Views: 593

Reply to This

Replies to This Discussion

Great video

interesting, did Honda test out the planetary gear box strapped up front, or as you say someone cobbled a bunch of parts together? 

Is a magneto sparked, gravity fuel fed engine with no external need except air a reliable design?  Or is a liquid cooled, electrical power dependent one more suitable?

Aircooled engines less efficient , yes.     Are automotive engines required  by law to be more fuel stingy, yes.

I'm sure Honda automotive does not actually support fit engines in aircraft use or they would market their own.

Despite knocking Lycoming, or indirectly Continental. Both build a crank designed to support front thrust bearings, providing self ignition, when fuel is provided.

If folks want to buy a Viking I support them, but it is still a conversion of related technology

You asked, "Is a magneto sparked, gravity fuel fed engine with no external need except air a reliable design?  Or is a liquid cooled, electrical power dependent one more suitable?"

According to Mark Kettering (former aerospace engineer at NASA) a modern auto engine with fuel injection and single electronic ignition is far more reliable that an engine with two magnetos. Add in the possibility of carburetor failure and it gets even worse for the legacy engines.

Just the facts ma'am.

this discussion seems to be going south now, so a(former aerospace engineer at NASA) is now an expert in internal combustion engines, claiming a single source failure mode is more reliable. I guess if the "expert" says so.

P.S. never had engine failure with conventional engine 12,000+ hours , except in turbine powered  helicopter.     Damn army crap (joking) failed oil line after depot maintainance.

just checked Mark is also selling car parts

Proper failure analysis can (and does) predict with near certainty the overall chances of failure of various components and groups of components. One can choose to believe these statistics, or not. Personally I tend to give great weight to scientifically derived data, and far less weight to a single person's anecdotal experience. Others approach this differently. But it was you who asked the question. I merely attempted to give you an answer based on fact.

Don’t think the Viking gear box is a cobbled together bunch of parts. Jan’s gearbox is a well thought out and engineered PSRU.

I am a retired mechanical engineer with 44 years of machine design experience. I was very impressed with Jan’s Honda based engine which is why I have one in my Zenith 750.

Lycoming and continental have been around a long time and both have a well proven design. Still they are both based on 1930’s technology. Direct drive, air cooled, magneto ignition, with temperatures that range from below zero to upwards of 500 degrees F. Air cooling inherently is less efficient than liquid cooling and as a result has an extremely wide temperature range. Wide operating temperatures can cause their own problems is not well managed by the pilot. As a CFI who has been flying for over 50 years, I have seen a lot of pilots that haven’t a clue about the nuances of managing an air cooled engine. Many think it is just like there care. Get in, turn the key, and go fly with little regard to managing temperatures. Liquid cooled with an ECU can greatly reduce the pilot workload and potential engine abuse.

Many aircraft had liquid cooled,gear box engines. I.e. the mustang, p-38, spitfire, etc

Lycoming has produced geared engines used in the C-175 among other.

ROTAX has become the “Standard” engine in LSA with over 50,000 flying. It originated as as a snowmobile/jet ski engine and is a geared, air/water cooled hybrid.

Don’t think Honda is going to pursue the very small aviation market, just not economically worth it . Viking only has less than 1000 engines in the market place, but it is growing so it is a limited market.

The beauty of the experimental movement is we have the option to try lots of different ideas and we can think outside the traditional box. Jan is definitely an “outside the box” thinker with his conversion of a great Honda engine. Other “out of the box” thinkers are Burt Rutan, Vans, Chris Heinz, as were the Wright brother who all were stretching the boundaries of “traditional”.

my 1930's technology engine is powering my 1903 technology aircraft, just a few questions (inspired by your geared engine discussion ) What RPM did the Lycoming or Continental geared engines operate? what engine RPM is used in Viking cruise, how about when used in a car; what RPM at highway cruise? apparently the room maintains that this new technology is somehow safer and more reliable, I guess time will tell. When removing the previous car engine from my airframe I did consider Viking but did not want to deal with extensive fuel system rework

Your rpm questions seem to imply that because autos run at much lower continuous rpm, then pushing them to much higher continuous rpm would naturally be unadvised. This would be a natural response. However, you might be interested to know that Honda uses the same engine that Viking uses in their marine applications, where continuous rpm is right up there with aircraft applications (as well as coupling them to gear reduction). 

Ok you win, geared continental uses in c-175 3000 rpm geared down to 2400, I don’t actually believe it is “the same” as used in their boats, but I might be wrong

You could well be right about them not being the same. Could have different cam, etc. I have never been able to find out. But it is the same "basic" engine.

I have about 34 hours on my VIking on a Zenith 750, another fried finished his air-cooled airplane about the same time. We both had some temperature issues with our cowls soon after first flights, I was able to add some ducting and wrapped the exhaust and now I have almost unlimited ability to use WOT on a hot day. 

I had to tune for one number, the coolant temperature. My friend is weeks into his testing and still not able to leave the pattern dealing with head temperatures and balancing out his CHT across several cylinders.

This really simplified the equation. I also don't have to worry about carb heat or mixture and it starts every time without any though or effort. In hundreds of hours of flying Lycoming and Continental engines I maybe get one start in 4 on the first crank, and that usually involves a long sustained use of the starter, not the tiny blip you need on the Viking. 

Certainly time will tell as to if I have any downsides to the technology, but so far I am really enjoying the advantages. Oh and with the money I saved I am enjoying that new-tech glass cockpit I could afford. :-)


New from Zenith:

Zenith Planes For Sale 

Classified listing for buying or selling your Zenith building or flying related stuff...

Custom Instrument Panels
for your Zenith

Custom instrument panels are now available directly from Zenith Aircraft Company exclusively for Zenith builders and owners. Pre-cut panel, Dynon and Garmin avionics, and more.

Custom Upholstery Kits for your Zenith Aircraft:

Zenith Vinyl Upholstery Kits

Zenith Apparel from EAA:

Zenair Floats

Flying On Your Own Wings:
A Complete Guide to Understanding Light Airplane Design, by Chris Heintz

Builder & Pilot Supplies:

How to videos from

Developed specifically for Zenith builders (by a builder) these videos on DVD are a great help in building your own kit plane by providing practical hands-on construction information. Visit for the latest DVD titles.

Aircraft Insurance:


West Coast USA:

Pro Builder Assistance:


Transition training:

Golden Eagle Aviation

Pianosa Flying Farm

Aircraft Spruce & Specialty for all your building and pilot supplies!

© 2022   Created by Zenith.Aero.   Powered by

Badges  |  Report an Issue  |  Terms of Service