A pressurized,.turbine Mooney?

[bcg]

This is just a thought experiment to see how feasible people think this would be.
 
If someone had the tools and skills to build their own plane from scratch, modeled on a Mooney and wanted to power it with a turbine, say a PT6, and pressurize it to say 6PSI, what would the challenges be? Would the design of the airframe support the higher altitudes and speeds? Obviously the pressure vessel would not be trivial but, is it doable in such a small airframe?
 
Forget the cost, if we're considering that then the answer is a PA46, TBM or Evolution but, I like to work through the engineering challenges in my head sometimes.
 
So what do you guys think? Doable?
 
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[takair]

I think it would start to look more like a M22.  I suspect it would have been a game changer had they put a PT6 in it.  In my lottery dreams I would pick one of the remaining ones up and do just that.  Of course, in my lottery dreams I’d also buy a TBM.  I don’t see it as practical to modify even an Acclaim to be pressurized.  Turbine, maybe….

[bcg]

I think it would start to look more like a M22.  I suspect it would have been a game changer had they put a PT6 in it.  In my lottery dreams I would pick one of the remaining ones up and do just that.  Of course, in my lottery dreams I’d also buy a TBM.  I don’t see it as practical to modify even an Acclaim to be pressurized.  Turbine, maybe….

I'm talking a scratch build as an experimental. I agree, modifying an existing model wouldn't make sense. By the time you were done, you'd have essentially scratch built it anyway.

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[N201MKTurbo]

You can buy one today! It is called a TBM 900. The M is for Mooney. I’ve never flown one, but I hear they are a fantastic airplane.

If you did a full design study, you would end up very close to one of the three planes you mentioned.

[N201MKTurbo]

Thread slip alert!

About two years ago I was departing Santa Barbara. In the FBO (Atlantic) there was a very good looking couple. 
 

I was at the end of the runway. I had my clearance and was waiting for release. This TBM with the hot couple taxied up and I was told to hold short and they gave the TBM takeoff clearance. I could lip read her words and her expressions. The hot copilot (or front seat passenger) obviously was saying “I’m sorry, we didn’t mean to cut you off. Tower did it”.

Ever since then I have a soft spot for TBM people.

[Rick Junkin]

3 hours ago, bcg said:

This is just a thought experiment to see how feasible people think this would be.
 
If someone had the tools and skills to build their own plane from scratch, modeled on a Mooney and wanted to power it with a turbine, say a PT6, and pressurize it to say 6PSI, what would the challenges be? Would the design of the airframe support the higher altitudes and speeds? Obviously the pressure vessel would not be trivial but, is it doable in such a small airframe?
 
Forget the cost, if we're considering that then the answer is a PA46, TBM or Evolution but, I like to work through the engineering challenges in my head sometimes.
 
So what do you guys think? Doable?
 
Sent from my Pixel 9 Pro XL using Tapatalk
 
 
 

You’ve said modeled on a Mooney and also said scratch built. If you’re talking a clean sheet design, it’s been done. Take a look at the Lancair Evolution.

EDIT: My bad, you mentioned the Evolution. I missed that.

[1980Mooney]

3 hours ago, bcg said:

I'm talking a scratch build as an experimental. I agree, modifying an existing model wouldn't make sense. By the time you were done, you'd have essentially scratch built it anyway.

Pressurized, PT6, Scratch build, no modification of tired old existing design.  It is called the Epic LT which became the Epic E1000.

Spot on. 

[toto]

I’d be interested to read about the engineering challenges with the P210 or other airframes where they retrofitted a pressure vessel and associated systems into a legacy airframe. It’s got to be complicated, and there must be a lot of tradeoffs.

The PA46T was pressurized from day one, and there are a lot of turbine conversion STCs for piston airframes. But you don’t see that many that go from non-pressurized to pressurized. 

 

[bcg]

You guys are missing the spirit of the post. I know airplanes already exist that do this. Most of them are significantly larger, the Evolution is probably the closest in size to a Mooney. It's not about what options already exist, it's about what would be required to do it similar to a Mooney. To me, that also means metal construction. The TBM, Epic and Evolution are all composite. I don't know for sure about the PA46, the ones I've seen looked composite from a cursory glance, I didn't look at them too closely though.

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[toto]

1 minute ago, bcg said:

You guys are missing the spirit of the post. I know airplanes already exist that do this. Most of them are significantly larger, the Evolution is probably the closest in size to a Mooney. It's not about what options already exist, it's about what would be required to do it similar to a Mooney. To me, that also means metal construction. The TBM, Epic and Evolution are all composite. I don't know for sure about the PA46, the ones I've seen looked composite from a cursory glance, I didn't look at them too closely though.

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The Piper and TBM are both metal 

[bcg]

The Piper and TBM are both metal 

The TBM is metal? I'd have sworn it was composite. I saw an 830 on the ramp today.

Still, it's much larger than a Mooney.

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[toto]

17 minutes ago, bcg said:

The TBM is metal? I'd have sworn it was composite. I saw an 830 on the ramp today.

Still, it's much larger than a Mooney.

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Yeah I think the new ones have a carbon cowl, but otherwise metal 

[Schllc]

The TBM is an awesome machine. It is all metal, but it is a very large plane. It’s at least twice the size of a Mooney, you’d have to park them side by side to see. 
I think the only way you could clean sheet design a look alike Mooney, and pressurize it would be with composite. It would get too heavy using metal, and likely shrink the interior space as well. 
The pt6 is also rather large. 
Since we are talking fantasy here, I would use the wing of a Mooney, lots of room in there for more fuel. 
use the Allison turbine, since it’s really the only option, and build a carbon fiber pressure vessel/fuselage.  
The challenge would be the tail, and the landing gear.  If you can’t significantly increase the speed, and find a way to bump the gross weight, the whole venture is somewhat pointless. 
If I had money to burn I would absolutely try!  
too bad we can’t crowd fund it, I’m sure embry riddle of a military college would partner for the brain horsepower. It would be a really fun project. 
who knows, with all of the tech going into drones, there will likely be some smaller turboprop development closer than we think. 

[N201MKTurbo]

1 hour ago, bcg said:

You guys are missing the spirit of the post. I know airplanes already exist that do this. Most of them are significantly larger, the Evolution is probably the closest in size to a Mooney. It's not about what options already exist, it's about what would be required to do it similar to a Mooney. To me, that also means metal construction. The TBM, Epic and Evolution are all composite. I don't know for sure about the PA46, the ones I've seen looked composite from a cursory glance, I didn't look at them too closely though.

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My point is, if you do the design study, the plane you come up with will be that big. Or at least could be for almost no speed or cost penalty, so why not?

By the time you build an airframe that can support the weight of the engine and a decent amount of fuel and the pressure vessel, and deicing system, there will be little reason to build a cabin as small as a Mooney. 

[N201MKTurbo]

One thing I’ve noticed is if you a get fire breathing speedster, it isn’t much good for just going out and boring holes in the sky just for the hell of it. They are only good for long cross countries. If you fly long cross countries every few days, then a speedster is the plane for you.

[exM20K]

https://www.lx7aircraft.com/lx7-turboprop.html

there is one for sale on controller

25% faster than an acclaim

3x the cost

insurance?

-dan.

[Schllc]

I cannot stand the side stick. 
when I got checked out in the cirrus, I was surprised at how easily I transitioned to the side yoke, I thought it would be more difficult to get used to. 
 
I am not arguing the rationality of this aversion, and I’m sure I’m in the minority, but it just sucks, I hate it, and I would not own a plane with this control configuration.  

[A64Pilot]

On the whether or not a Mooney sized pressurized turbine could be built.

Of course it can, it’s been done before, and fully Certified in 1971 maybe? Interceptor 400, a Garrett powered Meyers 200 which I believe is still the fastest single engine NA piston civilian 4 pax aircraft, but the Interceptor 400 was supposedly a 300 kt airplane at fl 240, probably very optimistic as all marketing claims are, but I’m sure it was fast.

For those that have not flown a Garrett they are a fine engine they are a little loud on the ground but quiet in the air and unlike a Pratt they respond instantly to throttle like a piston does.

http://www.meyersaircraft.com/200D and 400 Intro.html

It has a -6 Garrett which is a 750 SHP engine when put in a Thrush crop duster, but it was derated to 400 SHP in the Meyers, which was an Aero Commander airplane. Being derated so much I wouldn’t be surprised if it could carry 100% power in the flight levels, or if not it wouldn’t lose much.

In fact you can buy it and put it in production

https://www.flyingmag.com/interceptor-400-barn-discovery/

Edited October 27 by A64Pilot

[802flyer]

On the whether or not a Mooney sized pressurized turbine could be built.
Of course it can, it’s been done before, and fully Certified in 1971 maybe? Interceptor 400, a Garrett powered Meyers 200 which I believe is still the fastest single engine NA piston civilian 4 pax aircraft, but the Interceptor 400 was supposedly a 300 kt airplane at fl 240, probably very optimistic as all marketing claims are, but I’m sure it was fast.
For those that have not flown a Garrett they are a fine engine they are a little loud on the ground but quiet in the air and unlike a Pratt they respond instantly to throttle like a piston does.
http://www.meyersaircraft.com/200D and 400 Intro.html
It has a -6 Garrett which is a 750 SHP engine when put in a Thrush crop duster, but it was derated to 400 SHP in the Meyers, which was an Aero Commander airplane. Being derated so much I wouldn’t be surprised if it could carry 100% power in the flight levels, or if not it wouldn’t lose much.
In fact you can buy it and put it in production
https://www.flyingmag.com/interceptor-400-barn-discovery/

That’s super cool!


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[PeterRus]

Turbine makes sense (economically) for HP more than 350, the more, the better. 4 seater with a smaller turbine will burn too much fuel for speed and payload -- the range will suffer. What I'd like to see is a Wankel aircraft.

Here is a teaser: https://turb.aero/how-to-buy/certificated-engines

Fuel consumption: 12 gph @ 150 HP (or more like 13+ gph) at 10,000 and targeted TBO 3000 hours. 

I am sure it will be more expensive to maintain, with fewer mechanics knowledgable, etc. 

[Pinecone]

3 hours ago, N201MKTurbo said:

One thing I’ve noticed is if you a get fire breathing speedster, it isn’t much good for just going out and boring holes in the sky just for the hell of it. They are only good for long cross countries. If you fly long cross countries every few days, then a speedster is the plane for you.

I feel that way about my 252.  Great for XC, but not a go out for 30 - 60 boring holes or doing patterns flight.

[wombat]

This is why you can't have fewer than two airplanes.    One for XC flights.   One for making holes in the sky.

 

Also, one for landing on water.

One for STOL.

One for maintaining multi currency.

Keep going like this and the money will start to add up though.

[Will.iam]

1 hour ago, PeterRus said:

Turbine makes sense (economically) for HP more than 350, the more, the better. 4 seater with a smaller turbine will burn too much fuel for speed and payload -- the range will suffer. What I'd like to see is a Wankel aircraft.

Here is a teaser: https://turb.aero/how-to-buy/certificated-engines

Fuel consumption: 12 gph @ 150 HP (or more like 13+ gph) at 10,000 and targeted TBO 3000 hours. 

I am sure it will be more expensive to maintain, with fewer mechanics knowledgable, etc. 

not impressed at all. My trio-360 makes more power on less fuel and at even 180hp I could get there at same fuel burn. Only if I lived where no 100LL was sold or available would I see this being an alternative. 

[1980Mooney]

6 hours ago, bcg said:

You guys are missing the spirit of the post. I know airplanes already exist that do this. Most of them are significantly larger, the Evolution is probably the closest in size to a Mooney..... It's not about what options already exist, it's about what would be required to do it similar to a Mooney. To me, that also means metal construction. The TBM, Epic and Evolution are all composite. I don't know for sure about the PA46, the ones I've seen looked composite from a cursory glance, I didn't look at them too closely though.

When you say "similar to a Mooney", do you mean a fuselage with "steel frame and essentially non-loadbearing aluminum skin"?  The spirit of the post would be that you would not do it.  Even Mooney, when they designed the pressurized M22 Mustang, ditched the steel frame and went with conventional aluminum alloy semi-monocoque structure like everyone else.

https://1000aircraftphotos.com/Contributions/WestinLarry/12817.htm

[A64Pilot]

Wankel’s are cool, I wish they were further developed. They have similarities to turbines, sort of a middle ground between reciprocating engines and turbines.  Mazda was the first Japanese manufacturer to win the 24 hours at Lemans in 1991 with a four rotor 2.6L (158 cu in) Wankel capable of 900 HP but detuned to 700 for the race for fuel consumption and reliability, it is a 24 hour race after all, still 700 HP on 158 Cu in ain’t bad, not even turbocharged. Of course you can turbocharge a Wankel, the last RX7 was and I think in factory trim made over 250 HP from a 1.3 L engine, the 787’s engine was essentially two RX7 engines bolted together, hence 2.6 L. To me it’s among the sweetest sounding engines ever built.

Wankel's were banned in 1992 by the FIA.

Mazda Wankel conversions were popular at one time in the EAA world, but as with all auto conversions there were issues usually reliability.

Wankel’s died years ago as in I think 1973, due mostly to fuel consumption. Lots of power from a small lightweight engine but it drank gas, also due to very high exhaust temps it was tough to meet emissions.

GM had built a very good two rotor Wankel with astonishing reliability and an expected life in excess of 500,000 miles and those of us that were driving in the 70’s can attest that regular engines were horrible then, if you got 100,000 miles you were in the minority. Unfortunately it just couldn’t get good milage so it was scrapped and instead the Vega got that wonderful aluminum block in line 4 cyl. It was also I believe slated for the Monza

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

Edited October 28 by A64Pilot