Results 1 to 10 of 23

Thread: Compass swing on an RV6

Hybrid View

Previous Post Previous Post   Next Post Next Post
  1. #1

    Compass swing on an RV6

    Hi everyone. Anyone have any tips on swinging a new compass install on an RV6, amateur built? Do I need a compass rose or is there another better way to do it?

    Thanks for any suggestions

    H

  2. #2
    rwanttaja's Avatar
    Join Date
    Jul 2011
    Location
    Seattle
    Posts
    2,945
    Quote Originally Posted by Harold Line View Post
    Hi everyone. Anyone have any tips on swinging a new compass install on an RV6, amateur built? Do I need a compass rose or is there another better way to do it?

    Thanks for any suggestions
    EAA has a Tony Bingelis article online, on that very subject:

    https://www.eaa.org/eaa/aircraft-bui...ng-the-compass

    There's a lot of stuff you're SUPPOSED to do on a compass swing...have the plane propped up at flight attitude, pointing North on a compass rose, crank up the engine, fire up the all the avionics and lights, note the compass reading in all these different conditions. THEN shut the engine down, get out, re-orient the plane to East, and repeat. Repeat for South. Repeat for West. Better repeat for North again. Then do it all the way around at 30-degree intervals to generate your correction card.

    Me? I did what I call the "Hillbilly Swing." I bought a good-quality prismatic hiking compass and taped it to the aft turtledeck, propped up so it sat level with the plane in three-point attitude.
    Name:  swing.jpg
Views: 1209
Size:  46.3 KB

    Rolled the plane outside the hangar, cranked up the full avionics package, and swung the tail around until the hiking compass pointed "North." Noted the compass reading, then turned the plane East (airplane has a full-swivel tailwheel, so I could just spin it). Then South. Then West. Then back to North, re-check, do a bit of computation, adjust the compass, and run through the process again. Then turn the plane to the 30-degree increments, and write down the corrections necessary.

    Having a wood airplane helps. :-)

    But I think you could do similarly with your RV, just make a light wood frame that fits across your canopy rails and supports the compass in the middle, a couple of feet from any bits of metal.

    I've had three A&Ps for Condition inspections since I did that, and none have objected to the process. In the nearly 20 years since I did this, my compass has never led me astray.

    (Mind you, I don't actually USE it. I generally fly IFR (I Follow Roads), or follow the Kilowatt Compass, or pick my heading based on the Volcanic Loran....I live in an area with ~4 volcanos visible on a clear day at ~2,000 feet).

    Ron Wanttaja
    Last edited by rwanttaja; 01-10-2023 at 02:11 AM.

  3. #3
    Airmutt's Avatar
    Join Date
    Jan 2018
    Location
    NW. Atlanta GA
    Posts
    560
    Assuming you have a GPS in your RV, use that as your truth source. Far more accurate. Works well for on the ground and in the air. The GPS won’t be affected by magnetic anomalies like hangars, underground power, EMI, etc. With the proliferation of electronics and software, the mag compass is really becoming an unnecessary antiquity.
    Dave Shaw
    EAA 67180 Lifetime
    Learn to Build, Build to Fly, Fly for Fun

  4. #4

    Join Date
    Nov 2011
    Location
    Hood River, OR
    Posts
    31
    Use caution if you swing your compass using GPS as a reference. GPS may be displaying true not magnetic direction. You should be applying corrections to magnetic not true heading.

  5. #5
    Sam Buchanan's Avatar
    Join Date
    Nov 2011
    Location
    KDCU
    Posts
    567
    Quote Originally Posted by Airmutt View Post
    Assuming you have a GPS in your RV, use that as your truth source. Far more accurate. Works well for on the ground and in the air. The GPS won’t be affected by magnetic anomalies like hangars, underground power, EMI, etc. With the proliferation of electronics and software, the mag compass is really becoming an unnecessary antiquity.
    Works well on the ground but not necessarily in the air. If flying with a crosswind the nose of the aircraft will not be pointed in the same direction as the ground track. This can introduce several degrees of error.
    Sam Buchanan
    The RV Journal RV-6 build log
    Fokker D.VII semi-replica build log

  6. #6
    Airmutt's Avatar
    Join Date
    Jan 2018
    Location
    NW. Atlanta GA
    Posts
    560
    You’re not flying a track, you’re flying a heading and determining the compass correction input.
    Dave Shaw
    EAA 67180 Lifetime
    Learn to Build, Build to Fly, Fly for Fun

  7. #7
    Sam Buchanan's Avatar
    Join Date
    Nov 2011
    Location
    KDCU
    Posts
    567
    Quote Originally Posted by Airmutt View Post
    You’re not flying a track, you’re flying a heading and determining the compass correction input.
    Ok....looks like we have some thread drift (pun intended), the original post was about swinging a compass, I thought that was the topic being discussed.
    Sam Buchanan
    The RV Journal RV-6 build log
    Fokker D.VII semi-replica build log

  8. #8
    Dana's Avatar
    Join Date
    Jul 2011
    Posts
    921
    Quote Originally Posted by rwanttaja View Post
    I bought a good-quality prismatic hiking compass and taped it to the aft turtledeck,
    That looks like a lensatic compass to me...

  9. #9
    rwanttaja's Avatar
    Join Date
    Jul 2011
    Location
    Seattle
    Posts
    2,945
    Quote Originally Posted by Dana View Post
    That looks like a lensatic compass to me...
    I'll bow to your woodland knowledge!Name:  pilot_beer4.gif
Views: 1161
Size:  3.6 KB

    Ron "Been many things, but never a Boy Scout" Wanttaja

Posting Permissions

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