I hear you all good points
Become a member of SAE, buy the test papers for whatever engine you want to know about and see that modern engines are usually put through a series of dynos tests WOT, power peak rpm of at least 400 hours and some up to 1200 hours.
I have a lot of respect for SAE and have a PE license. I have read many SAE reports and test, but never on an auto engine. I know SAE is instrumental in making HP specs more standardized. However I am not sure about reliability and longevity standard test. No one advertises an X mile engine. 400 hours I can believe that. I know in my parents or grandparents days if you got 100,000 miles out of your car, it was good. Now we expect twice that or more out of our cars.
It just ain't true today anymore what you say. Get the facts, don't work on feelings. I just dismantled my EG33D with an estimated 2100 hours on it. No measurable wear on bearings, crank, cams, valve stems, guides, bores, pistons, ring lands etc. Not even .0001.
That is impressive. I find that incredible and a testament to not only the desgin but you skill in installation, operation and maintence. I love Subies. I had a 1982 4 door GL Subaru for 12 years. I got it used in 1984. I still regret trading it in. How you even you measure one TEN thousands of an inch is amazing; let's call it zero wear. I just have one question, WHY THE HECK DID YOU TEAR IT DOWN?
So with 0.0001 wear in 2100 hours, and say max wear is 0.005, TBO should be 10,500 hours!
It is true that we won't cruise at power peak rpm WOT on any aircraft engine at SL for its whole life. As a professional custom engine builder for 30 years, it is my view that most modern auto engines will last just fine at 75% and say 4000-4500 rpm.
Probably true, but talking to a guy who works For GM on their test track, they blow motors all the time when they intentionally abuse them. No man made thing is perfect or indestructible.
It is true that best fuel specifics are not achieved at super high rpm so we try to gear the engine to operate somewhere around torque peak or below for a decent compromise.
Right on.
I just don't see major wear or sudden failures on the hundreds of Subaru engines flying with probably in excess of 1/4 million flight hours. Maybe you don't realize the numbers of auto engines flying.
I do understand and the fleet has been growing. I think you are mixing failure with wear. Not with standing your 2100 hours as good as new, its wear that I am talking about.
Just between Don Parnham's conversions, RAF's and Groen's alone, we are talking over 1000 Subaru's. They are working just fine, not throwing rods, breaking cranks or wearing out rings. There are many of these going over 1000 hours being run between 4500-5500 rpm continuously.
I think you are sensitive about possible catastrophic failure. I am not saying that. In fact with a "transmission" properly designed to isolate the crank from harmonics a car engine in a car or plane should be what we all expect, reliable.
That being said, ANY reciprocating engine can fail and do and people die from this every year. I can think of a couple Conti and Lycoming failures in the last 4-5 years which killed people. Minimize your risks, give yourselves some options when you plan your flights.
That is true. However since data is hard to come by and statistics impossible to calculate or draw conclusions. I find most most alternative engine loss of power/failures/issues have more to do with anything but the CORE ENGINE mechanics (like electronics or belts). Also in general more people run out of fuel by a huge factor over cranks, rods or valve trains failure. Same with Lycs, engines "blowing up real good" are rare. However the Lyc does have the advantage of FARM TRACTOR technology for its ancillary systems, mechanical carb, FI, mags, fuel pump and so on. Alt engines usually have belts, water pumps and need electonics to work. All these can be reliable but just from a statistcal stand point, "If it ain't there to fail it can't fail".
And no, a Lycoming 360 won't even last a few minutes at 600hp. It is not designed for this and does not rev high enough to even achieve this figure naturally aspirated. It would simply melt down anyway without ADI and spray bar water as it does not have the fin area required to dissipate the heat generated at this hp level. The Cont twin turbo 550 I worked on at Reno this year is hard pressed to make this power at 3200 rpm and 60 inches with reworked heads and cam- and last 8 minutes even with ADI and spray bar water.
I hear you, but your are trying to compare apples and oranges. They are both round and sweet, but some people like apple juice and others oranges.
To make HP you need either displacement and/or RPM. The LYC is a 4 cylinder with twice to displacement per BORE than most car engines. The Lyc is an aircraft specific design, air-cooled engine, directly driving a prop at relatively LOW RPM, a torque motor if you will.
There is no way the 360 Lyc can ever make 600 HP EVER, since its Red line RPM is 2,700 rpm's. Over 10% of 2,700 rpm Lyc recommends a tear down. Now I know many racers run +3,200 rpm. That rpm limit does not make a Lyc bad, since over 2,700 rpm prop efficiency goes down. It is just a special purpose direct drive, low RPM aircraft engine.
It's like comparing a COX 0.049 cu-in model airplane engine that turns 15,000 rpm to a ships diesel engine, max turns 102 rpm and 109,000 hp!
LINK They both are good and neither can do the job of the other. The application is different. Auto engines are designed or optimized for cars. Airplane engines are optimized for planes. That is a fair statement. I will grant you the auto-engine makes a better plane engine than a plane engine makes a car engine. However the above diesel and 0.278 lbs per hp per hour is good, but only for the largest ships on the sea.
Your points are well taken, each engine is designed to operate for specific applications at specific limits and duty. A Continental at 60 inch boost
, will not last. Is that a surprise? However at Reno, what engine's where in the top and winning planes? Lyc? Cont? Falcon? Any car engines in there? If I wanted more power I would get a TIGO-541-D1B or IO-720 (8-cyl) Lyc. 400-450 hp out the box ain't bad. Just more displacement or RPM or both. Still direct dirve and air-cooled, simple and lighter. With a little tweak reliable +500 HP is possible (I am gussing).
