Hi All, I'm in the process of replacing my bellevilles with rubber donuts. The tail was about 8" low and the cockpit ledge was WAY out of level. When I pulled the belleville assembly, I had about 1/8" play in the stack. I replaced the bellevilles with a new rubber donut kit (saves a total of 5 lbs per airplane, BTW), and I still have about 1/16" play in the new stack. I'm also finding that the Skyport spacer is an ever so slight interference fit (maybe .001" undersize) with the top of the strut.
Interesting to hear about the aluminum spacers for the bellevilles. My stack didn't have any that I could see. Maybe my bellevilles weren't so worn out after all. I guess I'll keep them around if I decide to go back (but that extra .8 gallon of gas could come in handy). Thanks for all the info. Chris McGeary, N3044H --- In [email protected], William R. Bayne <ercog...@...> wrote: > > Hi Don, > > Comments interspersed below: > > On Feb 27, 2009, at 18:33, n2808h wrote: > > > Greetings all, > > > > Ever since I've owned my 415C I've tried to get the tail up to the > > recommended height. I started right after I bought the plane by having > > the A&P at the time do the sleeve or shim upgrade (I can't think of > > the correct description but I got the entire package and paperwork > > from Lee when he was running Skyport)...and I had them replace the > > existing Bellville springs with new rubber donuts. That got me close, > > maybe 1 inch or so low. Now, seven years later, is currently 3" below > > the recommended height from the top of the vert. stab to the ground. > > The "recommended height" is a red herring because of the variation in > nose strut/fork/wheel size-length combinations. It is NOT "one size > fits all". > The plane is set up correctly when the aluminum sill one each side of > the cockpit is LEVEL from side to side and fore-aft. > > > > It has an old style, double fork nose gear (not sure what that means > > but it what the current A&P said). > > The "old style, double fork nose gear" would have the close-fitting fork > fitted to Ercoupes serials 1 through 186. Your airframe should be > Serial > No. 3433, which is much later to have the "early" fork which had a Hayes > 5.00 x 4 two-bearing wheel fitted. > > If you have a 5" nose wheel and tire and a double fork, then you either > have the Univair double fork assembly U415-34310-1A shown on page 21 > of the Parts Catalog, or the Forney-Alon-M10 double fork shown in the > various Parts Catalogs and the Univair catalog. > > The Univair fork should not cause a tail low problem because it uses > taxi spring U415-34104. Because this fork was originally intended for > use > as a "steel gear" conversion that originally had a 4" wheel and tire, > the > taxi spring is shorter to compensate for the greater height of the 5" > wheel > and tire. > > > The A&P measured the entire donut > > stack and compared it to another Coupe he is working on an it is 1/4" > > shorter. > > > This does not make sense. The "height" of the taxi absorber stack > assembly is absolutely fixed when the retaining clip is installed. For > this reason I must "recant" my earlier belief that Bellevilles somehow > raised the tail. > > If rubber donuts are new (not "new-old" stock), it requires some method > of mechanical compression to hold everything so the retaining clip can > be installed (and when pressure is released, there should be no vertical > "looseness". > > The Belleville installation kit includes six aluminum washer spacers, > part number F-33254. These are used "as necessary so that there is > a maximum of 1/16" vertical free movement in the stack (and if it were > my plane, I would add another spacer if I had that 1/16" stack slop). > > > My question is this. Do most of you have Bellville springs or donuts? > > I don't mind putting donuts in periodically but my concern is whether > > even new donuts will get me the correct tail-up attitude that I want. > > The donuts are by far the most common. New donuts with spacers as > described should resolve your problem. > > > Can I find Bellville's out there? Are Bellville's the only real > > solution? > > > Yes, Bellevilles are available; but they are NOT a solution for your > problem as described. > > > > I live in Colorado and fly out of an airport the Eastern Slope of the > > Rocky Mtns. and the wind ALWAYS blows here. I landed last night in a > > quartering x-wind 14knts peak gusts to 21knts. Those conditions may be > > old-hat to a long-time 'Coupe driver, but they had my complete and > > undivided attention. 08H did its thing, touching down in a crab at > > about 60 mph, and I did my thing by relaxing control on the yoke as it > > swung around and started tracking straight. > > That's the right technique. > > > I always add a little forward yoke to firmly plant the nose wheel and > > then > > I'm driving it, but I'm thinking to myself that I've got to get this > > fixed. > > > > Don > > 08H > > If you gradually slow the plane to minimum speed and full back yoke in > the crabbed flare before touchdown, the plane will stay down once down. > > That said, anyone who continues to fly a bird with a genuine "low tail" > problem is accepting increased risk in high crosswind operations and > sooner or later may be called upon to "pay the piper". > > Understand, I'm not a mechanic; but I've done all this (under > supervision, > of course) > > William R. Bayne > .____|-(o)-|____. > (Copyright 2009) >
