Last month we discussed Greg Whitcombe’s micro infra red controlled SE-5A and Bristol Scout models. This time we will look at a much larger model.

Bruce Keegan wanted a larger, lightweight model which he could fly slowly and which had a scale appearance. He has chosen an Auster designed by Mike Roach. This appeared as a free plan in the April 2007 issue of Aviation Modeller International. Mike described it as a “lightweight, slowfly, “sort of scale” profile R/C model”.It’s certainly all of those things!

Bruce Keegan and his Auster

The model has a wingspan of 27½ inches and an overall length of 19 inches.  With a wing chord of 4⅜ inches, the wing area is 118 square inches, and quite large for such a light model.

The area of the horizontal tail is 23 square inches and the area of the tail fin 11 square inches.

The model weighs in at 1.85oz (52.5gr). This gives a wing loading of 2.25 ounces/square foot.

Front right view showing motor/gearbox installation and ESC mounted on fuselage stiffener

The profile fuselage is built in typical no-cal style and has a balsa stiffener on one side to keep it straight. Both sides of the fuselage are covered with blue japanese tissue.

Front left view showing motor/gearbox, battery and rudder servo installation

The flying surfaces are made up from balsa framing. The wing uses sliced ribs and has a single bamboo spar. It relies on the leading and trailing edges and the wing struts for alignment. Only the upper surface is covered with white Japanese tissue. Slight washout is installed at the wingtips.

The tail surfaces are built up from balsa and covered on both sides with blue tissue. The control surfaces are hinged with clear tape.

Close up of motor/gearbox installation

The power unit is a Bob Selman 4.2:1 motor/gearbox with a GWS B2C (N20) motor, driving a Bob Selman 120 mm blue propeller.