I've managed to be ill in bed with a fever during the recent dry
weather and so missed a chance to do the spar bush alignemnt stuff
outdoors, but I have another problem that's bothering me.
I attach 6 fairly small pictures which I hope illustrate what I'm
talking about.
I have fitted the bearings for both ends of the CS05 torque tubes and
was pretty happy with the way it was all going until I put the
cockpit module into the lower fuselage moulding (see picture
DSCN2491.jpg) to do the check of stick movement as advised in the
manual (page 13-10). If I don't sit in the CM, all is fine and
movement of the sticks is constrained only by the cockpit sides and
tunnel. However, when I sit in it, the movement is considerably
reduced; with only about 100mm deflection left or right from centre
at the top of the stick, there's a graunching noise as the corners of
CS07/08 scrape against the fuselage floor.
You'll see in the picture that the outlines of the brown foam inserts
in the lower moulding don't seem to have any real relationship with
the various cutouts and shapes of the CM. I'd have thought that
perhaps they would line up in places. They are not even symmetrical
port & starboard (the seats, on my CM anyway, have slightly different
shapes P & S).
I phoned up the factory when I found this and Roger assured me that
all will be well when the CM & lower moulding are bonded and thus
stiffened. However, as I look at things more closely, I am not much
comforted by that.
The cockpit flange at the bottom of the seat backrest is supported by
only fresh air, in the middle of the green area across the middle of
picture DSCN2496.jpg, and any pressure on the seat pan will bend the
CM down into that depression. That causes CS07/08 to touch the
fuselage floor where the small black marks can be seen on the brown
area at the rear of the green stripe. I checked that the clearance
for CS07/08 is correct (~6mm) as per the manual (picture
DSCN2501.jpg), but the depression in the green stripe is about 4mm
deep (picture DSCN2513.jpg) so if the CM is pushed down ito that
locally the clearance will be badly compromised.
Picture DSCN2515.jpg shows the width of the green depression, with a
ruler placed against the port CS07/08 witness mark. The depression
lies from about 25mm to 100mm on the ruler. Picture DSCN2516.jpg
shows the same ruler positioned on the CM underside against CS07,
demonstrating that the CM flange across the seat-backs falls between
the 25mm mark and the 100mm mark.
I think the engineering solution is to put packing between the CM and
the fuselage where there is no foam layer, so that the Redux will not
need to bridge the full 4mm gap. But what packing? It's got to be at
least as strong as the Redux. Maybe I should go the (expensive) route
of putting in a layer of Redux first with release film to fill the
gap, as I did on the ribs when closing the wings.
Has anyone else found this problem? Or is my CM/fuselage moulding a
mismatched pair?
All input appreciated!
regards
Rowland
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