pitot tube

crashley · #1 09-11-2009, 12:43 AM

I was wondering how the pitot tube is connected on the rv12

Geico266 · #2 09-11-2009, 06:09 AM

It starts at the tip of the spinner and connects to the back of the Dynon. The tube in the spinner is stationary and the spinner rotates around the tube. There is a ceramic bearing surface in the nose of the spinner minimize wear. The Rotax 912 has a hollow shaft through the gear box. It is located in the spinner rather than the wing to minimize complexity when removing the wings.

Hope this helps.

LIMA HOTEL · #3 09-11-2009, 07:22 AM

Van's design of this pitot system must be pretty good because in the Pilot Operating Handbook the airspeed calibration table has all the calibrated airspeeds identical to indicated airspeeds from 45 to 150 knots except; 55 cal is 54 ind., 60 cal. is 58 ind., 70 cal. is 69 ind., 80 cal. is 78 ind., 85 cal. is 84 ind., & 90 cal. is 89 ind. So the few anomalies are within 1 or 2 knots.
Larry H.

Geico266 · #4 12-13-2009, 08:07 PM

After 30 hours I thought VAF might be interested to see what wear looks like on the pitot tube. Not much at all, just a little buffing.

Vagabond 11 · #5 12-13-2009, 08:32 PM

Did you use any lube? A little should go a long way.

rvbuilder2002 · #6 12-13-2009, 11:33 PM

Quote:

Originally Posted by Vagabond 11

Did you use any lube? A little should go a long way.

Lube would not be a good idea and should not be necessary (which is the reason it is not specified in the maint. manual). The pitot tube is hard anodized to protect it from wear, and the bushing insert in the spinner is made from a special material that is impregnated with Teflon. A wear test was done for very significant amount of time and found there to me a negligible amount.

If you add some type of lube it will attract dust and grit...the wear will likely be greatly accelerated.

Geico266 · #7 12-14-2009, 05:18 AM

Quote:

Originally Posted by Vagabond 11

Did you use any lube? A little should go a long way.

Quote:

Originally Posted by rvbuilder2002

Lube would not be a good idea and should not be necessary (which is the reason it is not specified in the maint. manual). The pitot tube is hard anodized to protect it from wear, and the bushing insert in the spinner is made from a special material that is impregnated with Teflon. A wear test was done for very significant amount of time and found there to me a negligible amount.

If you add some type of lube it will attract dust and grit...the wear will likely be greatly accelerated.

I kept it dry per the maintainance manual. Like Scott said, I would think any lube would attract dirt and cause undo wear. The reason I posted the picture is this seems to be one of those areas when the airport "experts" come over to look at the RV-12 and tell me this will wear out in a few months. Part of the building process is to align the pitot tube so there is very little to no side pressure on the bushing. The ""unsusual" pitot system system seems to be working work very well.

ArlingtonRV · #8 12-14-2009, 12:11 PM

Quote:

Originally Posted by Geico266

I kept it dry per the maintainance manual. Like Scott said, I would think any lube would attract dirt and cause undo wear. The reason I posted the picture is this seems to be one of those areas when the airport "experts" come over to look at the RV-12 and tell me this will wear out in a few months. Part of the building process is to align the pitot tube so there is very little to no side pressure on the bushing. The ""unsusual" pitot system system seems to be working work very well.

The Maintenance Manual that I have, and that is posted on Van's web site does indeed specify a lubricant for the Pitot Tube Bearing. Pages 10-2 and 10-3 spell out the process. From page 1-10 we learn that when they say "Spray Lubricant" the mean either LPS-2 or Tri-Flow.

rvbuilder2002 · #9 12-14-2009, 12:43 PM

Quote:

Originally Posted by ArlingtonRV

The Maintenance Manual that I have, and that is posted on Van's web site does indeed specify a lubricant for the Pitot Tube Bearing. Pages 10-2 and 10-3 spell out the process. From page 1-10 we learn that when they say "Spray Lubricant" the mean either LPS-2 or Tri-Flow.

Person who wrote maint. manual did not verify...it will be changed.

Do not put spray lubricant on it.

Vagabond 11 · #10 12-14-2009, 02:14 PM

There is a dry teflon lube that's used in sail boat sail tracks. If we see it's needed should work.