Kitfox Aircraft Stick and Rudder Stein Air Grove Aircraft TCW Technologies Dynon Avionics AeroLED MGL Avionics Leading Edge Airfoils Desser EarthX Batteries Garmin G3X Touch
Page 1 of 2 12 LastLast
Results 1 to 10 of 16

Thread: magnetic compass

  1. #1

    Join Date
    Nov 2014
    Location
    Sebastian, FL
    Posts
    38

    Default magnetic compass

    Hi Guys,
    on my series 7 I find the magnetic compass is disturbed by the airframe resulting in the impression that I'm always headed west -- what solutions are out there?
    thanks,
    Karl

  2. #2
    Senior Member 109JB's Avatar
    Join Date
    Mar 2019
    Location
    Morris, IL
    Posts
    484

    Default Re: magnetic compass

    John Brannen
    Morris, IL
    Sonerai IIL (Single Seat)
    Kitfox 3/4 1050 - Rotax 582 (Back Flying and sold)
    Kitfox IV 1050 - Rotax 582 (sold)
    Kitfox IV 1200 Speedster - Rotax 912 UL (project)
    Piper Twin Comanche (Sold)
    Glasair 1 FT (Waiting to start)

  3. #3
    Senior Member Dave S's Avatar
    Join Date
    Oct 2008
    Location
    St Paul, MN
    Posts
    1,833

    Default Re: magnetic compass

    Karl,

    I originally installed a used vertical card compass mounted in the center-top of the cockpit off the carry through tube. Swinging the compass resulted in the best setting to be at least 165 degrees off reality or worse at any direction. Worse than worthless.

    Its the magnetic flux the fuselage has developed. I suspect this is hard or impossible to avoid with electric welding.

    So, got some sage wisdom from John Mc Bean......who suggested I get a SIRS compass which has a far better adjustment mechanism than the previous century's VC compass; and, if it is good enough for Boeing, it could be good enough for a Kitfox.

    Next - with a good compass in hand, I experimented with placement. Turned out, the center of the cockpit over the glareshield is the place that is most infected with magnetic voodoo - at least on our plane. The best place which avoided most of the voodoo was on the left corner of the glareshield and on right corner of the glareshield. I mounted the compass on the top of the glareshield just to the left of the pilot's view out the front window. That position resulted in very minimal adjustments to get the compass right; and, my correction card has correction values of 2 degrees or less all the way around.

    Happy as can be with the SIRS compass.
    Dave S
    Kitfox 7 Trigear (Flying since 2009)
    912ULS Warp Drive

    St Paul, MN

  4. #4
    Senior Member Dave S's Avatar
    Join Date
    Oct 2008
    Location
    St Paul, MN
    Posts
    1,833

    Default Re: magnetic compass

    See entry #5 under "Show us your panel" for my compass placement.
    Dave S
    Kitfox 7 Trigear (Flying since 2009)
    912ULS Warp Drive

    St Paul, MN

  5. #5
    Senior Member 109JB's Avatar
    Join Date
    Mar 2019
    Location
    Morris, IL
    Posts
    484

    Default Re: magnetic compass

    BTW:

    On my Kitfox 4 rebuild I will not even have a wet compass installed. A "magnetic direction indicator" is only required for night or IFR flight, and on top of that the "magnetic direction indicator" doesn't have to be a wet compass. Since my airplane will have a Garmin G5, I bought the GMU11 magnetometer with it and the GMU11 will satisfy the requirements for a magnetic direction indicator. Note that a GPS direction doesn't satisfy the requirements. This was verified by talking to a FSDO maintenance inspector I know.
    John Brannen
    Morris, IL
    Sonerai IIL (Single Seat)
    Kitfox 3/4 1050 - Rotax 582 (Back Flying and sold)
    Kitfox IV 1050 - Rotax 582 (sold)
    Kitfox IV 1200 Speedster - Rotax 912 UL (project)
    Piper Twin Comanche (Sold)
    Glasair 1 FT (Waiting to start)

  6. #6
    Senior Member
    Join Date
    Feb 2020
    Location
    Steilacoom, WA
    Posts
    730

    Default Re: magnetic compass

    91.205 still contains magnetic direction finder for day VFR
    Kitfox 5 (under construction)
    Commercial SE/ME, CFII

  7. #7
    Senior Member
    Join Date
    Jun 2008
    Location
    wales,ny
    Posts
    710

    Default Re: magnetic compass

    In this age of the ubiquitous GPS—handheld, panel-mounted, in your phone, even in your watch—the magnetic compass seems like an anachronism, a relic of a bygone era. But when the lights go out and nothing electrical works, the trusty magnetic compass will still tell you which way you are going Although a compass is not required in an Experimental airplane for day-VFR flight, some sort of “magnetic direction indicator” is required, by way of standard operating limitations, for IFR and night operations, even in an Experimental aircraft. A primary flight display connected to a magnetometer can meet the requirement, but for the highest possible level of reliability, nothing beats the old magnetic compass. The question is, what do you need to do to make one work correctly in your airplane?

    From a Kitplanes article , mine was always worthless in my day VFR Kitfox so the wet compass is a decoration on my desk. Bruce N199CL

  8. #8
    Senior Member 109JB's Avatar
    Join Date
    Mar 2019
    Location
    Morris, IL
    Posts
    484

    Default Re: magnetic compass

    In night or instrument conditions I would much prefer use my watch, phone, or tablet for GPS direction over any compass. Also, many these days are going the EFIS route and many have no round gauges. In this case, if the EFIS goes out you have lost a lot more that is concerning than a compass. I was simply pointing out that if you are comfortable not having a compass, then you don't have to put one in.
    John Brannen
    Morris, IL
    Sonerai IIL (Single Seat)
    Kitfox 3/4 1050 - Rotax 582 (Back Flying and sold)
    Kitfox IV 1050 - Rotax 582 (sold)
    Kitfox IV 1200 Speedster - Rotax 912 UL (project)
    Piper Twin Comanche (Sold)
    Glasair 1 FT (Waiting to start)

  9. #9
    Senior Member 109JB's Avatar
    Join Date
    Mar 2019
    Location
    Morris, IL
    Posts
    484

    Default Re: magnetic compass

    Quote Originally Posted by alexM View Post
    91.205 still contains magnetic direction finder for day VFR
    91.205 is for "Standard Category" airplanes. A Kitfox is not a standard category airplane.

    EDIT: Here is what the Op Lims for my project airplane state:

    "UNLESS EQUIPPED FOR NIGHT AND/OR INSTRUMENT FLIGHT IN ACCORDANCE WITH FAR 91.205, AND UNTIL COMPLETION OF LIMITATION NO. 2 THIS AIRCRAFT WILL BE OPERATED DAY VFR ONLY."

    The operating limitations for an amateur-built airplane determine what is required for flight in this case. Nothing is prescribed in the op lims regarding instrumentation for day VFR, only for night or IFR. For example, a replica Wright Flyer would not need a compass, airspeed indicator, altimeter, etc, and many instruments on such an airplane would just be extra weight and otherwise useless.
    Last edited by 109JB; 12-13-2020 at 11:43 AM.
    John Brannen
    Morris, IL
    Sonerai IIL (Single Seat)
    Kitfox 3/4 1050 - Rotax 582 (Back Flying and sold)
    Kitfox IV 1050 - Rotax 582 (sold)
    Kitfox IV 1200 Speedster - Rotax 912 UL (project)
    Piper Twin Comanche (Sold)
    Glasair 1 FT (Waiting to start)

  10. #10
    Senior Member jiott's Avatar
    Join Date
    Jun 2010
    Location
    Portland, OR
    Posts
    2,960

    Default Re: magnetic compass

    In my SS7 I am using a Falcon vertical card compass, mounted high in the exact center of my panel, just under the glare shield. After tweaking with the built-in adjustments My error in any direction does not exceed 2-3 degrees.

    I am not familiar with it, but I have heard that there is degaussing equipment that will remove much of the residual magnetic effects from a steel tube airframe. If you know a person or shop with this equipment it may be worth a try; can't cost too much.
    Jim Ott
    Portland, OR
    Kitfox SS7 flying
    Rotax 912ULS

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •