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VW engines - KISS


Soleair

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There is much excitement regarding a potential new aero engine on this forum. And rightly so, considering the outrageous price of Rotax engines.Their ubiquitous 80 h.p plus engine series is priced at this exorbitant level because there really just isn't much competition.

 

But one of the most popular homebuilt designs in the States was for many years the Evans Volksplane VP - 1 & -2. If you look at the plans for these aircraft they use an almost unmodified VW donk. Replacing the distributor with a magneto; a bit of re-jigging on the inlet manifold; some stubby exhausts, and minimal machining of the flywheel to convert to a prop hub, and that's about it - go flying!

 

So why must I now spend vast amounts of hard-earned modifying a standard Beetle engine, having already overhauled it fully? Last price I saw was over $7k for the add-ons, putting the engine cost up there with a Scrotex 582 2-stroke.

 

"Dual ignition" I hear. Why? Yes, maybe in the old days of dirty oils & dynamo driven ignition systems. But since the advent of electronic breakerless CDI systems, hands up anyone who's had an ignition failure on their car that would have been prevented with a dual system. And what constitutes dual redundancy anyway? Two magnetos driven off the same shaft?

 

So what else is so essential that I need to spend so much on a well proven (if inefficient) simple, robust air cooled engine with collectively more hours in the field by several orders of magnitude than any Scrotex 912 diamond encrusted dollar guzzler.

 

Keep It Simple Stupid: why do we need all these mods to a straightforward engine today when so many flew so successfully for so many years before the age of committee rule?

 

Right, I'd better go and lie down now. It's nearly time for my medication.

 

Bruce

I've never had any experience with the V-Dub engines except to see one flying in an early Skyfox in Coloundra once. But, I love ya work, my sentiments as well.

Greg

 

 

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Heard yesterday the VW engines have been banned for use in land based trikes due to pollution? One wonders if this will carry over to planes.

Well there's no way Lycombings, Continentals etc would pass emissions standards so it might be setting a very dangerous precedent.

 

 

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As an aside, there might be more value in the KISS system if we called them Sir and not Stupid.

 

This cannot be applied to women as, even though they may be great at Kissing, they simply don't relate to keeping thing simple.097_peep_wall.gif.dcfd1acb5887de1394272f1b8f0811df.gif

 

 

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  • 6 months later...
Revmaster R2300 - 82hp continuous $7,685 plus exhaust and freight costs etc from California, dropping Aus dollar affected tho. – reliability should be reasonable given the racing heritage and long development time, and perhaps at least as good as some other aircooled flat fours. Head cooling no doubt still an issue to be dealt with properly.

I fly the Revmaster 2300 in my new (prototype) Thatcher CX5 two place and I love that engine. Redundant ignition and alternators and 4o years of development have made it, IMHO, an exceptional engine. It really has lots of power and runs great. I use a Zenith carb on it though because I don't trust the guillotine type carbs. I do have a very good carb heat system on it for carb ice and intake ice. I can throttle back and cruise about 95-100 mph on less than 3 gph. At normal cruise of 125 mph I use about 4.5 gph . It has 8 coils running through 4 separate systems, an oil cooler, and lots of proprietary engine parts that make it a superb engine and , unlike certified engines, it really DOEs put out it's rated horsepower. I climb 1000 fpm and it has great control response- responsive but not too sensitive. Lands at 42mph.

 

I simply love it. I am flying it to SunNFun in two weeks. Hope to see some of you there in the Thatcher Aircraft booth.

 

 

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So basically from reading all this we whine about every manufacturers problems and slag off Rotax's prices!!!!!

 

If you want to fly instead of faff about open your wallet and spend the Cash. i truly believe that the Rotax cant be beat for $$ per effortless flying time. 1200 hrs on mine and just getting sweeter.

 

 

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I've never had any experience with the V-Dub engines except to see one flying in an early Skyfox in Coloundra once. But, I love ya work, my sentiments as well.Greg

The engine in the early Skyfox (CA 21) was an Aeropower (certificated) conversion based on VW components. I did the pre-certification flight test work on that aircraft. The engine was marginal on power to meet the climb performance requirement - its main problem was that it was rated at 3600 RPM, which is simply too fast for good propeller efficiency at Skyfox speeds. It worked, provided you did not flog it; means it took a long time to climb. Ran quite sweetly, but a bit like trying to fly something powered by a sewing-machine.

I had some experience with VW conversions in gyrocopters in the 1970s; it showed that the barrels were inadequately cooled due to their being too closely spaced, for more than about 45 HP; also the cylinder base flanges used to embed themselves into the magnesium alloy crankcase, and then crack off the cylinder skirt when the engine cooled down. One had to do a through-bolt conversion to get them to stay together. The crankcase was too flexible and the original crankshafts would not stand more then about 45 HP continuous before they fatigued due to flexure of the case. Aeropower got around that by fitting a forged steel crank, but the real problem was the case. The later Limbach conversions based on the 2100 VW Transporter engines fixed a lot of those issues, but were a lot heavier. The cylinder heads do not have sufficient fin surface area for aero-engine duty cycle.

 

 

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About 6 years ago I had a revisit to the VW possibilities and thought the later crankcases might be better. While it looks a bit like an aero engine , it ain't one. Maybe for a VP1 Or Turbulent when they were everywhere. Connecting the drive to the front through a keyway isn't much of an idea. I did a lot of work on them in the 50's. Nuff said. An aero engine should be purpose built. Built light, but strong enough in the essential places, and quality materials. Nev

 

 

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Dead right, Nev. It ain't one. No automotive conversion has the double front main bearing that you find in a Lycoming or Continental (or Jabiru) in order to carry the gyroscopic loads without feeding them back into the front crankweb & crankpin. Car engines are mostly NOT built for continuous operation at full throttle - and I defy anybody to hold a motorbike with an 80 HP or larger engine at full throttle for a minute. let alone continuously.

 

You can replace the crankshaft, the barrels, the pistons, the heads, etc etc on a VW - but the fact is, the cylinder centres are too closely spaced to allow good cooling between the barrels; and it hasn't the right main bearing setup to carry a propeller. Horses for courses. A car engine needs a reduction gearbox to be practical in an aircraft - ask Terry Kronk about the reliability of reduction drives for Chev engines . . .

 

 

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Had an Aeropower conversion about 2070cc built by Mike Muninger (snr) with through bolt conversion in my VP-2. Did 350hrs with no trouble. Drove a 56"x30" Sweetapple prop at 3600 max and 3200 continuous. Would cruise at 60kt and climb was gradual (250fpm) from 2500ft but I had a long strip. Aircraft was about 450kg full weight. No cooling issues, although the barrels were out in the breeze with scoops. Efi kept cht's to around 250C and egt's about 1100 F. Oil pressure sat at 38psi and temp at around 75C. Don

 

 

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Yes - Mike Munninger made possibly the best of the VW conversions, and it was just barely adequate for the Skyfox CA 21. I'm not sure what he did to solve the cylinder barrel spacing - possibly used the "Transporter" engine case. It was not a collection of after-market parts, I understand. But noise certification reared its ugly head, so 3600 RPM gave too much tip speed on a propeller of sufficient diameter to give good prop efficiency at low speeds.

 

 

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I defy anybody to hold a motorbike with an 80 HP or larger engine at full throttle for a minute. .

Come for a ride on the back of my old Gixxer.......065_evil_grin.gif.2006e9f40863555e5894f7036698fb5d.gif

 

 

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I thought the Aerovee in the Waiex I flew was not close to the claimed 80 hp. It pulled and climbed consistent with about 60 - 64 hp. I guess even that much output is pretty good for a vee dub. This airframe needs a Jab donk and some way to escape in a roll-over...

 

 

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  • 2 weeks later...

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