wrote in message
...
On Mon, 3 Oct 2005 15:32:04 -0400, "John Doe"
wrote:

Ok, another turbo question:

Can someone please explain to me the performance gain by going above 30"
MP
(say, during takeoff) on a turbo'd engine.

How much better performance are you getting from the engine at say 35"MP
on
takeoff vs a non-turbo'd engine that's going to max out around 29"?

Is it worth the strain put on the engine? I understand the turbo being
able
to maintain power at high altitudes, but I haven't heard it explained to
me
why I would need such a high power setting on takeoff/climb (assuming sea
level field).

I'm not sure exactly what you are asking for. If you are taking off @
sea level on a standard day the performance difference between a
turbo-supercharged engine rated @ 300 HP and a normally aspirated
engine rated @ 300 HP is ZERO.

During cruise flight, the performance difference between both engines
at 65% or 75% power is ZERO.

The "better performance" is derived by being able to develop rated TO
power on the turbo-supercharged engine above sea level on a
non-standard day. It also allows you to use cruise power settings at
higher altitudes than a normally-aspirated engine.

As one responder indicated, if your engine is rated @ 300 HP/36"
MAP/2700 RPM, reducing either the MAP or the RPM is reducing the HP
developed.

TC

The previous responder answered my question. You actually have to be at 36"
to get 300HP out of the engine. I wasn't sure how that worked, but the way
he explained it makes sense.

Seems like the turbo-normalized system is a better system.

Either way, it's been good learning....thanks