In article , Corky Scott
wrote:

On Fri, 25 Jul 2003 15:22:20 GMT, Kevin Horton
wrote:


It is difficult to compare the aviation engine type certification tests
with the automotive durability tests, as the two tests are doing
different things. The automotive test is trying to find problems that
will cause the manufacturer grief in automotive service.

I would say that any manufacturer of aircraft engines would be looking
for the same thing, only in aviation service.

Well, we are comparing tests that the automotive industry does at
their own discretion against tests that the aviation industry is
required to do. The aviation industry does many, many hours of
discretionary testing over and above the FAR 33 minimum standards. For
example, the turbine engine manufacturers that I deal with will use
flight test aircraft to conduct hundreds of hours of airborne testing -
this testing is over and above the FAR 33 requirements, as far as I can
tell (caveat - I am not a powerplants engineer, so I am not intimately
familiar with FAR 33 and the associated Advisory Circulars).

Continuing airworthiness issues also come into play here. The aviation
engine manufacturers are required to inform us about any major problems
they learn about. For automotive engines you may only learn about
problems and fixes through the grapevine (e.g. Ford V-6 coolant leaks
into the oil system).

So, in the end, the only way to figure out whether a given automotive
conversion will work is do fly it and find out. Eventually we'll have
enough service history to know what works, and what doesn't.

Well how many hours should that necessarily be? Bruce can cite two
examples that have reached 2,000 hours and beyond. There are many
models of aircraft engines that must be overhauled long before then.

Just because two examples have done 2,000 hours doesn't mean that you
or I will be able to achieve the same, unless we can gain the benefit
of all the lessons that were learned by the folks who had the success.

As I read on RAH recently, we really need access to some sort of
cookbook that explains exactly which engine and accessory configuration
has been show to have a good service history, and how it must be
installed, operated and maintained to achieve that good service
history. With an aviation engine, we can use the manufacturer's
installation manual + AC 43.13B + Tony Bengelis' (SP?) stuff + the
manufacturer's operating and maintenance instructions.

--
Kevin Horton - RV-8
Ottawa, Canada
http://go.phpwebhosting.com/~khorton/rv8/