question
>I could not find Neville's posting in the archives on using a light
>bulb to locate the distance
Andrew - I'm not sure who originally offered the idea, but here's the
one that worked very easily for me - I certainly don't claim to be
the originator.
Once you've made your hole in the spar, place a very bright light in
front of the wing leading edge (not too close, don't cook the wing!).
You should be able to look forward through the spar hole and note
that the light is shining through the leading edge skin. You may have
to arrange things so that the light is not shining directly in your
eyes above the wing skin while you're trying to squint through the
hole. Now ask your beautiful assistant to hold up an opaque sheet
(metal, wood, thick card) close to the LE. You should be able to see
the edge of the shadow cast by the opaque sheet. Now ask the
assistant (before she gets gets fed up & goes away again) to slide
the sheet inboard or outboard on the wing LE until the edge of its
shadow (as seen by you looking forwards through the spar hole) is in
the desired position relative to the edge of the rib nose. Next she
should use her marker pen to put a nice dot on the LE at the very
edge of her opaque sheet. That's got the position fixed in one plane
- nw use the template to fix the hole in the up/down direction.
It is possible to do a similar process single-handed - but as all the
best maths books say, this is left as an exercise for the student.
regards
Rowland
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