EAA has a Tony Bingelis article online, on that very subject:Originally Posted by Harold Line
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.
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
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