up through the engine mounts. And the similar acting forces when one
wing tries to pass the other in yawing conditions or in turbulence. If
you think of the forward and aft wing attach bulkheads (the 4 wing
attach points) as a square parallel to the ground - these would be the
forces trying to push it out of square with one side forward or aft of
the other. Yes the attached wings stabilize the 'square' left to right
but not forward and aft. However the stock setup with doublers around
the eyebrow windows appears up to the task. Heavy engines and floats
probably aggravate the situation somewhat though.
A somewhat similar situation exists on the cage when the aircraft lands
on one wheel and tries to twist the airframe under the wings. The term
used for that is 'racking' or 'wracking'? where the forces try to push
one side of the cage higher. In that example, the corner gussets on the
cage largely resist those forces. But any excessive 'racking' forces
coming up through the rear landing gear and especially the rear float
attachment points would tend to distort the skin and fuselage corner rounds.
Ken
On 6/12/2011 6:09 AM, schaumr@dcsol.com wrote:
Marc,
comes together after installation of the wings. Think about it: once the veryFrom my study of the plans, the strength of the upper cabin really only
rigid wings (and their spars) are connected to the front and back carry-
throughs (in the cabin), and the wing struts are attached, the whole unit is
really 'locked' into place laterally and longitudinally. The rest of the aircraft
simply hangs off this structure.
This is why the already flimsy roof skin can accept so many large windows to
begin with. Thicker roof skins will only add unneccessary weight, not
strength. (That said, if you add the full complement of windows, a lot of that
extra weight will end up being cut out in the end!)
There's a bit of rigidity/strength that comes from the overhead channel, but
that is mostly there to keep the shape of the roof and to support the loads
from the flap mechanism (cable).
My 2 cents. Curious if others agree/disagree.
Rob
Rebel 786
On 6/11/2011 5:25 AM, Marc van Hulzen wrote to Marc van Hulzen:
-> Hello all,
->
-> I have to replace my rooftap plate after all.
-> The problem with the protection plastic can't be solved without serious
-> damage on the plate. It seems the plastic had to much UV-radiation in all
-> these years.
->
-> Does anybody know if it is usefull to make this topplate thicker then
original?
-> Original the topplate is 0.020". A 0.025"or even a 0.032" plate does make
the
-> top stiffer ecspecially when placing windows. (or do the windows make the
-> topplate stiffer?).
->
-> Any thoughts?
->
-> Kind regards,
->
-> Marc van Hulzen
-> PH-REB
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