# Non- Biased Engine Reviews -Aeromomentum

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#### Arkan

##### Well-Known Member
I would love to run one of my engines at full power until it fails. A customer (airboat) went 4000 hours. Admittedly, it was not always full power. But also it had very limited maintenance. So 4000 hours at full power with regular oil changes should be possible. Assuming 6gph (on our 100hp at full power) and $3/gal the fuel alone is$72,000.00. We have 8 versions with most being more powerful and thus using more fuel. So about \$1,000,000.00. Just for the fuel.

But this is way more than what is required for certified aircraft engines. According to §33.49, engine certification endurance requirements are 150 hours total test run time! Of this 150 hours only 105 hours is at max power. We have done more than this and inspected for wear.
I am impressed, AeroMomentum. I know this is supposed to be a thread about a different engine company. I have a thread called Project Bush Demon. I am designing a STOL bush plane. I would like to ask some questions there if you if I could. My thread is totally a design thread, I don't have a pilots license, or funds to build a plane. I am working on sketching designs, and ultimately blue prints for a STOL back country bush plane. I believe I found the power plant I want to base those designs on, and would love your input.

#### Oliver

##### Member
[...] A customer (airboat) went 4000 hours. [...]
Hello Mark,

You keep stressing how you are using airboats as a test bed. Hundreds of them, for thousands of hours!
I was never able to independently verify this for the AM15, which I had bought from you, even though I spent a considerable amount of time trying to find manufacturers or owners of airboats who are using your engines.

Now, I am certainly not saying that your claims are false, but I am wondering to what extend they are true!?

I believe you launched the AM13 only 2 or 3 years ago, if I am not mistaken. What kind of testing went into it before you started selling it to aircraft customers?
The page for the AM20T is (still) showing the engine sitting on a pallet: AM20T
The AM20 and the AM24 only have ‘Information coming soon’: Untitled Document

The information on your airboat website is also rather on the ‘light’ side. The AM20 and AM24, as well as the ‘low profile versions’ are not offered at all: airboat engines
No videos, no pictures, do data, besides of a few close-up images.

I am sure that potential customers would like to see some hard evidence for the amount of airboat- as well as aircraft-testing, that went into your engines – not just in general but broken down by variant.
Personally, I would also expect to see on your FB posts like ‘Gator Airboat Rides have successfully accumulated 2,500 hours with three of their airboats, which we are using as a test-bed for our new AM20T aircraft engine’.
But, again, nothing. No pictures, no videos, no data, just nothing.

I hate to rain on anybody’s parade, especially publicly, but you and I had this discussion over the course of several years and I think that potential customers should be aware of the lack of test-data as well as the quality and completeness of the fwf ‘kit’, before they make a decision.
I also believe that hard test-data is in case of Aeromomentum particularly important, since you are not only significantly modifying these engines, compared to a stock Suzuki, but since you are also manually assembling them in your shop with (primarily) aftermarket components, which might or might not be of the same quality as Suzuki OEM parts.

Oliver

#### BoeveP51

##### Well-Known Member

Non- Biased Engine Reviews -Aeromomentum (or whatever)

#### narfi

##### Well-Known Member
Log Member

Non- Biased Engine Reviews -Aeromomentum (or whatever)

#### PagoBay

##### Well-Known Member
This post should be here.

"Oliver, post: 600750, member: 106255"
Hello Mark,

You keep stressing how you are using airboats as a test bed. Hundreds of them, for thousands of hours!
I was never able to independently verify this for the AM15, which I had bought from you, even though I spent a considerable amount of time trying to find manufacturers or owners of airboats who are using your engines.

Now, I am certainly not saying that your claims are false, but I am wondering to what extend they are true!?

I believe you launched the AM13 only 2 or 3 years ago, if I am not mistaken. What kind of testing went into it before you started selling it to aircraft customers?
The page for the AM20T is (still) showing the engine sitting on a pallet: AM20T
The AM20 and the AM24 only have ‘Information coming soon’: Untitled Document

The information on your airboat website is also rather on the ‘light’ side. The AM20 and AM24, as well as the ‘low profile versions’ are not offered at all: airboat engines
No videos, no pictures, do data, besides of a few close-up images.

I am sure that potential customers would like to see some hard evidence for the amount of airboat- as well as aircraft-testing, that went into your engines – not just in general but broken down by variant.
Personally, I would also expect to see on your FB posts like ‘Gator Airboat Rides have successfully accumulated 2,500 hours with three of their airboats, which we are using as a test-bed for our new AM20T aircraft engine’.
But, again, nothing. No pictures, no videos, no data, just nothing.

I hate to rain on anybody’s parade, especially publicly, but you and I had this discussion over the course of several years and I think that potential customers should be aware of the lack of test-data as well as the quality and completeness of the fwf ‘kit’, before they make a decision.
I also believe that hard test-data is in case of Aeromomentum particularly important, since you are not only significantly modifying these engines, compared to a stock Suzuki, but since you are also manually assembling them in your shop with (primarily) aftermarket components, which might or might not be of the same quality as Suzuki OEM parts.

Oliver

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#### aeromomentum

##### Well-Known Member
Hello Mark,

You keep stressing how you are using airboats as a test bed. Hundreds of them, for thousands of hours!
I was never able to independently verify this for the AM15, which I had bought from you, even though I spent a considerable amount of time trying to find manufacturers or owners of airboats who are using your engines.

Now, I am certainly not saying that your claims are false, but I am wondering to what extend they are true!?

I believe you launched the AM13 only 2 or 3 years ago, if I am not mistaken. What kind of testing went into it before you started selling it to aircraft customers?
The page for the AM20T is (still) showing the engine sitting on a pallet: AM20T
The AM20 and the AM24 only have ‘Information coming soon’: Untitled Document

The information on your airboat website is also rather on the ‘light’ side. The AM20 and AM24, as well as the ‘low profile versions’ are not offered at all: airboat engines
No videos, no pictures, do data, besides of a few close-up images.

I am sure that potential customers would like to see some hard evidence for the amount of airboat- as well as aircraft-testing, that went into your engines – not just in general but broken down by variant.
Personally, I would also expect to see on your FB posts like ‘Gator Airboat Rides have successfully accumulated 2,500 hours with three of their airboats, which we are using as a test-bed for our new AM20T aircraft engine’.
But, again, nothing. No pictures, no videos, no data, just nothing.

I hate to rain on anybody’s parade, especially publicly, but you and I had this discussion over the course of several years and I think that potential customers should be aware of the lack of test-data as well as the quality and completeness of the fwf ‘kit’, before they make a decision.
I also believe that hard test-data is in case of Aeromomentum particularly important, since you are not only significantly modifying these engines, compared to a stock Suzuki, but since you are also manually assembling them in your shop with (primarily) aftermarket components, which might or might not be of the same quality as Suzuki OEM parts.

Oliver
Hi Oliver,

You seem to be mistaken about what I have said. I have said that we have delivered about 100 engines for use in airboats. I have also said we have delivered over 100 engines for use in airboats. These are true and consistent statements. By far most have been AM13s and many were shipped to Dragonfly. (
) Note that the post date is early 2013. The longest running was told to me to be 4000 hours with 2 oil changes and no belt changes. This engine was operated by Loy Fishers in UT and the person you should contact for proof is Cody Loy. After this engine failed we sold them an AM15 long block and they changed over all the original 4000 hour external parts and ran this engine for 1500 hours before the original OEM Suzuki alternator bracket cracked and failed. We no longer use this part and now make our own. This failed bracket caused the water pump to stop and they kept going and overheated the engine. They then bought a new AM15 and have been using it since. I do not know the hours but from past usage I guess a few thousand hours. They rebuilt the overheated AM15 themself and put it on the shelf as a spare. They have told me that they work their equipment hard.

I do not have an exact hours on the fleet but I would estimate over 50,000 hours at this time. I estimate that before we started selling them for aircraft there was well over 10,000 hours in the fleet. In our testing we had well over 500 hours on test stands, air boats and jetboats.

Exactly what is included in the FWF packages is listed on our web site.

We have over 100 hours testing on the AM20T so far. None on the AM20 but it is the same engine without the turbo. When we have the testing done we will be updating the website.

None of the internal parts are aftermarket. Everything in the long block is OEM Suzuki. Yes the external parts like the gearbox are not. We have also recently switched from an OEM Suzuki starter to a non Suzuki gear reduction starter since Suzuki starters are very sensitive the wiring issues. Everyone seems to want to do the wiring in their own way and that is not correct for a Suzuki starter. We also now source our Walbro fuel pumps and our Denso alternator in the USA. All of the FI sensors and components are OEM Suzuki except the ECU and wiring harness that are sourced/made in the USA.

What test data does Rotax, Lycoming and Continental publish? Can you provide a link and we can provide similar data.

#### aeromomentum

##### Well-Known Member
The certified engine needs to test run again for each engine-prop combination or measured with instrumentation.
No requirement for experimental but the pilot should understand and be prepared for dead stick anytime, even after 150 hrs.
This is very true both with both direct drive and geared engines! We have tested a few props for a few hours on test stands. We have also run a few props now for 400 hundred hours each in flight. Some of our engines have been run a few thousand hours with our props in airboats. Our fleet time with various Luga props is over 50,000 hours. While this is very useful it is not exhaustive testing. There have been many prop/engine combination AD's on certified aircraft even after full certification testing.

#### Oliver

##### Member
Hi Mark,

I'm not sure that this is the kind of public debate you want, but this is of course up to you.

I also have to correct myself, it was the AM10 I had in mind, when I said that you launched it only two or three years ago.
As the AM20T, your website shows it sitting on some kind of mount, no gearbox or other auxiliary components attached, but yet you are already promoting it to aircraft customers.

[...] You seem to be mistaken about what I have said. I have said that we have delivered about 100 engines for use in airboats. I have also said we have delivered over 100 engines for use in airboats. [...]
Really? Screenshot, taken from your website just today:

[...] These are true and consistent statements. By far most have been AM13s and many were shipped to Dragonfly. Note that the post date is early 2013.
This airboat company and the fishery are exactly the two references I was referring to above and all you ever shared with me, despite of our many, long conversations.

Looking at their Facebook profile, it appears as whether Dragonfly only briefly promoted their Mini Airboat with your Suzuki engine and then focused more on their bigger boats with the GM Ecotech engine.

It also appears as whether they have been out of business for some time. Their website is dead, the last post on their Facebook is from 2018:
Website

Due to the poor quality of the video it is hard to see details of the engine:

I'm however fairly certain that these are photos of the boat in the video, I took them from Dragonfly's Facebook:

The gearbox seems to be an adaption of some kind of Rotax reduction drive to the Suzuki engine. Obviously, you now have your own gearbox, the engine itself also looks quite different from what you have on your website: www.aeromomentum.com/am13.html

As of 2013, Dragonfly airboats were pretty much unknown in the airboat forum: dragonfly airboats - Southern Airboat
There is also only just one single post of a person who owns a Dragonfly with the Suzuki motor: New airboater - Southern Airboat

So, where are all the other 100s of engines? What is the mix of AM10, 13, 15, 20T? How are they being used? Since you are confidently stating that the fleet has accumulated over 50,000 hrs, you must be in pretty close contact with all of these customers, right?

I think the question still remains what kind of development and testing went into your various engines and reduction drives.

[...] I do not have an exact hours on the fleet but I would estimate over 50,000 hours at this time. I estimate that before we started selling them for aircraft there was well over 10,000 hours in the fleet. In our testing we had well over 500 hours on test stands, air boats and jetboats.

Exactly what is included in the FWF packages is listed on our web site.

We have over 100 hours testing on the AM20T so far. None on the AM20 but it is the same engine without the turbo. When we have the testing done we will be updating the website. [....]
I'm glad to hear! You have been promoting your new AM10 as well as the AM20T for some time now for experimental aircraft. If I understand you right, these engines were put through their paces for an extended period of time before you started selling them to aviation customers.
When did you start testing them and how? I find it hard to believe that absolutely zero photos or videos were taken when you started testing your engines and that you did not post any of them or even just updated your website with more current pictures, when you introduced these engines to the aviation market, several years ago.

[...] None of the internal parts are aftermarket. Everything in the long block is OEM Suzuki. Yes the external parts like the gearbox are not. We have also recently switched from an OEM Suzuki starter to a non Suzuki gear reduction starter since Suzuki starters are very sensitive the wiring issues. [...]
You promised me and others that we will get an entire list of Suzuki OEM reference part numbers, so that we could source service parts elsewhere, in case you go out of business. Despite of several reminders, I still haven't received this list (btw. the 'nostrils' for the cowling are also still missing, it's now been almost 4 years since I paid for everything in full!)

I would understand if you don't want to post the entire list publicly - to build trust, you might however want to consider posting at least the OEM part numbers for the starter, alternator, coil packs and the long block. That way, we can all compare the brands and models of the OEM parts with what I have on mine.

[...] What test data does Rotax, Lycoming and Continental publish? Can you provide a link and we can provide similar data.
For starters, they have certified variants of their 912 and 915 engines available (I believe the 914 as well): https://www.easa.europa.eu/sites/default/files/dfu/TCDS_E 121_Issue13_20200915.pdf

This is a big deal! While not a lot of hours are to be demonstrated for certification, many of the requirements are very strict and can't be met without serious development efforts. I guess I don't have to tell you how many engine manufacturers attempted certification but failed. The other thing are possible AD and liability related issues down the road, if the engine turns out to be problematic. This can easily tank a company. It is therefore in their own interest to be very thorough with their development.

They have also built over 180,000 aircraft engines of which over 50,000 are of the 4-stroke kind, thus gained a lot of trust over the years: https://www.rotax.com/files/userdata/rotax/downloads/produkte/BroschuereAircraft_210x297mm.pdf

As per Rotax's brochure, their 4-stroke fleet is accumulating about 5 million(!!!) hours each single year!

Frankly, to me this is more confidence inspiring than a grainy airboat video from 2013.

Finally, you'll find several articles and videos of in-depth Rotax factory tours on the internet. E. g.:

Rotax's YT channel is also quite interesting: https://www.youtube.com/channel/UCzQOSZbiROVBY_4NoCHbXbA

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#### Victor Bravo

##### Well-Known Member
HBA Supporter
Aeromomentum, what is the reason that the smaller 3 cylinder engine is "not currently available"?

It would seem like a very good choice for smaller single seat aircraft where weight and fuel consumption are primary considerations.

Although I have to admit I'm not in the immediate market to buy one, I will say there have been several designs, sketches, debates, discussions, ideas, and proposals on this forum for homebuilt aircraft that would likely make good use of this smaller engine.

If the engine were available, one of our more distinguished members has a well-documented history of launching epic, wide-ranging, and very well-attended discussion threads.... for a very very small bribe (likely a hamburger at a fly-in) he might launch the "21st Century Aeromomentum Powered 3 cylinder runabout" thread.

This would certainly result in putting you into an entirely different tax bracket

#### TarDevil

##### Well-Known Member
Aeromomentum, what is the reason that the smaller 3 cylinder engine is "not currently available"?
I am very sorry for this both to you and to other AM10 customers. At the beginning of the year we thought we would have the final change needed for production in our hands in under 2 months. Then our gear supplier stopped making gears to concentrate on making machines to make COVID masks. At that time we had no idea on how soon we would get the new gear sets so decided to concentrate on the AM20T. Our gear supplier is now back to making gears but we need to first get the AM20T into production.

As an aside, we did look at the 3 cylinder Mitsubishi engines as possible base engines for conversion. We found the 76hp 3A92 1.2 liter 3 cylinder engine was too heavy. Actually it weighs more than the more powerful 4 cylinder Suzuki G13bb base engine.

#### rv6ejguy

##### Well-Known Member
I think the price point is very important here. Most folks interested in a Viking or Aeromomentum are there because of Rotax sticker shock. They are looking for a well supported, reliable engine which weighs close to what a 912 does and puts out similar or more power at a much lower price.

#### rv6ejguy

##### Well-Known Member
I guess I should have added if not completely obvious, it's impossible for a small new upstart to have anywhere near the numbers produced or flight hours compared to a large company like Rotax who has been in the game for decades. So why bother going down that comparision road at all? If you want that kind of track record, open your wallet and simply buy the Rotax.

#### Oliver

##### Member
[...] Rotax sticker shock. They are looking for a well supported, reliable engine which weighs close to what a 912 does and puts out similar or more power at a much lower price.
Well, I have to admit that these were exactly the two reasons why I was first close to ordering a Viking and then, just before pulling the trigger, switched over to an Aeromomentum, not realizing what I would get myself into.

I guess I should have added if not completely obvious, it's impossible for a small new upstart to have anywhere near the numbers produced or flight hours compared to a large company like Rotax who has been in the game for decades. So why bother going down that comparision road at all? If you want that kind of track record, open your wallet and simply buy the Rotax.
I went down this road because Mark asked what data Rotax is posting. Rotax, with their many engines in the field, have already earned the trust of many. He, on the other hand, still has to get there. Mark is the new kid on the block, I therefore think that he should be extra transparent with his engine development.

I, of course, also never expected that Aeromomentum engines would have the same track record as Rotax.
But, since Mark keeps stressing at every opportunity that his fleet has accumulated an "estimate (of) over 50,000 hours", I guess that this is the standard by which he wants to be measured.

Even if he would claim just 500 hours, it is still a fair question to ask how these hours break down into the different engine types and to request some evidence. If all of these hours are to be of any value, I would also expect that he gets regular, detailed status reports, data logs and oil analyses from his development partners and that at least some of these engines and gearboxes get torn down and inspected after every few hundred hours.

I honestly wish that Mark can put up some evidence for his claims and that he (finally) gets his stuff together and starts producing proper fwf kits. We wasted a ton of time messing with the fwf 'kit' and also lost a LOT of money selling our AM15. I would hate to see others go through the same thing.

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#### Vigilant1

##### Well-Known Member
Mark Kettering is a frequent contributor here, and I have always appreciated his candor and openness about his designs.

Oliver is is among the first of Mark's customers to provide firsthand reports here at HBA on his experience. As we often say, "the plural of 'anecdote' isn't 'data'," but it appears that Oliver is asking useful questions and I am optimistic that Mark will take the opportunity to shine some more light on the total fleet experience his engines have seen and maybe provide more information on aircraft installations and any results he's obtained in addressing delivery timeline issues that apparently exist.

Aeromomentum appears to have a solid approach: Take well engineered, reliable, lightweight, inexpensive automotive powerplants that are available new from the OEM, make modifications as needed for aircraft use, fit a well engineered PSRU, and sell the package at an attractive price. Obviously, though, all the details, follow-through, etc are important.

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#### aeromomentum

##### Well-Known Member
Over 100 engines in airboats. Over 100 engines to aircraft. A bunch of other engines for other uses. This is what I call hundreds. As I said the 50,000 hours are estimated and I expect it is conservative. Most of these are in airboats since we delivered most of the airboat engines before starting to deliver them for aircraft. Many of the airboats were delivered ready to go by the airboat company so they were put into service quickly. Most aircraft take years to build and some engines delivered 4+ years ago are still not in service. Keep in mind that if you let your engine sit for so long you will have problems. You must inspect for corrosion and you must preoil. After Duck Dynasty went off the air, the market for small duck hunting airboats just about dried up. For the first dozen or so airboat engines we bought gearboxes from others. While they were good we could not get them consistently so we developed our own and it has been extremely reliable.

I would estimate that about 35,000 hours are AM13 and 15,000 hours are AM15 since we delivered AM13's first and more to airboats, PPCs and trikes and these tend to be put into service quicker than fixed wing aircraft.

Keep in mind that even a multi BILLION dollar company with 10,000+ employees like BRP/Rotax has had issues. The early 912's had lots of failures and even the recent 915 had valve and other issues grounding the whole fleet. We are not so big.

Yes the AM10 is on the back burner and may be for some time but has completed some testing. The AM20T is complete and currently undergoing testing. We are trying to be responsible and not release engines or more information about these before we complete our testing. Yes we have be overly optimistic about delivery but we will not be pushed into delivering before they are truly tested by us.

Yes we have had issues with suppliers, especially for cowlings. We can and have been delivering 701 and RV12 cowlings and universal nose-bowls. Our engines will also fit into other cowlings, with modification, like the Continental cowling for the 650/750. Rotax does not provide cowlings. We now have 650/750 cowlings of a new design since our previous 650/750 cowling supplier passed away. We will have these at Oshkosh.

I am not a big picture or video taker. I am more a doer and less a promoter or marketing person. Plus our main issue is keeping up with demand so have little need to do promotion videos. I will try to start doing some informational videos.

Oliver, I am sorry that we could not meet your expectations. We are a smaller company with more limited resources. While I know that we have better engines, maybe it is best that you stick with a huge company like BRP/Rotax. While Rotax does not supply cowlings and FWF kits, third partly suppliers do.

#### rv6ejguy

##### Well-Known Member
Mark has had long delays in delivering engines to some customers. We've heard some of that before from other customers and himself. Mark has mentioned supplier problems and there may be other problems as well. On something like gear cutting, if your first supplier suddenly can't, it can take months to find another to do the job right and on your cost and time schedule. Many machine anf fab shops have long backlogs. I have gone through these things myself in my business where we go through thousands of CNC'd parts per year.

I don't know all of Mark's problems but in general, before you start selling a product like this, you need established supply chains and suppliers. You are at their mercy. Short one critical part with only one source and you're hooped- you can't sell anything.

#### BBerson

##### Light Plane Philosopher
HBA Supporter
What is the average or recommended TBO based on testing or aircraft owner field reports?

#### BJC

##### Well-Known Member
HBA Supporter
Keep in mind that even a multi BILLION dollar company with 10,000+ employees like BRP/Rotax has had issues. The early 912's had lots of failures and even the recent 915 had valve and other issues grounding the whole fleet. We are not so big.
For those not aware of the Rotax’s teething problems, see Rotax-Owner.com - SERVICE BULLETINS

BJC

#### poormansairforce

##### Well-Known Member
We are not so big.
Which is exactly why I would consider you! I know where you work.

#### Oliver

##### Member
[...] I am not a big picture or video taker. I am more a doer and less a promoter or marketing person. Plus our main issue is keeping up with demand so have little need to do promotion videos. I will try to start doing some informational videos. [...]
Oh, don't worry, you are an outstanding sales man! People (including myself) are buying your engines and believe what you are telling them, even though you have very little to show.

So, overall your response to my very specific questions is still the same as what I (and others) heard over the last, almost 4 years:
• Some apologies (we had problems with vendor x, y, z)
• Promises that things will get better
• No pictures, videos, boat manufactures, anything, supporting your claims, other than a fishery in Utah and a grainy video from 2013, showing an airboat with an engine that looks very different than what you are selling today.
You are quite regularly posting pictures and videos on FB, showing aircraft customer projects and your sales promotions. Just absolutely zero about your biggest selling point, airboat testing. Odd, isn't it?

Nobody is expecting you to be the new Rotax. I would however argue that most people are expecting honesty and transparency, particularly because you are a small company who has still to earn the trust Rotax has already gained through millions and millions of flying hours.

For those not aware of the Rotax’s teething problems, see Rotax-Owner.com - SERVICE BULLETINS [...]
Exactly. Even companies like Rotax (the same is true for Lycoming and Conti) with their massive development budgets, engineering teams, controlled production environments and their enormous experience are having teething problems.

This makes it even more important for small companies, like Aeromomentum, to be transparent about how they develop, test and produce their engines.
I always thought that testing in airboats is a brilliant idea. I also actually believe that Mark sold some engines to airboat customers. I am however somewhat skeptical, when it comes to the number of engines, total hours and particularly to what engine variants have been tested. He also told me at Airventure 2 or 3 years ago that the AM20T hasn't run yet, while he was already promoting it to aircraft customers, literally doing exactly what he accuses Jan from Viking of: Selling untested engines. Well, Jan at least flies behind his products.

Anyways, I think that I said what I had to say. Take it for what it's worth.
People who are also in the Zenith forum know that I supported Mark for a very long time and that I am an actual customer.

The Canadian buyer hasn't picked the engine up yet, as the border is still closed. It is therefore still sitting in our hangar, outside of Detroit, in case somebody wants to check it out.

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