Phillosan (oz15327)

About this Plan

Phillosan. Radio control sport model. Wingspan 49 in, for Enya 35 four-stroke engine.

Quote: "During the autumn of 1988 I decided to finish off my Brian Taylor Spitfire Mk.1 for the '89 competition season. The Spitfire was going to be a little bit different for me as the model would have a retracting undercarriage and flaps, I had flown several models previously that had flaps but thought that it might be useful to get in some practice over the winter.

It meant building a new model and 'Phillosan' is the result of my deliberations in this direction. I wanted a model that would be fun to fly, would be quite suitable for grass field flying and one which, when fully rigged, would fit into my car. The model had to have flaps but no retracts.

I had built a small sport model a few years ago powered by an Enya 35 four-stroke and decided to use the dimensions and wing section of this model for 'Phillosan'. At first I thought of using split flaps made from plywood but after looking at the wing construction, decided that it would be easier to use inset ailerons and flaps in Mustang style. After drawing out a pseudo Spitfire I eventually finished up, after several more no goes, with the model presented here.

Construction follows simple, well-tried techniques that I have used on several models in the past. The fuselage is a box with ply and balsa top decking. The wings are built flat on the plan and feature a 'D' box leading edge. The tail unit is all sheet balsa, 1/4 in being used for the fin and rudder, 3/8 for the tailplane and elevator. The undercarriage is a simple torsion bar unit fixed directly into the fuselage and the engine is mounted on a paxolin or aluminium plate which is in turn bolted to beech bearers. The tank is accessible from the front and there is adequate room for the radio gear in the section above the wing. I have used a glass/epoxy cowl on my model but one from balsa could be substituted.

Getting started: I like to get all the pieces cut out for a model before I start assembling it. All the ribs for the wing have been drawn out individually as I think that this is easier than cutting them using the sandwich method - it is best to stack them together on completion just to make sure that they are the right shape though, The fuselage sides are from 4 in wide sheet; note the angle of incidence on the tailplane.

Fuselage: The fuselage sides are cut from 4 in wide 1/8 sheet balsa. 1/32 plywood doublers are impact bonded onto the sides along with 1/8 balsa treblers prior to assembly. I built the fuselage upside down over the plan with former F1 hanging over the edge of the board. This does enable a true fuselage to be built easily. When the basic box has been removed from the plan the formers for the rounded decking can be added - the front part back to the cockpit area is covered in 0.4mm plywood. I found it best to attach this ply covering to one side of the fuselage and let it dry completely before trying to roll it over the formers and glue down the other side. When gluing the second side use masking tape to hold the plywood in place.

The rear decking uses 3/32 sheet balsa again, rolled around the formers and a 1/2 in soft sheet top. I flattened the top surface by rubbing it down on a full sheet of garnet paper flat on the building board. It is then an easy job to add the top 1/2 in sheet. Masking tape is again useful for holding this part in position. To finish off the decking carve the I/2in sheet to the required final shape. The rear underside of the fuselage uses sheet balsa with the grain running crossways.

The undercarriage fixes forward of the former F2, the vertical ends fitting into slots in plywood. There is a 1/8 plywood piece across the fuselage forward of F2 along with ply packing pieces. A 1/8 ply piece encloses the undercarriage unit and 1/8in balsa sheet completes the covering.

Tail unit: Cut the fin and rudder to shape and sand to the required section. The tailplane and elevator should be made up as shown on the plan and then carved and sanded to shape. Note the wire elevator joiner and the stearable tail skid - the skid needs to be fastened to the rear of the fuselage before fitting the tail unit.

Cowl: I made the cowl for the original model over a blue foam pattern, carving the foam to shape and making it slightly undersize to allow for the build-up of glass and resin. If you want to use polyester resin it is necessary to coat the pattern with white PVA glue or the resin will melt the foam. I used epoxy resin which has no effect on blue foam. A couple of layers of glass tissue were used on the original cowl but I feel that glass cloth would be better. I did, however, reinforce the rear of the cowl with glass tape.

On completion of the moulding process the blue foam has to be removed. I found this quite easy to accomplish without having to resort to cellulose thinners to melt out any excess. The cowl will need to be sanded down and filled as it will be quite rough on the outside; I used car body filler to fill any indentations before a final rub down with wet and dry..."

Direct submission to Outerzone.

Phillosan from Radio Modeller, April 1989.

Supplementary file notes

Article pages, thanks to RFJ.

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