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  #41  
Old 07-06-2017, 11:21 AM
tspear tspear is offline
 
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A point of consideration.
To match performance, you ideally would want an TIO-320 160HP engine.
But I cannot find any such exists. The closest, seems to be a 180HP or 200HP IO-360 depending on if you are trying to match cruise at roughly ~10K or ~20K.

Going on memory since I am feeling too lazy to look up the numbers.
The FWF package on the C172 is 54K.
Compared to a Superior IO-360 is 35K, plus you need to spend ~6K on parts for the EFI systems, and likely another 6K for a shop to install/tune it for you (I asked two shops with dyno/test stands the estimate to install an EFI on an IO-540, came in at 8K in labor, so I guessed 25% cheaper).

That means you are likely comparing 54K for a CD-155 versus 47K for an IO-360.

When you look at the Sportsman pricing, you now see they no longer offer a premium price for the diesel, it is the same price.

Therefore, the price delta between the engine choices is declining...

Hopefully someone can do a little research and get more accurate numbers.

Tim
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  #42  
Old 07-07-2017, 02:48 PM
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Av8torTom Av8torTom is offline
 
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Quote:
Originally Posted by penguin View Post
Why would you be nervous about a liquid cooled engine? How many aircooled cars are produced today?
Because virtually every break-down I've ever had with a car has been due to a problem with the cooling system - hose, pump, radiator.

I read someplace that nearly every P-51 that went down in WWII with engine trouble was the result of the cooling system getting compromised. There's a good reason airplane engines are air cooled. They follow the KISS principal...
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  #43  
Old 07-07-2017, 04:03 PM
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DaleB DaleB is online now
 
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Quote:
Originally Posted by Av8torTom View Post
Because virtually every break-down I've ever had with a car has been due to a problem with the cooling system - hose, pump, radiator.

I read someplace that nearly every P-51 that went down in WWII with engine trouble was the result of the cooling system getting compromised. There's a good reason airplane engines are air cooled. They follow the KISS principal...
I agree with you that KISS is indeed a good idea, and it doesn't get much simpler than air cooling (if you don't count the but baffling issues).
Eventually, though, you have to deal with the limitations of any system. When was your last cooling system problem? Just curious. The last time I can recall having a cooling system related issue with any vehicle I have owned was when our kids were in high school, when a water pump on an old and very poorly maintained Toyota we bought for them to drive disintegrated internally. Yes, I used to have a lot more problems when we were young and dirt poor and ran radiator hoses until they burst, then used duct tape to patch them. Not so much as a leaky radiator cap since, oh, about 2002. Maybe I've just been lucky.

Since no one is shooting at my RV-12 and materials have gotten a little better since the 40s, I'm not so worried about the P-51's problems.

Even Harley-Davidson is moving to water cooling. Slowly, but they're doing it.
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  #44  
Old 07-07-2017, 06:59 PM
kgood kgood is offline
 
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Quote:
Originally Posted by DaleB View Post
I agree with you that KISS is indeed a good idea, and it doesn't get much simpler than air cooling (if you don't count the but baffling issues).
Eventually, though, you have to deal with the limitations of any system. When was your last cooling system problem? Just curious. The last time I can recall having a cooling system related issue with any vehicle I have owned was when our kids were in high school, when a water pump on an old and very poorly maintained Toyota we bought for them to drive disintegrated internally. Yes, I used to have a lot more problems when we were young and dirt poor and ran radiator hoses until they burst, then used duct tape to patch them. Not so much as a leaky radiator cap since, oh, about 2002. Maybe I've just been lucky.

Since no one is shooting at my RV-12 and materials have gotten a little better since the 40s, I'm not so worried about the P-51's problems.

Even Harley-Davidson is moving to water cooling. Slowly, but they're doing it.
I agree. Cooling systems are pretty reliable these days. IMO, one of the best things for aviation liquid cooling is silicone hoses. Both of my diesels have them and I've had no troubles. And I live in Las Vegas! It's 114F here today...

Kurt
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  #45  
Old 07-24-2017, 07:20 AM
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rv6ejguy rv6ejguy is offline
 
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Stumbled on this very interesting article from The Aviation Consumer by Paul Bertorelli on actual lifecycle costs of the CD engines vs. Lycoming and other diesels: http://www.aviationconsumer.com/issu...cs_6962-1.html

His conclusion was that there were no great savings in the US using the CD series diesels. If you were to invest the initial purchase money saved, it would be a complete wash. If you added the installation price, the diesel is quite a bit more expensive. That may change as the TBO/TBR improves but lots of Lycomings in Experimental and flight schools are operated well past 2000 hours on condition too.

No fuel burn specs were given for any engine types so we don't know what figures were being used for the comparison there.
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  #46  
Old 07-24-2017, 07:54 AM
tspear tspear is offline
 
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Ross,

I also crunched the numbers, assumed replacement/overhaul at TBO/TBR. Using contract fuel prices for Jet-A and LOP of .39 for avgas, I would save 500 bucks in the USA. The real savings came in two forms. One international travel, Jet-A is a lot cheaper. Two the Jet-A has a longer rangeb so could save time.

When I get home in a couple of weeks I can look for the spreadsheets if want them.

Tim
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