Wills Electric Aeroplane Page

The following should be considered as building hints and tips and not building instructions.

Wasp has been designed for 4 minute pylon racing. As such it is not considered as a beginners model. Micro servos and receiver are required. Choose a high visibility colour scheme it’s a fast model. Try to use wood that is not too heavy. Cover with iron on film.

The wing skins are from 1.5mm balsa, the lower one has a hole cut to accept the aileron servo, (see plan).

Mark all rib positions spars onto the lower skin.

All ribs are from 1.5mm balsa, these can be cyanoed into place (lower skin only), the false spar can be positioned at the same time.

A torque tube and rod is made up from 18SWG i.d. brass tube and piano wire.

The trailing edge is from 6mm balsa. This can be Pre-shaped.

Both the leading edge and false spar are sanded to shape before fitting the upper skin and the trailing edge. All webs have vertical grain.

With the wing in one piece, cut off the aileron (Yes it really has only one aileron), a razor saw can be useful here. With the aileron off, cut a small groove in the upper surface of the wing at the torque rod position. A piece of sharpened tube is used. The aileron is refitted after covering.

The fuselage sides are from 1.5mm balsa with a 0.4mm ply doubler glued to the inside surface. We used PVA for this, applied to both surfaces allowed to dry then ‘ironed’ into place using a hot domestic iron. 10 mm fillet stock (triangular) is then cyanoed in place together with the 3 mm strip (see plan).

All the ply parts are then made up, drilled and shaped before fitting.

The fin needs to be made up now. A plastic tube for the elevator needs to be glued to the inside of the fin (see plan). When the fin is completed it can be sanded to shape before gluing in place.

A simple jig made from scrap Balsa can be useful to keep the fin straight and true ( see fig.1)

This is cut from 3mm sheet balsa and sanded to shape. Mark the elevator hinge line and cut the elevator away. The elevator is top hinged and needs a chamfer sanding into it's leading edge (see plan side elevation). A small dia. brass tube is epoxied to the underside of the elevator 9mm from its leading edge. This tube must be a good fit on the elevator push rod, which is made from 24 SWG piano wire.

In the rear fuselage drill a small hole to take the Elevator control tube. Pass the control tube through the hole fixing it and the fin in place with either epoxy or cyano. The root leading edge of the fin can be filled at this stage. Once fixed the push rod can be inserted. The plan shows both ends. The servo end is made up so that adjustments can be made before soldering.

The wing mount plate needs to be tapped to accept the wing hold down bolt.

At the nose the ply motor mount is from 1.5mm ply and has a 3mm ply ring glued to it.

The hatch is spot glued (PVA) in place prior to sanding the whole fuselage to the correct contour.

Fit a type ball clevis to the aileron torque rod and fit the servo. The aileron is top hinged with 'DIAMOND' tape after covering.

Fit a Speed 400 motor and switch/speed controller. The motor can be either a 6 volt or a 7.2 volt motor. The 7.2 volt motor will draw a lower current giving a better power duration but a lower top speed. The 6 volt motor gives the best speed but a smaller duration.

Check that the throws are as indicated on the plan. Batteries can be 500 mAh or the larger 700mAh. Propellers used are the 5x5ins or 4.7x4.7ins Graupner Cam Speed props.

A firm launch is required. I would strongly suggest getting someone to launch for you. This allows you to be ready on the controls. The model requires a fast, firm, flat launch. Launch the model from above your head. It should be like a javelin throw but flatter. It should be a high-energy launch. This should prevent the model tip stalling. As this is a racer it is not intended that it be flown very slowly. Despite this it can be slowed to a sensible landing speed. Landings are best made from a flat approach.

The Graupner 5x5ins Cam propeller has been found to give the best performance. Unfortunately the small size of this and similar props give the model a relatively slow acceleration. Do not make large control inputs during this stage. If the model is allowed to accelerate unhindered it will achieve a very high speed.

Two different size battery packs have been tried (see fig.2). The smallest and lightest being the 7x 500AR Sanyo Ni-Cad pack. This is recommended for initial test flying as its size makes it easier to fit and its weight makes launches easier. But watch out for the short duration (about 2 and a halve minutes) if you are using the 6Volt 400. The 7.2Volt 400 is recommended for sport flying as this will give reasonable speed and about 4 minutes duration.