[RV7Factory]

Happy Easter Everyone!

I've been trying to think of a simple solution that will allow me to secure the fittings that connect the aluminum tubing of my Dynon pitot tube to my SafeAir1 pitot tubing kit. The brass SMC fitting that is used to attach to the plastic tubing of the SafeAir1 kit (using the the provided AN adapter) is a little heavy, and I don't want it shaking or vibrating against anything inside the wing.

I thought I had a great idea... I was going to do away with SafeAir1's provided adapter and instead use a -3 AN bulkhead fitting through one of the ribs, attaching the pitot to one side, and the brass SMC connector to the other. The problem is the brass SMC connector has 27 tpi while the AN bulkhead fitting it 24. So that idea is a no-go.

Anybody have any suggestions on how to secure these? Pics would be great!

 

[fstringham7a]

Brad

Here is a pix of my solution.



I know that this is only half of the solution you need. I will secure the Dynon Al tubing to the Safeaire with the suggested fittings and then secure them at the rib. New problem for me: I am going with the new Dynon heated pitot so that adds a new wrinkle to my solution

Frank @ SGU RV7A "NDY"

 

[bullojm1]

Brad,
Dan C. had a nice easy lightweight solution he documented on his web page using a short length of silicone tubing to transition between the metal and plastic tubing. His log entry is here:http://www.rvproject.com/20031222.html

And a pic is here:

 

[Paul Eastham]

I cut my aluminum tubing down pretty short so that the fittings will reside in the pitot mast. It's a pretty snug fit, the short length of aluminum tubing is pretty strong, and I tie-wrapped the two fittings together to add some more resilience.

This also reduces the amount of slack you'll need to remove the Dynon pitot when you do your pitot/static check. The internal leaks in the pitot mean you will need to bypass it.

Paul

 

[RV7Guy]

Use the Safeair stuff

Hi Brad,

I used the Safeair fittings and secured with a couple of wire tie down fittings. Worked great. Sorry no pictures.

 

[frankh]

Just about to do this myself

The pitot mast fittings are 3/16th and the typical tube is 1/4".

So either finde some 3/16th fuel hose that will stretch over the 1/4" and secure with a hose clamp (like Dan checkoways solution)...Will easily withstand the heat of a heated tube.

Or push 1/3ths" length of the 1/4" nylon tube (supplied for baffles, also available from the local hydraulics shoppe) over the 3/16ths pitot head tubes....Then push the 1/4" fuel hose connector over the nylon hose and pitot lines as above.

No fittings needed apart from short length of hose and two hose clamps...Cheap too!

 

[PaulR]

Here's how I did it

Yesterday.
I finished this up last evening. I need to find a larger Adel clamp for the two lines together, but I believe this will work. I seem to have plenty of clearance from the pushrod, and I believe I can access the connectors through the inspection plate.




Suggestions are always welcome.

 

[az_gila]

tube size

The pitot mast fittings are 3/16th and the typical tube is 1/4".

So either finde some 3/16th fuel hose that will stretch over the 1/4" and secure with a hose clamp (like Dan checkoways solution)...Will easily withstand the heat of a heated tube.

Or push 1/3ths" length of the 1/4" nylon tube (supplied for baffles, also available from the local hydraulics shoppe) over the 3/16ths pitot head tubes....Then push the 1/4" fuel hose connector over the nylon hose and pitot lines as above.

No fittings needed apart from short length of hose and two hose clamps...Cheap too!

Or switch to 3/16 tube all the way to the instruments.....

gil in Tucson

 

[frankh]

Yup...Or

Just use 1/4" nylon tube pushed over the 3/16ths tube....Gives a nice tight fit and you end up with 1/4 tube and fittings at the instrument.

Frank 7a

 

[az_gila]

Tubing...

Just use 1/4" nylon tube pushed over the 3/16ths tube....Gives a nice tight fit and you end up with 1/4 tube and fittings at the instrument.

Frank 7a

Ahhh.. but the nylon tube is not very expandable/compressible and may not make an airtight seal, even with a hose clamp on it.

If you slide it over, then a short length of highly expandable rubber surgical tubing slipped over the metal/nylon joint should give you an airtight seal.

This is an old glider trick used in very sensitive variometer systems to interface different diameter tubing interfaces...

gil in Tucson

 

[frankh]

yup..or

a piece of 1/4" fuel hose.

Anything to avoid spending 10 bucks on the right fittings eh?...

Frank

 

[az_gila]

Correct fittings

a piece of 1/4" fuel hose.

Anything to avoid spending 10 bucks on the right fittings eh?...

Frank

Actually, I prefer the right fittings approach....

Does the 1/4 fuel hose really seal over 3/16 metal tubing???

gil in Tucson

 

[frankh]

No but

it will if yu streatch the nylon over the 3/16th and slide the fuel hose over nylon....Hard to imagine how it would leak...I'm about t do mine sometime this week whn I fir my Dynon heated tube.

If your nervous then a smear of silicone will do the deal but I highly doubt it would be necessary.

Cheapskate Frank 7a

 

[frankh]

another thought

So I started on my heated pitot today and found that you can get 3/16th fuel hose that fits both the pitot mast tube and will stretch over 1/4" no problem.

You can also get 5/32nds vacuum tube hose that gives a bit snugger fit too.

I will finish it up tomorrow.

Cheers

Frank