Turbine Bonanza

Challenged

Challenged

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Challenged
I got to ride in a turbine powered B36 yesterday; what an interesting airplane. The pilot who owns it offered to bring me back from another field about 40 minutes away where I'm getting some maintenance done, it was definitely a neat experience. The thing I noticed the most about it was how smooth it felt. 35gph is what I saw on the fuel flow indicator pretty much the whole flight.
 
My original IO-550 came from such an aircraft. Bought a new Bonanza and took it to Tradewinds for the conversion. It had 9 hours on it when I got it (including the prop, a bunch of Beech engine instruments, and exhaust). I had to add a 14-to-28V converter and a 12V boost pump to get it to work on the Navion.
 
Challenged said:
I got to ride in a turbine powered B36 yesterday; what an interesting airplane. The pilot who owns it offered to bring me back from another field about 40 minutes away where I'm getting some maintenance done, it was definitely a neat experience. The thing I noticed the most about it was how smooth it felt. 35gph is what I saw on the fuel flow indicator pretty much the whole flight.
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I love frankensteined aircraft as much as the next guy but if I’m buying I’d just go for a TBM, or Meridian, something with a PT6 on the original TCDS. Sometimes, there is too much of a good thing. I bet a used Meridian could be had for the same cost to acquire and convert a Bo, which of course means it’s turn key, no down time.
 
Geosync said:
I love frankensteined aircraft as much as the next guy but if I’m buying I’d just go for a TBM, or Meridian, something with a PT6 on the original TCDS. Sometimes, there is too much of a good thing. I bet a used Meridian could be had for the same cost to acquire and convert a Bo, which of course means it’s turn key, no down time.
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Some guys can't handle a Piper aircraft properly. ;) I bet the turBo was all sorts of cool to fly in!
 
If these turbine upgrades are so wonderful, why are there so few of them? A great turbine airplane leaves the drawing board as a turbine airplane. That’s why TBM is great airplane, the Piper Meridian isn’t such a great airplane and the rest with turbines upgrades not very good at all.
 
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A few years ago my wife and I got a flight in a Valmet L-90TP Readigo powered by a Rolls 250. We were both amazed by how smooth the engine was. Turbine power makes flying a completely different (and more enjoyable) experience.

It was a fantastic experience, but it makes me sad that I might never touch the controls of another turboprop powered aircraft

35177B0C-5081-420A-BDF6-EDFD92CA5519.jpeg
 
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Bell206 said:
The turbine conversion cost plus increased DOCs did not increase the airframe book value proportionally. No bang for the buck.
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skier said:
A few years ago my wife and I got a flight in a Valmet L-90TP Readigo powered by a Rolls 250. We were both amazed by how smooth the engine was. Turbine power makes flying a completely different (and more enjoyable) experience.

It was a fantastic experience, but it makes me sad that I might never touch the controls of another turboprop powered aircraft

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You do realize that is a really slow turbine airplane?
 
Clip4 said:
You do realize that is a really slow turbine airplane?
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Hence the reason there are not many of them. The engine swap didn't change max cruise but did greatly improve certain performance parameters. However, the conversion worked better in the Cessna 206/207 series than the Bonanza, but neither ever recouped their conversion costs.
 
Bell206 said:
Hence the reason there are not many of them. The engine swap didn't change max cruise but did greatly improve certain performance parameters. However, the conversion worked better in the Cessna 206/207 series than the Bonanza, but neither ever recouped their conversion costs.
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and it’s a fuel pig.
 
Clip4 said:
If these turbine upgrades are so wonderful, why are there so few of them? A great turbine airplane leaves the drawing board as a turbine airplane. That’s why TBM is great airplane, the Piper Meridian isn’t such a great airplane and the rest with turbines upgrades not very good at all.
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The real issue is the conversion cost being too high and then usually the pressurization of a piston aircraft doesn’t do well enough for altitude. The Cessna 340 Silver Eagle is a great conversion, very efficient. 340s are popular size wise. But something like $1-$1.5M for the conversion, plus the aircraft, and you still have a 4.2 psi cabin. Fine in the low flight levels, not so fine in the mid to upper 20s where the conversion shines.

But if it wasn’t so expensive compared to a 425, I bet they’d sell more.

Bell206 said:
FYI: All turbines gobble fuel up. Main reason they developed the fan side of turbo-fans to get better gas mileage.
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All turbines gobble fuel down low. I’ve gotten the MU2 down to 48 GPH combined at FL250. There are 421 owners who burn that.

When you get into jets that’s another matter, but even then some of the tiny ones aren’t bad. The Eclipse jet I think gets down to 60 gph in the low 40s.
 
I suppose there are specific missions that better fit a go fast Non pressurized turbine conversion but personally I would much rather have a Malibu for much less money. Sure the climb suffers but you get a better useful load, nearly the same true airspeed, lower fuel burn, and most importantly pressurization.

I suppose my tune might change though if my mission was shorter hops over lots of water or mountainous terrain though I think I would opt for a fast twin over the turbine Bonanza.
 
Ted DuPuis said:
combined at FL250.
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Agree. But the Bonanza, Cessna, or other helicopter turbine conversions don't live or work at those levels. On the helicopter side some conversions may work in a commercial ag environment, but substituting a $50k engine with no life-limited parts for a $350k engine with a number of life-limited parts boils down to more a personal want vs benefit or need. Very few turbine conversions come out ahead financially at least from the mx side in my experience. But hey, it's aviation, who wants to save any money?;)
 
Even if you gain 50-100kt cruise and quicker climbs, when you have to stop every 90 minutes for fuel did your total trip time really improve?
 
The bush pilot I know in Canada put a turbine on a De Havilland Beaver. I don't know what the fuel burn is but boy can that thing climb, even fully loaded.
 
I always wonder what the purpose of these conversions are... you aren't changing Vne or yellow arc speeds, and the structure of the plane stays largely the same.. so you aren't carrying a lot more, and not going much faster.. just burning loads more fuel

If you have the kind of money to burn on something like this why not a TBM / Cheyenne / MU2 .. really *anything* that was designed from the outset as a turboprop

??
 
A company I used to work for had a turbine bo. Fun airplane to fly but not super practical. Rather have a Baron, it's actually faster and has better numbers.
 
Todd82 said:
Even if you gain 50-100kt cruise and quicker climbs, when you have to stop every 90 minutes for fuel did your total trip time really improve?
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BuT yOU gEt To BUrN JeTA aNd SaY yoU FLy a TURBINE pLaNe! aNd JeTA is CHeApeR!

upload_2019-12-11_12-35-17.png
 
Reduce take off roll by 40%. Decrease landing distance by 50%. Double your rate of climb. Shorten block-time up to 25%. Performance achieved with a Rolls-Royce Turboprop Engine conversion by Soloy Aviation.

Some of their listed benefits.
  • Far lower cost than any new turbo-prop
  • Utilize lower cost jet fuel
  • 3500 hour engine TBO
https://www.soloy.com/a36-bonanza.html
 
Almost all the turbine conversions I've seen include additional fuel (BDS or Osborne tanks for example). But yeah, to be useful, you need to get up, high and fast to make it worth the effort (but such is not an uncommon issue with turbine-power in general).
 
What I know about turbines is apples and oranges on this format. I recall my helo experience with the RR250-20. Thats one of the available conversions for the Bo. 8,000 ft fuel flow is less than 25 GPH. 28 GPH down in the bozo sphere. When I was in the Bonanza group, I noted that there were both RR & PT-6 conversions. USN is retiring a couple hundred T-34Charlies for the new T-6. The T-34C's are mostly Bonanzas with Baron wings and LG. They are powered with a 550 HP PT6. Navy got a couple of decades out of them. Air conditioned to boot.
 
Ted DuPuis said:
...All turbines gobble fuel down low. I’ve gotten the MU2 down to 48 GPH combined at FL250...
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Grum.Man said:
I suppose there are specific missions that better fit a go fast Non pressurized turbine conversion but personally I would much rather have a Malibu for much less money. Sure the climb suffers but you get a better useful load, nearly the same true airspeed, lower fuel burn, and most importantly pressurization...
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This above is the reason I've never understood the appeal of the turbine Bonanza conversion. You want to get up high, over the weather and where the fuel burn is reasonable with the turbine. Why would anyone want to constantly be in the flight levels in an unpressurized airplane? Never made any sense to me.
 
GRG55 said:
This above is the reason I've never understood the appeal of the turbine Bonanza conversion. You want to get up high, over the weather and where the fuel burn is reasonable with the turbine. Why would anyone want to constantly be in the flight levels in an unpressurized airplane? Never made any sense to me.
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That was more or less my thought as well. I get it on some of the larger non-pressurized aircraft like the Caravan, Beech 99, or the Sherpa. Those were intended to be low-altitude, short-haul aircraft and the turbine is more a function of required horsepower to do the job. Yeah they guzzle fuel but compared to the maintenance on a big old radial, it's still a better deal.

The turbine Bonanza is a real head scratcher for me. As someone who's managed both pressurized and non-pressurized aircraft (and I used to fly the 310 and even sometimes Aztec at O2 altitudes), yeah, pressurization all the way if you're flying that high.
 
The additional reliability would certainly be worth something, this is what Plane and Pilot says about the Tradewinds conversion "...the Allison’s failure rate is one every 115 years. That makes the engine 100 times more reliable than a piston-aircraft engine."
 
Tradewinds is gone I believe. That being said, the Allison on the Bonanza is almost sure to have outlived the POS IO-550-B that it replaced.
 
Challenged said:
The additional reliability would certainly be worth something,
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I guess that would depend on how you define "worth something." From the mx side, the 1750hr inspection on a Tradewinds A36 turbine engine starts around $55k+ (2017 dollars) and the 3500hr O/H starts around $125K. Both costs heavily subjective to component conditions. Add that to the initial $400k+ conversion cost, one would be better served to buy an existing used turbine powered aircraft.
 
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My uncle flew a Turbine Bo for a few years for some dude, back and forth between Austin and somewhere in Cali. I got to have 15 mins of front seat time with his instructor once when my uncle was getting checked out in it. It was AWESOME!!!! If I'd had a logbook back then he would have put 15 mins of turbine time as my first entry, unfortunately I didn't follow up and get one then (I was in high school).

Follow up 25+ years later, the same instructor got his medical back after some serious cardio illness, and was at my uncle's house last year (he lives on an airfield neighborhood) and my dad flew our plane over (Piper PA-28) to see him also. The instructor guy used our plane back in the day to give BFRs and instrument training to my uncle and the previous owner, and had flown it many times (side note, my uncle has a '47 Bo with throw over yoke so BFR's were usually done in Archer). My dad let him fly it together with him and my uncle for an hour or so, he really enjoyed being back in the plane again. I was sorry I wasn't able to be there to see him too.
 
These are neat airplanes but generally impractical, as others have stated. Turbine engines work best on aircraft designed to be mated to them. The benefits of a turbine on an airplane like a Bonanza are fairly minor for the cost involved.
 
To make matters worse, I’m pretty sure the Turbine converted Bonanza red lined at like 170 knots indicated. So not only were you chugging fuel down low but you couldn’t even go that fast. You certainly couldn’t haul anything by the time you loaded it up with fuel.
 
There are some engine service requirements not yet addressed here. RR Maint manual calls for Daily engine water wash if operating within 75 KM of salt water. Could be with in 75 miles, I forget. Then dry the engine with bleed air/heater/engine anti ice on. RPM at 100%.
US Navy at Whiting field blew that off for their TH-57 fleet. (RR 250-C20, same as Bonanza conversion) After a rash of catastrophic compressor failures, they managed to suck up the world supply of C20 compressor assemblies. Get-well-time frame was more than a year. Info from my brother who attended the meetings. He was a contract Line Chief at south field at the time.
 
Maxnr said:
Could be with in 75 miles, I forget.
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FYI: 75 to 150 miles is the RR recommendation for salt-laden areas but industrial areas also qualify. Regardless, it all leads to internal engine sulfidation which can cause premature engine failure. And with the compressor on C-20s it was usually evident after an engine failure to find the forward compressor support bullet laying in the intake cowl after the shaft failed behind the 2nd stage compressor blade assembly due to corrosion.;)
 
Right on. I can believe that some body with the cash to go TURBINE and only TCM or Lyc experience will go the same way the Navy did at Whiting. Timely corrosion inspections are also needed.
 
Clarification. Tho 206 and I referenced RR 250-C20's, the Bonanza conversion uses the RR 250-C17. Its the same as the C20, but flipped upside down. C17 exhaust and inlet are now under the engine instead on top. The better engine is the PT-6. More power, more fuel consumption, more dependable.
 
I bet a turbine conversion of an aerobatic Bonanza would be fun...
 
Let'sgoflying! said:
When they turbine a Bo, do they add fuel somewhere?
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I'm pretty sure all the conversions have tip tanks.

Clip4 said:
If these turbine upgrades are so wonderful, why are there so few of them? A great turbine airplane leaves the drawing board as a turbine airplane. That’s why TBM is great airplane, the Piper Meridian isn’t such a great airplane and the rest with turbines upgrades not very good at all.
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The TBM was designed originally as a piston airplane. One with the tail on correctly. The Mooney 301. Pity they didn't keep the tail, or put on a Garrett engine.

Also, to say the Meridian isn't a great airplane ignores just how efficient it is.

Ted DuPuis said:
All turbines gobble fuel down low. I’ve gotten the MU2 down to 48 GPH combined at FL250. There are 421 owners who burn that.
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The MU2 and Cheyenne IV have the advantage of not using the guzzling PT-6. Those Garretts are really superior.
 
The Mooney 301 had a typical aft swept vertical stab and also typical trim tab on the elevator, no moving tail.
 
david.h said:
The Mooney 301 had a typical aft swept vertical stab and also typical trim tab on the elevator, no moving tail.
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Really? I totally thought it had the Mooney tail. But it was still designed as a piston and became the TBM.
 
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