Having hacked off my first anti-servo tab, I'm about to tackle the
tailplane rear close-out.
The dimensions given in the manual for the principal pieces seemed
out of proportion to the actual shape of the tailplane, so I did some
measuring.
The rear face of the exposed foam measures about 650mm from the
trough at the tab-tip end to the face that forms the root rib. The
manual calls for 65cm x 10cm (I wish they'd stick consistently to mm,
I find that much easier for some reason) and also says that all
overlaps must be on the fore-and-aft surfaces, with none on the
trailing edge face.
So, to allow the desired 20-30mm overlap, the rear closeout piece
should be 710mm x 100m.
The root rib area does not seem to need the 80cm length called for,
and I would be happy with 770mm here (ie, 30mm shorter). (Yes, I
remembered the edges go right to the TE of the glass, and there's
enough for the LE flange too.)
Could it be that the dimensions given were perhaps for a previous
layup scheme where the overlaps were on the rear face? Then when they
discovered that made things a bit tight for hinging the tab, they
changed the words but forgot to change the sizes. The only evidence
against this deduction is that the tip rib is already pretty nearly
correctly dimensioned for no overlap onto the rear closeout.
Cross-checking the dimensions called out for the trim tab itself a
few pages later shows that I have made no gross errors in any of my
measurements or cutting lines.
I guess the factory are all at Sun'n'Fun and much too busy to watch
the forum at present, but has anyone else noticed this discrepancy,
or would anyone care to comment? Perhaps the volatile nature of BID
dimensions once bias-cut have let people get away with slightly wrong
sizes?
regards
Rowland
| PFA 16532 EAA 168386 Young Eagles Flight Leader 017623
| Europa builder #435 G-ROWI e-mail <rowil@clara.net>
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