Michael wrote:
: On Aug 23, 9:24 pm, (Frank Ch. Eigler) wrote:
: It may be interesting that the vulnerable time between the spark and
: TDC is also to some extent under one's control, with the blue knob.

: Good point, and you are of course correct. This takes us into a whole
: 'nother discussion - not can you run oversquare safely (because of
: course you can, and virtually every flat-four, six, and eight out
: there does) but how much oversquare you can run and under what
: circumstances. This is precisely the factor that limits how much
: oversquare you can run in most circumstances.

: I left that part of it out mainly because I've never heard anyone
: advocating making high density altitude takeoffs at reduced RPM, and
: the post was already longer than most people will read.

: Michael

...but it does bring up an interesting point. One that I have yet to see adequately explained anywhere. I've seen a
few engine operating curves that limit max manifold pressure as a function of RPM, there are many that don't. My fixed-pitch
Cherokee doesn't have the option, but I'd be interested to know any source that explains it adequately.

-Cory

--

************************************************** ***********************
* Cory Papenfuss, Ph.D., PPSEL-IA *
* Electrical Engineering *
* Virginia Polytechnic Institute and State University *
************************************************** ***********************