Vickers FB5 Gunbus (oz16233)

About this Plan

Vickers FB5 Gunbus. Radio control scale model for electric power with b rushless AP05 motor. Wingspan 22 in.

Quote: "Free Pull-out Plan. 22 in span Vickers FB5 Micro RC. An indoor/outdoor EP RC scale model of the early WW1 fighter. Gunbus, by John Watters.

In 1912, the Vickers Aircraft company had forethought and decided to build an aircraft capable of carrying a forward firing machine gun. After much experimentation with guns and fitting arrangements, they came up with a pusher design, which was called the FB4. This design was further refined and fitted with the new, and now readily available, 100hp Gnome Monosoupape motor. This aircraft then became known as the model FB5. The aircraft soon earned the nickname 'Gun Bus'.

A number of these aircraft were sent to France in mid 1915 to form No.11 Squadron. For the next year they did some good work and recorded a number of combat victories, but as the German Fokker Eindekker joined the battle, the Gun Bus was soon outclassed. Further modifications were tried. The 110hp Clerget engine was fitted along with a simpler 'V' strut undercarriage arrangement, this became the FB9, but there is doubt if it ever came into service. Faster and better aircraft had joined the battle and this aircraft had had its day.

My first encounter with pusher type models stems back to 1985 ,w ere •ui t a sma 18 span free flight Co2 powered version of an FB5, Vickers F5B Gun Bus (oz2106). This was quite successful and performed well both indoors and out. It became quite worn over time and as do many models, was finally removed to that model heaven, the scrap bin.

Not so long ago, I came across old photographs of my Co2 powered FB5. What if I enlarge the original plans to 22 in span (almost 1:20 scale)? This would make a unique model for the Spektrum AR6400 receiver from my now defunct Parkzone Suhkoi RTF, with a slight modification to allow the receiver to run from a 2s lipo and a Falcon coreless PUO2 motor, which I already had doing nothing.

BUILDING: This is a fairly straight forward model to build. providing the builder studies the plan beforehand. We all have our own building methods, so what follows is a guide.

Fuselage: The operating controls for pusher aircraft of this period were all via cables and pulleys. To get the operating control surfaces to work, this model uses the same method, but obviously on a smaller scale. It will be best to start constructing the elevator control assembly before building the fuselage. This is the real heart of the model. Make sure that the pivot tubes are free on the axle, and that the control horns (one each side of the body) are extremely secure on the axle. I would recommend that these horns are made from thin brass or copper sheet and soldered onto the axle.

Form the servo pushrod attachment arm from thin piano wire and bind and solder onto the axle. Again check the free movement of the pivot tubes. This assembly can now be fitted in position onto the 1/32" sheet fuselage floor. Add the inside side strips again, making sure that the assemble moves freely. The rudder horn can also be located at the same time. This horn can be made from thin plywood and fixed with a small screw. Check that this also moves free, but not sloppily. The servo/ receiver should also be positioned and the small pushrods from each servo connected.

Before doing anything else, connect a battery and check that everything is working. There should be a good degree of movement on both controls. When happy, the remaining body parts can be added. Glue the formers and nose block onto the base sheet and add the 1/32 side sheets too these. Add the top sheet decking and check everything is square. The fuselage struts can now be added through the top sheeting and glued in place to the inside of the side sheets. Cut out the cockpit areas and add the small tubes to locate the undercarriage wires. Finally shape and hollow out the nose block and give the body a smooth sanding. Position your motor onto the former. connect up the radio and check everything works and that the controls operate smoothly.

Wings: The only difference with the wing build on this model, against normal design, is that the trailing edges are made from 1 mm dia carbon rod. Usually the trailing edges are triangular balsa strips. The idea behind this is to keep what is a relatively thin wing flat and straight. And it works. Although a bit fiddly to construct, it all holds together nicely. The spars and leading edges are from conventional hard balsa strips..."

From R/C Model Flyer, November 2013.

Direct submission to Outerzone.

Supplementary file notes

Article pages, thanks to RFJ.

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