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Converted Auto Engines for permit aircraft

Posted: Wed Jan 30, 2019 1:07 pm
by DShewan
Has anyone out there looked at the viability of using a converted auto engine like those available from Aeromomentum or Viking Engines in the US? These converted engines seem to be fairly common in the States and firewall forward packages are available for these from several kit manufacturers. I'm not aware of any flying in the UK but I'm sure that someone out there will have looked into using such a motor for their project. Any feedback would be welcome.

Re: Converted Auto Engines for permit aircraft

Posted: Wed Apr 24, 2019 7:07 am
by ROB. THOMASSON
I played around with motorbike engines for microlights a while back and they always came out a lot heavier than you would expect despite being all aluminium. Subaru conversions appear to have died the death over here despite being a flat 4. The Honda conversion does not have a good reputation either. VW engines are a known conversion but don't tend to go much over 60 hp I gather the problem is flexing of the crankcase at higher rpm unless someone here can correct me. Corvette engines are fairly common in America at 350 hp but that's a bit high for most LAA designs.
I have a friend in the USA who may know more and I've emailed him for the lowdown on conversions rather than the advertising hype

Re: Converted Auto Engines for permit aircraft

Posted: Sun Apr 28, 2019 9:05 am
by ROB. THOMASSON
I received this back from my friend in the USA
I'm familiar with the Corvair / flat 6 cylinder air cooled. Thy run 100hp to about 130hp depending on the Cubes. They are a good "experimental" aircraft engine with the "5th bearing" and the new manufacture forged cranks.

Re: Converted Auto Engines for permit aircraft

Posted: Mon Aug 05, 2019 11:38 am
by BobD
I have just watched a couple of videos from Oshkosh 2019 from the homebuildhelp website, which brings the question from this thread back to the fore. Has anyone in the UK had experience with installing either Aeromomentum or Viking Engines in their project ?

https://www.youtube.com/watch?v=8mMBxwFrwK4

https://www.youtube.com/watch?v=IskkEPh09aA

Re: Converted Auto Engines for permit aircraft

Posted: Thu Aug 29, 2019 1:15 pm
by DShewan
To those who may be interested in pursuing this route this is the reply I got from LAA Engineering when I questioned them on this subject.


]Thanks for your query. In general it is much easier to use an engine that we’re already seen before. It has to be said that there have been many previous examples of automotive conversions that have been marketed before they were properly developed, where purchasers have had their fingers burnt by promises that were not delivered – including for example, promises that certification was ‘just around the corner’.



The airworthiness rules for amateur built aircraft in the UK are very much more stringent than in the USA, where amateur built aircraft operate in an experimental category at the owner’s own risk, and builders can incorporate whatever modifications they wish without the need for any safety determination. Here, if an engine conversion does not have a history of reliable use in aircraft, we would need technical justifications showing the engine to be safe via an assessment against an acceptable design (e.g. CS-E or ASTM F2339). This can be a challenging procedure and generally takes some considerable time. A new aircraft engine type also generally takes several years to ‘get the bugs out of it’ and approach the real-world reliability level of a proven powerplant such as a Lycoming or Rotax, so the first few hundred customers are in effect guinea pigs allowing their aircraft to be used to complete the engine development program.



I am sorry this is a bit of a negative response; it’s true that all technological steps forward require a degree of risk but on the other hand, sadly we’ve also several times seen our members exploited by ‘snake oil salesmen’ in this field whose products have not come up to scratch. Having said that, if you really want to pioneer a new engine on the fleet then we will try to support you in that.

Re: Converted Auto Engines for permit aircraft

Posted: Sat Sep 14, 2019 2:29 pm
by braywood
Id love to see a Diesel engine developed for permit aircraft use. Wilksch had one years ago, but it did not really get off the ground..... Most development today is for large, 150+ hp engines. Something 80 to 100 hp would be just the ticket.

Re: Converted Auto Engines for permit aircraft

Posted: Sat Sep 14, 2019 7:06 pm
by Macleesh
Take a look at the Gazaile 2
Originally designed around a normally aspirated 1.4 PSA diesel they have moved on to the 1.4/1.6 PSA DV4/DV6 range which are in just about every diesel Peugeot, Citroen and some Fords.

The ECU is usually binned and the engine converted to use a mechanical pump.

These would be right in the power range you're interested in.

Lovely looking Aeroplane too.

Re: Converted Auto Engines for permit aircraft

Posted: Sun Jul 12, 2020 8:04 pm
by Andy Kennedy
DShewan wrote:
Thu Aug 29, 2019 1:15 pm
To those who may be interested in pursuing this route this is the reply I got from LAA Engineering when I questioned them on this subject.


]Here, if an engine conversion does not have a history of reliable use in aircraft, we would need technical justifications showing the engine to be safe via an assessment against an acceptable design (e.g. CS-E or ASTM F2339). This can be a challenging procedure and generally takes some considerable time. A new aircraft engine type also generally takes several years to ‘get the bugs out of it’ and approach the real-world reliability level of a proven powerplant such as a Lycoming or Rotax,.....
Thankfully the BMAA managed to convince the CAA on SSDR so the SSDR guys have been busy proving that there are alternatives out there.....if I recall correctly the LAA weren't in favour of SSDR......

Has it been established yet if modern electronic 'coil on plug' ignition is sufficently reliable so to consign the dual mags to the history bin yet?
I've said this before, but the biggest impediment to new auto conversions is that there is no way an additional sparkplug can be added to a modern 4 valve cylinder head, so dual ignition is not possible.
In the UK, how has the Titan T-51 Honda V6 gotten around this?

Dual mags are also not really required as modern electronic ignition have multiple coils and no moving parts, so their failure modes are different from a pair of magnetos.

Lastly, at least with aeromomentum, there are now two RV-12s equipped with said engine and despite a block failure on the one in Oz, both are still flying.
I quite like the look of them as they are based on factory new engines, not rebuilt junk yard reclamations.

Oh, and Viking Engines are well known on the interwebs for financial irregularities, cavet emptor, do you research etc.

Andy