Phaeton (oz13488)

About this Plan

Phaeton. Radio control FAI pylon racer model.

Quote: "Fastest at the Nats! Frank Van den Burgh's Phaeton FAI Pylon Racer. If you fly FAI pylon, you either build a Phaeton now or chase 'em around the pylons from now on!

According to the legends of the Ancient Greeks the sun was driven across the heavens every day by the Sun God, Helios, in his chariot. Helios had a son named Phaeton (pronounced Fay-etton with accent on the 'Fay') and, perhaps finding his daily drive rather monotonous year in - year out, one day the Old Man incautiously agreed to let Phaeton have a go with the chariot. Now Phaeton was only a very junior God and in his youthful exuberance he went in for some low flying that could be called the Great Original Burn-up in every sense of the term and thereby achieved everlasting fame! A couple of centuries ago Phaeton gave his name to a light, two-horse carriage much-fancied by the young bucks of the time, and now, although he may not know it, he has given it, with the help of a rather horrible phonetic association, to an FAI pylon racer.

The FAI first decided to recognise R/C Pylon Racing for international competition by adopting a set of rules in November 1969. These rules required a new class of model based closely on the US Formula II Class which was, believe, intended for less ambitious flyers than the well-established Formula I in case further development should raise flying speeds to a dangerous level. Thus the FAI rule calls for a bigger wing area (close on 700 square inches including tail surfaces) and a minimum wing thickness of 11 inches measured at the root but outside the fuselage. Height and width measurement of the fuselage can be fractionally under the 7 x 31 inches of Formula I, but as a further speed reducer only 'straight' methanol castor oil fuel is permitted. Silencers are compulsory but tuned pipe exhaust systems are excluded. A basic requirement is for a 'semi-scale' model, which is understood to mean that it must follow the general lines and layout of full-size aircraft but need not be a replica of any one type.

This new class was open to criticism on the grounds that it was too close to Formula I to be worthwhile making a change, and, from an aesthetic point of view, the large wing area in relation to fuselage makes for a less attractive looking model. But these were minor points compared with the main question - was it likely to produce some good racing sport? Believing that it would, I decided to design and build a model for the 1970 season. The design had to be reasonably simple to co-struct, of pleasing appearance and avoid any extreme features which might be outlawed by future amendments to the provisional rules. It also had to be fast as I reckon I am getting too old to take on younger men and faster models.

In quest of speed the Phaeton design does not resort to any way out subtleties of aerodynamic theory (I don't know any). The required measurements are just tucked away tidily to minimise the frontal area, the wing taper concentrates the rather large wing area towards the root where the thickness is specified, and care is taken to keep the whole shape clean and free from excresances. As required by the rules, the motor is fully cowled except for the cylinder head. The inlet and outlet apertures for engine cooling air are smaller than normally seen on R /C models, but have not led to any overheating.

To achieve this I have taken care in shaping the airflow passage inside the cowl so that the airflow is ducted closely round the cylinder and I hope that this feature will be apparent in the accompanying photos. Actually, the initial flights of Phaeton were made without the detachable cowl in order to make sure that the motor was adequately run-in and to eliminate the risk of damaging the cowl by nose-over landings on rough ground before I had some experience of the landing characteristics.

Phaeton is of basically quite simple construction which is just as well because some time and care is required on the important points for a racer of motor mount, cowling shape and wing seating and fairing for a smooth joint between wing and fuselage. Taking the wing first, the original Phaeton uses a foam wing, veneer covered, and the ailerons are of the 'strip' type except that only the outer halves move and these are operated by long torque rods of 10 swg wire faired in with a fixed balsa trailing edge along the inboard half of the wing.

The landing gear is also of 10 swg wire which is adequate with the fairly short leg length, and the inboard torsional anchorage is provided by making the wire long enough to protrude through the top surface of the wing near the centre-line where a small ply patch is glued on the outer surface.

At the editors request I have also sketched a structure for those who prefer to make a built-up balsa wing. It will be noted that no dihedral braces are specified as the stresses are spread evenly over the exterior sheeting along the large root chord, and plywood braces would tend to set up undesirable local stress concentrations. I would suggest cementing the sheeting to make up the shape required for covering each wing panel surface in one, and using either PVA or contact adhesive applied to both ribs and sheet for attaching this sheeting.

Turning to the fuselage and tail unit, this uses quite a large volume of very light balsa which can easily be sanded to a curvy shape. You must therefore make a nuisance of yourself at your local model shop by feeling every sheet of balsa and when your finger nails meet in the middle you have found the right grade..."

Phaeton, RCM&E, September 1970.

Direct submission to Outerzone.

Note this is a low resolution plan.

Update 11/12/2021: Added kit review from RCM&E, January 1972, thanks to RFJ.

Update 5/1/2022: Replaced this plan with a higher resolution version, thanks to Circlip.

Supplementary file notes

Article pages, thanks to RFJ.
Review.

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