My airspeed doesn't work. I have checked all the hoses and they are connected correctly to the AHRS. Tomorrow I plan on pressure testing the lines. I can blow into the pitot and the IAS goes up to around 75 mph. In flight the IAS is 0. My pitot is mounted exactly as my friends plane, and his works perfectly. So I don't believe that is my problem. Does anyone have any ideas about my problem?
Airspeed
- Thread starter mcnabb
- Start date
jakej
Well-Known Member
How long ago did you buy the pitot ?
I'd confirm, by blowing into the pitot ( with hoses disconnected) which one is the correct pipe. I have seen one that had a pipe reversed in manufacture.
Jake J
I'd confirm, by blowing into the pitot ( with hoses disconnected) which one is the correct pipe. I have seen one that had a pipe reversed in manufacture.
Jake J
Carl_Froehlich
Active Member
- Joined
- Aug 22, 2007
- Messages
- 324
End the guess work. Build a simple manometer. It comes in handy for static leak checks as well. One option attached.
Make sure you cove up the pitot drain hole when doing the check.
Make sure you cove up the pitot drain hole when doing the check.
One thing to make sure of is that you don't have the AOA line from the AOA/Pitot probe connected to the ADAHRS' static port. If that were the case, you'd have "static" pressure that is higher than actual static because the aoa port does carry positive pressure.
Similarly, if you've got the AOA line hooked to the Pitot input on the ADAHRS, you'd see lower airspeed than you should since of the way its port is angled.
Looking at the ADAHRS connnectors, it's AOA, Pitot, and Static from left to right.
Similarly, if you've got the AOA line hooked to the Pitot input on the ADAHRS, you'd see lower airspeed than you should since of the way its port is angled.
Looking at the ADAHRS connnectors, it's AOA, Pitot, and Static from left to right.
Thanks for the comments, all lines were hooked up correctly. We did find a small leak at a 90 degree fitting. The IAS still only shows around 40mph. We are going to check the pressure on the line and AHRS Monday. I will post the results then.
jakej
Well-Known Member
Another simple check is to disconnect the AOA line at the pitot end, then test & see what IAS you're getting.
The better method would be to blow into the pitot tube from the front of it to confirm which one is the actual pipe, blowing into AOA pipe, with the air coming out the front, can appear to be the ASI one when it's not. Blow into each of them & you'll see what I'm getting at
Jake J
The better method would be to blow into the pitot tube from the front of it to confirm which one is the actual pipe, blowing into AOA pipe, with the air coming out the front, can appear to be the ASI one when it's not. Blow into each of them & you'll see what I'm getting at
Jake J
My buddy made a pitot static device to check my AHRS and pitot lines.The AHRS was working properly, we keep unhooking fittings until we found the one that was leaking. A 90 bend was leaking at the pitot.
I'm very fortunate to have a friend who is a retired avoinoics engineer. Be sure to look at the attached photo. The pressure used was between .1- .2 psi. Amazing!
Thanks for the help and comments. My airspeed is working now.
I'm very fortunate to have a friend who is a retired avoinoics engineer. Be sure to look at the attached photo. The pressure used was between .1- .2 psi. Amazing!
Thanks for the help and comments. My airspeed is working now.
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jakej
Well-Known Member
Thank you for posting the end result - it may help others
Jake J
Jake J