Suzuki 1200 Bandit engine for light airplanes.

Capt.Crash'n'Burn

Capt.Crash'n'Burn

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Capt.Crash'n'Burn
I was thinking, of all the motorcycle engines out there that could be converted to AC use, the 1200 Bandit engine (also used in the early GSX-R-1100's) would be a great choice because of its large displacement combined with the fact that it's air/oil cooled (SACS), that gives it a great HP to weight ratio. It's also simpler to install since you don't have a radiator and glycol based coolant to deal with, just a large oil cooler.

I found a company in France that is already doing this (http://vija-engines.wixsite.com/vija-en) but from what I can gather, their prices are higher than a Rotax 912 (close to $20K) which has the same power, so what is the point?

Is there anyone out there who has seen this conversion done for less??
 
the tough part is the reduction unit. I'm guessing the power band on that engine is well above 6k RPM. reduction drive design is complex and is the downfall of a lot of engine conversions. i love seeing people try though, it is what experimental aviation is all about.4

bob
 
If you want to spend your time screwing around with an engine then build what you think will work, if you want yo spend your time flying then buy something made for it. Your choice. Many have tried auto conversions but most are a complete disaster and not worth the time or expense.
 
unsafervguy said:
the tough part is the reduction unit. I'm guessing the power band on that engine is well above 6k RPM. reduction drive design is complex and is the downfall of a lot of engine conversions. i love seeing people try though, it is what experimental aviation is all about.4

bob
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I was thinking I could weld it into 1st or 2nd gear and remove the rest of the transmission guts to save weight. Or use some kind of belt drive gear reduction.
 
Acrodustertoo said:
If you want to spend your time screwing around with an engine then build what you think will work, if you want yo spend your time flying then buy something made for it. Your choice. Many have tried auto conversions but most are a complete disaster and not worth the time or expense.
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A conversion like the 1200 Bandit wouldn't have the pitfalls of an auto engine. It's light, compact and doesn't require liquid cooling, just a large oil cooler.
 
Capt.Crash'n'Burn said:
A conversion like the 1200 Bandit wouldn't have the pitfalls of an auto engine. It's light, compact and doesn't require liquid cooling, just a large oil cooler.
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The term "auto" implies motorcycles and the like. People have been trying to find the magic engine for a very long time now. Including boat motors and generator power plants.
 
Acrodustertoo said:
The term "auto" implies motorcycles and the like. People have been trying to find the magic engine for a very long time now. Including boat motors and generator power plants.
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To my knowledge, there has never been a car engine with anything close to SACS (Suzuki Advanced Cooling System) technology. It's a combination of air and oil cooling jackets that adds no additional mechanical complication to an air cooled engine while allowing it to produce near liquid cooled power to displacement ratios.

It solves many of the problems encountered with auto conversions. It uses less parts and weighs less per HP.
 
Acrodustertoo said:
The term "auto" implies motorcycles and the like. People have been trying to find the magic engine for a very long time now. Including boat motors and generator power plants.
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Do you consider the Austro diesel, or the Theilert Diesel to be airplane engines? How about the Orenda/Trace engines?
 
Dav8or said:
Do you consider the Austro diesel, or the Theilert Diesel to be airplane engines? How about the Orenda/Trace engines?
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Are these engines pulled from a scrap yard and built in a guy's garage next to his plane? You are comparing apples to oranges here.
 
Acrodustertoo said:
Are these engines pulled from a scrap yard and built in a guy's garage next to his plane? You are comparing apples to oranges here.
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No, not really. The original premise of this thread was about using a Suzuki engine as a basis for an aircraft engine. You proclaimed that any engine from any other application ends in disappointment and disaster. This thread said nothing about salvage yards, or some guy's garage. I think the Austro, Theilert and Orenda engines have been successful airplane engines, however not a commercial success.

It turns out that in the end, that once you make a car engine ready for prime time in an airplane, it costs the same if not more than the traditional airplane engine. It also turns out that these engines haven't been able to best the old bull crap tractor engines we all use for longevity either. Efficiency isn't that much better either.

IMO, what is needed is a clean sheet design airplane engine, but the market just isn't there to justify the huge expense like it once was 50 years ago.
 
Dav8or said:
It turns out that in the end, that once you make a car engine ready for prime time in an airplane, it costs the same if not more than the traditional airplane engine.
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With the Suzuki SACS engine, you might be able to avoid that since it has many characteristics that are aircraft friendly.

IMO, what is needed is a clean sheet design airplane engine, but the market just isn't there to justify the huge expense like it once was 50 years ago.
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I've felt for a while that the long stroke experimental engines like the IO-408 were the future of aircraft engines. For the RPM's that aircraft engines operate at, big bore short stroke just doesn't make sense. Long stroke engines are more thermally efficient.
 
Capt.Crash'n'Burn said:
To my knowledge, there has never been a car engine with anything close to SACS (Suzuki Advanced Cooling System) technology. It's a combination of air and oil cooling jackets that adds no additional mechanical complication to an air cooled engine while allowing it to produce near liquid cooled power to displacement ratios.

It solves many of the problems encountered with auto conversions. It uses less parts and weighs less per HP.
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If cooling was the only issue, you'd be on to something. Power at prop RPM is also a big problem with these conversions, hence the need for a reduction gear. Welding the transmission and removing extra gears is not the issue. You need to have the engine turning in its; power band (say 7.5K for the sake of argument) and have the prop turning in the 2200-2500 RPM range. So you need a 3 to 1 REDUCTION gear that can handle the gyroscopic loads of a propellor.

John
 
Capt.Crash'n'Burn said:
I've felt for a while that the long stroke experimental engines like the IO-408 were the future of aircraft engines. For the RPM's that aircraft engines operate at, big bore short stroke just doesn't make sense. Long stroke engines are more thermally efficient.
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I assume the short strokes are for packaging and space savings. Longer strokes means wider engine (assuming traditional boxer design) and less aerodynamic. I'm not sure about weight differences. Maybe short fat cylinders are lighter than long skinny ones?? Don't know.
 
Anybody trying a conversion without having an expert in harmonics and loads WILL fail. The harmonic issues in the reduction gears are huge and it takes an expert in that field to handle it.

Bob
 
I would think that a high torque, low RPM engine like a Harley would be more suitable for aircraft use as it could probably be used in a direct drive mode. Plus it's air cooled.

Although, in any case, the engine would have to be modded to accept axial crankshaft loads, or a transfer gear or belt would still be required. Maybe a BMW opposed twin would work better.
 
Sac Arrow said:
I would think that a high torque, low RPM engine like a Harley would be more suitable for aircraft use as it could probably be used in a direct drive mode. Plus it's air cooled.

Although, in any case, the engine would have to be modded to accept axial crankshaft loads, or a transfer gear or belt would still be required. Maybe a BMW opposed twin would work better.
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For an engine of this size, the low RPM makes too little HP. A Harley or BMW would be lucky to make 50 HP at the revs they turn at. Actually, in direct drive, even less.

Just remember, twice the RPM's =~4x the power. In this case a 1200 Bandit engine turning 6,000+ RPMS could only be beat by a 4800cc engine turning at 3,000 RPM's. Have you ever seen an MC engine that big???
 
Dav8or said:
I assume the short strokes are for packaging and space savings. Longer strokes means wider engine (assuming traditional boxer design) and less aerodynamic. I'm not sure about weight differences. Maybe short fat cylinders are lighter than long skinny ones?? Don't know.
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If you adopted SACS technology in a Lycoming or Continental, you could fit the cowling a lot tighter since the cylinder heads would have oil cooling. This would of-set the difference in engine width.
 
jsstevens said:
If cooling was the only issue, you'd be on to something. Power at prop RPM is also a big problem with these conversions, hence the need for a reduction gear. Welding the transmission and removing extra gears is not the issue. You need to have the engine turning in its; power band (say 7.5K for the sake of argument) and have the prop turning in the 2200-2500 RPM range. So you need a 3 to 1 REDUCTION gear that can handle the gyroscopic loads of a propellor.

John
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Actually the engine only has to turn in the 6K range.
 
Capt.Crash'n'Burn said:
For an engine of this size, the low RPM makes too little HP. A Harley or BMW would be lucky to make 50 HP at the revs they turn at. Actually, in direct drive, even less.
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What makes you think that? My Harley engine produces over 85HP in the 2500-3000 RPM range (according to the dyno sheet, and that's at the rear wheel) and it's nowhere near its potential. It's a 13 year old 95-inch motor with nothing but some mild cam work. A newer 103 incher would do quite a bit better at cruise RPM -- as would mine with some head work. I wouldn't want to bump the compression up any.

That said, I've wondered why Harley and other motorcycle engines have not found much if any use in airplanes. The fact that we've had fairly powerful motorcycle engines around for decades and no one seems to be using them indicates to me that there are some pretty major issues getting them to work and work reliably.

If you're convinced the Suzuki engine will work, then by all means go scrounge one up and figure out how to hang it between the firewall and the prop. Perhaps you'll have a better understanding of why the guys in France or wherever are getting over $13K for one.
 
Capt.Crash'n'Burn said:
For an engine of this size, the low RPM makes too little HP. A Harley or BMW would be lucky to make 50 HP at the revs they turn at. Actually, in direct drive, even less.

Just remember, twice the RPM's =~4x the power. In this case a 1200 Bandit engine turning 6,000+ RPMS could only be beat by a 4800cc engine turning at 3,000 RPM's. Have you ever seen an MC engine that big???
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My 1200RT engine put out 110 hp at the crank, at somewhere around 5,000 rpm. Actually I think the newer wetheads are more than that.
 
Sac Arrow said:
My 1200RT engine put out 110 hp at the crank, at somewhere around 5,000 rpm. Actually I think the newer wetheads are more than that.
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1200 wethead:

Rated output 125 hp (92 kW) at 7,750 rpm
Max. torque 92 lb-ft (125 Nm) at 6,500 rpm

I love my new R 1200 GS, it moves out smartly, handles well, killer brakes, all day comfortable.
 
In Germany, BMW conversions have gained some (limited) popularity. Actually, when my wife ad I still lived there, we got our German pilot's licenses for weightshift LSAs on trikes with BMW engines.
I liked it and then engines were plenty powerful. I also felt that torque (and resulting from this power) was sufficient over a wide rpm band, a constant speed prop would certainly further improve this. The fuel consumption of the fuel injected engine was also impressively low, overall a very nice package.

However - don't expect the same reliability and durability from any of the conversion as in a dedicated aircraft engine.
Our flight instructor crashed his trike, because the non-redundant ECU crapped out right after take off. There are also reports that the bearings in the reduction drive will have to be replaced every couple hundred hours.
Or google for Jan Eggenfellner with his infamous Subaru conversions, who is now trying to sell Honda conversions: Many enthusiastic initial reports, which however usually quickly turn into massive frustration, because of all kinds of issues which can't be solved.
As always, you get what you pay for...

I am not saying that it can't be done. Some of the aircraft diesel engines are actually based on car engines. By the time proper research, development and testing is done, the cost are however the same, if not higher than for other aircraft engines.
 
> "Many have tried auto conversions but most are a complete disaster and not worth the time or expense."

Oh yeah? They used Suzuki engines for the Bugatti 100P replica that flew recently. I bet you didn't think about that one.
 

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Acrodustertoo said:
Many have tried auto conversions but most are a complete disaster and not worth the time or expense.
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A lot of VW power airplanes flying around. The Sonex series of airplanes and Airdrome Aeroplanes WW I replicas for example. William Wynn and his Corvair conversions are popular as well.

Cheers
 
Dav8or said:
IMO, what is needed is a clean sheet design airplane engine, but the market just isn't there to justify the huge expense like it once was 50 years ago.
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I fly behind a clean-sheet design airplane engine, HKS 700E. Works great, although a few days ago the U.S. distributor announced a price increase.
 
German guy said:
In Germany, BMW conversions have gained some (limited) popularity. (...) However - don't expect the same reliability and durability from any of the conversion as in a dedicated aircraft engine.
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Euros in general have a wide selection of oddball engines. Both ULpower and Hirth are over there. Raikhlin, too. And then you have hopefuls like BOT and ICP M09. In America, all we have is Generac with Culvert's belt PSRU.
 
DaleB said:
What makes you think that? My Harley engine produces over 85HP in the 2500-3000 RPM range
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Umm, not even close. I've got 3 NHRA National Championships building engines. You can't BS me with these numbers.

A 95 c.i. air cooled engine would be lucky to make anything over 50 horse at 3000 RPM's... at the flywheel.
 
Capt.Crash'n'Burn said:
Umm, not even close. I've got 3 NHRA National Championships building engines. You can't BS me with these numbers.

A 95 c.i. air cooled engine would be lucky to make anything over 50 horse at 3000 RPM's... at the flywheel.
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OK, whatever. I guess the dyno was lying.
 
DaleB said:
OK, whatever. I guess the dyno was lying.
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Let's take your numbers here. 85HP @3000RPM (I'll be generous and use the high number) out of 95 cubic inches, and at the rear wheel no less.

That would equate to a volumetric efficiency ratio of aprox. 167% (maybe more) just at the flywheel (you see, I'm being generous again). The most efficient, liquid cooled racing engines (think F1, NASCAR, NHRA Pro Stock) have a V.E. of slightly over 130%.

So where does this 37% increase in volumetric efficiency come from? Out of an air cooled 45 deg V-twin???
 
DaleB said:
OK, whatever. I guess the dyno was lying.
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Very likely it was. Dynos need to give repeatable results, the actual numbers are just approximations.
(I own two, I know pretty well how they work).
 
mtuomi said:
Very likely it was. Dynos need to give repeatable results, the actual numbers are just approximations.
(I own two, I know pretty well how they work).
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Nope. Dyno wasn't lying. I was mis-remembering my read of it from about 10 years ago. Peak HP was 92, but that was at a significantly higher RPM. In the cruise RPM range it was indeed significantly lower.

Totally my mistake.
 
>"They used Suzuki engines for the Bugatti 100P replica that flew recently."

I was expecting someone to jump right in telling me just what happened on that flight. I'm sorry to say that gorgeous plane's last flight ended in disaster for both it and the pilot. I've no idea if the engines had anything to do with the crash. If the two bulletproof Suzuki's I've owned are any measure, probably not. This is to correct my earlier dumb post. Garrison says in his write-up (current issue of Flying) that it had handling problems. The article will be online as soon as next month's Flying comes out.
 
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