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Europa-List: Saggy outriggers

Subject: Europa-List: Saggy outriggers
From: Kingsley Hurst <kingsnjan@westnet.com.au>
Date: Thu, 21 Nov 2013 13:40:14
All,

The following is posted on behalf of Fred Klein who is having a few 
computer problems at the moment.

Cheers
Kingsley


  All Mono Driver / Builders,

  I've always marveled at the precision, geometry, and ingenuity of the 
outrigger retraction / latching mechanism on my monowheel...I recall the 
first time I heard that satisfying "THAAAWHACK" when retracting the flap 
and outrigger as the nylon rod engaged the end of FL3 when the wing was 
resting in its vertical rack. (the pix below shows my stbd outrigger 
encased in Kingsley Hurst's wonderful fairing).

  Alas...when the wing was rotated horizontally and mated to the 
fuselage, the weight of the outrigger was just enough to prevent full 
retraction and the nylon rod w/ the outrigger wheel sagged about 3/4". I 
was disappointed with this, particularly because whatever benefits to be 
derived from Kingsley's fairing depended upon full retraction, or at 
least that is what I thought.

  Upon inspection, I concluded that the sag was due to an accumulation 
of the tolerances for fit of the various components of the retracting 
mechanism, notwithstanding the high precision of their manufacture. 
Ultimately it became clear that the problem could be solved by a slight 
increase in the rotation of the outrigger w/ respect to the retraction 
of the flap.

  See Fig. 17, p. 12, chap. 9M of the build manual.

  See also Fig. 24, Section 6, p. 16, chap. 9M.

  I've accomplished this by putting an eccentric on the leading radius 
of the spacer OR10. I've made NO alterations to the slot in OR5; 
however, I have enlarged the 0.25" hole in the plastic washer adjacent 
in order that the spacer bears fully on the AN960-10L washer. Following 
trial mock-ups in aluminum, a local machinist has made me a new pair of 
OR10 spacers from stainless steel; the new spacers still fit in the 
0.25" slot in OR5...see photo below alongside standard OR10 spacer.

  (The black marking on the side of the new spacer is just marker ink to 
differentiate it from other trial spacers.)

  The results could not be better...the sag is totally eliminated and 
there is no perceptible difference in the flap retraction / deployment 
lever movement or amount of force necessary.

  My machinist has saved the program for his CNC cutter and is willing 
to make up more in batches of 10 or more...contact me off list if you'd 
like a set.

  Fred


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11/18/13


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