pitot tubes

[themonarch]

Hi all,
Does the length of the pitot tube have a bearing on the accuracy of the airspeed indicator? I am upgrading the original tube which is a thin wall 4.5" long section of aluminum tubing, 3/16" diameter id., replacing it with a 6" section of 3/8" diameter od with same id. of 3/16". I tapered the tip of the new tube beginning one inch back. Polished it, looks nice and is more stout, but is it going to be too long for accuracy? The hose between it and the AI is 1/8th id. The length of this hose is 8" approximate. The same as original. My AI is digital, MGL Avioncs, Stratomaster Maxi Single. Will I still get a good reading with this slightly longer tube? This is my question. Thank you for your response. MJD.

[phantom]

longer is better, the reason that there is a tube is to get out in clean airflow but a few years ago I hit a boat in a gyro on floats and didn,t notice that the pitot tube was broken off at the last thread outside the nose cone, I flew around and every thing worked fine so I didn't get around to replacing it til I put it back on skis for the winter. I don't like straight tubes on gyros or any aircraft that sits back on it's tail due to rain water running back into it when parked.

Norm

[Mike484]

Originally Posted by phantom

I don't like straight tubes on gyros or any aircraft that sits back on it's tail due to rain water running back into it when parked.

Norm

You should always keep it covered when not flying. I wouldn't be afraid of rain water because I wouldn't leave my gyro out in the rain anyway but I would be afraid of bugs crawling into the tube and building a nest.

[phantom]

in a perfect world a pitot tube is always covered when not flying, in my world over the years I have let it sit outside with no cover and a few times I have flown for a while before I noticed that my asi was reading 0 because the cover was still on, I don't think that I am the only one that have ever had this happen and if I am then I feel that I must be somewhat special.

Norm

[CLS447]

Cool.....you switch from floats to skis ! Alot of people still say you can't do floats on a gyro.

Any pics ?

How do you prerotate ?

Anyway, about the ASI.......what are the general rules for piping them up ?

[ckurz7000]

A pitot-static system should have a moisture trap and drain system apart from having a protective cover.

Longer is better but there is no hard and fast rule that says how long is good enough.

-- Chris.