Airbrakes

[Peter Balcombe]

Andrew,
I think the Skylark brakes are top & bottom scissor schemp-hirth types as on many gliders. These are normally made up as separate units each fitted in a 4 sided box (having the same depth as the wing) which fits into a multi rib bay width slot prepared in the wing as shown on the plans. These bays will have sub spars as necessary to support the ribs once the slot is cut out.
This method enables you to get the blade arrangement set up and checked for basic operation before it is positioned & glued into the prepared wing slott. If the assembly is positioned centrally (top & bottom) then you can normally plane/sand the outer capped surfaces of the brake blades down to the wing surface profile. You can either profile the blades to the unsheeted surface & fit sheeting over the blades when sheeting the wings (remembering to mark the blade positions so that they can be released afterwards, or fit the brake assemblies after sheeting, making good around the blades and carefully sanded down to profile.
Have a look at some of the various build threads to see what has been done in each case.
I hope this helps.
Peter

[RobbieB]

Andrew,

Download this from the main site: http://www.scalesoaring.co.uk/VINTAGE/H ... rakes.html

It might de-mystify the Schemp Hirth airbrake situation a little.