Not quite an auto engine

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Johnny luvs Biplanes

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Mar 23, 2003
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283
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Epsom Downs, Surrey, England
Hi all, I have a question relating to using motorcycle engines (not auto). Has anyone seen or heard of a conversion using either the Honda Pan European V4 or the Honda Goldwing flat 6 or early flat 4 engines? They would both make ideal aeroplane engine conversions I think, particularly the 6 as it looks so good, any comments? Thanks, John. :rolleyes:
 

orion

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Mar 2, 2003
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Western Washington
Good morning;

Although I am not familiar with the V4 engine you mention (unless it's the same one used on the Magna series of motorcycles here in the US), I have seen several attempts at converting the Honda Goldwing engines. This always seemed to me a logical choice as the engines are well made and balanced for very smooth and quiet operation.

I have only seen one power/torque plot for the flat six, and as this was quite a few years ago, I do not remember the exact specification.

The work at converting the engines that I saw though was rough (poor reduction design) and none of the individuals intended to go beyond a one-off. I do not know how well their work held up for the long run.

I think that one of the reasons we do not see more of these engines in aircraft is due to their very high cost. About four years ago I looked into doing just this with the six cylinder engine. The engine seems ideal for a number of applications and although it would end up with a bit of a weight penalty when compared to other, more aircraft oriented alternatives, I thought its reliability and quality of construction would more than make up for the small disadvantage.

But when I checked into acquiring one for the prototype, a motorcycle salvage operation wanted almost five thousand dollars for a good condition engine. The Honda importer wanted nine thousand. In sets of ten from the latter, the price was still quite high.

I do not know if this is the case today but if the engine prices are still this high, it would certainly be a detriment to anyone attempting this application. Technologically though, it would be a nice package.
 

Johnny luvs Biplanes

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Joined
Mar 23, 2003
Messages
283
Location
Epsom Downs, Surrey, England
I used to work for a specialist car company many years ago that had an ofshoot making hovercraft. They used to buy a new bike and take the engine out (when Goldwings were fours) then sell on the remainder. I gues though that even this is probably cost prohibitive, a damaged might be viable iof not the engine. Did the conversion you saw utilise the gearbox still? Cheers, John :p:
 

orion

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I remember seeing at least four different attempts at using this line of engines. The two I remember most clearly were quite different from each other.

The first modifed the existing gearbox, adding an output housing that apparently incorporated the output shaft and its bearings. What I didn't like about this one was the way the individual attached the new housing to the original parts. The new mating surface did not look of sufficient gauge (he machined the original box, which is pretty marginal to start with for flight purposes) and due to the side location of the output shaft, it required a somewhat ackward mounting in the aircraft. I do remember that he locked the gear ratio on one of the gears (but I don't remember which one) and removed all other unnecessary parts. It had potential but required a bit more refinement in order for it to provide what I would consider reliable service.

The second unit also used the gearbox as it was however the ratio was locked on the final 1:1 gear. All other components were apparently removed. The final reduction drive was remote mounted from the engine, although it was still attached to the engine through several struts. This gearbox had the final reduction necessary and the offset as well so the engine and prop ended up pretty much on the same centerline.

This second design seemed to be a good, simple solution that required virtually no modification of the original engine and case. The problem though that I saw was that it was done in a very sloppy manner. The individual used nothing more than standard hardware store components and the connecting members looked like they were formed with a set of pliers and and a hammer.

As I said above, I think this would be an excellent engine but someone should take a bit of extra time and spend a bit of money doing it right.
 

mr157ifhz

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Dec 16, 2006
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Ontario, Canada
Tried to pick up a complete 4-cyl goldwing engine off the floor at the motorcycle wreckers; I couldn't. Don't know about the six. Whereas I could pick up my Subaru ea81 engine w/gearbox without too much trouble. Unless the 'wing engine was bolted to the floor, I would guess it is much heavier than the soobie. Pure heresay here, but I read somewhere that the Honda Accord 4-cyl is lighter than the Goldwing engine.
Some of the most promising I think to convert to aircraft use are the 4-stroke personal watercraft or snowmobile engines that seem to be the rage now. They have no integral gearbox, ready for your reduction drive. Had a close look at an Arctic Cac Jaguar that uses a Suzuki twin. Compact, 120hp FI, dry sump. Though this particular snowmobile has only been out for a year, a low milage engine can be had for $2500.
-Matt
 
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