Hidden costs with pistons vs turbines.

stratobee

stratobee

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stratobee
Case 1:

I like to change my oil every 25hrs. I don't do it myself, and it takes the mechanics a few hours each time and usually costs around $300-400. For a TBO of 1800hrs, each 25hrs, that means I've spent $29K in oil changes over the lifetime of the engine!

No oil changes on turbines. And, that's about the cost of a hot section inspection. Same time interval.

Case 2:

How many turbocharged engines will go to 1800hrs without changing at least 2 cylinders, a couple of spark plug sets and overhaul the turbos? We're talking a minimum of $10-15K here in cost over the lifetime.

Turbines generally go from HSI to HSI without any fuss. Same time interval.

So, as you can see - I need a turbine in order to save some money here!:yes::D;)
 
stratobee said:
Case 1:

I like to change my oil every 25hrs. I don't do it myself, and it takes the mechanics a few hours each time and usually costs around $300-400. For a TBO of 1800hrs, each 25hrs, that means I've spent $29K in oil changes over the lifetime of the engine!

No oil changes on turbines. And, that's about the cost of a hot section inspection. Same time interval.

Case 2:

How many turbocharged engines will go to 1800hrs without changing at least 2 cylinders, a couple of spark plug sets and overhaul the turbos? We're talking a minimum of $10-15K here in cost over the lifetime.

Turbines generally go from HSI to HSI without any fuss. Same time interval.

So, as you can see - I need a turbine in order to save some money here!:yes::D;)
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You're getting a HSI for 29k? What engine?

Also you don't even change your own oil?
Your A&P changes you $400 for a oil change?!
 
stratobee said:
Case 1:

I like to change my oil every 25hrs. I don't do it myself, and it takes the mechanics a few hours each time and usually costs around $300-400. For a TBO of 1800hrs, each 25hrs, that means I've spent $29K in oil changes over the lifetime of the engine!

No oil changes on turbines. And, that's about the cost of a hot section inspection. Same time interval.

Case 2:

How many turbocharged engines will go to 1800hrs without changing at least 2 cylinders, a couple of spark plug sets and overhaul the turbos? We're talking a minimum of $10-15K here in cost over the lifetime.

Turbines generally go from HSI to HSI without any fuss. Same time interval.

So, as you can see - I need a turbine in order to save some money here!:yes::D;)
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Turbines are great! I added up the parts billed to just one MPI on a TFE731, and it was over $700,000.

This is just one squawk out of 171 that are written up ---> "All High Pressure Turbine blades are eroded beyond limits" = 56 new blades at ~ $3,000 each.
 
All is well with a turbine......until there is a problem.

Does the US still print $100,000 bills? You will need plenty of them!
 
bnt83 said:
Turbines are great! I added up the parts billed to just one MPI on a TFE731, and it was over $700,000.

This is just one squawk out of 171 that are written up ---> "All High Pressure Turbine blades are eroded beyond limits" = 56 new blades at ~ $3,000 each.
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"Can't we just let that go until next year?"
 
300 -400 for an oil change - too rich for me. It takes me 45 minutes to do the cirrus by myself - and thats because the lower cowling is a *****.

But if you dont want to do it- gotta spend the money. I do 25 - 35 hour changes myself... Is what it is...

Good luck.
 
The piston will likely consume nearly half the gph of the turbine for the same horsepower; over the life of the engine, that's probably low six figures in savings.
 
No reason to change oil every 25 hours on Lycomings. So cut that in half by changing it to 50, and save $15k per TBO. HSIs are normally around $50k/engine as I've heard/seen. Then there's the first time you hot start it.

Turbine engine parts are made of materials like inconel and unobtainium. They are held to very precise tolerances as well, making them very expensive. They do normally go between hot sections without much fuss, but when there is fuss, it's expensive fuss.

But everyone who's been trying to sell me a turbine has insisted otherwise. :rofl:
 
You definitely have to change oil in turbines too. The interval varies, but it has to be done. While neither is cheap, turbines are more reliable, yet much more costly when something breaks or needs attention! :mad2:
You could likely buy a turbine with a fresh o/h or hot section and fly it for 1500 hours without issue, or like a piston, it could puke tomorrow! :dunno:
 
Funny thing, I really flew my pistons quite a bit with what didn't seem to be much more trouble than my neighbors with turbines.
 
Yeah, the TPE331 is 800hrs between oil change. Another thing - the plane I'm looking at is on manufacturer approved 100hr phase inspection (basically an annual), which means if you only fly them 50hrs a year, you can go two years between annuals.

You see - this turbine business is making more sense by the second!:D

Nah, but seriously. When the engines need doing, it's seriously expensive. To the point where it's not worth it on an old airframe. So the solution is to not do it: there are two ways to save beacoup money - part 91 no need to follow TBO if you don't want to. Just HSI them until you can't stomach it anymore. Or you can exchange the engine. There are plenty of exchange turbine engines with 1000-1500hrs left on them for about the same cost as a firewall forwarded piston.
 
stratobee said:
Yeah, the TPE331 is 800hrs between oil change. Another thing - the plane I'm looking at is on manufacturer approved 100hr phase inspection (basically an annual), which means if you only fly them 50hrs a year, you can go two years between annuals.

You see - this turbine business is making more sense by the second!:D

Nah, but seriously. When the engines need doing, it's seriously expensive. To the point where it's not worth it on an old airframe. So the solution is to not do it: there are two ways to save beacoup money - part 91 no need to follow TBO if you don't want to. Just HSI them until you can't stomach it anymore. Or you can exchange the engine. There are plenty of exchange turbine engines with 1000-1500hrs left on them for about the same cost as a firewall forwarded piston.
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I've seen more than my share of folks who operated piston twins get turbine fever, go out and trade up to a twin turbine.......have a great time.

Then the bills come in, the party is over, the plane sells cheap due to big $$$ items need attention.
 
RotorAndWing said:
I've seen more than my share of folks who operated piston twins get turbine fever, go out and trade up to a twin turbine.......have a great time.

Then the bills come in, the party is over, the plane sells cheap due to big $$$ items need attention.
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You mean a King Air for under $500k isn't a great deal???
 
Fearless Tower said:
You mean a King Air for under $500k isn't a great deal???
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A 90 can be ok in that price range, lots of variables.

But there are a couple for $150k or so. Those should be avoided like ebola.
 
Ted DuPuis said:
No reason to change oil every 25 hours on Lycomings.
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If it takes you 6 months to fly 25 hours then you should probably be changing the oil at 25 hour intervals Lycoming or Continental. On the other hand, if you're only flying 50 hours a year you're probably not the ideal candidate for a turbine either.
 
James331 said:
I've seen a few DZs buy cheap KAs and make some good money with them.
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Yeahbut those are past their pressure vessel life and can't be flown pressurized any more, at least not without a very expensive inspection which is probably more than the whole airplane is worth.
 
spinfire said:
If it takes you 6 months to fly 25 hours then you should probably be changing the oil at 25 hour intervals Lycoming or Continental. On the other hand, if you're only flying 50 hours a year you're probably not the ideal candidate for a turbine either.
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Point taken. I was referring strictly to the hour time, not incorporating the calendar time.

I run 50 hours or 4 months, whichever comes first. And I won't go over 50 hours intentionally, so it's not uncommon for me to change a bit early and get them at 40-45 because of that (my round trip hobbs times are usually 10+ hours).
 
If you need to start justifying a turbine using inaccurate as well as skewed numbers, you likely aren't in a position to have an enjoyable ownership experience. The only time turbines make sense is when you need dispatch reliability and a high power to weight ratio.
 
Henning said:
If you need to start justifying a turbine using inaccurate as well as skewed numbers, you likely aren't in a position to have an enjoyable ownership experience. The only time turbines make sense is when you need dispatch reliability and a high power to weight ratio.
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Or when you finally put a price on becoming mentally unstable by having to deal with:

Carb ice
LOP/ROP
Shock cooling
Bootsrapping
MP split/drift
EGT spread
CHT spread
Turbos
Wastegates
Spark plugs
Valves
Camshafts
Morning sickness
Vapor lock
Rich cut
Mixtures
Vibrations
Leaning
Cracked cylinders
 
stratobee said:
Or when you finally put a price on becoming mentally unstable by having to deal with:

Carb ice
LOP/ROP
Shock cooling
Bootsrapping
MP split/drift
EGT spread
CHT spread
Turbos
Wastegates
Spark plugs
Valves
Camshafts
Morning sickness
Vapor lock
Rich cut
Mixtures
Vibrations
Leaning
Cracked cylinders
Click to expand...

None of those are a burden to me.
 
The only question left to be answered is "How much time CAN you afford to save?":D:D:D
 
stratobee said:
Or when you finally put a price on becoming mentally unstable by having to deal with:

Carb ice
LOP/ROP
Shock cooling
Bootsrapping
MP split/drift
EGT spread
CHT spread
Turbos
Wastegates
Spark plugs
Valves
Camshafts
Morning sickness
Vapor lock
Rich cut
Mixtures
Vibrations
Leaning
Cracked cylinders
Click to expand...


Yes, but if those factors make you mentally unstable, turbines won't likely cure you of mental instability.:D;) It's not like turbines don't have their issues and don't break down, need maintenance, or repairs.

"Do you want it? Can you afford it?" Those are the only questions to answer and you should be using one word, one syllable answers. Don't rationalize, don't justify, just yes or no. When you have to rationalize the answers, especially with overly optimistic data, that's when you are setting yourself up for problems down the line. It will likely cause you to make poor decisions down the line in order to try to make those predictions come true.

If you want to buy and fly a 331-10 powered Commander and have the financial wherewithal to do so at the moment, by all means, have fun and enjoy life. Just don't base your ownership relationship on a foundation of unrealistic expectations. A simple "**** it, I want this" is more than sufficient.
 
What's bootsrapping? Or maybe you means bootstrapping? Still, I know what bootstrapping is, but not in reference to engine management...
 
spinfire said:
What's bootsrapping? Or maybe you means bootstrapping? Still, I know what bootstrapping is, but not in reference to engine management...
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When you don't have full deck referenced wastegate controllers on a turbo engine, you need to monitor your manifold pressure because the turbo can 'pick itself up by the bootstraps' and start the MP climbing.
 
Henning said:
Half of them are the fun of it all, the other half a non issue....;) except Rich Cut, no clue what that means.:dunno:
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Exactly. Turbines are boring.
 
Henning said:
Half of them are the fun of it all, the other half a non issue....;) except Rich Cut, no clue what that means.:dunno:
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Rich cut is a scenario where the engine gets too much fuel. Can happen when carbs get flooded or when mixtures are too rich at high elevation airports (for example). Not very common, but it happens.
 
stratobee said:
Rich cut is a scenario where the engine gets too much fuel. Can happen when carbs get flooded or when mixtures are too rich at high elevation airports (for example). Not very common, but it happens.
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Had it happen to me on takeoff in a Seneca II with a "mis-adjusted" fuel meter on the left engine. I thought the instructor was "simulating" an emergency, but it was a real problem.

Did not get higher than 500 AGL on that trip around the pattern!

The owner of the flight school tells me "oh, don't you know you need to lean for takeoff? That's standard procedure"

Ummm, sure, in a turbocharged engine at 1100 MSL. Right.
 
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