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Continuing C.K.'s discussions on engines, let me add my 0.5Cents worth. The Cont 550 engine model started life as the original Cont IO-470 engine
which developed 235hp. The crankcases are the same. The Cont. 520 was
born by boring out the cylinder. If you compare the crankcase of a 520 to
a 470 you will see the same casting pattern was used. The cylinder bolt
studs are in the same location. There is just less meat between the
cylinder cut out hole and the stud. Then the 550 was born by stroking as
C.K. mentioned. If you look at the inside case of the 550 you'll see where
Cont had to cut some of the case away to make room for the reciprocating
parts with the longer stroke. When turbocharged, this 550 will now make
350hp. This engine does not have the same reputation as the bullet proof IO 470. Why? IMHO, it is obvious. Cont. has squeezed out every last hp
this design can deliver. The result is an engine which performs fairly
well, but not as well as the lower horsepower variant.
My interest in the Eagle 540V8 concept is that it is designed to run at
over 600hp and is derated to run in the LIV or most other applications. In concept, this appeals. to me. Running the Eagle at 75% power means
375hp which is 63% of its capability. 375hp continuous in the LIV will be
within the design parameters of the plane and yet not tax the powerplant. Now, having said all that, C.K. is absolutely correct in noting that none
of these alternative powerplants are proven. I've operated Turbo charged
Continentals and turbocharged Lycomings for the past 21 years with over
4500 hours and while I grip about exhaust risers burning up, wastegate
deteriorations, poor cylinder life, magnetos failing, etc, etc. overall, I
have rarely been grounded because of engine failures. Not a bad record for
these dinosauers. Most people want reliability, even if it costs. And
right now the only proven engines for them are Lycomings and Continentals. For those who are more "adventureous", and this is where the experimental
classification fills the niche, we look forward to better powerplants. But
we aren't naive. It will take years and thousands of hours of operations
before we can say that a certain new powerplant is better and more reliable
than the Cont or Lyc. In the meantime, the smoothness of rotary power, or
the smell of burning jet fuel, or cruising at 345kts at 25k in a V8 is
enough for them and I to make that leap right now. Marshall Michaelian (SQL, 80% LIV-P, Eagle 540V8) P.S. Charlie, the Cont TSIO550 O&M manuel says the weight is 571lbs +/-
2.5%
LML website: http://www.olsusa.com/Users/Mkaye/maillist.html
Builders' Bookstore: http://www.buildersbooks.com/lancair
Please send your photos and drawings to marvkaye@olsusa.com.
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