Directional Gyro

cessna1502978

cessna1502978

Pre-Flight
Joined
Feb 11, 2019
Messages
35
Display Name
Display name:
Butler2978
Hi All i am having trouble getting my DG working it is a vacuum gauge. it has never worked seance i purchased the plan. I removed and bench tested 30psi air and the dg works fine. I know it is a problem with the lines but was hoping someone had a diagram of the vacuum the plane is a 1967 150G. Any help would be much appreciated.
 
30 psi???? By definition, vacuum levels can be no more than 14.7 psi (29.92" Hg), and the correct vacuum level for gyro instruments os 4.5-6.5" (2.2-3.2 psi). Applying 30 psi (are you putting it to the filter side?) would almost certainly damage or destroy the instrument... though if the gyro wheel is gunked up it certainly might get it going...
 
My AP told me to put 30 psi on the air side i assume that is correct. The vacuum pulls air threw the air filter to air inlet on 1 side and vac line goes on the other. i do have 5 HG at the gauge it is just that the last owner must of had someone reroute lines or something. We all know how some planes have been molested threw the years.
 
cessna1502978 said:
Hi All i am having trouble getting my DG working it is a vacuum gauge. it has never worked seance i purchased the plan. I removed and bench tested 30psi air and the dg works fine. I know it is a problem with the lines but was hoping someone had a diagram of the vacuum the plane is a 1967 150G. Any help would be much appreciated.
Click to expand...

How is your Attitude gyro?
 
Is there a vacuum regulator? Check that.
Are there filters on the DG instruments (easy check for that is to just temporarily remove the filter).
A spare vacuum gauge with a piece of tubing is a handy thing for checking the various tubing involved. A visual inspection is perhaps the best... look for kinks and cuts, especially where it goes thorugh any unprotected holes in things.

I agree, 30 PSI air is way too much. You were lucky. Five inches of Hg is only 2.5 psi.
 
Last edited:
Thanks for the replies all instruments are working except the DG. I will get to the bottom of it my plane is 1.5 hrs away need to move closer.
 
You must log in or register to reply here.
Back
Top