Gull (oz3004)

About this Plan

Gull (Gull Flying Boat, Gyford Gull). Rubber twin flying boat.

Uses complex gearing and a flexible drive to get power to the twin props. Span 52.5in, length 36.75in, weight 15.75oz, area 2 sq ft. Wing section RAF32 at 4.5deg.

Update 18/8/2022: Added article, thanks to Pit.

Quote: "Flying Boat, by AKE Gyford. This particularly handsome scale type flying boat is capable of making consistently good flights. ROW.

The photographs onthese pages show its unique and graceful lines. The one bottom left very clearly demonstrates the Jig method of construction compar-able with that of full size aircraft.

Built in slots are employed in the main wings and the method of construction will be quite simple to follow from the plan.

Drive: A flexible drive is provided from the rubber motors which are located in the hull. The drive as shown on the plan was developed after considerable experiment with a system of scratules. The idea briefly was as follows.

Four motors were located in the hull and cranked together approximately under the CG. Further cranks to the airscrews were carried through the front portion of the wings. A great deal of trouble was experienced with sticking at TCD, however, and it was finally decided to use gears and flexible drives. Each flexible drive is 12 inches in length. They are attached to the airscrew shafts and gear box drive stubs by tapered copper and solder, Whipping is prevented by two steel bearings and five sets of 3/64 fly plates drilled to take the flexible shaft at the appropriate angles.

The mechanism may be a little stiff when new but with careful running in this will soon disappear. All soldered joints should be very truly made, especially in the case of the copper tubes as considerable strain is taken by these joints.

Power: The motors are arranged as follows. Four of 8 strands 1/4 flat 20 in long on lower set of hooks and two of 6 strands 1/4 flat 18 in long on top set of hooks. Safe turns 560. Weight of rubber 3.75 oz.

Airscrews: 11 in Dia. Pitch 14-3/4 in. Two airscrews rotating in opposite directions. Each airscrew has a free wheel and clutch and may be removed from the shaft.

The hull is balsa covered and has a detachable hatch for easy access to the gear box.

The 'Gull' will fully justify, both in flying capabilities and general good looks, use of material and the time spent on its construction. It is stable in flight and has a very flat glide."

Supplementary file notes

Article.

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