LS3a Airbrake question

On Apr 28, 5:36*am, JJ Sinclair wrote:
if it is sticking up anywhere, it did NOT pull down
the required 1mm (dime width). Adjust the linkage, probably at the
spoiler box to make the spoiler pull down more.

If, as the OP suggests, if the over center mechanism is not set
correctly the spoiler caps may pull down the correct amount and then
relax as the linkage goes further over center.

I had a discussion with Waibel about the airbrakes on my ASW-28. Mine
go much further over center than the factory specs say they should.
The solution is to shim the pad where the over center bell crank
contacts the spoiler box. To find out how much over center there is
at the current adjustment you can put temporary shims on the pads.
Slowly increase the thickness of the temporary shims until the
airbrakes just stay locked. Then remove the temporary shims, measure
them, subtract the factory spec over center measurement, and fix
appropriate thickness shims in place. I used aluminum shims
sandwiched with double sided tape for the temporary shim stack.

I am not familiar with the LS linkage so the specifics for changing
the over center adjustment may be different. However, all over center
mechanisms must use an over center stop and the position of the stop
controls the amount the mechanism relaxes after passing the over
center point.

You will need to know how much over center is required. Reduce it too
much and the airbrakes will come unlocked in flight.


Andy

Thanks for your answer, unfortunately I do not understand fully you:
"Then close and lock the spoiler. Now look at the closed
cap.............if it is sticking up anywhere, it did NOT pull down
the required 1mm (dime width). "
It would be nice to discuss it with you off-line, I have a drawing
about the airbrake mechanism from LS, I could send it you.

Sorry, I forgot to mention my email:
It would be nice to discuss it with you off-line, I have a drawing
about the airbrake mechanism from LS, I could send it you.

Recommend you take your LS-3 to a mechanic that understands
sailplanes. Probably not a good idea for unskilled hands to be
adjusting the spoiler caps or over-center stops. Copy the responses
you got, it may help with the adjustment process.
Cheers,
JJ

wrote:
Thanks for your answer, unfortunately I do not understand fully you:
"Then close and lock the spoiler. Now look at the closed
cap.............if it is sticking up anywhere, it did NOT pull down
the required 1mm (dime width). "
It would be nice to discuss it with you off-line, I have a drawing
about the airbrake mechanism from LS, I could send it you.