A fuselage should be made from a good high quality Epoxy resin, combined with good glass fibre cloths. Often made using a range of other products for filling in sharp corners and extra strength, i.e. localised carbon fibre. Be careful if the carbon runs full length of the fuselage as this can effect radio reception.

Other materials used for fuselage making are Polyester resin and glass mat. Polyester resin is not as strong as Epoxy, is more brittle, and prone to higher shrinkage rates. Glass random weave mat is heavy to use and not strong (unless thick as it usually is). The advantage of polyester / mat is that it is cheap.

Most fuselages have what is known as a gell coat, and many epoxy fuselage will use a polyester gell coat (especially if white). The gell coat is an initial, thin (hopefully) layer of resin to improve the finish of the fuselage, preventing any cavities in the cloth pattern being on the outside.

Colour gell coats look good if the mould is perfect, however they can be heavy in order to achieve a good depth of colour. Clear gell coats are much easier to work with, allowing the builder to look through the fuselage when installing gear etc.

Take care that you know which material your fuselage is made from as it effects the choice of glues to use. Epoxy will adhere to polyester, but polyester will not adhere well to epoxy.

The following is a guide to preparing a GRE (Glass Reinforced Epoxy) fuselage.

1) Remove all traces of release agent.

a) Wash with water

b) Wipe with a solvent, ie - acetone

c) If painting, lightly sand with fine paper or rub with steel wool.

2) Check the joins for any pinholes, mismatches, etc. Fill in any holes with a filler, either epoxy / Q-Cell mix or an automotive knifing putty.

3) Sand filler smooth, then spray a primer to spot any extra problems.

4) When all is OK, wet rub to remove most of the primer etc.

5) Spray with your favourite paint.

Some epoxies go 'soft' when subjected to a pool of fuel, ie, leaking tank. Always place a small drain hole in the fuselage in case of such an accident.

The flexibility of Epoxy fuselages can often lead to problems with servo mountings etc. Always use a servo tray, use a 3mm light ply stiffened with 6 x 6 balsa cross pieces, or even better, glassed 3mm balsa with spruce backing rails.

It is vital that any area to be glued, be thoroughly cleaned and sanded.

When attaching the servo tray, there are 2 options.

a) Tack in place with cyno, then use large fillets of Epoxy/Q-Cells filler, top and bottom of the tray to totally encapsulate the tray.

b) Tack in place with cyno, make large fillets top and bottom of the tray using a good silicon glue. Try to use a non acetic acid based silicon.

For models that have a long tail moment or a deep flat section at the rear of the fuselage it is necessary to install a vertical lightweight former at the base of the fin / tailplane area. This is to prevent unwanted flexing of this area.

Special attention must be given to the installation of tailplanes in GRE fuselage.

When a tailplane receives a knock, ie, cartwheel etc, it is easy to damage the tailplane mounting.

The problem is easily solved by either:

a) Make sure the tail has an inside and outside glue filleted.

b) Insert a 1/16 Balsa horizontal former.

Do not store a GRE product in a hot stressed environment as it may distort, (ie, leaning against a tin shed wall in Summer, or with a weight resting against it).

The hardest task preparing a GRE fuselage is the placement of the plywood firewall (engine bulkhead, etc). Here is our favourite way: (having 3 hands helps...)

a) Mount the engine in its intended engine mount, usually an alloy radial mount.

b) Calculate the approximate position of the firewall, and shape the plywood until it is a reasonable fit.

c) Mark the approximate centre position of the engine mount on the firewall and drill a hole, say 3mm.

d) Use a 3mm bolt, nut and a scrap ply plate to hold the engine mount in position onto the firewall, ie, loosen the bolt to slide the mount around.

e) For models using a nose ring in glass, mount the spinner to the engine, and tack a spacer to the rear of the spinner. Hold the spinner (and spacer) firm against the fuselage, and whilst holding the fuselage vertical, find the mount position on the firewall.

f) After finding the mounting position, attach the engine to the firewall (usually bolts and blind nuts).

g) Reassemble the complete assembly, when happy with the firewall position, tack glue it to the fuselage with cyno.

h) Remove the engine, mount etc, then using Bolly epoxy, brush resin over both front and rear of the firewall. Mix up a paste of epoxy and glass powder. Use this paste to make a filleted glue line into the fuselage (similar to the way a tailplane has glue fillets).

Many kits have a removable cowling etc. For the larger cowls, pins need to be inserted to prevent excessive flexing. The best method is to use a metal (wire) pin (in the cowl) inserted into a plastic sleeve (in the fuselage). For small models the perfect components are a nyrod inner for the sleeve and an appropriate size piano wire pin. Also popular is the use of piano wire and an appropriately good fitting fuel tubing. The fuel tubing method is quieter in a high vibration environment.

Mark out the positions, glue (using a epoxy / glass powder mixture) the pins into the cowl, making sure the wire is kinked to key in place. Drill the fuselage slightly oversize to accept the outer, and with the outer slipped onto the pins, tape the cowl in place and with a epoxy / glass powder paste glue the sleeves into the fuselage (from inside the fuselage).