Building Scale Model Helicopters

Building The Graupner/Heim BO 105
By Jeff Barrington - Mid Devon Heli Club

Part 3 - Scale Details & Finishing
The windows should be test fitted and trimmed as required. The main front screen fitted perfectly but all the others needed trimming. They are all tinted but there is an optional clear set available at around £28, should you wish to fit a scale cockpit set. The engine covers and dummy jet outlets should also be cut out, trimmed and test fitted. When your happy with the fit put them to one side, as they will be fitted after painting.

At this point you need to decide on the colours for the model, there are plenty of full size examples to choose from or you could go your own way. I decided on the Devon Air Ambulance as I had some photos for reference and being almost all red it was a fairly simple paint job. The model was rubbed down using 600 wet 'n' dry used wet. It was then sprayed with 4 coats of Flair enamel, a tip when using spray cans, especially in colder conditions, is to warm them up in hot water before use as this makes the paint flow better and gives a finer spray.

The dummy jet outlets were sprayed with gold paint and while still wet the silver paint was sprayed very lightly. Once this was dry matt black was applied using foam sponge to give the illusion of exhaust carbon.

John Bowden Graphics supplied the lettering in stick on alphabet sheets available in various sizes and colours. The other logos were made by taking digital photos of the full size, scaling down on computer and printing on to self adhesive paper, once stuck on they were coated with clear varnish. The stripes were cut from Solartrim.

Aerials, door handles and the windscreen wiper are from Vario and are fitted by drilling a small hole and fixing with slow cyano. The landing light and search light are Mag torches which have the back section cut off and are connected to nicad packs via an electronic switch. They are a bit bigger than scale size but they can be clearly seen in flight.

The cockpit area was made using a light ply base with balsa for the seats and instrument panel, again not exact scale but loosely based on photos of the full sized. Pete's Pilots supplied the pilot and paramedic. The whole thing can be removed for access by undoing four screws.

I have painted the main blades one black and one white to give the illusion of a lower head speed, which is much more realistic than the true model head speed of 1650 rpm. They were balanced after painting of course.

The model flies well and looks great in the air making it all worth the effort. Maybe I'll build another scale model in the summer.

Specifications :
Graupner/Heim Unistar 60 and BO105 Fuselage kit.
OS 61 RX HGL and Zimmerman muffler.
Graupner/Heim 45 degree tail gearbox.
JR 8231 Servos for CCPM.
Futaba 502 gyro and 9253 tail servo.
TG 66cm mild S main blades.
SAB tail blades.

This page has been contributed by Jeff Barrington
Web Site: Mid Devon Heli Club