Junior 60 vintage model aircraft

This example of the Junior 60 has been flying for nearly 14 years. The machine is holding up very well after considerable use. The only slight problem is a warp developing in the wing, however a bit of heat applied to the covering and some twisting straighten it out for flying.

The 19 year old OS20 four stroke engine.
A truely fine piece of miniature engineering.

The famous vintage Junior 60 has been around for many years now, originally designed as a free flight model it makes an excellent radio control conversion with rudder, elevator, throttle control.

This example was built around 1990 from plans. It's a quick and easy build of totally conventional balsa/ply construction. Some modifications were employed, chiefly a one piece wing instead of the plug in halfs of the original. This one is covered in solartex which has proven ideal for the model.

Power is supplied by an old OS20 four stroke engine. This power plant provides ample power for this model aircraft and has always proven a near faultless runner while using meagre amounts of fuel. The aircraft can cruise around at half throttle for over 20 minutes on it's 4oz slec square tank and still have fuel left after landing.

Covering is Solartex, this adds much toughness and rigidity to the open construction of the aircraft.

Close loop control system operating the rudder using laystraight wire. Elevator is operated with a pushrod.

Aerobatics with this model are obviously limited by the design. It will inside loop very well and can be made to perform stall turns and tight ww1 biplane style 'turn on a sixpense' turns etc, it's good fun throwing the model about like this at low level.

The aircraft handles windy weather surprisingly well. With such a low flying speed you can point the Junior 60 into wind pull a little elevator and enjoy the site of an aircraft going backwards!(relative to the ground that is).

The model aircraft in it's element.
The Junior 60 is a superb little flyer but takes a very different technique to modern designs.

Flying speed is slow but it's surprising how well the plane can handle fairly rough weather. What you have to watch is a gust of sidewind getting under the heavily dihedraled wing and flipping it (especially on take off).

A distinctinve feature of the Junior 60 (and other vintage model aircraft) is the large amount of dihedral angle of the design. This makes adding ailerons pretty well useless so I made another junior 60 with a much lower dihedral angle (actually almost no dihedral) so I could fit ailerons.

The resulting aircraft was fitted with a OS25FP two stroke and flew extremely well. Now rolls, inverted flight and most combinations were possible. The fun ended when I fitted a hot 40 two stroke and pulled the wings off by puling too many G. Actual cause of failure was traced to a dodgy piece of ply used as a dihedral brace.

The original 3 channel model as pictured is still going strong some 13 years or so after being built. Flight hours must run into several hundreds by now and the only major job has been a decoke of the engine. The OS20FS had done that much running the exhaust had almost completely clogged up with carbon deposits.

The Super Junior one and a half model aircraft page

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