Puffin (oz16311)

About this Plan

Puffin. Free flight sport model. Wingspan 24 in, for electric power with direct drive motor, or CO2.

Quote: "Lightweight electric free flight design. Puffin, by Colin Read.

Built light, Puffin makes an ideal calm weather or indoor flier, using low power - long motor run. Puffin is an updated version of an earlier (1960) model. It can be built in a few hours.

The prototype model used a 60p hobby motor of 3.5 volt powered by the flight cells from a KPO1 motor. The choice of motors is varied; I have even used one from an electric toy aeroplane purchased new for £1.00. Taking it to pieces I found a nice small 3.5 volt motor with an extended shaft, just right for an 'Electric Star' propeller. It is ready wired, just waiting to be used.

CONSTRUCTION: An all sheet fuselage takes care of any heavy handling and at the same time forms a nice box structure for the flight cells and charging socket, plus a miniature slide switch if required. Cut all formers, fuselage sides and wing mounting from a light flexible grade of balsa, taking note of the cut-outs in formers F2 and F3, make these to suit your required electrics.

Form the undercarriage from 18swg wire and firmly fix to former F2. Araldite two-part adhesive is ideal for this. At the same time bend, from 20 swg wire, the tail skid and in a similar manner firmly fix to former F8.

Assemble the fuselage ensuring all formers are upright and square; use a plastic clothes peg to hold the rear of the fuselage together while the glue is setting. Cover the top and bottom of the fuselage using cross grain 1/16 sheet. Plank the top with 1/4 in wide strips of 1/16 sheet or if you have some nice 'bendy' balsa, cover in two pieces, one to the cockpit and one from the cockpit to the rear. Sand smooth before adding wing mountings, a good strong joint here is required.

After installing the motor and electrics, build up the cowling from soft 1/4 in sheet and sand to shape. Finally add the 1/16 sheet tailplane mounting and all 1/16 dowels. The cockpit fairing is best added after covering as it makes for a much neater finish.

WING AND TAILPLANE: Build the wing panel in one piece and, after final sanding, cut through at the dihedral joints. Use the dihedral diagrams as a guide in completing the wing, adding the 1/16 sheet gussets for added strength. The soft balsa wing tips can be sanded smooth after fixing.

Construction of the tailplane is very simple, build flat and keep it light, also the fins should be of light balsa.

ASSEMBLY AND COVERING: For a nice looking model, a smooth airframe is a must before covering. The original and indeed almost all of my models built since 1949 have used orange tissue by various manufacturers. Today I use Esaki lightweight Japanese tissue - using the clear dope/thinners method of covering. You simply give one coat of dope to all surfaces and edges, sanding smooth when dry. Then apply the tissue pieces using thinners, when dry, water spray - a garden hand sprayer is ideal for this. Finally give 2 coats of 60/40 dope/thinners clear shrinking dope.

Add all fairings and tissue trim plus any other decoration required. Finally add a thin clear plastic windscreen, pilot's seat and dashboard, even a pilot.

FLYING: Calm weather or indoors are better for the first flights. A KPO1 will have more power; but it is great fun using the cheapo motors.

Puffin glides well and a name and address label is a must, you can never be too careful. Sports free flight as we used to know it enabled many flights to be made in one day, but with larger models and long engine runs. Today these small span models are taking their place."

Puffin from Model Flyer, August 2000.

Direct submission to Outerzone.

Supplementary file notes

Article pages, thanks to RFJ.

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