On Fri, 02 Jan 2004 05:37:58 GMT, "Mike Rapoport"
wrote:


I think (guess) that they were looking for somewhat better performance than
a turbocharged piston Bonanza across the existiong flight envelope, but not
to extend that envelope too far in either speed or altitude. If they put an
engine into the airplane that would make 300hp at FL310, they would probably
have to completely re-flight-test the airplane.

You seem to have hit the nail on the head, intentionally or
accidentally. A turbo-normalized or turbo-supercharged engine in an
A-36 should have no issues with delivering 75% of rated TO hp well
into the teens.

Again, it has admittedly been several years since I did the research
for a prospective customer (for whom $$ was by no means an issue), but
the power "curve" of the 250 was less than desirable when compared to
a turbo piston-pounder.

Specific fuel consumption was approximately 1/3 higher, with the
additional fuel storage neccessary to retain "acceptable" range
capabilities.

There are many existing aircraft types that have been "re-engined"
with powerplants drastically exceeding the original installations. In
a lot of cases, no "flight-test"-ing is required, nor is it needed.
Engine operating limitations are changed so as not to exceed the
original levels.

I would certainly agree that testing would need to be performed if
increasing the usable hp-thrust rating.

I am a little confused by your post as well. An engine can only make its
thermodynamic horsepower at sea level and ISA, so you are below that at any
flight altitude.

I apologize if I wasn't clear, or it may be a case of
miscommunication. It's likely when looking at "newer" t-prop aircraft
you will notice that the gas generator is likely capable of exceeding
airframe limitations at max thermo-hp.

Hence, at altitude it has no problems producing a very high percentage
of "max take-off" power. I'm sure you know this.

They are few and far between, but there are A-36's flying around with
350 hp turbo-supercharged Lycoming engines. Aside from the differences
in initial rate of climb, I would be willing to bet the the overall
performance numbers would be more than comparable to the turbine
conversion.

The guy I spoke to that had one could only lament the fact that he had
to burn 22-25 gph in cruise...

Regards;

TC

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