Degausser

mrpibb · Post by **mrpibb** » Fri Jul 07, 2006 2:49 pm

This non 170 realated but is aircraft related, I need to find plans or a formula to determine the winding and power supply to make a large degausser to demagnetize a nose landing gear on a B757. The aircraft experienced a lightning strike that magnetized the landing gear so every time the gear retracts it's throwing the standby compass 15-20 deg off.
I located the magnetized parts but the hand held degaussers not strong enough.
I know there are a lot of brainiacs here in the forums, and my knowlage on magnetisim is on the weak side so anyhelp would be great as our engineers and senior management want's to just replace the landing gear to eliminate the problem, I as a hourly technician would like to build a degausser to demagnetize the nose gear than replace it.
Thanks
Vic

Post by **Bruce Fenstermacher** » Fri Jul 07, 2006 6:50 pm

Go getum Vic.

George don't disappoint me here.

tshort · Post by **tshort** » Fri Jul 07, 2006 8:51 pm

There was a recent discussion about degaussing over on the Van's forums - altho not as big (a canopy frame) several had ideas - I'll cut and paste your message over there and see what I get...

Thomas

jims170 · Post by **jims170** » Fri Jul 07, 2006 9:34 pm

When I worked as a Broadcast engineer at a TV station we had a large one used to bulk erase large magnetic tape reels. Basically it is just AC current going through a coil. The constant 60 cycles changes the current direction which will demagnatize the object. You can either slowly increase the distance of the object you are trying to demagnatize or reduce the current slowly the end of the demagnatizing process.

Question: Can you hold a compass next to the strut and determine if it has north and south poles? One end of the strut would draw the needle toward the north and the other end of the strut would draw the needle toward the south. If the strut does not do this, look elsewhere for your trouble.

I will try to follow up on this later; I have to go to work now.
Jim

cessna170bdriver · Post by **cessna170bdriver** » Fri Jul 07, 2006 11:01 pm

Could you use a magnaflux machine to degauss it, or are you trying to do it in place on the airplane?

Miles

kloz · Post by **kloz** » Fri Jul 07, 2006 11:58 pm

Why not talk to a TV repairman. I would think a TV degauss would work.

mrpibb · Post by **mrpibb** » Sat Jul 08, 2006 1:56 am

WE made a degausser this morning, we got about ft of wire and made a 4 ft diameter loop to pass up and down the nose gear while the nose is jacked in the air and used V to power it but its not Strong enough, using a gauss meter several steel components pinned the meter at 20+ before but only got it down 5 units to about 15+.
in the cockpit when the gear retracts the meter shows 6 gauss net to the standby compass. So I wanted to build a stronger degausser but 220 and 440 scare me, would really hate to electrocute someone (unless they had more seniority). I was trying to look for some more educated means to construct one like finding a power versus windings for a more efficient setup. Boeing shot us a figure of 20000 amps turns min needed? any thoughts?

mit · Post by **mit** » Sat Jul 08, 2006 6:50 am

We do mag particle insp. on the rear axle of KC-135's every phase. I don't know if that equipment is big enough for you? Where is your closest tanker base? Ask the NDI shop?

Post by **GAHorn** » Sat Jul 08, 2006 12:58 pm

Sacramento Sky Ranch will rent/loan their degausser. I seem to recall they once wrote an article about how an entire cockpit of a DC-9 can be degaussed.
A current (sorry for the pun) discussion on the subject is:
http://www.sacskyranch.com/degaussi.htm
800-433-3564 Talk to John.

AC current does not degauss very "deeply". You may need to use DC current. A thorough discussion of deguassing equipment, construction, etc. can be found in "Air Force T.O. 33B-1-1 NONDESTRUCTIVE INSPECTION METHODS, Section VII Demagnetization February 1966". While out of print, it might still be available from your nearest GPO or public library.

Post by **Bruce Fenstermacher** » Sun Jul 09, 2006 1:55 am

Boy I was getting worried George. Thought you were going to dissapoint me but you were just making me sweet a little.

A rental source, web discussion, phone number and a contact not to mention the Airforce TO, though out of print.

Nice tip about the AC/DC thing to cap it off.

Sure glad you didn't buy a Cherokee instead of your 170 cause you'd be their Parts/Maintenance Coordiantor, web forum moderator and not ours.

mrpibb · Post by **mrpibb** » Mon Jul 10, 2006 4:57 pm

Well Senior management prevailed, were replacing the 3/4 million $ nose gear

Only good thing is I'm on my days off.

Romeo Tango · Post by **Romeo Tango** » Mon Jul 10, 2006 7:25 pm

Ask if they'll let you have the 'bad' unit as a memento. I'm sure you can resell it for enough to pay for a few annuals and 37 gallons of 100LL.

The International Cessna^® 170 Association

Degausser

Degausser

If management is that clever...