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----- Original Message -----From: Roy StubbsSent: Friday, August 18, 2006 1:56 PMSubject: RE: [COUPERS-TECH] Problems??----[Please read http://ercoupers.com/disclaimer.htm before following any advice in this forum.]----Ed,I think you summed it up quite well from what I have learned over my time as an Ercoupe owner/pilot.Also, I have been told, but have not tried it, that one uses a level on the window sill and adjusts for "level" and that will take into account the landing gear configuration. Has anyone else heard this?Roy
From: Ed Burkhead [mailto:[EMAIL PROTECTED]
Sent: Fri 8/18/2006 7:20 AM
To: 'Harry Conner'; Ctech
Subject: RE: [COUPERS-TECH] Problems??----[Please read http://ercoupers.com/disclaimer.htm before following any advice in this forum.]----
Harry,
WELCOME!
First advice: there are no dumb questions except those not asked.
The factory designed the Ercoupe so it would have a very low angle of attack when on the ground. Its not quite a zero angle of attack, but its so close that theres virtually no lift when the airplane is on the ground when it is level, as designed, from front to rear.
With the original single fork nose gear, that made the tail height 75. But, Forney, the 50s manufacturer, started using the double fork nose gear which is about 1.5 longer. So, ideally, to make the aircraft level on the ground, the tail would need to be 76.5 on those aircraft with the double fork nose gear.
Short answer: if youre going to be working on the main gear, Id improve it with new donuts and/or shims to get to ideal. If youre not working on the main gear right now, keep it in mind and monitor and tweak it sometime.
Long answer:
In practice, if you are close, you get most of the benefits of the landing gear design. At this point, you are two inches low from that ideal tail height. At that point, youd probably be OK.
But, if the tail is low and the angle of attack on the ground is too high, you can get lifting of the up-wind wing in strong crosswind situations. It can not lift high enough to touch the opposite wing but it can give a wild ride and in the worst case one could lose directional control enough to swerve off the runway into objects.
At two inches low, I wouldnt expect any wild ride problems. Itll probably behave OK. But if thats your height now, then as they sag itll get worse.
Suggestion: If youre going to take the main gear apart, Id tweak the tail position to get it up to ideal. First, if the donuts havent been replaced recently, get new ones. If your donuts are pretty fresh (a term I wont define), and your tail is still two inches low, then Id see about getting shims and putting them in some afternoon. It takes a couple of hours, mostly cursing that [EMAIL PROTECTED] retaining spring clip as you put the stack back together. Shims are available from Skyport and I think he includes a sample form 337.
With the tail up to, or very near to, the ideal spot, the Coupes have exceptionally good crosswind landing capability. Ive often been the last plane flying as I practiced crosswind touch and goes. As always, you should approach higher crosswinds slowly, developing your skills and comfort level.
Again, welcome to the Coupe family and this group.
Ed Burkhead
http://edburkhead.com
ed -at- edburkhead???.com (change -at- to @ and remove "???")
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