Don,
As I previously stated, the thickness of the "taxi stack", whether it
be rubber donuts and spacers or Belleville springs and spacers should
have NO "slack" or "play" when first installed. I would WANT to use
enough of the appropriate spacers to compress Bellevilles just a tad
rather than assemble them with play.The rubber donuts will normally
have to be compressed a bit to get the clip installed. The part number
of the spacers, if I recall correctly, is not the same. Let's call
these "stack spacers". They DO NOT reduce effective oleo travel and
are required on ALL of our birds.
Then there is (are?) the spacers installed above the "taxi stack" to
raise the tail on those birds with the a 5" nose wheel and tire and the
Forney double-fork or the ERCO single fork support on the 415-E and G
models. I got the impression from an earlier of your posts that your
gear already had these spacers installed too, but you haven't shared
with us how thick these are. These spacers DO reduce effective oleo
action, but you need a lot less help from your oleos in crosswind
takeoffs and landings if the relationship (angle of attack) between the
wings and the runway (when the weight of the plane is fully on all
three gear) is that of a level sill on a level surface when static.
There's an expression...if you can't raise the bridge, lower the river
;<) We may be using (or understanding) some of the same words
differently between us, but this is my "take" so far:
1. You have described no different a "problem" than many have had (and
fully resolved by the methods thus far discussed), so no, you're NOT
"alone" in the basic problem. Once all of the "truth" of your
particular situation emerges, there IS a solution. An example of an
"odd-ball circumstance" as yet undiscussed would be if your 5" nose
tire was an 8-ply retread that is unusually tall. How tall is that
tire?
2. If I had an Ercoupe that can not achieve a level sill with the
standard Skyport spacer package, then I would install a thicker spacer
as necessary to achieve the level sill condition rather than operate
"tail low". That's in the instructions. But you have other choices,
too.
a. You could go back to the 4" nose wheel and tire that the bird came
out of the factory with. There is nothing wrong with the design or
reliability of that configuration, properly maintained; although the
tires and tubes are more expensive. Any difference if a few cents per
operating hour...of absolutely no genuine long-term consequence. In
such case, I WOULD recommend Skyport's M10 steering bolt kit (to
replace the original ball).
b. You might "find" that if some prior owner ;<) were to have
substituted taxi spring U415-34104 in your nose gear that you might not
even need tail raising spacers. It is a part approved for installation
in Ercoupe nose struts with the Univair 5" wheel and tire conversion
shown in Fig. 19 of Univair's ERCOUPE Parts Manual reprint, so it would
be a safe and functional substitution that would increase safety of
operation of the aircraft. It is NOT, however, approved for
installation on Ercoupes without the Univair conversion "kit".
c. You could, as a mechanic, make an "adjustment" to the length of the
standard spring already in your nose strut to accomplish a level sill.
Since your 5" wheel and tire installed is in the TCDS, THAT
installation is legal (if logged or otherwise properly documented). In
approving that change, the FAA obviously did not comprehend that design
flying characteristics were adversely affected.
Since the sill is the sole leveling criteria described in aircraft
data, such adjustment to level a bird with the 5" wheel and tire would
seem to be a "minor modification" to restore the original exemplary
design flying characteristics. It would seem to be the professional
responsibility of a competent and conscientious mechanic to do this,
and of FAA representatives to support such efforts without hesitation
or reservation in any manner possible.
Regards,
William R. Bayne
.____|-(o)-|____.
(Copyright 2010)
--
On May 26, 2010, at 16:59, Donald wrote:
Well, there was a little play, and things I read say that is normal,
you don't have to compress the belleville washers to put in the lock.
They still measured a bit over 4 inches, and still do when the weight
is on them.
I guess the question I am coming up with now, is how thick can/should
you put spacers in. As you put them in, you pull the piston up out of
the hydraulic fluid I think. At the point I am right now, I could add
spacers so quick and easy.
--- In [email protected], iflysmo...@... wrote:
Hey Don: I realize this may be a little late now, but before you put
the
Belleville spring stacks on the airplane did you make certain that
there was
no play or slack in the stack? There should be none, and I have seen
the
stacks wear to the point that they are over 1/2 inch short.
Lynn
In a message dated 5/26/2010 12:51:46 P.M. Eastern Daylight Time,
dongen...@... writes:
I give up. The main tires are at 20, the nose at 15, still get 72-73
inches on tail height. I really wonder how many people have actually
measured or
leveled theirs. Surely I am not alone in this.
