Sig Kadet - Twin Otter winter project

[Michael]

I have acquired a Sig Kadet Mark II model airplane balsa kit. It is a build-up balsa model intended as a trainer, to be powered with an glow (small internal combustion) engine.

I will try my best to finish this as an electric twin-motor model, resembling a deHavilland Twin Otter airplane.

[Michael]

The first hour or so was spent examining the instructions, examining the plans, and separating the parts needed to build the wing. The wing ribs needed a lot of x-acto-knife cutting to get them loose from the die-cut balsa sheets.

[GuyOReilly]

Great project!

[octagon]

Looking forward to seeing your progress Michael. Interesting conversion for sure.

[Michael]

Most lower wing sheeting and lower cap strips pinned down.

Lots of measuring, cutting, fitting, fine-sanding and gluing.

[Michael]

Front and rear spars glued down (measured and fitted several times before gluing), and ribs sanded carefully.

I cut out holes/areas at the front of all ribs that go out to about 6" from the fuselage sides for wires from the motors/ESCs.

The 6" distance is to ensure propeller clearance to the sides of the fuselage. I am sure, based on experience, that I will not need 6" clearance; most likely I will use 9 inch or 10 inch propellers, requiring just over 4½ or just over 5" clearance.

I am not cutting holes for servo extension wires for aileron servos, as I will use a single servo in the mid-wing to control the ailerons. That's what this (older) kit shows on the plans, and it has worked well on other models for me in the past.

[Michael]

I will scratch build nacelles and fit them to the wing before I finish the wing.

[Michael]

The ribs, spars, wing-tips, and webbing are glued into the wing, and everything has been sanded smooth and to shape.

Other than the cut-outs in the ribs for wires, everything has been built exactly as per the instructions.

Before continuing with the wing, I will start making the nacelles.

[Michael]

Nacelles construction underway.

There's a right and a left, to suit the dihedral (wing shallow-v-shape angle).

[Michael]

Nacelles sheeted on the bottoms, and hatches made to help with access to wiring, ESCs, etc.

Wings have placement guides for the nacelles, and holes for wiring.

The nacelles are formed enough; now I'll finish the wing.

[Michael]

Change of plans. (Like the pun?)

I'm not finishing the wings yet.

I read the instructions and looked at the plans, and I see that the wing is to be held onto the fuselage with elastics. I'm not doing that.

I'll build the fuselage first, and then I'll figure out a way to attach the wing to the fuselage without elastics. In order to do that, I can't glue on the upper wing sheeting yet.

[Michael]

Fuselage construction started; so far as per instructions and plans.

Modifications will include a battery hatch, re-designed fuselage upper-front and nose, wing attachments, and float attachment points.

[Michael]

Fuselage is completed enough to start planning and building the modifications.

[Michael]

This drawing (lower image) is of a Sig Kadet, but it's close enough in shape to a Kadet Mark II.

The red marks indicate the outline I'll construct so the plane resembles a Twin Otter.

[sihinch]

Very clever Michael