Mooney Turboprop. . .

[N201MKTurbo]

52 minutes ago, Austintatious said:

thats wonderful... but what do you think of the engine design?

Exactly what I said above on Nov 12.

[N201MKTurbo]

56 minutes ago, Austintatious said:

thats wonderful... but what do you think of the engine design?

What does it matter? I'm not a turbine engine engineer. It doesn't take much to put together a SolidWorks model of some turbine machinery and call it revolutionary. Lets wait to hear from a bunch of experimental guys that have actually flown the thing and get their opinion. 

Don't hold your breath, you will pass out. 

[AH-1 Cobra Pilot]

1 hour ago, Austintatious said:

Maybe this engine will pan out https://www.astronaerospace.com/

 

How would you like a 800 HP motor that weighs 200 lbs ?

If you do the Math with the listed specs, you find that the engine speed is at 10,000 rpm.  At a more airplane-normal 2500 rpm, that will be 200 hp.  Or you can have a heavy, expensive, and high-maintenance gear box added to the mix.

[N201MKTurbo]

https://www.kitplanes.com/turbine-powered-rv-10/

Here is one that looks like it actually flew. It makes 241 HP. It seems to say that it uses twice as much fuel as a piston engine of the same size and it was expected to sell for $175000 in 2015 dollars. 

It seems to have gone nowhere.

[AH-1 Cobra Pilot]

11 minutes ago, N201MKTurbo said:

https://www.kitplanes.com/turbine-powered-rv-10/

Here is one that looks like it actually flew. It makes 241 HP. It seems to say that it uses twice as much fuel as a piston engine of the same size and it was expected to sell for $175000 in 2015 dollars. 

It seems to have gone nowhere.

SFC = 0.83!?!  Gawd, is that crappy!

That is possibly the main reason it has/will not "go(ne) anywhere".

Edited December 13, 2021 by AH-1 Cobra Pilot

[Browncbr1]

6 hours ago, N201MKTurbo said:

I didn’t know there was a diesel option for any Mooney. Do you know something I don’t? 

That’s my point….  There is no 100UL option for mooney either.    I was wondering why there hasn’t been incentives for developing a new power plant to run on JetA instead of trying to redevelop fuel.  

[Jerry 5TJ]

7 hours ago, Browncbr1 said:

I don't know why no one else seems to think a FADEC controlled turbo diesel burning JetA is the the future for piston powered planes.

Maybe it is because people have been trying for at least 90 years to develop a good aviation diesel and none have been successful.   

[EricJ]

9 minutes ago, Jerry 5TJ said:

Maybe it is because people have been trying for at least 90 years to develop a good aviation diesel and none have been successful.   

Actually there have been a number of successful diesel aviation engines, but most of them were on the "other" side in WWII or after (Germany and Russia).   If development had continued we'd probably have a pretty sweet solution right now.

[Hank]

2 hours ago, EricJ said:

Actually there have been a number of successful diesel aviation engines, but most of them were on the "other" side in WWII or after (Germany and Russia).   If development had continued we'd probably have a pretty sweet solution right now.

Once upon a time there was a sweet biplane with a steam engine, too. Quiet, and could stop and reverse the prop on the ground. YouTube has videos . . . .

[Jerry 5TJ]

1 hour ago, EricJ said:

Actually there have been a number of successful diesel aviation engines, but most of them were on the "other" side in WWII or after (Germany and Russia).   If development had continued we'd probably have a pretty sweet solution right now.

Well, we were quick to snap up German Rocket specialists and all the unfired V2 hardware we could find in 1945, but we ignored the Junkers Diesel Aero engine technology, which was equally available to the victors.    

The Soviet AЧ-30 aviation diesel engine series also seems to have been quietly abandoned just after WWII.   

What about the DA62, tho?   It sports a pair of production aero diesels.  Nice plane, and you can have a new one right now for around $1.2M.  Mandatory engine overhauls and inspections at specific hour limits are required, last I checked, but $75 reserve per engine per hour should cover all those.  

Like you, I await the fabulous Aero diesel powered Mooney of the future.  For now, I’ll put my faith in Pratt & Whitney.  

[exM20K]

@Jerry 5TJ I'd say the Austro engines have been a big success:

https://www.austroengine.at/uploads/pdf/mod_products9/AE330FactSheet.pdf

1800 TBO, and the intervals are, in my experience, quite a bit less that providing for the care and feeding of my TSIO 550.

The DA42NG is a superior product to the DA40NG simply because it was designed around a diesel, albeit the lighter Thielert now CMI powerplant.  The DA40 NG had the much heavier AE300 grafted onto the nose in place of an excellent gas-powered installation.  The W&B envelope that resulted was very nose-heavy when I flew one many moons ago.  The gas engine DA42's, which diamond built to keep ERAU from blowing a gasket when the original 1.7L Thielerts proved to be not great, suffer the balance problems in the opposite direction:  they carry lead weights in the nose.

The long body mooneys, especially the TN with its nearly 500# engine ( and the "G" is the lightest of them all) already is kinda nose heavy.  Grafting a CMI CD300, weighing 100# more than the TSIO 550 would probably exceed the ability of the tail to keep the nose up.

The long-term viability of the high-horsepower gas engine planes is probably dependent on a suitable fuel.

-dan

[exM20K]

18 hours ago, Jerry 5TJ said:

you can have a new one right now for around $1.2M.

Not any more,  you can't.  Closer to $1.6 MM and next available is out into 2024 last time I checked.

-dan

Edited December 14, 2021 by exM20K

[Jerry 5TJ]

5 hours ago, exM20K said:

Not any more,  you can't.  Closer to $1.6 MM and next available is out into 2024 last time I checked.

Thanks for the update.  

Cessna keeps trying to get me to pre-order my new Denali and it’s not even been certified yet.   

[TheAirplaneNerd]

On 12/13/2021 at 11:37 AM, AH-1 Cobra Pilot said:

If you do the Math with the listed specs, you find that the engine speed is at 10,000 rpm.  At a more airplane-normal 2500 rpm, that will be 200 hp.  Or you can have a heavy, expensive, and high-maintenance gear box added to the mix.

That’s true, but don’t most turbines run in excess of 30,000 rpm? And it’s my understanding that they use a gearbox to achieve normal propeller speed, yet they have a much longer TBO then pistons (5000hrs vs 2000hrs right?). Am I mistaken or missing something?

[Jerry 5TJ]

2 hours ago, TheAirplaneNerd said:

That’s true, but don’t most turbines run in excess of 30,000 rpm? And it’s my understanding that they use a gearbox to achieve normal propeller speed, yet they have a much longer TBO then pistons (5000hrs vs 2000hrs right?). Am I mistaken or missing something?

The PT6A-35 has a 15:1 propeller gearbox.  With the prop at 2170 RPM the power turbine is … spinning real fast.  TBO is “only” 3,600 hours. 

[EricJ]

38 minutes ago, Jerry 5TJ said:

The PT6A-35 has a 15:1 propeller gearbox.  With the prop at 2170 RPM the power turbine is … spinning real fast.  TBO is “only” 3,600 hours. 

A friend that had an MU-2 was remarking about how tiny the output shaft was from the turbine to the gearbox.   We figured out that at the rate it was spinning it was carrying very little torque, so didn't need to be very big.   Stuff got bigger inside the gearbox. 

[N201MKTurbo]

27 minutes ago, EricJ said:

A friend that had an MU-2 was remarking about how tiny the output shaft was from the turbine to the gearbox.   We figured out that at the rate it was spinning it was carrying very little torque, so didn't need to be very big.   Stuff got bigger inside the gearbox. 

Check out the SSME turbopump, that sucker is about as big as a breadbox and makes 25000 HP!

I wonder what the specific fuel consumption of that thing is?

Edited December 16, 2021 by N201MKTurbo

[jaylw314]

17 minutes ago, N201MKTurbo said:

Check out the SSME turbopump, that sucker is about as big as a breadbox and makes 25000 HP!

I wonder what the specific fuel consumption of that thing is?

Good grief, and that's just the low pressure turbopump!  The high pressure one makes 75,000 HP?

[Hondo]

https://www.lx7aircraft.com/

Maybe Lance can afford it.

 

[AH-1 Cobra Pilot]

5 hours ago, TheAirplaneNerd said:

That’s true, but don’t most turbines run in excess of 30,000 rpm? And it’s my understanding that they use a gearbox to achieve normal propeller speed, yet they have a much longer TBO then pistons (5000hrs vs 2000hrs right?). Am I mistaken or missing something?

The point of my post is that some people tend to overhype things and not tell the WHOLE truth.  They definitely DO NOT have an 800hp, 200 lb airplane engine.

[carusoam]

The problem with the turbine engines….

Is the TBO of 3600hrs….

 

When you do the math on a 310hp engine with a pair of turbos on it…. With its 2K hrs TBO….

 

Suddenly the P46T, starts looking really good…. (Way to go Jerry!)

Go Rocket Engineering!

Best regards,

-a-

[carusoam]

I spent a minute reading the Astron engine page…

Where they listed Torque in pounds…. Try and convert that to foot-pounds…

If they are engineers… they can’t deliver the tech details required…

If they are sales guys… they need to hone their tech skills…

Looks like they took a page from the engineers cook book… building a turbine from turbocharger parts…. Watched a few YT videos…

Its technically possible, just not very feasible… outrageous FF inefficiency…

 

What are the smallest turbines from GE, RR, and P&W…. Or Garret….

Hey… fresh on the internet….   

https://www.experimentalaircraft.info/homebuilt-aircraft/aircraft-turbine-engine-manufacturers.php

-a-

[Austintatious]

16 hours ago, carusoam said:

I spent a minute reading the Astron engine page…

Where they listed Torque in pounds…. Try and convert that to foot-pounds…

If they are engineers… they can’t deliver the tech details required…

If they are sales guys… they need to hone their tech skills…

Looks like they took a page from the engineers cook book… building a turbine from turbocharger parts…. Watched a few YT videos…

Its technically possible, just not very feasible… outrageous FF inefficiency…

 

What are the smallest turbines from GE, RR, and P&W…. Or Garret….

Hey… fresh on the internet….   

https://www.experimentalaircraft.info/homebuilt-aircraft/aircraft-turbine-engine-manufacturers.php

-a-

I agree with you that there are a few of their specs that are suspect.  I do however find the design interesting.  I do not believe they will achieved the claimed RPM's, but for aviation the high RPM's are not needed anyway.. With several of these stacked, say 4 of them, you could still see a lot of power output with a very constant power output to the shaft.  The design would have the "piston" being pushed for 3/4ths of the rotation.  This means that with 4 of them stacked, at any given moment you have 3 rotors driving the output shaft.  That is obviously not as smooth as a turbine output, but it is far better than current piston engines where there are many moments of NOTHING driving the crank (which is why we need a flywheel, which the propeller acts as).

 

It isn't on that video, but In another I saw a running prototype.  It was running at low RPM however.  Edit: here it is   Notice the flames!  a lot of times they run these off compressed air which is useless IMHO... they appear to actually be combusting fuel/air.

 

 

 

 

  My biggest concern is how they plan to cool it.  High power output from a small package is problematic when it comes to cooling.

 

Who knows, It may jut be another scam to soak investors, but I did find the design ingenious.  The ultimate internal combustion engine is certainly a symmetrical rotary engine that has a fully closed combustion chamber which is forced open by expanding gasses.  This is much more efficient than gases blowing past a turbine.  The Wankel engine was close, but the rotary part wobbles which is less than ideal.

Edited December 16, 2021 by Austintatious

[carusoam]

Austin,

Thanks for sharing the details on that….

Rotary engines spent eons in development…. Trying to improve on two things…. Seals… keeping the oil from getting burned up, and keeping the exhaust gasses from escaping….

 

The Mazda RX7 was the king of rotaries….

Not a lot of experience with them…. some one around here probably has some experience to discuss…

Getting 300k miles out of one vs. a Chevy 350…. The Chevy, you definitely get your moneys worth out of it….

 

This device shows a lot of asymmetric rotating parts and timing gears….

Getting through the basics of engine development is going to be a huge effort… for such precision…

Just the uneven temps and part expansions will be an interesting challenge….

 

Our cylinders use a choke (varied dimensions) for handling the varying CHTs, with rings to hold the exhaust gasses in place, throw on an oil ring to keep the oil separate from the combustion chamber….

Similar challenges for all ICEs….

The HP claims for this engine kind of fall on deaf ears….  How do they get 1k cfm of air to go into the tiny intake? 
 

Their intake is about the size of their spark plug…

Their graphics show a continuous stream of exhaust leaving the engine….

Yet, their running model sounds a lot like a cylinder ICE, spouting a flame, cyclically….

And some liquid dripping out near the center shaft… what is that?

Don’t be an early investor with this one…. Lots of work to go through still….

Best regards,

-a-

[N201MKTurbo]

I have a two rotor dual turbocharger Mazda motor on a stand in the garage. I was going to build a sand rail around it. But I spend too much time working on airplanes.