AoA tube bent too much?

[mfleming]

I'm having a hard time learning the lesson of NOT doing anything critical at the end of the day

Last evening I was trying to figure out how my Garmin Gap 26 heated Pitot/AoA tube tubing was going to be routed around the aileron pushrod. I successfully bent the pitot but may have over bent the AoA tube.

What the consensus? Build on or shorten the AoA tube. The Garmin manual recommends a minimum of 8 inches before any plastic is used due to heat.

Here's som pics:

[KRviator]

Originally Posted by mfleming

I'm having a hard time learning the lesson of NOT doing anything critical at the end of the day

Last evening I was trying to figure out how my Garmin Gap 26 heated Pitot/AoA tube tubing was going to be routed around the aileron pushrod. I successfully bent the pitot but may have over bent the AoA tube.

What the consensus? Build on or shorten the AoA tube. The Garmin manual recommends a minimum of 8 inches before any plastic is used due to heat.

If you can still blow through it a reasonable amount, I wouldn't be too worried about it. There is bugger-all flow through the tubes, so even if you had a restrictor in it in a similar vein to an oil pressure fitting, it would still work - just being slow to respond.

[rvbuilder2002]

These tubes are used to sense an air pressure value.
There is no flow through the tube.
So as long as the tube is not completely blocked and it doesn't look like a crack has started that could fail in the future, it will probably be fine.

[mfleming]

Originally Posted by KRviator

If you can still blow through it a reasonable amount, I wouldn't be too worried about it. There is bugger-all flow through the tubes, so even if you had a restrictor in it in a similar vein to an oil pressure fitting, it would still work - just being slow to respond.

It seems to be fully open...I sure wouldn't want the AoA to be slow to respond though

Originally Posted by rvbuilder2002

These tubes are used to sense an air pressure value.
There is no flow through the tube.
So as long as the tube is not completely blocked and it doesn't look like a crack has started that could fail in the future, it will probably be fine.

Yes, there's no flow through these...I think I was more worried about the tubing starting to flatten out.

I've decided to use the tubing as is.
There are no signs of over stress or cracks and the inside diameter of the tubing is only marginally reduced. Also, the tubing will be well supported and not subject to undue loads.

[bkervaski]

I haven't installed my Pitot yet so no experience in that area but I was wondering what would be wrong with just shortening the tubes past the bend and then just running your AOA/PITOT tube a bit further?

[Greg Arehart]

Worth buying one of the $30 tubing benders to help avoid this if you end up bending any other tubing. should not be an issue unless there is a leak or the tube is completely squashed flat.

[Sam Buchanan]

Originally Posted by mfleming

It seems to be fully open...I sure wouldn't want the AoA to be slow to respond though

Shouldn't have any effect on response. The AOA port on my LRI probe is a hole probably smaller than 1/16" diameter and it responds very quickly to changes in AOA (ram pressure).

[mfleming]

Originally Posted by bkervaski

I haven't installed my Pitot yet so no experience in that area but I was wondering what would be wrong with just shortening the tubes past the bend and then just running your AOA/PITOT tube a bit further?

That's what I would have done if I rejected the bend.

BUT Garmin requires a minimum of 8 inches from the pitot to any plastic. So I would have had to splice in some more aluminum tubing to get the distance.

[mfleming]

Originally Posted by Greg Arehart

Worth buying one of the $30 tubing benders to help avoid this if you end up bending any other tubing. should not be an issue unless there is a leak or the tube is completely squashed flat.

I have one...The Gamin manual says the tubing is designed to be hand bent...so like a robot...I hand bent it...not very smart

[mfleming]

Originally Posted by Sam Buchanan

Shouldn't have any effect on response. The AOA port on my LRI probe is a hole probably smaller than 1/16" diameter and it responds very quickly to changes in AOA (ram pressure).

Yes, I agree. That's why I continued on