Compass problems
- Thread starter gzlf3p
- Start date
Jonathan Baron
New member
If your compass does not work on all headings, when you factor in documented magnetic deviaton in the earth, or deviation in your compass, then the answer is to overhaul or replace it. Many pilots do tend to forget the magnetic dip lead/lag momentary heading distortions when turning from a heading of north (tends to lead the turn) or south (lags) depending on the rate of the turn...mostly because we've become spoiled by DGs and such.
The formula can get complicated - latitude, degree of bank and such - but generally overshooting a turn from or through a turn to the south by 30 degrees (unless you're honking that baby over), and undershooting by the same amount if you're turing from or past a heading of north, works out pretty well.
East and west courses have fewer distortions...unless you're accelerating or slowing down.
Of course, I may have it all backwards or sideways...I dunno. When first I flew my airplane had nothing so fancy as a DG, but that was a long time ago. Just look it up.
Oh, and as bizarre as this sounds, the law insists you have a compass deviation card attached to this ancient instrument or, technically at least, the aircraft is not legally airworthy. A few years back I swung my compass...oh what a PITA!
Jonathan
The formula can get complicated - latitude, degree of bank and such - but generally overshooting a turn from or through a turn to the south by 30 degrees (unless you're honking that baby over), and undershooting by the same amount if you're turing from or past a heading of north, works out pretty well.
East and west courses have fewer distortions...unless you're accelerating or slowing down.
Of course, I may have it all backwards or sideways...I dunno. When first I flew my airplane had nothing so fancy as a DG, but that was a long time ago. Just look it up.
Oh, and as bizarre as this sounds, the law insists you have a compass deviation card attached to this ancient instrument or, technically at least, the aircraft is not legally airworthy. A few years back I swung my compass...oh what a PITA!
Jonathan
Alain1
New member
About swinging
Nothing to do with your heading direction problem but just because I have time this morning...
2 years ago, took me a few minutes to figure it out, I had to keep the engine running 1200 rpm or above to be able to set the compass. :? It was deviating 20 degrees when idling. All that mass of gears and gizmos turning up front upset the poor little thing. But in general, it went well and it's pretty good. Last year, to renew the card, same thing. But when above 1200 r.p.m. I can navigate. Don't you too find it easier to navigate when the engine is runing? :lol:
Maybe it's a normal practice when swinging a compass but it was my first time!, My AME checked it out after and was happy to sign the card so I guess I was OK.
Now, just for sanity check, sometime I compare it with what my GPS says when I fly around :idea:
A.
Nothing to do with your heading direction problem but just because I have time this morning...
2 years ago, took me a few minutes to figure it out, I had to keep the engine running 1200 rpm or above to be able to set the compass. :? It was deviating 20 degrees when idling. All that mass of gears and gizmos turning up front upset the poor little thing. But in general, it went well and it's pretty good. Last year, to renew the card, same thing. But when above 1200 r.p.m. I can navigate. Don't you too find it easier to navigate when the engine is runing? :lol:
Maybe it's a normal practice when swinging a compass but it was my first time!, My AME checked it out after and was happy to sign the card so I guess I was OK.
Now, just for sanity check, sometime I compare it with what my GPS says when I fly around :idea:
A.
Alain:
Thank you for the help.
If you go to AC43.13-2A Turn to page 12-13 (Paragraph 12-38) then if your well-rested read. I did, then I took the old sweat hart up to Watertown (KRYV) where I could use a compass rose.
With the engine off I "swung the compass" with the engine off and took notes every 30 degrees. I found 0 degrees and 180 right on. Same thing in the air at cruise. East and west about 30 degrees out. Close to the same thing in the air. North east about 55 degrees out. Southwest about 45 Degrees out.
Then I took the compass out of the in wind screen bracket and checked it again. It was allso out but almost exactly 180 degrees out of faze with the in plane error. But only about 10 or 15 degrees.
Got to go to hockey!
Thank you for the help.
If you go to AC43.13-2A Turn to page 12-13 (Paragraph 12-38) then if your well-rested read. I did, then I took the old sweat hart up to Watertown (KRYV) where I could use a compass rose.
With the engine off I "swung the compass" with the engine off and took notes every 30 degrees. I found 0 degrees and 180 right on. Same thing in the air at cruise. East and west about 30 degrees out. Close to the same thing in the air. North east about 55 degrees out. Southwest about 45 Degrees out.
Then I took the compass out of the in wind screen bracket and checked it again. It was allso out but almost exactly 180 degrees out of faze with the in plane error. But only about 10 or 15 degrees.
Got to go to hockey!
Jonathan Baron
New member
I hate to say it but I don't understand what you wrote. Pardon the question, but is English your primary language, GZ? I don't mean that in any snide or sarcastic fashion...I simply don't understand....really.
Jonathan
Jonathan
Somehow or other the metal cage of the Bellanca can become magenetic... If that is the case, then the frame needs to be de-gauzed which is a form or witchcraft performed by people with the right equipment. You should not have 30 degree compass variations. Another cure is to place mu metal around the compass. the more you place, the more the compass will resist the magnetic pull of your frame-also the more you place, the less the compass will be influenced by the magnetic force of the earth. De=gausing seems like the right course. Ask around.
OK OK I guess I misspelled de-Gauss. Anyhow, there is a device that that applies a magnetic field to the metal cage structures and (though it seems to me it should just make things worse) and somehow it neutralizes everything. If it's your crank that is magnetized, degaussing is a bit tougher. Anyhow, in my area (Northern California) I know that the shop at Sac Sky Ranch has the device and will rent it. I met a guy at the last Columbia meet who lives in Livermore and has the device as well. I'm not sure how the metal fusselage parts become magnetized, but I've been told it's related to current flow through the fusselage when used as a ground.
Jonathan Baron
New member
Ah...now all of it is making sense at last. If Peter is right, and I bet he is, no compass would work correctly in your 'Master.
Jerry - degaussing won't hurt a thing...though I'd remove the compass beforehand. BTW, I sent you a photo from Russell Williams' web site showing his -2 flying in formation with your 14-19 at Blakesburg back when Robbie Bach owned it
Sorry, again, for my failure to understand your earlier post. I write for a living which can make me a poor reader at times
Jonathan
Jerry - degaussing won't hurt a thing...though I'd remove the compass beforehand. BTW, I sent you a photo from Russell Williams' web site showing his -2 flying in formation with your 14-19 at Blakesburg back when Robbie Bach owned it
Sorry, again, for my failure to understand your earlier post. I write for a living which can make me a poor reader at times
Jonathan
Jonathan Baron
New member
Sorry, Alain, but I stupidly assumed that everyone on this forum knew of Russell Williams' web site:
http://www.russellw.com/
Jonathan
http://www.russellw.com/
Jonathan
Jonathan Baron
New member
BTW, here's the link to that formation photo I mentioned. It features Russell's -2 in the foreground, and Jerry's 14-19 to the right. This is when Robbie Bach owned Jerry's airplane.
This is but one of a gazillion photos of Cruisemasters, Cruisairs, and all sorts of other aircraft on Russell's site
http://www.russellw.com/photoalbum/
photo_drilldown.asp?ID=3722&qManufacturer=
cBellanca&qModel=cCruisemaster&StartRecord=110
Jonathan
This is but one of a gazillion photos of Cruisemasters, Cruisairs, and all sorts of other aircraft on Russell's site
http://www.russellw.com/photoalbum/
photo_drilldown.asp?ID=3722&qManufacturer=
cBellanca&qModel=cCruisemaster&StartRecord=110
Jonathan
Thanks for the help, you all.
I bought a gizmo, on EBay, called a Hozan Demagnetizer model HC-21. I will try to see if that helps to fix my problem. There is two short falls with this de-gausser.
First: the de-gausser has a button that I need to hold to keep it energized.
Second the de-gausser works on 120VAC and draws of only 2.27 amps. That may not be enough power to scramble all those tiny little dipoles in my steel airframe.
Peterdeon asked about how the frame could have become magnetized. Well I have two theories. First the plane sat 8 years without being moved. If a peace of pipe as aligned with a north to south direction it will become magnetized over time. Eight years is a long time.
Second, the gas welders’ say, "If you TIG weld on a steal air frame it will become magnetized." I could write a whole page about the back and forth of that, but I will save both of us the agony of that.
Someone also mentioned a spelling mistake. I hope it wasn’t my mistake? I cann’t spell shet. Microsoft loves it. I need to buy a new spell checker twice a year I wear out the old ones.
I bought a gizmo, on EBay, called a Hozan Demagnetizer model HC-21. I will try to see if that helps to fix my problem. There is two short falls with this de-gausser.
First: the de-gausser has a button that I need to hold to keep it energized.
Second the de-gausser works on 120VAC and draws of only 2.27 amps. That may not be enough power to scramble all those tiny little dipoles in my steel airframe.
Peterdeon asked about how the frame could have become magnetized. Well I have two theories. First the plane sat 8 years without being moved. If a peace of pipe as aligned with a north to south direction it will become magnetized over time. Eight years is a long time.
Second, the gas welders’ say, "If you TIG weld on a steal air frame it will become magnetized." I could write a whole page about the back and forth of that, but I will save both of us the agony of that.
Someone also mentioned a spelling mistake. I hope it wasn’t my mistake? I cann’t spell shet. Microsoft loves it. I need to buy a new spell checker twice a year I wear out the old ones.
Gud two no u cant spel eether. I gut a spelll czech butt forgett to uze it. When I wrote degauze and then you wrote "degauze-that's the word I was looking for", I thought you were chiding me for my poor rendition of degauss. Glad to hear you were actually duped into thinking that was the right word
alabamaflyboy
New member
As an electrical and computer engineer, I would suggest that you pull the radios out of the panel before doing the degauss. The high powered degausser used on aircraft can induce some pretty significant currents in the antenna and power wiring.
The older, tube type radios were nearly impervious to this, but the transistors and ICs used in the front ends of modern radios are much more sensitive to this.
Dave York
The older, tube type radios were nearly impervious to this, but the transistors and ICs used in the front ends of modern radios are much more sensitive to this.
Dave York
alabamaflyboy
New member
Unfortunately, the one local, long-time mechanic that I knew had an airplane size degausser, retired a couple of years ago and sold off all his equipment. I don't know where the degausser went.
However, a Google search found an article by Sacramento Sky Ranch which goes into aircraft magnetism and its affect on the compass. They apparently have a degausser that you can rent.
http://www.sacskyranch.com/degauss.htm
Several other hits on degaussing aircraft on Google as well.
Dave
However, a Google search found an article by Sacramento Sky Ranch which goes into aircraft magnetism and its affect on the compass. They apparently have a degausser that you can rent.
http://www.sacskyranch.com/degauss.htm
Several other hits on degaussing aircraft on Google as well.
Dave
I don't think that a piece of steel that is just sitting there will become magnetized by the earth's magnetic field unless it is heated. I think archeologists figured out where the true north pole was thousand of years ago by measuring the magnetic alignment of ferrous rocks that were in the firepits of ancient peoples. That they remained pointing to the pole that existed thousands of years ago and haven't changed in thousands of years would indicate that alignment does not occur at normal ambient temperatures.
Peter S.
Well maybe you can answer that question for yourself. The softer the metal the faster it will magnetize. Thin wall steel conduit or EMT is softer and cheaper than 4130 tubing. Hang the stick of pipe, EMT, by a peace of string so it can’t be bump by anything and can swing 360 degrees with out touching anything. The test for magnetism will need to be with filings grinding or dust that contains iron or iron allow steel. Because the EMT is so small and thin and soft very light tack will probably work.
If we need to know how long this will take we need to record time and date and any other data we can think of.
Well maybe you can answer that question for yourself. The softer the metal the faster it will magnetize. Thin wall steel conduit or EMT is softer and cheaper than 4130 tubing. Hang the stick of pipe, EMT, by a peace of string so it can’t be bump by anything and can swing 360 degrees with out touching anything. The test for magnetism will need to be with filings grinding or dust that contains iron or iron allow steel. Because the EMT is so small and thin and soft very light tack will probably work.
If we need to know how long this will take we need to record time and date and any other data we can think of.