CA-27 Sabre of Indonesian Airforec display team
|Steve Houghton||04/06/2020 23:26:51|
580 forum posts
The wings are now sheeted and joined. Foolishly I sheeted the left panel before joining them together. I feared a poor join coming up, but thanks to the fabulous G&M wing jig I was able to pin and weight the panels into the jig absolutely flush together whilst the epoxy set, without being able to clamp the two R1s together:
Straighten up the Ply Right!
Having completed the remaining wing sheeting, I trimmed the wing seat in the fuselage to see how well the leading edge fitted against F4 before fixing the 5mm ply facing. It was a poor fit, and rather than sanding away at the wing I glued a shim of 1/16" balsa behind the ply. I could then dry fit this and sand away at the balsa shim to level it up against F4. When satisfied, I finally glued the ply into place. The shim is just visible here, needing about 1/16" on one side and virtually nothing on the other. This is the bottom of the wing:
I bought 3/8" thick TE stock but found it to be slightly undersize for my wing. I laminated a layer of 1/32" balsa to the underside of the TE, where it wouldn't show. I then sanded the top of the TE to fit, rather than risk thinning the lamination to nothing and leaving a thin glued edge that would probably lift in places:
What, no torque rods?
The torque rods will need to be flush with the lower surface of the wing to cope with the bottom hinged flaps. I thought it best to fit the root TE first, and then cut slots underneath for the full length torque rod tubes afterwards. That way I was more likely to get the TE correctly aligned with the wing profile, having the full depth of TE to glue on. Here's the top view:
The slots have not yet been cut, until I finish the wing seating area.
(is it June already?!!)
Edited By Steve Houghton on 04/06/2020 23:27:34
|Steve Houghton||24/06/2020 23:30:10|
580 forum posts
Ah, The Torque Rods!
Nothing very exciting tonight. Just trying to convince myself that I am progressing. The flap torque rod slots were gouged out on the bottom of the wing using the traditional sharpened brass tube, plus a round file:
The ends of the root TE were reinforced with 1/32" ply for ding-resistance, and to support the torque rods:
The torque rods had full length plastic tube bearings which were buried just below the surface, allowing a finishing filler of 1/32" balsa to be inserted to cover the slots, after the application of a smear of vaseline to the sensitive rotating areas:
Chiselled ends to the rods, to minimise the risk of bursting out of the flaps:
Ball links on the rods, and kwiklinks to be used on the servo end, although not yet trimmed to length and fitted. I noted Phil's comment about possible trim changes from the horns rotating, but mine are far too stiff - would need brute force to twist them round.
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