If this became available, would you?

Would you do it?

  • Yes.

    Votes: 10 20.0%

  • No. I don’t trust it.

    Votes: 11 22.0%

  • No. Too much involved for not enough gain

    Votes: 29 58.0%
  • Total voters
    50
genna

genna

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ТУ-104
An engine discussion in another thread gave me an idea on a hypothetical scenario. I fully realize that this may not be technically possible the way I put it and almost certainly not financially feasible for anyone to actually do. Or even if someone did or do it it would be a financial flop almost certainly. I get all of that. So this is a purely hypothetical “what if” for pilots here

Some trustworthy company came up with an STC that takes a crate Chevy LS motor(no modifications other than ECU mapping) adds a gear drive and uses it in place of IO540/550 in your plane. Similar power output(a little more to account for extra engine weight). Same useful load. Same performance. Some weight & balance. On MoGas with full FADEC, turn key operation. Like in a car. They successfully tested the combination a number of times for at least 2000 hours in test chambers that simulate all the flight conditions and then some, but they put the tbo at 1000. With a mandatory gear drive replacement at 500h.

The one time conversion(tanks, lines, cooling, prop, etc) cost is $30K. Engine itself is $10K. Gear drive is $5K

current io540 price is around $50k

Would you do it?

EDIT: Just to clarify cost schedule. Assuming no rebuilds, no failures, no cylinder replacements and everything gets replaced at TBO. If you were to fly this for 4000h and NOT install a new engines at the 4000h(just to keep it simple). You would have spent
With LS:
30K initial
4 engines: 40K
8 gear boxes: 40K
Total 110K

With 540
2 engines: 100K
16 mags: 15K? - not really sure here.
Total 115K

So yes, takes a long time to gain engine cost savings.

EDIT #2: Plane would be heavier due to heavier engine. However, the engine will be producing somewhat more power and be more efficient. So gross will go up and fuel quantity will go down to maintain the same performance, range, useful load and balance.
 
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With no modification to at least one set of plugs in a mag- no thanks...
 
IO-540/550, simple straight forward engine purpose built for application.

Car engine, modified for application, gear box that adds weight and complexity. Nope.

You see guys do these car engines in experimental airplanes. More often than not they spend more time and money trying to make it work, and a lot end up having to change it out to a Lycoming in order to sell it.
 
midwestpa24 said:
IO-540/550, simple straight forward engine purpose built for application.

Car engine, modified for application, gear box that adds weight and complexity. Nope.

You see guys do these car engines in experimental airplanes. More often than not they spend more time and money trying to make it work, and a lot end up having to change it out to a Lycoming in order to sell it.
Click to expand...

No question. I'm not advocating that someone puts an auto engine into a plane and makes it better. This is a purely pie-in the sky hypothetical with my imaginary parameters. Same performance is one of those parameters. Testing is another. Mandatory gear drive replacement at 500h is another.
 
I wouldn’t convert a certified airplane but may consider it for an experimental. There would have to be a bigger cost delta though for me to seriously consider it especially with the 500 hour gearbox.

If Rotax came out with a 300 hp engine for about the same price as an IO-550 I would jump on that though.
 
If you want to sell something like this, you have to think of the first buyer who has to pay for the conversion.

Buyer would be a person with a used up traditional engine. Overhaul or buy this new engine to get another 2000 hours?

Overhaul my current engine = $40,000 ??

Buy this new engine - $30,000 for the conversion, $15,000 for gearboxes, $10,000 for the initial engine, $10,000 for second engine/overhaul at 1000 hours, subtract what you could get for your old engine / old core ($5,000??). That's $60,000 for 2000 hours of use.

Hard to be competitive when you are charging 50% more. Love the FADEC, but also have more downtime replacing my gear box every 500 hours, replacing engine every 1000 hours, lack of AP familiarity / availability to work on, etc.

Now, if Honda, Rotax, Allison, or a company like that sold and supported it, and if you cut the price of conversion to $5,000, moved TBO to 3000 hours, had a 2000 hour / 10 year full replacement warranty, and didn't have gearboxes being replaced every 500 hours, then maybe.
 
Nope. I'm actually not a fan of true FADEC. True full authority digital engine controls have no form of manual override available, placing full authority over the operating parameters of the engine in the hands of the computer. If a total FADEC failure occurs, the engine fails. To get to a 2000 hour TBO running your numbers you'd have 4 gearbox changes with that cost, labor, and downtime. Another point of failure. You may need a prop swap as well

Look at the Archer DX vs LX. Less cruise speed, more weight, more cost. Anyone traveling 1200 NM in an archer non stop? So I don't think today's diesels are the answer either.
 
Grum.Man said:
I wouldn’t convert a certified airplane but may consider it for an experimental. There would have to be a bigger cost delta though for me to seriously consider it especially with the 500 hour gearbox.

If Rotax came out with a 300 hp engine for about the same price as an IO-550 I would jump on that though.
Click to expand...

I get that. I deliberately put at at initially roughly the same cost as a new 540. The savings come later(MoGas, much lower engine replacement costs, no cylinders to replace. gear drive is at about the same interval as mags - albeit a bit more money). Assuming nothing fails and we are doing all TBO replacements(no rebuilds and no cylinder replacements and other failures in either setup), at 2000h you would have spent 40K on engines and gear drives vs 55ish to replace 540 and mag replacements.
 
There is a RV 10 out here with IO540 and FADEC , I think the builder have some sort of manual over ride too, but I could be wrong. It’s one of the best -10 I have seen (that includes spending ton of time looking -10 on YT and Vans forum)
 
Grum.Man said:
I wouldn’t convert a certified airplane but may consider it for an experimental. There would have to be a bigger cost delta though for me to seriously consider it especially with the 500 hour gearbox.

If Rotax came out with a 300 hp engine for about the same price as an IO-550 I would jump on that though.
Click to expand...

Rotax made a 300hp 6 cylinder. Compared to legacy engines it was heavy, unreliable, and not fuel efficient. Project was shelved in 2006 I believe. The market wasnt there to warrant keeping the project going
 
WannFly said:
There is a RV 10 out here with IO540 and FADEC , I think the builder have some sort of manual over ride too, but I could be wrong. It’s one of the best -10 I have seen (that includes spending ton of time looking -10 on YT and Vans forum)
Click to expand...
If FADEC has a manual over ride it's considered an EEC. All for that.
 
What happens to your cheap supply of crate motors the first time GM gets sued by a grieving widow?
 
D: none of the above (not enough information)
 
In principal yes, in practice I want to see it proven in actual use for a few years and find what it would do to my resale value.
 
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Racerx said:
Nope. I'm actually not a fan of true FADEC. True full authority digital engine controls have no form of manual override available, placing full authority over the operating parameters of the engine in the hands of the computer. If a total FADEC failure occurs, the engine fails.
Click to expand...

I think you're being overly cautious. I was reading about a new FADEC integrated with AI offered by a company called "SkyNet".
 
aftCG said:
What happens to your cheap supply of crate motors the first time GM gets sued by a grieving widow?
Click to expand...
GM gets sued all the time. I doubt they would care that much. I also think that they would be removed from this potential lawsuit in the same way as when their engines are used in the race cars.

In any case, this is outside of scope of this exercise.
 
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Small sample for now. And I expected more "No" than "Yes". But we haven't had any "I don't trust it" yet which is not what I expected and also not matching some of the responses. I find that curious.
 
Racerx said:
Rotax made a 300hp 6 cylinder. Compared to legacy engines it was heavy, unreliable, and not fuel efficient. Project was shelved in 2006 I believe. The market wasnt there to warrant keeping the project going
Click to expand...
A lot has changed since 2006 though. I can still see where there isn’t a large enough market though. There just aren’t enough EXP planes that can use or need a 250-300 hp engine and that’s where the supply chain starts. If they can develop a scaleable architecture similar to what they have done with the 912is, 914, and 915 I could see a pathway. Same family of engines that produce 180-210-250 hp. Now you have every RV model covered to spread the cost out.
 
I probably wouldn't at those numbers, but mostly just due to the low gearbox replacement times and initial conversion cost. I wouldn't question much of the reliability of the LS push-rod v8, even though I still think a lightweight diesel would be a better "fit" for the GA fleet. I mean, having to replace a gearbox once every 5 years (assuming 100hr/yr) isn't major, but it is a hassle and a potential failure point if something that critical didn't get installed/built correctly. Having a magneto fail after overhaul generally doesn't result in an emergency situation.
 
SoonerAviator said:
I probably wouldn't at those numbers, but mostly just due to the low gearbox replacement times and initial conversion cost. I wouldn't question much of the reliability of the LS push-rod v8, even though I still think a lightweight diesel would be a better "fit" for the GA fleet. I mean, having to replace a gearbox once every 5 years (assuming 100hr/yr) isn't major, but it is a hassle and a potential failure point if something that critical didn't get installed/built correctly. Having a magneto fail after overhaul generally doesn't result in an emergency situation.
Click to expand...

I want to point out that in my scenario, the combination was tested and passed to at least 2000h. The 500h gearbox limit is out of abundance of caution because this seems to be a generally weaker and less trusted point in the system than the engine. The engine 1000h limit is also out of caution. Both numbers may go up(although i did not include that into my scenario)

Mags can also fail rather spectacularly as was discussed elsewhere.
 
Increased complexity / lower reliability. Much higher weight, lost of useful load - there's no way you're getting a car engine without a weight penalty. Declining gains from the increase in HP.

No thank you, i'll pass.
 
I don’t get the mogas savings, unless I’m going to land on a road and taxi up to the local gas station, it’s a big hassle. Sure, I could get a 1000 gallon tank filled and pump out of that, but I’m pretty sure most municipal airports have a problem with fuel tanks in hangars.
The only place I’ve seen mogas being realistic is for float planes pulling up to a boat fueling station.
 
I already have one of the most popular aircraft engines ever manufactured, high serviceability, good reliability, and burns 87 mogas. The only things it doesn't do is very high efficiency.

No parts aren't cheap but still a lot cheaper than an engine conversion.
 
Depends on who designed the conversion. There have been many auto conversions in the experimental world that failed miserably because of gearbox issues. If a known and established company did the design work and testing then maybe (cost aside). If this is another conversion from the guy who made subaru conversions famous (for the wrong reasons) I wouldn’t touch it with a 10 foot pole no matter how many hours they spent testing it. Same reason I won’t put a Honda conversion on my Sonex.
 
genna said:
An engine discussion in another thread gave me an idea on a hypothetical scenario. I fully realize that this may not be technically possible the way I put it and almost certainly not financially feasible for anyone to actually do. Or even if someone did or do it it would be a financial flop almost certainly. I get all of that. So this is a purely hypothetical “what if” for pilots here

Some trustworthy company came up with an STC that takes a crate Chevy LS motor(no modifications other than ECU mapping) adds a gear drive and uses it in place of IO540/550 in your plane. Similar power output(a little more to account for extra engine weight). Same useful load. Same performance. Some weight & balance. On MoGas with full FADEC, turn key operation. Like in a car. They successfully tested the combination a number of times for at least 2000 hours in test chambers that simulate all the flight conditions and then some, but they put the tbo at 1000. With a mandatory gear drive replacement at 500h.

The one time conversion(tanks, lines, cooling, etc) cost is $30K. Engine itself is $10K. Gear drive is $5K

current io540 price is around $50k

Would you do it?

EDIT: Just to clarify cost schedule. Assuming no rebuilds, no failures, no cylinder replacements and everything gets replaced at TBO. If you were to fly this for 4000h and NOT install a new engines at the 4000h(just to keep it simple). You would have spent
With LS:
30K initial
4 engines: 40K
8 gear boxes: 40K
Total 110K

With 540
2 engines: 100K
16 mags: 15K? - not really sure here.
Total 115K

So yes, takes a long time to gain engine cost savings.
Click to expand...


What kind of propellers will this thing be able to use? Are these going be constant speeds? Fixed pitch? Hydraulic or electric?

There aren't many airplanes running IO540/O540 that are fixed pitch...

Add $15k for a prop at engine conversion?
 
I would be more interested in something like the TP100. 240 hp and only weighs 135lbs. Granted fuel burn is significantly more. But probably looking at a 3500tbo minimum.
 
bflynn said:
Increased complexity / lower reliability. Much higher weight, lost of useful load - there's no way you're getting a car engine without a weight penalty. Declining gains from the increase in HP.

No thank you, i'll pass.
Click to expand...
bnt83 said:
What kind of propellers will this thing be able to use? Are these going be constant speeds? Fixed pitch? Hydraulic or electric?

There aren't many airplanes running IO540/O540 that are fixed pitch...

Add $15k for a prop at engine conversion?
Click to expand...

You can use the same prop you are using now
 
bflynn said:
Increased complexity / lower reliability. Much higher weight, lost of useful load - there's no way you're getting a car engine without a weight penalty. Declining gains from the increase in HP.

No thank you, i'll pass.
Click to expand...

In my scenario, weight penalty is minimum and it is offset by power gain. The plane will have all the same performance numbers, W&B(with higher gross), and useful load.
 
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kmacht said:
Depends on who designed the conversion. There have been many auto conversions in the experimental world that failed miserably because of gearbox issues. If a known and established company did the design work and testing then maybe (cost aside). If this is another conversion from the guy who made subaru conversions famous (for the wrong reasons) I wouldn’t touch it with a 10 foot pole no matter how many hours they spent testing it. Same reason I won’t put a Honda conversion on my Sonex.
Click to expand...

"Some trustworthy company". There is no conversion in the engine. It is a straight crate LS engine from GM. The only adaptation is mapping in ECU and gearbox(by said "trustworthy company")
 
Wagondriver said:
I don’t get the mogas savings, unless I’m going to land on a road and taxi up to the local gas station, it’s a big hassle. Sure, I could get a 1000 gallon tank filled and pump out of that, but I’m pretty sure most municipal airports have a problem with fuel tanks in hangars.
The only place I’ve seen mogas being realistic is for float planes pulling up to a boat fueling station.
Click to expand...

I think for me this is probably the biggest issue as you will be severely limited to where you can go or have to carry some 5g cans with you. definitely a pain in the ...
 
genna said:
You can use the same prop you are using now
Click to expand...


So the gearbox is going to drive hydraulic constant speed props already found in service? Will these contain a regular GA "off the shelf" prop governor or some other proprietary governor integrated into the gearbox?
 
genna said:
In my scenario, weight penalty is minimum and it is offset by power gain. The plane will have all the same performance numbers, W&B(with higher gross), and useful load.
Click to expand...

Got it.

I don't deal with hypotheticals. Carry on.
 
Wagondriver said:
I don’t get the mogas savings,.
Click to expand...

The airplane holds 5 hours of gas. Flying 2 hours away leaves me 3 hours of gas to get back. At most, I may pickup 10 gallons of avgas to get back, once or twice a year maybe 20 gallons.

I can haul 30 gallons in 20 minutes, saving $60. When I have the 182 (78 gallon tanks) I can easily save $100 in 40 minutes.

I flew about 70 hours last year, lets say 60 of it was mogas,

60 hours X 10 GPH average = 600 gallons. Saving $2 a gallon, well that's $1200 saved last year using basically 6.6 hours of labor.
 
bnt83 said:
So the gearbox is going to drive hydraulic constant speed props already found in service? Will these contain a regular GA "off the shelf" prop governor or some other proprietary governor integrated into the gearbox?
Click to expand...

Details, details. :)... Ok, the electric governor is part of the 30K initial investment. The overhaul times on that are same or similar as your current hydraulic one. i'm trying to keep it simple here,
 
How about this? A 4000 hour TBO diesel you can put anywhere in the fuselage turning an alternator/generator, and have electric motor(s) turning a prop(s). No gearboxes to replace every 500 hours. You can configure the generator to produce all the power you want at low RPMs, moderate to high loads on the engine to run it as efficiently as possible. Heck, you can even have a 5 minute power reserve to keep the props running if you loose the engine.

Return of Skymaster .....
 
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