Static line configuration

[Michael Burbidge]

I want to button up the top skin on the rear fuselage. But I wanted to make sure my static line configuration looks good. Here's a picture. Does this look acceptable?



Thanks,
Michael-

[Vlad]

Better then mine for sure. Button up Michael.

[Rupester]

DItto.

[terrye]

Most builders recommend putting the tee at the top of the bulkhead so that the static line from the left port and right port are the same length. Apparently (mine isn't flying yet) this makes a slight difference in the static response during yaw or sideslip. Nitra makes a union Y fitting that has a bolt hole molded into it for convenient attachment to the bulkhead. See this link and scroll down.
http://www.automationdirect.com/adc/...stic)/Union_Y#

[rzbill]

Originally Posted by terrye

Most builders recommend putting the tee at the top of the bulkhead so that the static line from the left port and right port are the same length. Apparently (mine isn't flying yet) this makes a slight difference in the static response during yaw or sideslip. Nitra makes a union Y fitting that has a bolt hole molded into it for convenient attachment to the bulkhead. See this link and scroll down.
http://www.automationdirect.com/adc/...stic)/Union_Y#

I strongly disagree that "Most Builders" recommend this. It is BAD practice to put the tee at the top. It prevents condensation from running out the left vent as Van designed the system to do. A tee at the top WILL trap condensation if it occurs.

In regards to differential static pressures, mmm.. maybe, but it is a very hard case to make that the tee location will make a difference because there is little to no flow and therefore little to no friction loss to cause a differential reading.

[terrye]

Yes, "most builders" was a poor choice of words. I just looked at the Van's static line kit and it shows the routing exactly as the OP's picture shows.

What I remembered was Kevin Horton's comments in this thread, see post 2.

http://www.vansairforce.com/communit...ad.php?t=16292

So a tee on one side or a tee in the center will both work.

[rzbill]

Yes that thread is mostly concerned with static measurement during slips. Kevin is correct regarding the physics of the pressure reading vs tee location. I wonder whether the tee location will actually make a practical difference to the pilot.

One thing to note is the first post. The certified craft places the tee in the center but in order to do that it has a condensate drain in the cabin to allow expulsion of the moisture the designers knew would become trapped.

It is certainly the builders choice on how to do it. Your DAR or FSDO may or may not look or care. Van chose a very good way (simple and effective). I ask that builders that choose to do the tee in the middle also include the drain valve.

[txaviator]

Originally Posted by rzbill

I strongly disagree that "Most Builders" recommend this. It is BAD practice to put the tee at the top. It prevents condensation from running out the left vent as Van designed the system to do. A tee at the top WILL trap condensation if it occurs.

In regards to differential static pressures, mmm.. maybe, but it is a very hard case to make that the tee location will make a difference because there is little to no flow and therefore little to no friction loss to cause a differential reading.

Van's puts the tee at the top of the fuselage, in the high performance RV-12, so I can't see how it's "bad practice"?

[pilot28906]

Is there a drawing that shows the static line layout for the RV7? I have the SafeAir system but wanted to know how Van's suggested it be done.

Thanks,
John