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BERGFALKE IV CABRIO 1:4.7 SCALE**
Posted: 05 Jun 2021, 21:32
by chris williams
This has proved itself to be a very practically-sized model & a smooth performer. As far as I know, there are no IV's in this particular configuration, although there seems to be a variety of Bergfalke 3's thus modified. The unusual scale is due to the 1/4 scale version being scaled down to a size that suits existing stock material dimensions. The last minute decision to hide a motor in the fuselage has proved well-founded, as last weeks inaugural slope flights demonstrated in the light conditions...
Construction starts on the jig: note that the longerons are cut longitudinally at the front to ease the curvatures...
Re: BERGFALKE IV CABRIO 1:4.7 SCALE
Posted: 06 Jun 2021, 11:48
by chris williams
Once all the longerons are in place, the tail mount can be added, and then a template made up for the top sheeting...
Re: BERGFALKE IV CABRIO 1:4.7 SCALE
Posted: 07 Jun 2021, 10:53
by chris williams
Once the front planking & the top deck are in place, the fuselage can be removed from the jig. Note that there is a slight compound curve at the front of the top decking, hence all the masking tape. An alternative would be to separate the panel at F8...
Re: BERGFALKE IV CABRIO 1:4.7 SCALE
Posted: 08 Jun 2021, 11:56
by chris williams
To allow for the tapering thickness, the tailplane is built inverted on the board, than sheeted on top. Then it's inverted once again, with jigging supports spot-cyano'ed to the top sheeting, placed back on the board, and the bottom sheeting added...
Re: BERGFALKE IV CABRIO 1:4.7 SCALE
Posted: 09 Jun 2021, 10:57
by chris williams
The making of the 'cab'...
Re: BERGFALKE IV CABRIO 1:4.7 SCALE
Posted: 10 Jun 2021, 10:17
by chris williams
With some 5mm sq balsa added to increase the glueing area, the ply side panels are added, followed by the top panels...
Re: BERGFALKE IV CABRIO 1:4.7 SCALE
Posted: 11 Jun 2021, 11:04
by chris williams
Now, the ply sheeting can be finalised at the front...
Re: BERGFALKE IV CABRIO 1:4.7 SCALE
Posted: 12 Jun 2021, 11:08
by chris williams
Now the wheel mount can be finalised...
Re: BERGFALKE IV CABRIO 1:4.7 SCALE
Posted: 13 Jun 2021, 10:13
by chris williams
Now for the elevator: the first job is to hinge up the false LE to the tailplane and sand it flush. It can then be removed, and the elevator built over the plan. Then the final LE is added and rounded off...
Re: BERGFALKE IV CABRIO 1:4.7 SCALE
Posted: 14 Jun 2021, 11:03
by chris williams
Details of the elevator actuating pushrod arrangement...Now, construction of the fin/rudder starts.