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Bob is right - don't discount the magnetic compass. I remember doing cross countries in a J-3 cub using a magnetic compass. It can be done; you just have to really pay attention. Now, I don't leave home without my Garmin. Roy N70UF > -----Original Message----- > From: Bob Branch [mailto:[EMAIL PROTECTED] > Sent: Thursday, December 29, 2005 10:20 AM > To: [email protected] > Subject: Re: [COUPERS-TECH] Deviation chart - engine on or off? > > ----[Please read http://ercoupers.com/disclaimer.htm before following any > advice in this forum.]---- > > > Don > > While I am firmly of the opinion an aircraft compass is a woefully > inadequate device, especially vfr, the odd thing is ifr it can save you > bacon if you have an electrical failure. I've had the experience during > ifr > training of having to fly an approach under simulated complete electrical > failure and one engine (multi of course). > > Of interest to many might be my experience when I went to swing the new > out > of the box airpath compass in my ercoupe. There was about a 14 degree > error > before I swung and adjusted it. So just setting correctors to zero and > forgetting it is not a good plan. My experience with compasses over the > years in all types of vehicles is that this is not unusual. That is why > the > corrector magnets are in them. Some aircraft, Mooney's most notably, can > be > just aweful to get corrected decently. My avionics shop did not want to > even > try to do a verticle compass card because of the troubles they have had > with > them in aother aircraft in the past. Perhaps someone who has one in an > ercoupe could relate to where they mounted (glare shield, panel, winshield > post) and if they had any issues getting it adjusted. I know the company > who > makes them makes available seperate corrector magnets... man that is a > tough > mounting to get those issues worked out... been there, done that. Anyway, > a > 15 or more degree error can cause you to certainly miss the town or > airport > you are trying to fly over. Everything does look rosey when all the > electronics are working, but stuff happens. Satellites get knocked out by > solar storms, electrical systems fail, and we just plain get lost. When > all > else fails, there is still nothing more reliable than a well swung > compass. > And if it happens, looking at the correction card and seeing corrections > of > under 5 degrees can make your day and your math alot easier. > > Swinging I know sounds like a tough time consuming issue but it really > isn't. It will take you less than 30 minutes to do it right and that > includes really nailing down the correctors to the best you can get them. > Once you have them, and 2 or 3 passes over the rose should get the n-s and > e-w correctors done, then its just drive over and write down the numbers. > When I used to race sailboats it would take a 3 hour evening session in > dead > calm water and wind to do it. We'd align over about a 1/4 mile distance > for > each 10 degrees of the compass. Its much easier in an airplane with a nice > compass rose painted on the airport. > > bob branch > N99891 > > ======================================================================== == > ==== > To leave this forum go to: http://ercoupers.com/lists.htm > Search the archives on http://escribe.com/aviation/coupers-tech/ > > ============================================================================== To leave this forum go to: http://ercoupers.com/lists.htm Search the archives on http://escribe.com/aviation/coupers-tech/
