heated pitot - piper

[miyu1975]

Has anyone installed an o/h'd piper heated pitot...I was thinking of buying one instead of gretz as they are about half the price.. just wondering if it has been done successfully...thoughts?

[Ironflight]

Yup - I've had one on the Val since day one, and had zero problems - I think it looks pretty cool too! Just use it ONLY for pitot - hook up the standard Van's static ports on the fuselage, or you'll have pretty inaccurate results....

Paul

[RVFlyer]

My RV4 has one. I didn't build the plane so I can't speak to any installation problems. Unlike Iron's, mine has the static hooked up as well, with no problems. I can't think of why keeping the static on the Piper blade would automatically cause errors (shape of the bottom of the wing?). Maybe Paul will come back and enlighten us on that one.

[SteinAir]

I don't know why leaving the static on the Piper blade seems to cause errors, but we do an awful lot of Pitot/Static checks and I can tell you with good authority that they are almost always (obviously not all the time, because some people get by) less accurate when installed with the static plumbed to them. Of course you'll never notice an error during a pitot/static check because the box is plumbed relative to the instruments and they will always match. But, that being said in flight my experience has been over the years that they are almost always less accurate (even by a small margin) and do in fact have errors that many times the pilot doesn't even know he has. You won't see any obvious problems, because relative to your plane you won't know you even have any errors to begin with.

The fact is that again, almost always the Van's standard pop rivet ports are the best solution for static ports on these RV's.

My 2 cents as usual!

Cheers,
Stein

[Kevin Horton]

Originally Posted by RVFlyer

I can't think of why keeping the static on the Piper blade would automatically cause errors (shape of the bottom of the wing?).

The wing, by design, creates low pressure above it, and high pressure below it. Thus it is hard to find a location near the wing where the pressure will be the same as the free stream static pressure over the whole speed envelope. Piper pitot-static probes have the static port on the bottom, or near the bottom (it has been years since I looked closely at one). The bottom face is at an angle to slightly change the pressure at the static port. There are several different part number Piper probes, each with a different angle on the bottom, to provide a different correction to the static pressure.

So, if you want to use the static source from a Piper pitot-static probe, you will most likely have static source errors, affecting both the ASI and altimeter. You might not know you have an error, unless you do the flight testing to look for it. You can check for a gross error by setting the altimeter to read the runway elevation when stopped on the runway, then doing a low pass down the runway. Note the altimeter reading - does it make sense considering your height above the runway?

If you find someone that is using the static source from a Piper pitot-static probe, and you are convinced that they have low errors, you could copy their installation. You need to copy the exact location of the probe, the angle it is mounted at, and the exact part number of the probe.

[LifeofReiley]

I installed one on my plane but did not use the static port. I have Van's, it would be interesting to experiment and see if there is a difference in actual performance.