Musical Chairs - AVGAS - Next Airplane

[Seth]

A friend of mine mentioned to me that should I purchase a larger airplane at some point in the future, I would want to go turbine and not piston twin. He knows I have a fascination with Aerostars. The reason, he said, is simple.

If I purchase a larger airplane, pressurized, for a hopefully growing family in the next few years, I'll likely slowly spend money on that airplane over time, getting it to where I want. It would be a shame if after getting it where it's exactly how I want it, I then can't fly it as a replacement for AVGAS is not found, doesn't include my piston engine, or harms my performance and future resale value.

He has a point, when the music stops on AVGAS at some point, we won't want to still hold our piston powered aircraft. The Mooney I see as different as there are too many piston singles in the fleet. A slight reduction in power ratings affecting useful load or modifications to a single engine may be needed for common engines like the IO360 or I0550 (and the turbos we run as well). But an old piston pressurized twin? A C414, Aerostar, BE58P - There are some, but not a ton, and the SE performance or useful load may really harm the aircraft ability. A SETP may be the solution there, or an older Cheyenne, or something like that. Purchase price will be more but operating costs will in the end be equal due to lower fuel prices on Jet A and maintenance on the engine. I'm not doing anything anytime soon. It was an honest good piece of advice.

"Don't be caught with a large pressurized piston twin when the AVGAS music stops." What are your thoughts with this analogy/advice?

-Seth

Edited March 31, 2021 by Seth

[philiplane]

Operating costs of anything turbine are always higher than the closest comparable piston airplane. Cheaper fuel, but it burns more. Longer overhaul intervals, but costs are 4x to 8x higher. If your Mooney battery gets weak in the middle of a start, the engine may not start. If your SETP battery gets weak in the middle of a start, and you over-temp the engine by a measly 15 seconds, you're looking at a $45K bill, minimum. A new starter is $650 for a Mooney, it can be $8000 for an overhauled Cheyenne/King Air starter generator. Anything turbine costs $700 and up for hourly operating costs. Turbine twin...double that. Get one with Garrett engines on an MSP program, and you write a $200-300 check for each engine for every flight hour. A windshield for a new $850k Mooney costs $450. A windshield for a $450k King Air, is $7k per side, and you replace them if the internal heat fails or if they delaminate, which happens a fair amount. A windshield for a $650K Cheyenne is $26k. A windshield for an $850K Eclipse Jet is $55k.

Annual insurance company required training...$3-7k.  

And, the purchase price will always be more. 

If you thought your Mooney mechanic loved you, just wait till you buy a turbine powered anything.

Edited March 31, 2021 by philiplane

[ArtVandelay]

I see no reason why our engines won’t run on 94 octane minus the ethanol with electronic ignition. Our compression ratios are similar if not less than most automobiles engines

[KLRDMD]

1 hour ago, Seth said:

If I purchase a larger airplane, pressurized, for a hopefully growing family in the next few years, I'll likely slowly spend money on that airplane over time, getting it to where I want. It would be a shame if after getting it where it's exactly how I want it, I then can't fly it as a replacement for AVGAS is not found, doesn't include my piston engine, or harms my performance and future resale value.

"Don't be caught with a large pressurized piston twin when the AVGAS music stops." What are your thoughts with this analogy/advice?

Having owned more than a few airplanes over the years I've considered this. Some time ago I decided that for any airplane but especially so for a piston twin and more so yet for a pressurized piston twin, you have to be OK with the value being scrap only at some point. If you can't afford to walk away from the airplane with scrap value in your pocket, I suggest not buying it in the first place. I say this as a current pressurized piston twin owner, too.

Turboprops are not the same, but the cost of entry is high and the cost of maintenance is eye watering. On a bad day with a pressurized piston twin you may have a $25,000 bill. With a turboprop, that may be a $250,000 day.

[Seth]

Yes, it's eye watering. Good point about the piston pressurized twin - understand it's a total loss that equals scrap metal going in and you're A-Okay! Just like a 20 year turboprop or jet is simply purchasing an engine or two and whatever comes with it is bonus.

Maybe an Aerostar is in my future after all!

-Seth

[carusoam]

Good news!  If you go twin, with big motors...

They are already heavily discounted...

The attraction of going single turbine...  centerline thrust... of all that HP.

If the second engine fails during the climb, the pilot has his hands full... (except for Ken’s twin)

A pilot like Seth... not so much of a problem...   For A pilot like -a-,  single engine turbine would be much better... 

 

We have had several MSers max out the usability of their Mooney... at least three went turbine... and a handful went twin...

Mooney plans get sort of fuzzy while building a family... what happens when you plan for a second child, and you get a lucky set of twins?  (Long body with a bench seat in the back...)

Single engine ops in a twin turn tragic too often... stay current.

PP thoughts only, not a futurist...

Best regards,

-a-

[A64Pilot]

On 3/31/2021 at 9:27 AM, ArtVandelay said:

I see no reason why our engines won’t run on 94 octane minus the ethanol with electronic ignition. Our compression ratios are similar if not less than most automobiles engines

Automobiles or motorcycles have nothing to do with our aircraft engines, much smaller combustion chambers with much increased swirl brought about largely by four valve heads etc just are a whole different animal than our combustion chambers.

‘Electronic ignition doesn’t either, unless it’s advanced enough to have a knock sensor and or other sensors, perhaps timing reduction with higher manifold pressures?, electronic by itself doesn't mean anything, except that there may not be points, but a few electronic ignitions back in the day kept the points, just they carried very low current and therefore lasted a long time.

‘However I’m sure we could run 94UL with our N/A engines just the way they are, probably back off on timing a few degrees and my Guess wound be a reduction of manifold pressure maybe to 25” but maybe higher, there is margin now and we could probably run 94UL just the way we are, but at a reduced margin, and that may restrict LOP somewhat.

Back in the 70’s I believe it was the University of Tennessee that was conducting testing with what was then called Gasahol. they were running it in one engine of a Cessna twin, and they got it to work, it was car gas. But there are I believe many other issues, so that takes us back to 94UL, which I believe has no issues, except the lower Octane.

 

I know people that have run straight 93 Octane car gas in higher compression engines, 100LL in one tank, car gas in another and did so with no issues, much more susceptible to vapor lock though on a hot day after shut down, but obviously they were operating closer to detonation than if they were running 100LL

Edited April 1, 2021 by A64Pilot

[A64Pilot]

Pressurized is what adds to the cost significantly, ask what it costs to add an antenna to a pressurized airplane.

B-55’s are so cheap and have been that way for decades, because nobody wants one, it cost three times as much to fly a B-55 than say a V-35, ask a Duke owner what it costs

‘Fuel cost on a small single engine turbine is insignificant, it’s dwarfed by other costs, as far as hot starts, you have to be stupid to hot start a PT-6, and I mean stone cold stupid, they are such a benign start you have plenty of time. Other wise they are so easy to operate, no mixture, no cowl flaps, no cyl head temp to monitor etc, just three limits to watch, usually torque on take off and that transitions to usually ITT in climb and cruise, sometimes Ng  speed, prop RPM is just for comfort / noise. leave it full all of the time if you want to, it doesn’t hurt.

‘Now starting a Garrett without auto start is an emergency procedure, be sure you have nothing else going on when you start that motor, same with the little Allison, with it you will be several seconds into the I believe it’s a 6 sec limited range, either can be hot started in the time it takes to glance at your phone or watch.

Walters and the new GE are about like a PT-6

[KLRDMD]

22 hours ago, Seth said:

Maybe an Aerostar is in my future after all!

Aerostars are nice. I almost bought one a few years ago but they won't fit in my current hangar so I'm not even considering one today.

[KLRDMD]

23 minutes ago, A64Pilot said:

B-55’s are so cheap and have been that way for decades, because nobody wants one, it cost three times as much to fly a B-55 than say a V-35.

Having personally owned both, that is not true. Look for any number of my previous posts on MS where I outlined specifics with listing actual $$$. A Baron or 310 runs 50% more than a good single.

[Seth]

After being on the other threads, I started thinking diesel again. Though I do want pressurized, a DA62 or a DA50 may both be good airplanes. JetA powered. Those could be alternatives, as could a Mooney with a diesel engine.

Now a Mooney wing, new gear, and a composite fuselage pressurized with a diesel engine or small turbine, now that's a niche that doesn't exist right now.

-Seth

[Niko182]

This doesnt exactly answer the question, but they do mention a decent amount of info on TP vs Piston operating costs. 

https://www.beechtalk.com/forums/viewtopic.php?f=49&t=192325

Edited April 2, 2021 by Niko182

[MIm20c]

How much HP would it take to haul a long body 240 kts at 18k?  If a turbo diesel could do that I’d be in and willing to spend a lot for it. 

[ArtVandelay]

How much HP would it take to haul a long body 240 kts at 18k?  If a turbo diesel could do that I’d be in and willing to spend a lot for it. 

Rough guess, 350hp. Acclaim gets that speed with 310hp but I think it’s at a higher altitude.

[Niko182]

Just now, ArtVandelay said:

Rough guess, 350hp. Acclaim gets that speed with 310hp but I think it’s at a higher altitude.

Didnt the acclaim type s get 242 knots with 280hp? They come stock with 280, or at least used to.

[McMooney]

Personally, 

I think it's silly to have delayed phasing out 100LL for so long, All of these changes could've been done 40 years back. I say bring it on and be done with it

Edited April 3, 2021 by McMooney

[philiplane]

40 minutes ago, Niko182 said:

Didnt the acclaim type s get 242 knots with 280hp? They come stock with 280, or at least used to.

It will, at FL250, optimum CG, and running the engine hard enough that the cylinder life might be 600 hours...

[Tim Jodice]

On 4/1/2021 at 8:07 PM, KLRDMD said:

Having personally owned both, that is not true. Look for any number of my previous posts on MS where I outlined specifics with listing actual $$$. A Baron or 310 runs 50% more than a good single.

I had the same experience with my Baron.