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Aircraft certified motor vehicle engines. Is there a niche for them


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We've operated Limbachs for neatly 20 years. They are the certified versions of aviation developed flat four air cooled direct drive VW engines with either 1000 or 1400 hrs TBO. Ours are older versions of lower output 80hp (yes same as those used by the blimp that operated around Oz) and 94hp. Under stressed, economical, relatively light, very reliable with regular maintenance. Continuous operating range of 2300-3000rpnFor a home builder, VW parts are often interchangeable, cheap, widely available and there are a host of racing enthusiasts who offer specialised parts and advice on souping up performance. Newer versions have FI and EI and much higher output ratings but also prices of course :>)

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A PT6 has no gearbox. The RB211and all of its derivatives that drive a shaft has no gearbox. The PT6 is a brilliant design

 

Are you sure about that? I have just looked at a page on Wikipedia about the PT6 and right up front is a big gearbox with planetary gears. The power turbine apparently turns at 30,000rpm, so not much hope of driving a propeller off that without a gearbox.

 

What is quite amazing is that the PT6 design process started in 1958. The first ones entered service in about 1964 and they (Pratt & Whitney Canada) have been building and developing them ever since - almost 60 years! Their reliability is just about off the scale - one in-flight shutdown per 651,000 hours. Phenomenal.

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They do have a gearbox, my previous posts where tongue in cheek to the original poster of that comment? They are a good donk, some prefer the Garret of similar size power output cause they are more fuel efficient but I loved the free turbine of the Pratt, 4000 hrs I never had one hiccup on me actually 8000 hrs as they where in pairs?

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My apologies to all. It is correct the power turnip does have a gearbox. My mistake arose from work that I have done on the design of low speed (3600RPM) direct drive turbines and multiple shaft engines. I assumed that the power turbine would run like direct drive after being told that the PT6 was of a similar design. Sorry. I still like the Rolls Royce 3 shaft machines. My experience with gas turbine design is from 70MW Rolls Royce Trent through to 200MW Siemens machines. Assuming has been my error.

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Are aircraft engines running an Nikasil bore?

with modern car and motorcycle engines, the revs come at the expense of being rebuildable (in an economical manner).

the old top end rebuild is a rare thing now

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Are aircraft engines running an Nikasil bore?

with modern car and motorcycle engines, the revs come at the expense of being rebuildable (in an economical manner).

the old top end rebuild is a rare thing now

 

I guess theoretically. I wonder how many car engines get rebuilt nowadays?

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A lot of modern stuff is not rebuildable in a general sense. You reface something and the deck height is wrong straight away. Bearings run in the parent metal. It's throw away. Generally Nikasil is done on aluminium and it''s fused into the metal . Aluminium has an expansion problem with long studs that are exposed to cooling air directly. .Nev

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Nikasil plating can be done, and has been available for some years. Probably still cheaper than a genuine Rotax cylinder.

I'm largely guessing, but I recon a full after market big bore kit (pistons,rings,cylinders) would probably be cheaper than a couple of Rotax cylinders (just the cylinders). Some of the kits are not far off factory capacity for those worried about overpowering their engine.

 

Edit. CPS show a Rotax piston/cylinder unit for $1530 usd, so $2200 aud direct conversion. I recon ultimately you'd be looking at close to $3000 ( with seals etc) PER CYLINDER replacement before labour......

Edited by Downunder
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Was just thinking about inline fours today, after the pietenpol was brought up. Obviously it originally used the model A. And there are some modern conversions I think of Suzuki and Honda engines. Are there any older inlines that were converted? I did a quick google of ford escort and Datsun for examples but came up.blank. a pietenpol wth a ford escort engine could be just the thing ?

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The model A was used because they were the common engine of the day. 1ZZ-FE out of a Corolla? Probably not. By the time the variable cams and immobiliser are stripped out, a proper aero engine is looking more attractive. Not to mention any twin cam auto engine will have single spark plug heads. Some exceptions:

 

1100cc Kawasaki Zephyr

 

Nissan Gazelle/200sx with a Z20 engine (NAPS-Z)

 

Mazda Renesis (if you must)

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It doesn't seem to be widely known, but a lot of gyro guys run Subaru EJ22s with Rotax redrives and use the factory ECU and apparently have little problem.

They are a little on the heavy side, but make good power and are quite cheap. They certainly make the extra few kilos Rotax lack look very expensive.

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I've got a very low km (11,000 kms) 2014 Subaru Boxer diesel available for a very modest price, if you want to try something different. But they do weigh around 140-145kgs, I believe.

The huge advantage with the Boxer engine is that they are the ideal engine layout for aircraft. And the diesel's fuel economy is renowned, and the turbo improves performance at height.

However, the power pulses of the diesel are higher than petrol engines, and I believe you need to install some kind of cushion coupling in the drive to reduce the intensity of the diesel power pulses.

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I've got a very low km (11,000 kms) 2014 Subaru Boxer diesel available for a very modest price, if you want to try something different. But they do weigh around 140-145kgs, I believe.

The huge advantage with the Boxer engine is that they are the ideal engine layout for aircraft. And the diesel's fuel economy is renowned, and the turbo improves performance at height.

However, the power pulses of the diesel are higher than petrol engines, and I believe you need to install some kind of cushion coupling in the drive to reduce the intensity of the diesel power pulses.

Looking at the power graphs for that engine, you could probably get away with direct drive. Peak power is just above 3000 rpm and peak torque is around 2500.

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And.

Someone converted a ISUZU 3.2 ltr, V6, fot their spitfire. ( Jackaroo )

It looked very good,

spacesailor

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Looking at the power graphs for that engine, you could probably get away with direct drive. Peak power is just above 3000 rpm and peak torque is around 2500.

Still better of going through gear box - that engine should be able to maintain 5000 rpm - modify/change the turbo to give good altitude performance and you may just have a flyable engine.

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Because diesel is a slow-combusting fuel, fuel economy starts to suffer in diesels run at speeds over about 3200-3300 RPM. You get a lot of still-combusting diesel going out the exhaust, from 3500 RPM upwards, in diesels.

I've got an Isuzu 5 tonner with the venerable, unbreakable old 6BG-1, 6 cyl diesel. It redlines at 3100 RPM, and it will sit there all day, if I want to push it - but I really notice the fuel consumption going up, if I sit on peak revs.

Sitting on 2500-2750 RPM gives me good fuel economy, and good highway speed (100-110kmh).

 

The Subaru diesel would perform quite adequately at 3000-3300 RPM with a direct drive to the prop.

The EE20 Subaru diesel produces its maximum 150HP (110Kw) at 3600 RPM, and the EE20 power graph shows the HP falling away rapidly from 3600 RPM upwards.

 

Maximum torque of the EE20 is 350 Nm at 1800 RPM and the torque output starts to fall away quite substantially from 2500 RPM upwards.

Of course, you could chip the engine to improve the output at higher RPM's, but I don't know that chipping would be advisable for an aircraft installation.

 

https://www.fsb.unizg.hr/miv/MSUI/KonMot/Uravnotezavanje/Podloge_klipni_mehanizam/Subaru/MTZ-2008-09_Subaru%20Boxer%20Diesel_(engl.).pdf

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Still better of going through gear box - that engine should be able to maintain 5000 rpm - modify/change the turbo to give good altitude performance and you may just have a flyable engine.

No point really....Power peaks at 3600 rpm and torque peaks at 1600 and is flat until around 2500. Good propeller RPM.

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I

What else but a Pietenpol Aircamper? (but I'll cut you some slack). I needed a new engine because the original Corvair suffered a catastrophic in-flight self destruction - burned piston face, broken rod, split cylinder barrel and other massive problems in 3 out of the 6 cylinders. Guess the Alsatian must have got to that one first? I got called out to retrieve it from the forced landing site and ultimately bought the carcass from the disgruntled owner a few years later and have just completed the much-longer-than-anticipated repower. Looking now for a decent w/end met forecast to hopefully put the old girl back in the air. If it works well I'll crow like a rooster but if it fails, I'll just hide in the corner and change the subject. cheers

 

Is it Sunday today?????? ;)

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