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Aeromomentum

D

dsm8

Well Known Member
Patron
Good Evening RV-12ers:

While watching videos of Oshkosh saw an aeromeomentum video and RV-12 FWF kit. Although I love the concept of experimental/amateur built category advantages, the reliability of the Rotax 912 ULS cannot be discounted. I am always open to considering alternative options. Any one with experience with aeromeomentum engines or alternatives, I am willing to consider. I know there are strong opinions out there and do not want to get into a "primer war", just would like to hear about anyone's regrets or successes

Have a great evening
 
Same here. 450+ troublefree hours with original carb floats! I flew a Skyhawks with a O300D Contienental for 31 years before building my RV12. I have the same confidence in the 912ULS I had with the O300D!
 
I had a great time at Oshkosh and was able to spend a little time at the AeroMomentum booth with both Mark Kettering, owner, and Dick Gossen- who has an AM15 on his RV12.

Dick is the best resource for this engine on a 12; he is very happy with the setup, it is performing well for him, is fuel efficient and a fraction of the cost in comparison to a Rotax.

I took a bunch of photos, but posting them here is a hassle, so suffice it to say the quality of work is very good. One thing to note is that Mark is an actual engineer who designed his gear boxes with actual good engineering practices and stress analysis (as opposed to another “entrepreneur” selling gearbox packages that look shiny).

Mark claims he has several gearboxes with 4000 to 5000 hours on them running on airboats, so reliability appears good
 
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What would be helpful is for alternative FWF vendors to publishing some real numbers for weight and balance for their alternative engines in RV-12s. An engine weight increase of 40 pounds does not sound like much, however it is all over the nose wheel. Its not hard to be near the FWD CG limit at low fuel with a single pilot.

In my case, I was not happy with the forward CG situation and ended up moving both batteries and the dual fuel pumps to the tailcone. It was interesting to see Van's dual fuel pump mounting location in the 12is is also in the tailcone area.

If you do not like building, designing, and fabrication work I would recommend staying away from alternative engines, its a lot of time and work to do it right. In my case, I estimate it added at least two years to the build time.

John Salak
RV-12 N896HS
 
Weight decrease from batteries

I have installed 2 EarthX batteries to off set the increased engine wt.
 
I just went to Oshkosh with my brother and 85 pounds of baggage with 22 gallons of fuel: at that weight, I see 1100 fpm at Sea Level, but I climbed out of Bozeman, MT at a 11,900 DA at 600 fpm. I was pretty happy with that.

With 15 gallons of fuel and solo, I can see initial rates of 1700', and climb to 8500' in ~7 minutes from take off from SL, so his numbers are reasonable.
 
Personally, I wouldn't want to hang one on an RV-12 if I were building. By the time you're finished I'm not sure how much money you'll actually save, but I'm pretty sure you'll significantly extend the build time -- and it will (if history is any indication) be difficult to sell when you need to sell it. It certainly would be "experimental", though.

That said, I do like what I have seen of the Aeromomentum engines and PSRU. I talked to the guy for a while at Airventure in '17. I have another project under way that I may hang one on, if I live long enough to actually get to the point of needing an engine.
 
DaleB said:
By the time you're finished I'm not sure how much money you'll actually save, but I'm pretty sure you'll significantly extend the build time -- and it will (if history is any indication) be difficult to sell when you need to sell it.
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A very valid point. You will save $15k on the build. But if you take a $20k or $25k hit at resale time, what have you really saved?
 
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