For smart pilots

[stalion]

Hi Guys,
I know you may find my question boring and totally uninteresting but I'm still taking exams so if one of you can help here's the question:
You're making a 180°per minute right turn in the North Hemisphere with a 270° initial heading, what will you read on your direct reading compass after 30 seconds?
360°, a little less than 360° or a little more and especially could somebody explain why?
Thank you.
Have fun and safe fly.

[LGL737]

Hi !!!!

It would read a little less than 360, because its a clockwise turn which will make the DRC underread. Have you learnt the pencil pushing technique? Well let me explain it. take your pencil put it on the table, and put your finger on the middle. If your turn is in the northern hemisphere you push the top part of the pencil to see which way it goes, in this case you are turning right, so push the top part to the right, the pencil turns clockwise
clockwise = underread
anti-clockwise = overread.

hope this helps, if not I'll see if I can make it more clear.

PS. of course if your turn was in the southern hemsiphere you would have to push the lower part.

[babble]

Yes, it will undershoot going through north.

The reason is because the compass needle (and the cylindrical card attached to it) is pendulous, i.e. it is suspended from a pivot above its center of gravity.

If you make a big model of the compass with the needle suspended from above it's c of g, then put it a banked attitude to represent the turn and work out how the force of the earth's magnetic field acts on the needle, you may be able to see why it happens!??

[stalion]

Thank you very much.
The pencil pushing technique is very useful, I won't forget it.

Thanks anew.

Stalion

[girlpilot1978]

HI, STALION. I AM CURRENTLY TAKING EXAMS ALSO. I WANT TO DISCUSS SOME OF THE QUESTIONS. MAYBE WE COULD HELP EACH OTHER. MY EMAIL IS: [email protected]

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[MightyGem]

Girl pilot, you don't have to SHOUT. We are not DEAF.