Henry (Hank) Huddleston
SNIP
Comments: I basically am looking for engine technology that
is something later than 1935. It seems incredible to me that Lycoming and
Continental have been building what is effectively the same engine for over
60 years and have not yet managed to produce one that does not result in
several expensive AD's.
SNIP
Bill Freeman wrote:
While I generally agree that the rotary has tremendous promise, one does not
improve
his logical case by citing false statistics. All of the current crop of
certified A/C
engines were developed in 50's with a few exceptions in the late 40's. For
example,
the 0-470 replaced the E-225 in about '58, which replace the E-185 a few
years
earlier. Yes this is a long time ago, but it was not even within two
decades of
1935. Exaggeration is unbecoming in a technical forum like this one, and
trying to
make the case of technical superiority with false "facts" does not impress
anyone
that knows the actual facts. The facts are on your side, no need to
stretch things
and this sort of stuff drags down the overall very high tone of this
newsletter.
Stick to the facts, please.
Bill Freeman
I agree there Bill but I think you missed the point about the $14 Cummins
exhaust
valve fitting the Lycoming. I know for a fact the early valve lifters were
Cadilac V8 in origin. If I had a Lycoming I would look into it as why pay
$290 for a part you can buy for $14.
Paul Lamar
I absolutely agree that I would LOVE cheaper parts. I actually seriously
doubt the $14 price for a sodium filled valve, as a std non-sodium Chevy
valve is certainly more expensive than that. But, as I get older and a tiny
bit wiser
& see the incredibly small aviation marketplace, combined with the need to keep
engineers, technicians, etc on staff, I can at least partially understand the
problem. If Cummins has a fixed setup cost of $250,000 to start a valve
run, and can produce 20,000 valves for a cost per valve of $10, they spend
$450,000 on 20,000 valves. They cost $22.50 each and could be sold for
$40 with a reasonable profit. If Lycoming has an IDENTICAL cost structure
and only makes a run of 1000 valves, they spend $260,000 on 1000 valves,
which cost them $260 each, and need to be marked up to about $400 to
keep their doors open. Sad but true, and hard to find a way around it
except conversion of auto engines, which usually is not workable - as we
have thrashed out many times. Small quantities are a REAL killer.
I'd love cheap parts. I think Lyc and Cont could be more efficient than
they are. BUT - I doubt there is more than 25% fat to be trimmed out
by the smartest people when running the tiny production numbers currently
happening in the certified aircraft industry. Priced an outboard motor
lately? I dare ya. ;-)
Bill Freeman
The possibility is the Lycoming does not make their own valves. In fact I
am almost certain of it. Several years ago they sold all their machine tools
and now buy out absolutely everything. Continental on the other makes almost
everything including the steel from a Teledyne corporate umbrella company.
I have no doubt Lycoming are buying off the shelf sodium cooled valves
that are used in something else as they do with the valve lifters.
This is not to say the company that supplies the valves to Lycoming
do not increase the cost to cover the required FAA paper work trail.
Come to think of it the company is probably TRW.
Paul Lamar
The AirCraft Rotary Engine NewsLetter. Powered by Linux.
ACRE NL web site.
http://home.earthlink.net/~rotaryeng/ http://www.linux.org