Mark Discusses Advantages/Disadvantages of Different Engine Technologies

I visited the website and found an interesting write-up by Mark, the owner of Aeromomentum. In it he discusses the engineering choices that led him to choose the line of Suzuki engines that he uses for aircraft conversion. Here's a link:

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This is not "the one Aventura" -- rather it is the "First Aventura" with a Viking 130.   I am sure that the owner did his due diligence and chose the Viking Honda 130 on that basis.    Others chose the Aeromomentum.    Both good choices.

So....let's then let the market tell the tale.   Let's leave the "I am better" and let owners show the results of good old competition over time.   No need to debate design differences. 

Owners are quite capable of sorting things out.  

Hi Jan, Don't be silly, of course we should question the reliability of an economy car engine when used in an aircraft. I do and so should you. I use risk management and statistical analysis as I learned in aerospace graduate school and applied when I worked at Harvard University and NASA. While you may not want to look at the facts or discuss Honda reliability I think that is a great disservice to the Zenith customer. Looking at car brand reliability in the USA here are some real facts from a few reliable sources:
1) Lexus
2) Volvo
3) Subaru
4) Lincoln
5) Toyota
6) Audi
7) Honda
JD Powers rates them this way:
1) Lexus
2) Porsche
3) Buick
4) Infinity
5) Kia
6) Chevrolet
7) Hyundai
8) BMW
9) Toyota
10) Lincoln
11) Nissan
12) Honda

In outboards the rating seems to be:
1) Yamaha
2) Suzuki
3) Mercury
4) Honda
5) Evinrude

Keep in mind that these ratings change from year to year but the above is the most current I can find. Yes Honda is good. Maybe at one time they were near the most reliable but others have come up and Honda has gone down relatively according to JD Powers and others.

I am not claiming that chains are unreliable. Yes they can fail like anything. The timing chain in my Dad's Chevy failed at under 30,000 miles. One of the plastic sliders used by the hydraulic chain tensioner failed first and this caused the chain to become slack and rapidly fail. Yes the L15b uses little plastic parts for the chain tensioner inside. All I said was chains are heavy and modern belts are now reliable and light. You are the one claiming the belts and sealed greased bearings are unreliable. Keep in mind that just about all cars (including Honda) now use sealed greased service free lifetime wheel bearings with very high reliability. At the Sebring LSA show I talked with a guy that claimed he had 500,000 miles on his Suzuki G13bb engine! Our highest time on one of our engines (in a commercial use airboat driving the same prop we offer) and with the original cam belt is over 4000 hours! Again, what is the highest time on one of your cam chains (and little plastic tensioners) or high pressure mechanical fuel pumps when driving a prop at your recommended RPM?

To me it looks like you were the first one attacking the technology we use. I am actually grateful since it opened up the technology debate and getting real facts out to builders. I am very happy to debate my choices with real facts. How about us getting together with an independent third party moderator and videoing a debate? We can do this at Sun-N-Fun at one of the engine forums so we can also have a live audience. To me this is not about winning or loosing. It is about providing accurate information to Zenith and other builders so they can make informed choices.

Typically such brand reliability ratings are for the brand's entire line of vehicles. It takes quite a leap of faith to say that the overall brand reliability (as reported by consumers) relates in any way to specific engine reliability. While I agree that looking at specific engine reliability is useful and not to be ignored, and while it seems that looking at marine outboard ratings might be useful, this reference to overall brand reliability seems to me to be a red herring. 

Hi Ken Ryan, While I agree that the car and outboard reliability ratings are whole car and whole outboard I disagree that using more data points is a "red herring" and it was only presented to help people understand the need to question and analyze. I was just commenting on Jan's claim that "Honda reliability is not on the table to be discussed." Of course it is on the table to be discussed! We would be crazy to not discuss the reliability of the technology of an economy car engine when reused in an aircraft. Yes Honda has a fairly good reputation for reliability but not only is it not tops in reliability but I agree the reputation is more for cars, less for outboards and maybe not applicable for aircraft at all. So to be realistic and fair we MUST question and analyze all of the data, reliability and technology for all engines to the best of our abilities and using well established methods.

I thought there was an agreement that manufacturers (in this case Jan)  are neither allowed to promote their own products in a competitor's sub-forum nor to bad mouth the competitor's products!?

I also find it quite funny that that the Viking supporters cry foul because Mark lays out in the video, in general terms, why he thinks that a lower weight is better than variable valve timing and why he prefers port fuel injection over direct injection. At the same time, they don't seem to take any offence in Jan directly attacking AeroMomentum, stating that he doesn't 'think anyone would argue seriously about the clear advantages of a direct injection fuel system on an aircraft engine, or modern variable intake valve / lift systems'. ;-)

Car manufacturers struggled for many years to launch direct injected engines, this technology is anything but trivial. Tons of information is available on the internet, including scientific research papers.

While I trust that the big car manufacturers have figured it out by now, all the calibration work goes out the window if an aftermarket ECU has to be used, like in case of AeroMomentum or Viking. Maybe it turns out that the Viking 130 will after 100s of hours still be trouble free - personally, I however rather prefer the reduced complexity of the AeroMomentum engine.

Interestingly, even Honda themselves is not using direct injection in their outboard motors:

We have been watching you "almost fly" for some time.  I am sure, one day you will.  When you do, lets set up a basic cost / reliability / performance test.  

Jan Eggenfellner 

Jan, the way you present yourself in this forum is a big reason why I'm happy that I ultimately decided against using a Viking engine.

Being an engineer myself, I truly appreciate Mark's knowledge, experience, thoughtfulness and agree with his reasoning. I also like that he is much more of an engineer than a sales guy. 

Personally, I would really appreciate if you would stop spamming every other AeroMomentum thread with your aggressive Viking marketing.

As for "almost flying", you must be confusing me with somebody else!? As you probably know, building a plane is a long process, it will certainly take us quite a bit more time until the first flight.

Not at all true. 

You are just protective of your investment. 

I am an individual and I am a business person. 

I don’t care what you, or anyone else think. 

You deserve to order an engine. 

You deserve to get the parts you ordered

You are entitled to get parts that actually fit your aircraft

You should expect that the the parts that you paid for should have been tested, fitted and working on your aircraft model and type. 

You can continue to defend the choices you have made, it is all up to you. 

Viking has a one day turnaround on any Zenith engine model. We don’t have an approximate delivery time, we don’t have an estimated weight, we don’t have thousands of undocumented airboat hours and we actually deliver what we sell

We are all entitled to our own opinions, but we are not all entitled to our own facts.

Hi Jan, You really should see the workmanship, thought, engineering, craftsmanship and painting skills that Oliver has put into his CH750. Many Zenith builders want to get in the air as fast as possible and I fully understand this. Others like Oliver want to have a phenomenal build that is perfect in every way. Even with his extreme attention to quality and detail he is progressing very rapidly. You really need to see the pictures to appreciate his build.


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