Scratch building 1/4 scale Bell 206B, 206L and 407 fuselages

[Rotor George]

Last June I started scratch building three 1/4 scale fiberglass R/C helicopter fuselages. A Bell 206B Jet Ranger, a Bell 206L Longranger and a Bell 407. I wanted to make these for myself with the idea of having highly detailed parts complete with rivets right out of the molds.

It all started with a cardboard structure cut and hot glued together.

[Rotor George]

Once the structure was complete it was time to fill all the voids with foam then sand and shape the foam. The tail booms were spun on a lath to insure a prefect tapered shape.

[Rotor George]

After the shaping and filling of the plug was complete it was time to fiberglass it. Here we see the initial layer of 6oz glass cloth being applied to the various plugs.

[Rotor George]

Filling the glass cloth pattern is the next step. A thickened resin mixture is squeegeed out, once cured the surface is sanded smooth.

[Rotor George]

After alot of sanding, high build primer is sprayed and more sanding to achieve a smooth surface, then detailing can begin.

[Rotor George]

The window masking is the first step in the detailing process. All the window areas and "cut-out" areas are masked off then high build primer is applied leaving a recessed area after the tape is removed.

[Rotor George]

Rivets are the next step before the final finish coat goes on.

[Rotor George]

Final top coat is applied to give the plugs a nice glossy finish in preparation for mold making.

[Rotor George]

Here are a few detail items which will be applied to the finished parts. Items include scale vent grills, functional door hinges, cowling fasteners, landing gear saddles, the 407 intakes, and the list goes on and on.




Functioning door hinges



Fasteners, with screw heads at different angles.




The 407 vent intakes, different sizes for each side.

[Rotor George]

The making of the molds starts with the parting boards. The out line of each parts is traced out then cut out with a jig saw. The parts are then placed into the parting boards dividing each part down the center line.

[Hoverup]

Still following your thread. Thanks for tutoring all of us wannabee's out here.

[Rotor George]

Mold lay-up begins with the application of a mold release called PVA. A layer of surface coat is brushed on then several layers of fiberglass matt is applied to build up the thickness of the mold.

[Rotor George]

The parting board is removed and the process is started all over again for side two.

You'll notice in some pictures the gel coat is orange and in some it is black that's because the orange is polyester based and the black in epoxy. I've since switched to epoxy which produces a much nicer mold all-be-it more expensive.

[Rotor George]

After the second side cured holes were drilled and bolts inserted then the excess trimmed off and the edges ground smooth.

The fun part was next, breaking it open and removing the plug revealing the finished mold!

[Rotor George]

I'm currently at the stage of making the first few parts. I've been testing different layer and resin combs to achieve a light but strong part.




Nice "dry" part.

[Rotor George]

Here's an example of what the final parts will look like, pre primed right out of the mold!















Whew, that's it for now.

Until next time.
George

[Borneoben]

Great write up thanks very much

I am looking forward to seeing more

Ben

[Bostonewbie]

I must say ... YOU have an amazing talent. true artistic skill. I am a big fan of the Bell helicopters.. and you certainly have done a great justice. What mechanics are recomended for these Helis?

[Rotor George]

Thanks guys.

The mechanics are being custom designed specifically for these fuselages, but not by me. The motor (both turbine and electric) will be mounted in the scale location keeping the cabin completely open for a full scale interior. A couple of very talented guys have stepped forward since I started this project to help with the mechanics and interior.

George

[Skiddz]

Awesome George! Simply Awesome!