Move over ROTAX...

[RFguy]

https://www.snowtechmagazine.com/genesis998turbo/

 

 

[Blueadventures]

That conrod looks cooked (wrist pin end)?  (Heat treatment or out of a cooked engine?; looks interesting to me.)

 

Hopefully an aero engine in the future.

[turboplanner]

45 minutes ago, RFguy said:

https://www.snowtechmagazine.com/genesis998turbo/

 

 

6500 rpm max torque?

Intermittent power application in sub zero atmosphere?

[RFguy]

and there are aftermarket hotrod kits also. IE hot it up (even more). Skido engines are usually very tough. 

Reading some forums, there are quite a few in experimental aircraft . People just buy a snowmobile and remove the engine....

[onetrack]

The article is nearly 7 years old! The engine has probably already been made obsolete by Yamaha! 

 

Edited November 28, 2023 by onetrack

[facthunter]

The technology remains with the concept which is constantly improved.  Yamaha have contributed much to high power engines, over time. Nev

[onetrack]

You could be waiting a long time to acquire a Yammy sled engine for your aircraft. They can't supply the demand for sled orders, and they can't build in decent quantities because of a lack of parts. COVID supply chain difficulties are still hitting them.

 

https://sledmagazine.com/what-does-yamaha-have-in-store-for-2023-deniss-predictions/

[facthunter]

I don't believe THAT particular type of motor is best for an Aero engine.  An aero engine should be designed specifically for it's intended Purpose.  That rules out a large production run and the advantages of mass production. Aero engines don't need sudden Power changes for example. Nev

[RFguy]

I bring it  up because it sounds like good tech, and also because I understand it might have been involved in a experimental in flight fire -

 

https://www.facebook.com/photo/?fbid=689385833173694&set=a.439934824785464

 

the owner admits making  modifications to the engine  system that were ,  "not best practice" ... full credit to the pilot /owner  for owning up. 

Edited November 28, 2023 by RFguy

[facthunter]

So a lot of people will think Yamaha engines are crap and RV's are not safe. IF fuel was spraying around, He's lucky he didn't suffer one of the worst ways to die. In flight fire.   Nev

[Thruster88]

It is interesting how the fire seemed most intense right near the cabin air intakes. My RV6a has a piano hinge type cowl fixture all the way up each side, I don't see that on the accident rv9.

 

A good reminder to shut off fuel in engine fire situations. I will be conservative and stick with the dinosaur lycoming.  

[corvairkr]

 

[BurnieM]

Rotax are primarily a snowmobile/motorcycle engine manufacturer.

 

Yamaha, Honda, Suzuki and Kawasaki all have significant engine development/manufacturing divisions but seem to have choosen not to go into aviation. Too much legal risk for not enough volume ?

Edited November 29, 2023 by BurnieM

[turboplanner]

1 hour ago, BurnieM said:

Rotax are primarily a snowmobile/motorcycle engine manufacturer.

 

Yamaha, Honda, Suzuki and Kawasaki all have significant engine development/manufacturing divisions but seem to have choosen not to go into aviation. Too much legal risk for not enough volume ?

Well they go into all sorts of markets, but their typical intermittant power configurations and high rpm  profiles don't suit aero engines which ideally need low rpm and intermittant power.

[skippydiesel]

"............their typical intermittant power configurations and high rpm  profiles don't suit aero engines which ideally need low rpm and intermittant power."

 

Whaaaaat?

 

Care to rephrase?

[Litespeed]

I do not see any inherent problems with appropriate gear drive and installation but that's where homebuilders often fail.

 

Your Modern Yamaha motor punches big torque/power at moderate revs and smooth as silk.

 

Done well I think they are terrific, so does the market. If peeps are paying for a new snow mobile just to get a engine it says they are very good and cheap compared to a underpowered Rotax.

3 hours ago, turboplanner said:

Well they go into all sorts of markets, but their typical intermittant power configurations and high rpm  profiles don't suit aero engines which ideally need low rpm and intermittant power.

Intermittent? More like constant steady power bar takeoff.

 

As a bike rider for close to 40 years mainly touring, your missing the point, they don't have to rev like a race bike to make good power. They are designed for grunt and longevity not for race tracks.

 

Remember you can be just as dead when a snowmobile stops in snow as a aircraft. Yamaha know this.

[turboplanner]

6 hours ago, Litespeed said:

I do not see any inherent problems with appropriate gear drive and installation but that's where homebuilders often fail.

 

Your Modern Yamaha motor punches big torque/power at moderate revs and smooth as silk.

 

Done well I think they are terrific, so does the market. If peeps are paying for a new snow mobile just to get a engine it says they are very good and cheap compared to a underpowered Rotax.

Intermittent? More like constant steady power bar takeoff.

 

As a bike rider for close to 40 years mainly touring, your missing the point, they don't have to rev like a race bike to make good power. They are designed for grunt and longevity not for race tracks.

 

Remember you can be just as dead when a snowmobile stops in snow as a aircraft. Yamaha know this.

Give me an example of one you are taking about  with:

 

Max Power@rpm

Max Torque @ rpm

Chart showing the curves if you can scan as a jpg.

 

and I'll explain it.

[BurnieM]

Yes, the current enigines produced by these Japanese manufacturers are not ideal for aviation use (but they are close).

 

These manufacturers all have the expertise and manufacturing control to design and produce an aviation suitable engine to match and better (power, reliability, long life) Rotax. The question is why have they not done this ?

[RFguy]

"Yes, the current enigines produced by these Japanese manufacturers are not ideal for aviation use (but they are close)."

why not ?

 

[onetrack]

Because a motorcycle or snowmobile engine doesn't face the same constant heavy engine load as an aircraft engine does.

There's subtle changes in engine stress loads between loads that ease off for a period, before coming back on again - as compared to constant heavy load with no letup.

 

Caterpillar thought they could get into the rail loco business by installing their engines in locos. After all, they'd been building heavy duty tractor and construction diesel engines since 1931, so why not get into the loco business, it's just another engine-driven machine, isn't it?

 

Cat produced a number of diesel locos using their heavy duty construction engines, and they were an unmitigated disaster. Their unreliability was legend. Cat engineers failed to understand that loco engines require extremely heavy duty build, as the load on them is huge and almost constant and unrelenting.

 

And on long railway grades with a huge tonnage behind them, the stress buildup on loco engines producing maximum power on a constant basis for long periods, soon sorts the men from the boys.

Cat gave up on their foray into loco-building and left it to the people who knew what kind of build strength was needed for loco engines.

 

Then Cat decided they really needed to get a slice of the loco market - so they simply bought EMD, a long-established manufacturer of locos. They just renamed EMD to "Progress Rail", the supplier of "Caterpillar" rail products. 

 

Edited November 29, 2023 by onetrack

[BurnieM]

Agreed.

You would need to modify the design.

These 4 manufacturers all have the expertise and facilities to do this but they haven't.

 

Rotax was not a aviation engine manufacturer for 60 years until it was.

[facthunter]

Actually the best performing power plants in the field will always be purpose built. Reduction gears are always a critical item. You wouldn't like to listen to them running under load close up and they would often be better with their OWN oil. The Holden six engines lasted no time in cement mixers and that wasn't due to ingestion of dust. How an aircraft engine is Mounted is not the least of it's problems. Direct drive saves a lot of anguish IF you use it in an aircraft. Gears also absorb energy and have to be cooled and have to be coupled to things very firmly.  Nev

[Student Pilot]

GSIO 480/540, Tiara and GO300 continental are examples of geared engines in production and use, not the last few years but were used extensively. There are all sorts of old wives tails of gearbox's and the use there of. I think Rotax and PT6 engines have proven they are not a problem.

[turboplanner]

18 minutes ago, Student Pilot said:

GSIO 480/540, Tiara and GO300 continental are examples of geared engines in production and use, not the last few years but were used extensively. There are all sorts of old wives tails of gearbox's and the use there of. I think Rotax and PT6 engines have proven they are not a problem.

Some have been a problem like the fatal belt break on the Mustang in Queensland and failures from misalignment, poor mounting, out of balance etc.  and there is a small power loss because of driveline coefficient having to be added, but technically it's as you say; if the engineering is correct it works well. I'm not concerned about the driveline itself, but that fact that it allows a screaming engine speed by comparison with the long life aero engines operating around 2000 to 2600 rpm approx.

 

When you're analysing engine reliability and life and you put stroke length into the equation and multiply that by lengths per hour you come up with the total length the piston, rings and bore have/have been travelled. Usually the shorter travel length will win the reliability stakes.

[facthunter]

SP the geared Continental 300 wasn't a great success. The Rotax one is complex and most turbo props have" do not use" torque ranges. Piston speed limits lubrication and it's usually only about 30 MPH. Load Reversals  vibrations and thermal stresses cause fatigue. Detonation is catastrophic at  times. (Like if diesel gets mixed with the fuel or motor leaned out  at too high an MP)..   Nev