Refrigerator magnet

[DesertNomad]

I bought a digital thermometer to use in the airplane for inside ambient temperature. After opening it, I discovered it has a fairly strong magnet about 1cm in diameter so it will stick to a refrigerator. It will pick up a paperclip from a desk at a height of about 1".

Is this safe to have in the plane with regard to the compass (or anything else)?

The package said noting about a magnet.

I don't plan to stick it to the panel, but maybe somewhere on the back seat. It looked like it has a clip for the side pocket but it doesn't. Cheap Chinese thing.

 

[mscard88]

Probably keep you from lifting off the runway. Pretty powerful magnet, probably a lot of metal buried under the runway.

 

[trenton]

Magnetic fields drops off roughly proportional to the cube of the distance. So, if it has an effect at 1", keep it at least 2" - 4" away and you're probably fine.

Source: https://www.physicsforums.com/threa...ield-strength-decreases-with-distance.754213/

 

[DesertNomad]

Magnetic fields drops off roughly proportional to the cube of the distance. So, if it has an effect at 1", keep it at least 2" - 4" away and you're probably fine.

Source: https://www.physicsforums.com/threa...ield-strength-decreases-with-distance.754213/

Thanks for that!

 

[NordicDave]

Compasses are very delicate and sensitive instruments. How far away is the magnetic field that makes it point North?

 

[DesertNomad]

I would guess it's about 4-5 feet to the back seats. The compass is obviously my biggest concern.

How far away is the magnetic field that drives it? We'll magnetic north is thousands of miles away in Canada.

 

[Zeldman]

I bought a digital thermometer to use in the airplane for inside ambient temperature. After opening it, I discovered it has a fairly strong magnet about 1cm in diameter so it will stick to a refrigerator. It will pick up a paperclip from a desk at a height of about 1".

Can you get a pair of pliers and just remove the magnet.??

Just thinking..... if you put the magnet on the compass you will hold heading like never before...

 

[arnoha]

I would guess it's about 4-5 feet to the back seats. The compass is obviously my biggest concern.

How far away is the magnetic field that drives it? We'll magnetic north is thousands of miles away in Canada.

Don't think it applies to your plane, but one thing I learned is that magnetometers are often placed in the tail section. That's where they placed mine for my G5 HSI. Basically, there may be more than one magnetic compass so make sure you know your airplane.

 

[Tarheelpilot]

The magnetic field that your airplane senses completely surrounds the airplane... doesn’t it?

 

[MD11Pilot]

Proper placement makes it easy to swing your compass

 

[bkspero]

How about checking the compass reading on an open ramp with the magnet well away from the plane, and then positioning the magnet as you planned and see if the compass reading changed. Maybe do that for several different headings to cover the whole range of potential readings.

 

[Skip Miller]

Maybe do that for several different headings to cover the whole range of potential readings.

Not "maybe" The magnet's interference will change significantly from heading to heading.

Years ago, when soda cans were made of steel (and men were men... no, that is the wrong story) we were on a boat and weathered in Champlin's on Block Island, out of boredom we decided to measure and graph the compass deviation caused by a beer can. (Empty of course! and you all know how to empty a beer can...) Proximity to the compass was a significant variable, but also the can's orientation about all axes were significant, too.

Of course we experimented with many more than one can, just to be sure...

-Skip