex plumbing for liquid cooling, reliability, etc, etc...

However comma, Tracy Crook and I built our RV4's at the same time (20 years ago) and I followed his progress closely, visiting his grass strip home on the Suwanee River several times.
I always respected his endeavor and that his RV4 with the Mazda Rotary was truly an Experimental design. His refinement, engineering and innovation won me over. This guy is a true Experimenter...
His current RV8 with the Three Rotor Renesis Wankel Rotary is a beast and carries the refinement of 20 years of research.

These days I'm not as quick to criticize a new design or improvements on an old one...It's called innovation...
V/R
Smokey

My Sonerai II sports a 1835CC VW derivative that has been flying in Experimental designs for over 60 years. It's cost of operation was easily one third my RV's.
It is featured in this quarterly issue of Contact...

http://www.contactmagazine.com/
 
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I have to admit, as a three time RV builder and A&P I have always been leery of auto conversions.
Why? They were never engineered to run at 75% power for extended periods

These days I'm not as quick to criticize a new design or improvements on an old one...It's called innovation...
V/R
Smokey

My Sonerai II sports a 1835CC VW derivative that has been flying in Experimental designs for over 60 years. It's cost of operation was easily one third my RV's.
It is featured in this quarterly issue of Contact...

http://www.contactmagazine.com/

In fact, many auto engines are validated at 75-100% power these days for hundreds of hours and their specific output can be triple that of a Lycoming. There can be other reasons for not using an auto conversion but this isn't a valid reason for not choosing one.

I've posted the video links before of the Kia turbo engine running at 100% power for 300 hours (around 100hp/ liter specific output) and the Ford Ecoboost V6 torture test (also at over 100hp/liter)-still within spec at teardown.

With adequate development and testing, auto engines can work just fine in aircraft. It's been done thousands of times worldwide.
 
[...] They were never engineered to run at 75% power for extended periods [...]

I don't think that this is necessarily the case. The Suzuki engines, on which the AeroMomentum engines are based on, were always also used in Suzuki outboard boat motors, where they often see high loads at high rpm, similar to the profile in an aircraft: Some idling / low load, followed by full throttle to get on step and then slightly less throttle to quickly get to the fishing grounds.

Many of the airboat customers, to which AeroMomentum has been selling their engines for years, often use them in fishing operations, where they run almost full throttle for most of the day. Quite a few of their airboat customers accumulate around 1,000 hrs / year with minimal maintenance and under high load. I therefore think that airboats are a unique, valuable testbed for AeroMomentum.


[...] front crankshaft bearings are not sturdy enough to handle prop loads, heavy, complex plumbing for liquid cooling, reliability, etc, etc... [...]

The AeroMomentum is using a gearbox (just like the Rotax 912) which takes the loads of the propeller and which has also been used in airboats for many years. Heavy is, in my opinion, true and wrong at the same time. Compared to an Rotax 912 our AeroMomentum is a fat pig, but also has 17 more hp. Compared to a 115 hp Lycoming O-235, it is however pretty light.

I weighed all the components of our engine, including the engine mount, bolts, the radiator, hoses, oil, coolant, etc. but without prop, spinner and cowling. All in, I came out at 241.75 lbs. AeroMomentum believes that they can reduce the weight by 10 lbs, what would bring it down to just above 230 lbs.

According to wikipedia, the O-235 weighs 243 lbs, without anything and dry. I guess the wet installed weight, including the engine mount and baffled would be around 280 lbs.

I also weighed the components of a friend's Rotax 912 ULS. While the engine itself weighed only 131.6 lbs, all the stuff around it adds up. All in it came out at 194.69 lbs.

So, overall the AeroMomentum is around 40 lbs heavier than the 17 hp weaker Rotax, but (I guess) around the same amount lighter than an O-235.

As for the complexity, we only have to install one singe water cooler. That's it. No baffles, no oil cooler.
 
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The first part is good advice but "Never" is a pretty strong word...

Ross, do you know how fuel burn compares for your known examples, are any better than the aircraft engines at the same airframe/speeds?

Of course there is the bench/dyno aspect of BSFC, but also the installations and prop matches make a difference too, so the fully tuned installation should tell us more about the comparison.

Thanks,
 
A simple, dumb question here from somebody who has not spent any appreciable time behind a geared auto conversion...

How does it "feel" to have the engine turning at 5-6,000 RPM? Does it feel as frenetic as it does when that engine spins that fast in a car?

Our EAA chapter president flys a Cozy Mk IV with a 6-cylinder Subaru and geared drive. It sounds wonderful in ground ops. Since it's a pusher configuration he reports it is smoother than any aircraft engine he has ever flown. I just wonder what the high-revving engines feel like in a tractor configuration?

(I'm looking for input from those with real-world experience. This isn't about bashing auto conversions - it's about learning from those with experience.)
 
and...

I can tell you that I have experience in several GA aircraft with geared aircraft engines and it was no big deal...they were turning in the 3000-4000 range...
 
I have several hours of passenger time in Tracy Crook's Mazda Renesis powered RV-4, and a bit under an hour in a Mazda 13B powered RV-6. I can say that while rotaries can be painfully loud, some installations in a/c are as quiet (or, in some cases, quieter) as Lycs. In both the a/c I've ridden, the smoothness compared to a Lyc is almost unbelievable. Most operate rotaries at between 5k & 6k rpm in cruise. My experience is that the higher rpm, while initially obvious, is quickly forgotten, and with a decent set of headphones, all I remember is dead smooth 'hmmmm'.

Charlie
 
Ross, do you know how fuel burn compares for your known examples, are any better than the aircraft engines at the same airframe/speeds?

Of course there is the bench/dyno aspect of BSFC, but also the installations and prop matches make a difference too, so the fully tuned installation should tell us more about the comparison.

Thanks,

Some are better and some are worse. The LS in the P-85 burned something like 20% less fuel than the M-14P for the same TAS. Some of that was probably drag related between the radial and V configuration but most was due to the higher TE and lower mechanical friction of the modern engine. Jeff could comment on that more accurately.

From numbers on the EJ257 turbos in a couple RV-7s, the TAS vs. FF were pretty similar to a Lycoming setup.

The EZ30 turbo burns about 15% more than a Lyc running LOP.

The LS in the PA-25 was burning about 3-4 GPH less than the 540s, most of that mission is ROP, high power and then power off coming back down. The EFI shuts the fuel right off on descent.
 
A simple, dumb question here from somebody who has not spent any appreciable time behind a geared auto conversion...

How does it "feel" to have the engine turning at 5-6,000 RPM? Does it feel as frenetic as it does when that engine spins that fast in a car?

Our EAA chapter president flys a Cozy Mk IV with a 6-cylinder Subaru and geared drive. It sounds wonderful in ground ops. Since it's a pusher configuration he reports it is smoother than any aircraft engine he has ever flown. I just wonder what the high-revving engines feel like in a tractor configuration?

(I'm looking for input from those with real-world experience. This isn't about bashing auto conversions - it's about learning from those with experience.)

Most folks don't turn over 5K with medium to large sized engines except maybe for takeoff. You get used to the different sound pretty quickly. I turn around 4200-4500 in climb and cruise. Doesn't sound strained. The turbo helps clip off the sound levels a bit. I recall ground running an atmo EZ30 6 cylinder in Florida years back with no mufflers and it was pretty brutal. Kinda seared into your brain at high revs. Not a pleasant note at all. From outside, these engines sound nice and not all that loud.

Short clip of one of the Subaru EJ257 turbos: https://www.youtube.com/watch?v=om1GUJ5m1nY

Some ground and flight shots on the other RV-7 turbo we did up here: https://www.youtube.com/watch?v=No7BnIDAp-Q

P-85: https://www.youtube.com/watch?v=MQq2TE6vqIY
 
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