Turbine Bonanza setting the pace?

[Rick Junkin]

My apologies if this is old news but I saw it this morning. 

Folks talk about putting a turbine on our Mooneys, and here’s a quick overview of an example of a turbine STC for the Bonanza. For those interested in doing something similar this guy may be someone you’d like to talk to.

https://ctrk.klclick.com/l/01J9XK5VEWQEVG0J2KHMVV7MJN_14

[Hank]

I actually saw one on the ramp once, somewhere out in SD or somewhere. The pictures are on my camera not my phone. Jaguar logo, British Racing Green trim. It was a beautiful plane, despite the Beech logo on that funny tail.

[KLRDMD]

A few years ago the guy in the hangar next to me had one. They are definitely a niche airplane but if it fits your needs, it is very nice. The conversions have been done for probably two decades or so.

[N201MKTurbo]

A friend of mine used to fly a turbine Bonanza. Maybe he still does. The plane is for sale. Nobody wants to buy it. It doesn't go much faster than a stock Bonanza. It uses a lot more fuel. The range numbers aren't that good. 

He says it runs very smooth and quiet. And climbs like crazy.

[N201MKTurbo]

We are probably talking about the same plane.

[GeeBee]

Turbine conversions usually end up range/payload limited.

 

[McMooney]

there's a couple at hooks,  really nice and super smooth,  really expensive hamburger runs.

I imagine if you got it up to it's optimal altitudes it'd prob be awesome

[toto]

The Silver Centurion or whatever it’s called always made a bit more sense to me than the Bonanza. You take a P210 and put a turbine on it - at least you can get to the flight levels where there’s some advantage to the TP. 

The JetProp Malibu conversion that evolved into the Meridian/M* series is obviously good evidence that this can be successful with a pressurized single engine piston. 

[MB65E]

The Silver Eagle is what the 210 is called I believe. Really nice machine. There is a gentleman in Salinas California that still does the mods. As a tech, I’ve told myself never to own a Cessna retract…

Solair did some 207 conversions. Nice machines, fixed gear, but Gearbox’s are the issue. 
 
I’ll stick with my M20E!!

-Matt

[hubcap]

There is a turbine Bonanza based at my home airport. I know the guys who own it. It is for sale now.

The real shortcoming is that turbines fly best in the flight levels and the turbine Bonanza doesn't have enough fuel capacity for the turbine to make sense, even with tip tanks.

[GeeBee]

The C-210 conversion uses an installed fuselage tank to make the turbine work. It makes it a 4 place airplane. Otherwise it is an airplane in search of a fuel stop.

 

[Schllc]

That is the challenge with non pressurized planes and turbines. 
With a piston engine you have options for endurance, in a turbine, you are “x” gph, period. However, it can make planning somewhat easier.  
They, say turbines are safer, which is probably statistically true, but everything in aviation is a trade off.   
 

[Utah20Gflyer]

A non pressurized turbo prop seems very impractical to me.  

[exM20K]

7 hours ago, Utah20Gflyer said:

A non pressurized turbo prop seems very impractical to me.  

Mr. Market agrees.  Outside of ag application, meat missile lifting, and FedEx feeder type of freight duty, they haven’t gotten much traction especially in the owner-flown market. If you need to lift a bunch of stuff and fly it over short distances at high frequency, they excel. But that is not a typical owner-flown mission profile.

-dan

[1980Mooney]

No one has mentioned cost to acquire and maintain. The former Allison now Rolls Royce M250-B17F is used in most cases (and in that video above).  TurbineAir (Darwin Conrad/Rocket Engineering in Spokane did a conversion with the PW PT6A-21).  The PW PT6 has better high altitude performance than the M250 (which is basically used in helicopters that never go into the FL) but it burns even more fuel.  The turbine conversions are limited to what was the yellow arc - only 167 IAS.  So the only way to get speed is go higher.  But most Bonanza Turbine conversion owners don't like to fly into the FL.  So a PT6 Bo will fly no faster than a M250 Bo at let's say 15,000 ft but will be sucking down about 10% more fuel - probably into the 30's gph.  You don't see many PT6 conversions on Bonanza's.

Back to cost.  Past posts said a conversion cost about $600,000 - probably more now.  15 year old posts said it cost $225,000 + to overhaul a low end M250 - probably wayyyyy more now.  I saw one recent post claiming to be a new M250 costing $500,000.

There are 4 Bonanaza turbine conversions on Controller.  Three (3) are Allison/RR M250's and one (1) is a PW PT6 (but no listed price).  One is asking $784,000 and the engine is 74% to TBO.  The other two are $950-970,000 and the engines are about 50% to TBO.

If you were going to spend about $1 million on a used plane, would you buy an unpressurized plane that is slower than an Acclaim and really has about the same limited useful load (no way to fill all 6 seats in the Turbine Bo)?

https://www.aircraft.com/aircraft/238211755/n36np-2004-beechcraft-a36-bonanza-turboprop

https://rocketengineering.com/wp-content/uploads/2017/10/TurbineAir_Article_5-13-03.pdf

[Shadrach]

8 minutes ago, 1980Mooney said:

No one has mentioned cost to acquire and maintain. The former Allison now Rolls Royce M250-B17F is used in most cases (and in that video above).  TurbineAir (Darwin Conrad/Rocket Engineering in Spokane did a conversion with the PW PT6A-21).  The PW PT6 has better high altitude performance than the M250 (which is basically used in helicopters that never go into the FL) but it burns even more fuel.  The turbine conversions are limited to what was the yellow arc - only 167 IAS.  So the only way to get speed is go higher.  But most Bonanza Turbine conversion owners don't like to fly into the FL.  So a PT6 Bo will fly no faster than a M250 Bo at let's say 15,000 ft but will be sucking down about 10% more fuel - probably into the 30's gph.  You don't see many PT6 conversions on Bonanza's.

Back to cost.  Past posts said a conversion cost about $600,000 - probably more now.  15 year old posts said it cost $225,000 + to overhaul a low end M250 - probably wayyyyy more now.  I saw one recent post claiming to be a new M250 costing $500,000.

There are 4 Bonanaza turbine conversions on Controller.  Three (3) are Allison/RR M250's and one (1) is a PW PT6 (but no listed price).  One is asking $784,000 and the engine is 74% to TBO.  The other two are $950-970,000 and the engines are about 50% to TBO.

If you were going to spend about $1 million on a used plane, would you buy an unpressurized plane that is slower than an Acclaim and really has about the same limited useful load (no way to fill all 6 seats in the Turbine Bo)?

https://www.aircraft.com/aircraft/238211755/n36np-2004-beechcraft-a36-bonanza-turboprop

https://rocketengineering.com/wp-content/uploads/2017/10/TurbineAir_Article_5-13-03.pdf

Given the number of conversions, I’d say the market agrees with your analysis.

[A64Pilot]

Maule built a Turbine, with the little Allison, sold I think 6, it was of course the cheapest Turbine you could buy, although it climbed like a raped ape, it’s Stol performance wasn’t as good as the Piston Maules.

http://www.pilotfriend.com/aircraft performance/Maule/28.htm

The little Allison was developed by Detroit Diesel in 1958 specifically to be either in a small scout helicopter or a small observation airplane, it was used in the OH-6 and the OH-58, so no, no consideration for high altitude.

https://en.wikipedia.org/wiki/Allison_Model_250

 I was an OH-58 Crew Chief for three years before flight school, the baby Allison came in two flavors, 318 SHP and 420 SHP. For a small turbine to work efficiently you have to have extremely tight clearances on the compressor, the little Detroit Diesel / Allison gets that by its compressor halves are plastic lined on assembly the compressor blades contact this lining and you spin the compressor and it shaves itself in.

Starting one is sort of an emergency procedure, east to screw up as it WILL get hot and be in a time limited temp range that from 40 years ago was a six second limit.

You really had to give it full attention 

By contrast you have to be truly stupid to hot start a Pratt, about the only way you can is with a nearly dead battery and even then it gives you plenty of time to abort the start. I guess another way is to truly flood the motor and then hit the igniters.

[toto]

1 hour ago, 1980Mooney said:

No one has mentioned cost to acquire and maintain. The former Allison now Rolls Royce M250-B17F is used in most cases (and in that video above).  TurbineAir (Darwin Conrad/Rocket Engineering in Spokane did a conversion with the PW PT6A-21).  The PW PT6 has better high altitude performance than the M250 (which is basically used in helicopters that never go into the FL) but it burns even more fuel.  The turbine conversions are limited to what was the yellow arc - only 167 IAS.  So the only way to get speed is go higher.  But most Bonanza Turbine conversion owners don't like to fly into the FL.  So a PT6 Bo will fly no faster than a M250 Bo at let's say 15,000 ft but will be sucking down about 10% more fuel - probably into the 30's gph.  You don't see many PT6 conversions on Bonanza's.

Back to cost.  Past posts said a conversion cost about $600,000 - probably more now.  15 year old posts said it cost $225,000 + to overhaul a low end M250 - probably wayyyyy more now.  I saw one recent post claiming to be a new M250 costing $500,000.

There are 4 Bonanaza turbine conversions on Controller.  Three (3) are Allison/RR M250's and one (1) is a PW PT6 (but no listed price).  One is asking $784,000 and the engine is 74% to TBO.  The other two are $950-970,000 and the engines are about 50% to TBO.

If you were going to spend about $1 million on a used plane, would you buy an unpressurized plane that is slower than an Acclaim and really has about the same limited useful load (no way to fill all 6 seats in the Turbine Bo)?

https://www.aircraft.com/aircraft/238211755/n36np-2004-beechcraft-a36-bonanza-turboprop

https://rocketengineering.com/wp-content/uploads/2017/10/TurbineAir_Article_5-13-03.pdf

Following Mike Patey’s turbine Lancair conversion on YouTube, I learned that people can/will buy a timed-out engine from a charter aircraft (his came from a King Air) and just maintain it on condition. I think he paid a small fraction of what it would have cost for a PT-6 that wasn’t timed out for Part 135 purposes. 

The engine ended up exploding on him and he had to buy a new one, so you know - not a great deal in the end, but gave me a picture of how this kind of thing is possible without spending a fortune to source an engine. 

[A64Pilot]

1 hour ago, toto said:

Following Mike Patey’s turbine Lancair conversion on YouTube, I learned that people can/will buy a timed-out engine from a charter aircraft (his came from a King Air) and just maintain it on condition. I think he paid a small fraction of what it would have cost for a PT-6 that wasn’t timed out for Part 135 purposes. 

The engine ended up exploding on him and he had to buy a new one, so you know - not a great deal in the end, but gave me a picture of how this kind of thing is possible without spending a fortune to source an engine. 

If turbines are maintained IAW TBO etc, they have an unlimited life, nearly every component on a turbine has a life limit.

However many, many turbines are operated under part 91 or part 137 and are not required to follow TBO, in the US no Ag plane that I have ever seen follows TBO, they are all IRAN, however if they are smart they do keep up with hot section inspections and for Pratt’s especially the spray nozzles. If they do then I have seen them running fine with over 10,000 hours, however even before they get to that point they are essentially worthless as everything is well beyond the life limit.

On edit, they are also well down on power due to compressor wear. You have to stop adding throttle on a turbine when you hit one of three limits, Ng (compressor) speed, torque (gearbox limit) or temp (hot section limit) usually at takeoff on a good engine you always hit torque, on Pratt’s you adjust the fuel control that should never allow an Ng overspeed, and as engines age compressor wear means less airflow, so they run hot and hit temp limits early, but even at cruise the higher than normal temp causes excess stress on the turbines blades etc.

There are a great many nearly worthless turbines out there. I remember one Garrett -10 I put in a new airplane (customer supplied). The last entry before the one that returned the engine to service said the engine had been submerged in salt water and was uneconomical to repair, next entry said cleaned, inspected and returned to service. Engine lasted until Annual where the Magnesium gear box was found to be excessively corroded and had to be replaced of course, major $$$.

Be very careful if you’re buying a used turbine, stick with known good suppliers like Covington, yes you will pay way more but you will get a good turbine. There are a LOT of crooks selling turbines.

 

Edited October 12 by A64Pilot

[GeeBee]

Most part 135 PT-6 engines are trend monitored very few Ops Specs are written for PT-6s with hard times vs trend monitoring. (Most the time because the airplane was added to the fleet used without trend monitoring) Trend monitoring dates all the way back to the 1980s (because of the PC) and I know this because I ran a fleet of 3 King Airs under Part 135 in the 1980s all on trend monitoring. On average you can get about 2400 hours before hot section and 4800 to overhaul on a trend monitored engine.  Anything more is playing with fire, literally. If you acquire an engine that timed out on hard time spec under Part 135 you might get 600 hours out of it, but not much more and usually less as many have found out. They are great engines, but when hot section deterioration starts it happens fast and just gets more expensive putting it off. The problem with the acquisition of such an engine that was not trend monitored is you have no base line to know when things start going south....until they do.

[A64Pilot]

Many ways to extend Pratt TBO’s and trust me Pratt isn’t happy and it’s not just because it cuts into their profit either, see TBO is essentially similar to a Warranty in that Pratt says do this and your engine will never let you down,they won’t pay if it’s out of Warranty so it’s not a true warranty of course. But Pratt’s very robust record of reliability relies on it, their reputation is on the line, and that rep is worth I’m sure Billions.

So picture this, someone who has nothing whatsoever to do with Pratt comes up with a program that they convince the FAA will make Pratt’s parts last longer, now they don’t have a dog in the fight if your engine breaks you have no recourse, they pay nothing but they make a pretty penny with no liability and Pratt’s reputation is on the line.

https://www.aviationpros.com/home/article/10387088/adding-time-to-your-tbo-a-discussion-on-pt6-engine-stcs

If you have a fleet, it doesn’t have to be a big fleet Pratt can and will extend your TBO’s based on your engines history, this is often done for overseas Ag plane thst must follow TBO for example.

So along with everything else in Aviation be very careful on what you pay for, even STC’s. STC’s in particular in my opinion have become more and more BS over the years, one STC to extend Pratt TBO’s is based on infrequent vibe analysis of the engine (one accelerometer mounted and basically a prop balancer records vibes) and infrequent oil analysis, yet the FAA bought off on it, and yes it costs tens of thousands of dollars.

Edited October 12 by A64Pilot

[Utah20Gflyer]

5 hours ago, exM20K said:

Mr. Market agrees.  Outside of ag application, meat missile lifting, and FedEx feeder type of freight duty, they haven’t gotten much traction especially in the owner-flown market. If you need to lift a bunch of stuff and fly it over short distances at high frequency, they excel. But that is not a typical owner-flown mission profile.

-dan

Short hop cargo ops makes sense for non pressurized turbo props.  Power to weight is excellent and the high fuel burn doesn’t matter if you are only flying an hour away.  That leaves a lot of weight capacity for cargo. 

[GeeBee]

4 hours ago, A64Pilot said:

Many ways to extend Pratt TBO’s and trust me Pratt isn’t happy and it’s not just because it cuts into their profit either, see TBO is essentially similar to a Warranty in that Pratt says do this and your engine will never let you down,they won’t pay if it’s out of Warranty so it’s not a true warranty of course. But Pratt’s very robust record of reliability relies on it, their reputation is on the line, and that rep is worth I’m sure Billions.

So picture this, someone who has nothing whatsoever to do with Pratt comes up with a program that they convince the FAA will make Pratt’s parts last longer, now they don’t have a dog in the fight if your engine breaks you have no recourse, they pay nothing but they make a pretty penny with no liability and Pratt’s reputation is on the line.

https://www.aviationpros.com/home/article/10387088/adding-time-to-your-tbo-a-discussion-on-pt6-engine-stcs

If you have a fleet, it doesn’t have to be a big fleet Pratt can and will extend your TBO’s based on your engines history, this is often done for overseas Ag plane thst must follow TBO for example.

So along with everything else in Aviation be very careful on what you pay for, even STC’s. STC’s in particular in my opinion have become more and more BS over the years, one STC to extend Pratt TBO’s is based on infrequent vibe analysis of the engine (one accelerometer mounted and basically a prop balancer records vibes) and infrequent oil analysis, yet the FAA bought off on it, and yes it costs tens of thousands of dollars.

Even P&W highly recommends engine trend monitoring and even offers the own including automatic data acquisition. Hard TBOs are yesterday's news for turbine operators who want the most out of their engines.

https://www.prattwhitney.com/en/blogs/airtime/2018/12/11/why-engine-condition-trend-monitoring-is-a-must-for-pt6as

[NickG]

I think I just saw one at KHND.

[midlifeflyer]

I’ve been in one.