General Aircraft Skyfarer (oz14777)

About this Plan

General Aircraft Skyfarer. Radio control scale model. Wingspan 55 in, for OS 26 four stroke engine.

Quote: "A simple 55 inch span design, an ideal first scale model. General Aircraft Skyfarer, by Philip S Kent.

Stall and spin accidents were the number one killers of pilots in the early days of flying. It was therefore logical for designers to look at ways of overcoming this problem. In the early 1930s a lot of development and research on non-spinning aircraft was carried out by the American Fred Weick and his NACA associates. This led to several patents being taken out by Weick who used some of them in his light aircraft design, the Ercoupe.

When experimenting with earlier prototype designs, Weick and his team tried every combination of controls they could think of to try to eliminate stalls and spins. They found that a number of them worked: elevator and aileron only, aileron and rudder coupled together with elevator, elevator and spoilers, and rudder and elevator if a large amount of dihedral was used. There was a problem on the ground though and all of them were dependant on a steerable tricycle landing gear. It is interesting therefore to find that the Ercoupe was in fact a 3-control machine with ailerons, rudders and an elevator. It did however have the ability to couple the rudders and ailerons and become a 2-control aircraft.

Otto Koppen, the designer of the Skyfarer, used a different configuration to achieve the same end result. He chose a tricycle undercarriage, a high wing layout with side by side seating and eventually a twin fin arrangement without rudders. The 2-control aircraft did what was asked of it but the power was marginal. Due to the war and the need for a more powerful engine only 17 Skyfarers were built.

NC 29030, on which the model is based, is owned by Chris Cagle of Aviation Activities, Hemet, California, USA. Chris has been most helpful in photographing and measuring the aircraft so that an accurate model could be built.

The Model: The model is the second Skyfarer that I have designed and built. The first was slightly bigger, at 70 in span for an OS 40 four stroke, and was built to the BMFA Light Scale Class rules of some years ago. I got an offer for the model that I could not refuse before I had flown it and it was consequently sold. The model did fly and the new owner found it very easy to handle.

At 55 in span the model is ideal for the fine little OS 26 four stroke. The building is quite straightforward and should present few problems to the enthusiast who has got a couple of built up construction models under his belt. I like to get all the pieces for the model cut out first. This means that you will almost have a kit before you start sticking bits together. It is also a good idea to make sure that you have all the strip and sheet that you will need.

Building the tail unit: If you want to see something grow rapidly from your efforts, make a start on the tail unit. The fins and elevators use the very popular sheet core method of construction. Trace the outline or pin prick through onto 1/16 sheet. The fins have 1/16 ribs at each side and are sanded to an aerofoil section when these have been fitted in place. The elevator has 3/16 spars and 1/16 ribs attached to each side of the 1/16 sheet core. Sand the ribs to the section shown on the plan. The tailplane is built in two halves directly over the plan. Pin down the 3/16 square spar and 3/32 square leading edge and then fit the half ribs. Cover with 1/16 sheet balsa and leave to dry. Repeat the operation on the second half. Join the two halves, add the leading edge, and sand to the correct section. Fit the elevator horn and hinges and you have the tail unit made - easy!

The wings: When building wings I always use a plywood rib template. If there are a large number of ribs to cut use at least 1/8 ply. The Skyfarer wing is unusual in that it has flaps and ailerons that take up the full span and no dihedral. This does mean however that the wing is very easy to build. The wing is drawn out in two sections on the plan and it is a good idea to make the spars to the full length before starting.

Cover the plan with the clear backing from Solarfilm or Solartex and start the construction by pinning down the rear 1/2 x 1/4 spar directly over the plan. Next pin down the 3/16 square spars on 1/16 packing pieces again over the plan. I started work on the starboard wing first as this part of the drawing included the centre section. Add the ribs with the exception of the two at the tip, and then fit the false leading edge and top 3/16 square spar..."

Skyfarer from R/C Scale International, July 1999.

Direct submission to Outerzone.

Update 4/9/2023: Replaced this plan with a clearer copy, thanks to Circlip. This version shows complete fuselage layout on sheet #1.

Supplementary file notes

Article pages, thanks to RFJ.
Previous scan version.

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