Dick, It is really not so hard.
The ercoupe service manual spells out the proceedure - step by step. Basically here is how I would go about the process. First, I would check the nose wheel alignment by pulling the aircraft forward in a straignt line....about 10 feet. Now, check the aeliron alignment with the wings. Are they trailing the wings, and equal on both sides? If they are, then I would check the rudder alignment. Are the rudders aligned straight with the stabilizers ? Are the rudders free to travel? There is a potential problem with the rudder belcrank bearing seizing.......and the rudders frozen in a fixed position; or move and lock, etc. See Alon Service Bulletin # 14, which applies to all Ercoupes 415 UP. ( Mine had been "fixed", but when I checked it, the bearing was frozen! - Easy to fix) If the rudders cannot turn, the A/C will fly in a crab. If both the aelirons and rudders align up, and the nose wheel is straight, and the control wheels are in neutral position, the airplane is rigged properly ---probably. If the ailerons are not aligned with the wing, and everything else checks out, then the nose wheel push rod needs adjustment. Center the control wheel, and the aelirons should be faired to the wing. Now adjust the pushrod so that the nose wheel is straight ahead. This may take a few adjustments to get the correct position---check by pulling the aircraft forward about 10 feet in a straight line, and rechecking the aelirons position. When they line up with the wing, all is OK. ( that is , if the control wheels are in 'neutral', and the rudders align properly). Now if all these don't align properly, refer to the manual on how to completely rig the coupe: ie. center the 'mixer', center the control wheel quadrant; adjust the quadrant to mixer push rod; adjust the control wheel chains; the aelirons and rudder; and nose wheel push rod; etc., and start all over. Once rigged properly, you may need to slightly correct a heavy aeliron.....this is where slight bending of the trailing edge of the aeliron comes in...and test fly to insure porper non-skidding flight. Before doing all this, make sure the engine mounts are not damaged, and that the engine is mounted correctly. Using the window ledge as a standard, and a protractor, the engine should be mounted with a 31/2 degree down position , and a 5 degree to the right position ( as seen from the cockpit.). (There was an STC to install a straight ahead engine mount ---claiming increased speed....I think it was a mistake to allow the STC..... as I think it defeats Fred Weick's design and thrust safety designed into the Ercoupe.) If you have one of these engine mounts, the airplane will never fly correctly, with standard rigging. More modern airplanes, twist the wings, and mount the vertical stabilizer at an angle to accomplish what Fredd did with engine mount position. Hope this all makes sense. Get help and advice from your AI/Mechanic on checking the above, especially if you have to go beyond the nose wheel/aeliron check. Properly rigged --if the wings and fuselage and tail feathers are not bent, the coupe will fly straight and level ---ball in the center straight and level and throughout turns, etc. You will see a slight ---maybe 1/4 ball out of center on steep climbs.......but that is better than I can do on a three control airplane.....Ha. Regards, Fly Safe - Have Fun Harry Francis N-93530 Blacksburg, Va.
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