Compass Question

[gnflyn]

I am having a strange problem with my Taylorcraft logo compass, it mounts just above the instrument panel. Lately the compass seems to slowly revolve in flight, it goes through 360 degrees and then starts again. Am thinking a magnet or something has come adrift, is this a repairable issue????

[Pearson]

Re: Compass Question

I would check first to see if the fluid level was full. Next I would check to see if the two magnets were still attached to the bottom of the round thing inside where the markings are. In order to do that you are going to have to remove the compass from the aircraft, so you can tilt it back to see the bottom side of the ring. While you have it out, I would set it on a wooden bench and see how long it takes for it to settle down. If it settles down quickly, or doesn't rotate, I would suspect something in your aircraft is generating a field that is causing interference with the compass. Do you have an electrical system? Do you have a radio antennae mounted to the airframe? If so, check the compass with everything shut off. I have heard of the tubes becoming magnatized. It is very rare, so I would look at other possibilities first.

[Marv]

Re: Compass Question

Are you sure you are not flying in circles? LOL Marv

[Mark Julicher]

Re: Compass Question

I can't resist...

You don't need a compass in Florida. If you are seeing blue water that is the Atlantic and you are going E. If you see green water that is the Gulf and you are going W. If you see red dirt that is Georgia and you are going N. If you see fighter planes that is Cuba and you were going S.

Sorry.

I hope you find the mystery compass problem soon.

[Larry Lyons]

Re: Compass Question

I can't resist...

You don't need a compass in Florida. If you are seeing blue water that is the Atlantic and you are going E. If you see green water that is the Gulf and you are going W. If you see red dirt that is Georgia and you are going N. If you see fighter planes that is Cuba and you were going S.

Sorry.

I hope you find the mystery compass problem soon.

Flying east one day right over Datona Beach, kind of hazy, as the beach disappeared behind me so did the horizon disappear in front of me. In no time I was totally IFR just because I could not make out the horizon. By looking straight down you could see the water, that is no way to fly so I turned back but it was an eye opener! Larry

[paulnuss]

Re: Compass Question

I have had magnetized airframes in several of my aircraft over the years, including my BC12D-1 I now own. It is a problem! My best solution so far has been to locate a modern Airpath compass aft and down from the usual windshield mount, on an aluminum bracket I fabricated. That has minimized the interference, though not totally obviated it. The original compass did not have very strong compensating magnets, and of course the mounting was right next to the tube intersection where the magnetic field seemed the strongest. My Pitts airframe was so strongly magnetized that no compass ever could be made to work in it, in either front or rear cockpit. I have read about "degaussing" but I have no practical way to do that, as near as I can tell.

[magman]

Re: Compass Question

Mooney aircraft utilize a similar truss type fuselage as the T's.

4130 STEEL tubing is used in fabrication.

Since they are steel it is susceptible to magnetization.

Some causes are:

1. DC welding

2. Jumper cables

3. Routing Starter or Generator leads directly alongside

steel structure.

Mooney did publish a SB or SL addressing this problem.

It detailed troubleshooting methods & corrective actions.

[Pearson]

Re: Compass Question

Always look for the simplest solution!

[flyguy]

Re: Compass Question

Troubleshooting compass:
Remove compass from aircraft mounting. Can't do that, then ignore the following instructions.

In open area hold compass in front of you vertical as in normal mounting position. Make like a little kid who is playing "I am flying an airplane."

Does compass behave normally when turning? Yes; problem is in aircraft. No; problem is in compass.

Sorry, I couldn't resist.

I'll have to put my suggestion for degaussing a fuselage in the funny stuff section.

It is cloudy here and getting ready to rain. Plane is tucked away in nice dry hangar. Grocery and munchies shopping done. I am going to drink some coffee and eat cookies.
DC

[Forrest Barber]

Re: Compass Question

We degaussed any ship at the factory that had built in magnetism from welding or what ever. Take the compass out of course. Then find an old "growler" used for generator repair , hold it up to the tubes in the front of fuselage, make contact into the "V" turn it on and pull it away from the tube as you shut it off. Do this to tjhe tubes that form a V back of windshield and sometimes the carry throughs too. OR we had to use permanent magnets ; Piper has done that a few times.

[Larry Lyons]

Re: Compass Question

Hmmm, I will have to look around! I have a degauss machine from my old audio technophobe days. I used it on the big tape recorder heads every now and then. Larry
PS: Still have the tape player to. A monster 4head TEAC machine that weighs right at 70lbs.

[flyguy]

Re: Compass Question

Man, I haven't seen a TEAC reel to reel in a long time. Worked on a couple for the guys when I was in the Marshall Islands on the Nike X program around 1964. (TMI?) Strange seeing that name again.
DC
PS, I see they are still around.

[NY86]

Re: Compass Question

I've got a 7130 if anyone wants it...

[Larry Lyons]

Re: Compass Question

I've got a 7130 if anyone wants it...

OK that got me up out of my seat. Mine is a a-7010 I bought used in 1970. Still works and yes I thought about putting it on eBay but too lazy as I may have ship it then.
Larry