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Robert Anglin

Well Known Member
We have decided that the old Van's pitot-static is going away. In favor of a Garmin pitot, Safeair mast and the P-51 static ports. When removing the old Van's pitot tube it came to us to use the old hole for the temp. probe that comes with the G-3X set-up. Can someone be kind to me as I don't have one in hand at this time and tell me what the boss size is where the probe go's through the skin? We may have to make a shim, but this looks like a good spot to us. Thanks. Yours as always. R.E.A. III # 80888
 
Thanks.

Thanks, I know what to do now and can make a Washer to fit the hole that is there now, I think 5/8" and reduce it down to 5/16". Yours R.E.A. III #80888
 
I removed the Vans traditional pitot tube. I then installed the Garmin OAT probe in the old pitot location with no additional shim. I simply use the included crushable sealing orange washer.

I then installed the safeair mask and the Garmin heated tube one bay outside of the last inspection plate.
 
Sorry.

David Paule said:
What are P-51 static ports?

Dave
Click to expand...

Thanks, "Hump." I will used the old hole as this seams to be a good place away from the cabin and I have electrical conduit running through the wing just above that sight anyway.

The P-51-FM static ports are out of the Wicks catalog. This is there part number. They are very nice flush mount ports to the ".032" skin at that site on the tail boom. Those are in as of yesterday and look as good as any that I have seen on a "Heavy" on the ramp. My thought was If I was going to change out the stock pitot-static system that Van's had supplied, that I would install some very nice ports at the same time. Van sends out those pop-rivets that you "RTV" the tube to the shop-head side. I have not felt comfortable with those from day one, but they do work just fine. Yours as always. R.E.A. III #80888
 
I would really recommend against changing the static ports. Mess with the Pitot all day long, but leave the static system alone. I have read too many stories on this site of "better" static ports that end up causing all kinds of problems.

If you are looking to improve the hose connection to the ports. Order a couple tank drain bosses from Van's, bond them over the ports on the inside and you have a nice 1/8" NPT connection.
FP14042012A0004H.jpg


Standard Vans Pop-rivet ports on the outside.
 
Sure.

WingsOnWheels said:
I would really recommend against changing the static ports. Mess with the Pitot all day long, but leave the static system alone. I have read too many stories on this site of "better" static ports that end up causing all kinds of problems.

If you are looking to improve the hose connection to the ports. Order a couple tank drain bosses from Van's, bond them over the ports on the inside and you have a nice 1/8" NPT connection.
FP14042012A0004H.jpg


Standard Vans Pop-rivet ports on the outside.
Click to expand...

I have heard it both ways too. The P-51 ports are a little better fit and are pre-drilled with a thinner flange on them. If I find they don't do me right, I will just drill the center to the size of the old pop rivet and bond one in to match the old Van's set-up. But, yes it was the "RTV" and vibration with no pipe thread that sent me off to change them out.. Thanks good idea. Yours as always. R.E.A.III #80888
 
Robert Anglin said:
I have heard it both ways too. The P-51 ports are a little better fit and are pre-drilled with a thinner flange on them. If I find they don't do me right, I will just drill the center to the size of the old pop rivet and bond one in to match the old Van's set-up. But, yes it was the "RTV" and vibration with no pipe thread that sent me off to change them out.. Thanks good idea. Yours as always. R.E.A.III #80888
Click to expand...

Hi Robert, I've been down this path myself and helped a few others..the pop rivet is by far the most accurate and trouble free solution. If you insist on going aftermarket - in my experience the Cleveland ones are accurate for an RV7.

If you install flush ports I almost guarantee you will have a meaningful static position error. IMO, It's just not worth the trouble - especially if you want to fly IFR. The position error can easily be 100' of altitude at RV approach speeds and more at cruise speeds. Not to mention meaningful IAS errors.

FWIW, I originally had another brand flush mount 5yrs ago before they changed the design. I also thought that drilling them and fitting the vans rivet into them would solve the problem. It solved the accuracy problem but introduced a static oscillation.

As an aside...
Vans should put a big bold warning at the front of the build instructions. "Build the static system to plans"
I'm amazed at how many people try to change it. ( I did :eek: ) I've since wasted years of my life getting my static position error down to an acceptable level :eek:

Cheers

Richard
 
Robert Anglin said:
We have decided that the old Van's pitot-static is going away. In favor of a Garmin pitot, Safeair mast and the P-51 static ports. When removing the old Van's pitot tube it came to us to use the old hole for the temp. probe that comes with the G-3X set-up. Can someone be kind to me as I don't have one in hand at this time and tell me what the boss size is where the probe go's through the skin? We may have to make a shim, but this looks like a good spot to us. Thanks. Yours as always. R.E.A. III # 80888
Click to expand...

Dont be surprised if the probe reads several degrees higher that actual in this location.
 
Robert, I too bought the SafeAir static kit for the threaded internal connection. After studying the shape and all the issues with static errors, I modified my approach. I took the SafeAir ports, and machined the port off so it was flat. Then used preseal to bond to the inside of the fuse skin. For the outside the standard Vans rivet was used to mechanically hold the assembly together. I presealed the rivet as well to ensure a leak free assembly.

The picture shows a smooth surface but i machine three adhesive grooves in them before installation so the bond was better.

Just another way to have your rivet and threads too.

Also, Cleaveland (Boone,IA) has some ports with threaded connections with the outside shaped like the rivet head as an alternative to SafeAir design.

IMG_0681.JPG
 
I bought the Avery Tool static port which protrudes far enough past the skin to extend beyond the laminar flow and gives an accurate read. If I understand correctly, static ports flush with the skin will result in pitot error because they are in laminar flow which some have compensated for by adding a washer or dab of proseal to trip up the local laminar flow. The static port from Avery extends out far enough so this is not required.
 
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