We finally decided on an engine: We ordered an AeroMomentum AM15!

The engine is offered as a standard version with 117 hp @ 5800 rpm or 132 hp @ 6500 rpm, very similar to the Viking 130, which we were also considering. AeroMomentum however advertises only the 117 hp @ 5800, as this is the rpm at which Rotax engines make max. power and because they believe that pilots do not want to have their engines screaming at 6500 rpm.

AeroMomentum also offers a beefed up version, which makes, as indicated on their website, 131 hp @ 5800 rpm and 147 hp @ 6500. 

We decided to go with the standard, low profile, 117 / 132 hp version, as we didn't feel like spending another $3,500 for the additional 14 horses the beefed up version would provide. Another reason was, that the more powerful version contains custom made pistons and some other modifications. If we ever need spare parts, they will probably be easier to obtain for the stock version.

All engines are delivered with a dynamometer print out with the individual engine's torque and power curve. Pretty impressive and I believe unique in the industry!

I also like that AeroMomentum uses only brand new Suzuki engines, which have a very good track record in automotive applications and which are very popular, particularly in Asia and Europe.

Mark, the owner, said that he has been selling these engines for over 10 years to jet- and airboat customers. Most of them permanently run their engines full throttle.
The highest time engine accumulated over 4,000 hours without any issues, in a permanent full-throttle fishing net towing application. When the engine needed replacing, mainly due to poor maintenance, they even continued to use the original transmission. Very impressive, particularly considering that he is promoting his engines with a TBO of only 1,500 hrs.

I also like that the AM15 engine is only a little bit heavier than a 100 hp Rotax 912iS, but almost 40 pounds (!!) lighter than the Viking 130. AeroMomentum also advices against the installation of a header tank, what will save same additional weight, compared to the Viking, and also make the installation less complex.

Ultimately, the main reasons to choose AeroMomentum were the relatively low weight, good power, that they have been selling their engines for over 10 years to airboat customers, the attractive price and the very good impression I had of Mark, the owner. He always responded fast and detailed to my e-mails and was very patient and friendly on the phone. When I met him and Lilli, the lady who is handling the sales, at Airventure, my good impression was confirmed: Super friendly, humble and (we felt) honest.

They are still working on the firewall forward kit, we agreed to be Beta customers. We expect to receive the firewall forward kit, minus the cowling, in September. The engine is supposed to be delivered in October, the cowling towards the end of the year.

Very exciting!

HomebuiltHelp has a nice interview with Mark on his YouTube channel: https://youtu.be/xWOj5_0DoQI

Their website: http://aeromomentum.com/ 

Oliver