Aeromomentum engines

[SP1]

Had some additional email conversations with Mark K of Aeromomentum (seems like a real standup guy). The minimum installed weight of the AM15 is 208 lbs with radiator, coolant, exhaust and muffler.

There is one guy who did a trigear legacy with the AM15. Mark mentioned he had no concerns with the configuration.

[lakespookie]

Found out they will offer me an engine in parts so this is looking even more intriguing

[racaldwell]

I asked the builder with the Aeromomentum engine if he would part out the parts and he said it will probably come to that. He has a Wood Comp (I think???) inflight adjustable prop so this package together could be a good score for somebody. I am envious of his feathering prop. Wish my engine could handle one. This aircraft is at the Melbourne, FL airport.

Rick Caldwell
Xenos 0057

[lakespookie]

I am currently planning on the 147 horsepower low profile AM15. The plan is to get the airworthiness at 1200 as opposed to 1150, i should have more than enough power to handle the extra weight there is some small concern on gear loading but I am not planning on any soft field operations. The intention is to add a second battery either in the baggage compartment or if possible farther after as a secondary power source on an independent bus for power redundancy to alleviate some of the concerns regarding electrical dependence Given what we get away with with other power plants with a 20 or 30 Amp alternator i dont think a second battery will be to much of a strain my initial power estimation put me at between 18-28 amps depending on avionics and other things so a 65Amp alternator should go a long way to maintaining adequate charge in both batteries.

[racaldwell]

I have seen a Sonex that was overweight ( est. 1350 lbs) flying and do very poor landings (pilot error). On one landing the main gear titanium rod bent but that was it. New ones were installed and then more flying, well, sort of. In other words, the airframe can take it. That is the plane that may be parted out. For now the whole plane is for sale. And the hangar, and what's inside the hangar.

Rick Caldwell

[n307tw]

Hello all,

I just wanted to give the experience I have had so far with Aeromomentum.

Communication
I have had a really good experience regarding communication with Mark who owns and runs the company. He is very responsive to phone calls and a bit slower with e-mail communications but does take the time to answer all questions. Lili, his wife and owner, is amazing at getting billing and tech questions answered very timely. The entire company has been a pleasure to work with so far. Dick Gossen who has a business relationship with Aeromomentum owns his own company Aerosales, LLC. He primarily builds the FWF components for RV-12's for the AM15 but has extensive experience with integrating the Aeromomentum line into the G3X. He took the time to talk to me about my custom setup and how I could integrate it. He didn't need to do that since I wasn't buying anything from him, but he is a stand-up guy and a wealth of knowledge.

Single Point Failures
I will address some of the concerns that were voiced about the single point failures as I asked these as well. The oxygen sensor is only there to help lean out the mixture to improve fuel economy. If it gets fouled up and fails the engine is automatically put to a rich setting. I plan on running 93 octane MoGas 99% of the time but will keep a lead scavenge with me in case I need to use AvGas in a pinch. Mark reiterated that he has only had one ECU fail and said in so many words that it was due to improper wiring techniques by the builder. If any other sensor "dies" the ECU automatically goes to a rich power setting and you can plug in with a USB to analyze the code to replace them (similar to OBDII on our cars). The only sensor failure that will cause a dead engine is the cam sensor but he hasn't had one fail yet. At $47 its cheap insurance, so I may keep one in my bag. Mark says any sensor / coil pack failure is rare but can happen. The fuel pump system is completely redundant as well, only one pump can run at a time. He has not had a single failure of the 65-amp alternator yet. I feel confident that this will be a non-issue, but may integrate a second battery in the cargo compartment.

Mount
Mark has not developed a mount for the B-Model but I volunteered as tribute to get this done. I worked with Rich and Pete at Aviation Composites to develop a mount for the B-Model, Rich already has the mounting dimensions and jig for the A model. He essentially took my tri-gear Aerovee mount, recorded all of the mounting points and dimensions and modified it to work with the AM15. The AM15 uses the same conical mounting points as the Lycoming, so for those who are interested in that option, this mount may work as well. Moving forward Rich will not modify any existing mounts but will weld up brand new ones for A & B-model builders. I started this whole process mid-January and the mount was just shipped out this past Monday. Rich assured me other builders will get it within a 3-4 week timeframe as well.

Propeller
Going back and forth with Mark about the proper propeller for the Sonex was eye-opening and educational for me. I ended up ordering a 4-blade 60" ground adjustable composite propeller from Luga. He pointed out that Sonex sells a 60" for their Rotax applications in the webstore. The Luga is well priced at $1300 and actually was cheaper than the Prince prop I bought for my Aerovee Turbo. Mark says the small diameter needed on the Sonex will require more blades and will end up being quieter also. I was concerned about the increased drag with 4 blades but he reassured me that this is the best option. I have limited knowledge on the subject so I will trust the judgment of an Aerospace engineer. I'd be interested to see what others on here think (even though it's too late to change the order).

Order Timing
I put my deposit down on the engine on January 4, 2021, and I am picking it up while on vacation in Florida on March 8, 2021.
I brought the mount to Rich and Pete on January 7, 2021 and it was shipped this past Monday, February 15, 2021.
I bought the propeller on January 20, 2021 and it is expected to arrive in May 2021 from the Czech Republic.

Obviously I am excited to have everything and I will post updates as I start to mount it to my fuselage. I will also have updates on how I have integrated the engine into the G3X system. I look forward to input from the Sonex community as well.

[pfhoeycfi]

Although I have the aerovee turbo installed I'm very interested in this for the future. Will the fw and cowling mods be extensive?

[n307tw]

Hi Peter,

I already have the firewall stripped with the exception of the battery. I have a feeling I may have to move that as well. I am waiting for the mount to arrive and I will line everything up so I can see what needs to be moved. I discussed with Jeff Schultz whether I should take a fresh piece of stainless and cover the holes or individually patch. I don't want a hacked up looking firewall either. The only things I will need to mount is the fuel pumps. The ECU will be mounted in the cabin. The existing firewall bulkhead fittings for the throttle and fuel should be ok. I will need to make an additional bulkhead firewall fitting for the fuel return.

The cowling will probably need extensive fiberglass modifications to ensure the air flow goes 100% over the radiator. I will use the Sonex provided side exits for the cowling. I did end up ordering the nose bowl option from Aeromomentum so I will try to mate that to the existing cowling. Luckily I have a few months before I have to deal with that. We will see how bad it is at the time.

-Tim

[lakespookie]

Seems like it should be a pretty straight forward interface for the G3X using the can bus from my conversation with mark, I have gone back and forth between a second 7in panel and a single 10inch with the engine monitor they offer i have the panel designs in the panel forum in case you want to take a look at them, looking forward to seeing how you finish this puppy up, As far as the cowling I am planning to keep the existing openings and reposes them one for cooling air for an oil cooler and the other for intake air. Then i need to figure out how to plumb the radiator but i am thinking that something similar to how the a model used to do it with the bottom mount oil cooler was probably the best option. Its probably going to be some trial and error to keep cooling working with my setup and i may have to get creative with baffling but that is a bridge to cross another day. What version of the AM15 did you go with? Good to hear that you found an acceptable prop, given the minimal ground clearance going to a multi blade is really the only option i worked out some of the numbers and pretty much came to the same conclusion. I am very interested to hear for final measured ground clearance with a 60 inch given that most of the props installed on sonexes are 54 or 56, the rotax install is not directly in line with the crank which might be why they can get away with a 60, I was looking at a 4 blade 56 but if i can fit a 60 that would really help with the efficency.

In simple terms what it comes down to is induced drag due to the root of the propeller blade and added rotating mass but given the power level provided by the AM15 especially in the 147 flavor if thats what you went with you really need the extra blades grabing air to make use of the extra power. if we could fit a bigger prop it would be less of a tradeoff but it is what it is. Something else you should consider is how that extra drag will affect power off operation i.e. dead stick landings. From a lift perspective the wing should still fly pretty much the same but the extra drag may or may not have a significant affect on the glide range. Then again hopefully none of us have to unintentionally deal with that situation.

[n307tw]

Seems like it should be a pretty straight forward interface for the G3X using the can bus from my conversation with mark

That is not entirely correct. I too have gone back and forth with Mark about the CAN bus integration and the Garmin will not communicate with the MicroSquirt ECU on the CAN bus without a converter. He says they are in development to make one but doesn't have one working. I had a lengthy conversation with Dick Gossen about his G3X integration and he is not using the CAN bus. Instead the easiest method he found was using the tach pulse lead off of the ECU and put that into the GEA24. He then has separate sensors for oil pressure, manifold pressure, oil temp, coolant temp, and fuel pressure. I already have most of the sensors from my aborted Aerovee install and I will use brass Y's to put my sensor inline with the AM15's sensors. It may be a little more work, however I don't have the CAN bus architecture knowledge to try and make this work.

I have gone back and forth between a second 7in panel and a single 10inch with the engine monitor they offer I have the panel designs in the panel forum in case you want to take a look at them, looking forward to seeing how you finish this puppy up

I personally would not waste my time with the 7". I played around with both extensively at Oshkosh and there are features that the 10 has that the 7 does not. Go big or go home, haha.

As far as the cowling I am planning to keep the existing openings and reposes them one for cooling air for an oil cooler and the other for intake air. Then i need to figure out how to plumb the radiator but i am thinking that something similar to how the a model used to do it with the bottom mount oil cooler was probably the best option.

I plan on keeping it simple. I may integrate a NACA duct for fresh air into the throttle body but I plan on closing off as much of the cowling as possible. It is my understanding the focus of airflow needs to be over the coolant radiator. Throwing that on the front in the standard AM15 configuration will be best. Plus, you don't have to worry about custom coolant line fabrication. It comes with everything in the cooling kit to make it work. I am hoping my integration of Mark's nose bowl doesn't make it look like Frankenstein. Only time will tell.

What version of the AM15 did you go with?

I am going with the base AM15. I was initially going to go for the AM15HP but couldn't justify the extra 4 grand for 14 more HP. Remember that 147HP is only because the redline is higher at 6,800RPM. I personally wouldn't want to put the extra strain on the motor. As it is, 5,400RPM is a lot of work for the engine but it is designed for that. The extra HP for the 131HP is primarily from head improvements and an oil cooler and the higher 147HP is included in the 131 price but at the cost of the higher RPM like I stated above. Mark says I could always make these modifications in the future if I'm craving the extra HP. All his engines are underrated and Mark states real-world numbers for the base engine are just over 120HP (similar to the Jabiru but better fuel economy at 4.5-5GPH).

Good to hear that you found an acceptable prop, given the minimal ground clearance going to a multi blade is really the only option i worked out some of the numbers and pretty much came to the same conclusion. I am very interested to hear for final measured ground clearance with a 60 inch given that most of the props installed on sonexes are 54 or 56, the rotax install is not directly in line with the crank which might be why they can get away with a 60, I was looking at a 4 blade 56 but if i can fit a 60 that would really help with the efficiency.

This 60" 4-blade is the prop that Mark recommended. He says the prop line is higher than the Aerovee. Sonex does sell the 60 for their Rotax option so this decision is honestly a shot in the dark based on faith. I am really hoping it works out. There is another B-model builder on here that put a monster on his AM15. I think 70" but don't quote me. (see video below)