On Jan 31, 3:33*pm, Jim Logajan wrote:
" wrote:

... The Horsepower Myth was create by James Watt in order to sell his
modified Newcommen steam engine to mine owners. To do so he added the
element of TIME to the power equation

...

It makes no sense to claim "time" was added to the "power" equation because
"power" already is energy per unit time. Perhaps you meant to say time was
added to the "energy" equation?

I'm also not sure what the nature is of the "myth" you are complaining
about. You don't actually make it clear - at least it isn't clear to me.
Just so you know what level to respond at, I managed to somehow get a BSc
in physics, so feel free to use technical terms.

I don't get that statement either but the SFC is the more important
part. Those numbers add up, such that 3 gph means 36hp. Which veeduber
reports as indefinitely sustainable, which means I guess set the TBO
at what you want (barring other bad signs).

veeduber did I miss it somewhere, or what is the usual CHT of a 1300
sustaining 40hp on a standard day (or any day, that you might have
measured)? That would give a nice reference point to the max temps
given by pratt & whitney.

Is it fair to say that with a particular engine type, that SFC can be
used to estimate HP? (because that's what the equations are doing
seems to me)

Now check this related stuff out from a supplier's website:

Continuous HP, 3400 RPM 80 (note this is 6.6 gph, no?)
Bore (mm) 92
Stroke (mm) 82
Displacement (cc) 2180
Compression Ratio 8.0:1
Idle RPM 700-900
Cruise RPM 3200 +/- 200
Maximum RPM 4000
CHT @ Cruise 350-375 degrees F
CHT @ Climb (5 min) 420 degrees F
CHT Max 450 degrees F

What's the gph figure?

Hmm. Missing ... as is the amount of time that the engine was run to
reach those CHTs ...

Very slick.