Vivian Meazza wrote:
> The "takeoff" values. Are these the power absorbed by the propeller
> at propeller rpm, or the engine output at engine rpm, super- or
> un-supercharged?

Un-supercharged.  And the equations are solved such that both power
values are the same.  Basically, don't sweat this one; it affects
performance only at the very start of the takeoff roll.  Leave it out
until you get things working, and then start fiddling with it to get
the initial RPM right.

> Finally, I've had some difficulty understanding the concept of using
> absolute pressure for the Boost Control Valve (BCV). In the real
> world a BCV comprises [...] and is thus corrected for altitude.

Actually, everything I've read indicates that wastegate designs are
calibrated to absolute pressure, not relative pressure (which makes
sense, obviously, because what you are trying to regulate is the force
on the engine parts, not the overpressure in the manifold which is a
non-critical structural part).

Measuring absolute pressure is mechanically more difficult but not
impossible.  It doesn't have to be as simple as a single spring valve.

> I suppose that we should update the documentation to reflect these
> misinterpretations.

Roger.  See if what's there now makes more sense.


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