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Re: More temperatures from N6Q

>reliable as the micro monitor's.  Obviously, the
>oil cooler's oil exhaust temperature should be
>between what is coming to and from the engine.

Not necessarily. In the "engine in" port you see not only what comes from
the cooler but also what seeps through the differential valve. Even with
the washers in place, this valve does not remain closed. It will adjust the
flow rate through the cooler so that it takes 20 psi (with the washers, 14
without) to push it through. (Think of that valve as a Zener diode.) That
is why I don't think the cooler is a good place to measure the oil

>At 110 kt my airspeed reads 5 kts slow but
>1kt fast at 130 kts.  Also, today there was
>a lot of wind, so my error estimates may be poor.
>Regardless, I think I have found another
>complicated problem.  Any other experience
>out there?

You are simply seeing the difference between indicated airspeed and
calibrated airspeed.

I have a heated pitot tube with integrated static port. My air speed
indicator is the RMI µEncoder, which can be switched to show true airspeed.
I have done a whole series of calibrating flights and here are my results:

TAS  100  110  120  130  140  150  160
CAS  112  119  126  136  148  158  167

I have yet to see what the difference is at lower speeds. I expect the
difference to stay around 10 kt as I see 53 kt true as the slowest
sustainable speed. This difference at low speeds is to be expected as the
ram geometry is not ideal at high angles of attack.


Simon Aegerter, Winterthur, Switzerland