LS3 - It's not just for Corvettes

[Blue on Top]

So, a friend has gotten me interested in looking at certificating the Chevrolet LS3 engine for airplanes (or one of the 4th generation LT engines).  Looking into it, there are a lot of advantages.  I am not afraid of the certification process.  Thoughts?

PS. Yes, I know about the Porsche engine/airplane (M20L)

[carusoam]

Challenges of the past that would want to be looked into...

1) The road going version has expected max output for a few dozen seconds at a time...

2) what could the cruise output be?

3) The road going version is turning over 7k rpm, with max torque somewhere lower... (just guesses to illustrate the challenge)

4) Props have various limitations to rpm in the 2700 - 3000 rpm.

5) gear boxes are often used for matching engine output to prop speeds...

6) Gearbox strength and weight seems to be a big challenge for high output engines...

7) Proper strength and weight for a gearbox seems to get expensive...

This will be an interesting conversation...

PP thoughts only, just some ideas that come to mind...

Best regards,

-a-

[WilliamR]

Saw several on RV-10s.  They seem a little hard to setup and run well, but that's a very uninformed opinion.

 

William

[PT20J]

Seems like a good starting point would be to understand the reasons that past efforts to utilize automotive engines in aircraft have generally been unsuccessful. 
Skip

[carusoam]

It has been many years since I looked...

One known disaster was the plastic Comanche that had a gearbox failure... https://en.wikipedia.org/wiki/Ravin_500 (no mention of the auto engine here)

looking at more current and positive info...

http://autopsrus.com/about-the-ls3

Some nice comparison charts to traditional aircraft engines...

Best regards,

-a-

[Stephen]

3 minutes ago, carusoam said:

It has been many years since I looked...

One known disaster was the plastic Comanche that had a gearbox failure...

looking at more current and positive info...

http://autopsrus.com/about-the-ls3

Some nice comparison charts to traditional aircraft engines...

Best regards,

-a-

Nice breakdown. Mine as installed is 430 HP so the cited installation is definitely more conservative. 

[bob865]

Kinda like this guy?

 

[M20F]

It is actually a pretty easy pathway to certifying the engine.  The only requirement is money.  

[ArtVandelay]

14 minutes ago, M20F said:

It is actually a pretty easy pathway to certifying the engine.  The only requirement is money. 

The certification process consists of 3 test runs: Full power for 50 hours with adequate cooling to keep temperatures in green. Full power for 50 hours with temperatures at redline. 65-75% power for 50 hours at redline. Oil changes after each run, engine inspection is done. That’s it, there is no tests to see if engine will make TBO.

of course you’d have to have redundant ignition systems, that’s probably not a simple modification 

[steingar]

The only car engine I've ever heard of that really worked was Rotax.  That, and the Theilert Diesel engines were just jumped up Mercedes engines.  Usually the things that make them attractive, low cost and low parts cost, get swamped by the increased costs of coolant and gear reduction.  Also makes the darn things heavy.  I think they do use in the WWII flying boats,  the PBY Catalina, but only because they can't get the engine that goes in the darn things. 

We all complain about airplane engines, but they're actually really good at doing what they do.

[EricJ]

I'd second the concerns about LS engines never really amounting to much in airplanes.   It's been tried quite a few times.

Meanwhile, Lycoming is coming out with E version engines which have electronic fuel injection and ignition from the factory.   This seems promising to me, especially if they get certified as replacements for the traditional engines.   I'd be all over that when it comes overhaul time if it were available.

https://www.lycoming.com/engines/ie2
 

[Igor_U]

FYI,

In mid 90s Toyota certified an 350HP V-8 twin turbo automotive engine (from Lexus).they even got the production certificate. AFIK, it was never installed in production aircraft but, later Toyota was designing a 4-place composite air-frame as well (in LA). As far I know, that was never certified. 

In aerospace, it was often said that amount of certification documentation equals weight of the airplane. It can be that bad for the 'Vette engine considering the weigh, right? 

[kmyfm20s]

It would be exciting to see the use of an electric turbo charger to turbo normalize our engines. High altitude takeoffs and en route climb performance at the flip of a switch with no pressure on the exhaust system:)

https://www.forbes.com/sites/samabuelsamid/2019/10/17/garrett-electric-turbochargers-headed-to-production-in-2021/#6df60865180a

[Guest]

This guy has installed a Corvette engine in several Republic Sea Bees.

http://v8seabee.com/about-us.html

Clarence

[thinwing]

This Seabee was converted to corvette engine and has been flying since at least 2007...

[thinwing]

I’ve flown in the Seabee ,and say the 350 hp is a huge improvement over the original 210 hp Franklin

[FloridaMan]

5 hours ago, ArtVandelay said:

The certification process consists of 3 test runs: Full power for 50 hours with adequate cooling to keep temperatures in green. Full power for 50 hours with temperatures at redline. 65-75% power for 50 hours at redline. Oil changes after each run, engine inspection is done. That’s it, there is no tests to see if engine will make TBO.

of course you’d have to have redundant ignition systems, that’s probably not a simple modification 

You forgot that at teardown all parts must show no sign of changes from new. 

[Planegary]

I was looking at a P51 replica project a couple of years back and did extensive research on the subject all the way down to piston speeds in the cylinders. The biggest unknown seemed to be the PSRU. There are many variations but none that have been around to have a history of reliability to point at. Another problem is the single crank sensor to control the cylinder firing time. Good luck with it because if you make it work I see a replica P51 in my future

[Blue on Top]

7 hours ago, PT20J said:

Seems like a good starting point would be to understand the reasons that past efforts to utilize automotive engines in aircraft have generally been unsuccessful. 
Skip

I agree with you, and I need to learn a lot more.  We have data on this engine running at 100% for 2.5 - 3 years continuously (with breaks for oil changes only).  This engine, unlike most automotive engines, is designed to run at full power … like an aircraft engine.   Thanks! Ron

[EricJ]

Coincidentally I was learning today, totally unrelated, that there is already an FAA certificated liquid-cooled V8 based on re-engineered chevy V8s.   A guy even went to jail over it.   

https://en.wikipedia.org/wiki/Orenda_OE600

These guys do tons of stuff with aircraft V8 installations:   http://epi-eng.com/

...and had some interesting experiences and data that came from an attempt at an STC to put the Orenda V8s in Aero Commanders: 

http://epi-eng.com/aircraft_engine_conversions/orenda_on_aero_commander.htm

And some general views from them on putting V8 conversions in airplanes:

http://epi-eng.com/aircraft_engine_conversions/evaluating_a_conversion.htm#extbadexamp

 

OTOH, there are a lot of cool things out there like the Falconer V12 that powers the 3/4 scale P-51 Thunder Mustang:   https://falconerengines.com/falconer_v12.php

 

 

[Blue on Top]

7 hours ago, bob865 said:

Kinda like this guy?

@bob865  Yes, but less horsepower (more torque), better installation and certificated.  I bet his climbs like a homesick angel!

[Blue on Top]

6 hours ago, steingar said:

That, and the Theilert Diesel engines were just jumped up Mercedes engines.  Usually the things that make them attractive, low cost and low parts cost, get swamped by the increased costs of coolant and gear reduction.  Also makes the darn things heavy. 

We all complain about airplane engines, but they're actually really good at doing what they do.

@steingar  Thank you!  (I'm saving my emojis )

From experience, the diesels are VERY heavy, and they are not low cost!  I'll leave it at that.

I agree that certified aircraft engines do a great job at what they are designed to do.  They are just too expensive because the OEMs can't make enough of them.

[Blue on Top]

5 hours ago, Igor_U said:

FYI,

1) In mid 90s Toyota certified an 350HP V-8 twin turbo automotive engine (from Lexus).they even got the production certificate. AFIK, it was never installed in production aircraft but, later Toyota was designing a 4-place composite air-frame as well (in LA). As far I know, that was never certified. 

2) In aerospace, it was often said that amount of certification documentation equals weight of the airplane. It can be that bad for the 'Vette engine considering the weigh, right? 

@Igor_U  Thank you!  Again, saving emojis .

1) Very true.  The person that headed the project lives down the street from me.  Regretfully, a lot of people and companies have lost a lot of money $MM trying to certificate auto engines: Toyota, Orenda, etc.

2) True dat.  On this the paperwork will exceed the weight of the engine.   On a good note, it weighs a little less than an IO-540 or IO-550.

Thank you!

[McMooney]

Why not a turbo charged 6 turning at less than 3Ik Should be able to get 225 to 250 hp and it'll run forever

[Blue on Top]

4 hours ago, thinwing said:

I’ve flown in the Seabee ,and say the 350 hp is a huge improvement over the original 210 hp Franklin

@thinwing  Thanks!   I thought they left the original horsepower. ???