wrote in message
...
Mike Rapoport wrote:

: It doesn't work that way with a turbocharged engine since the ingested
air
: is heated by compression.

I would argue that it still works that way. In addition, however, the
heating
of the intake air reduces the effective mass on the intake charge.
Whether one or the
other dominates or they cancel each other out depends on lots of
factors... in
particular an intercooler.

I'm not being argumentative... just sharing info that I'd never thought of
before. It doesn't make a huge difference, but it does make a difference.
Running
24/24 doesn't *always* make the same power or burn the same fuel.
Altitude and
mixture both have 10-20% adjustment fudge factors in there.... throw in a
turbo with
heating and there's another 10-20% in the mix as well.

-Cory

--

************************************************** ***********************
* Cory Papenfuss *
* Electrical Engineering candidate Ph.D. graduate student *
* Virginia Polytechnic Institute and State University *
************************************************** ***********************


The heating of the intake and the consequent reduction in density is the
reason that I think it will take more MP to produce the same HP at higher
altitudes with a turbocharged engine. At the same MP/RPM a tubocharged
engine is effectively running at a higher density altitude than a normally
aspirated one. The turbocharged engine is also running at a higher density
altitude as altitude increases at the same PM becasue there is more
compression required, therefore more heating. The intake air is heated
*substantially* and its density is reduced substantially. Natually, the
effect is strongest at high manifold pressures and high altitudes. I agree
that reduced pressure at the exhaust helps and an intercooler certainly
helps too.

I don't have a flight manual for a turbocharged airplane here but hopefully
somebody here does.

Mike
MU-2