The Fairey Spearfish BCD model
Part 1 of 3
After a fair few years away from Carrier Deck, I decided to get building and get back into it. I thought I may as well start where I finished, with an own design Fairey Spearfish model.
Brief History of the full size Spearfish (from Wikipedia)
The Fairey Spearfish was a Second World War British torpedo bomber. It was one of the largest single-engine aircraft to ever operate from a British aircraft carrier.
The Spearfish was designed by Fairey Aviation to Admiralty Specification O.5/43. Having learned the lessons of the Fairey Barracuda, the Spearfish featured a much more powerful engine and an integral ASV anti-submarine radar (the external installation on the Barracuda caused problems with longitudinal stability). Problems with the Bristol Centaurus engine delayed the first flight until 5 July 1945. Only five aircraft were built before victory over Japan at which point further work on the project was stopped.
One of the real life prototypes.
Designing and building the model
Having previously built 2 own design Spearfish, but not having the plan, I had to start from scratch with a 3 view drawing, kindly supplied by Andy Housden. The Spearfish is a pretty good subject for Carrier. It has a fairly long but slim fuselage, perfect for keeping the weight down but still getting some good tail moment, which help keep you at a good angle of attack for the slow flight. My aims were pretty straightforward. A fairly large (close to wing area maximum of 450 sq inches), light model, with a conventional 3 line control system, that would be at least competitive (i.e. scoring happily above 200 points).
Being a Basic Carrier Model, we don't have to be worried too much about issues of scale, as long as we capture the character and it is identifiable as a Spearfish, that's fine. However, I did use the fuselage view to work out the correct proportions and position of the cockpit, wings and tail etc.
I began by drawing out a simple wing plan, which totals about 440 square inches (max 450 for BCD). For the most part, the build is very simple and straightforward.
Unfortunately I only started taking pictures after half building the wing, and only had my phone camera available at the time, so, apologies for the quality of the pictures.
I began by building the frame of the wing, i.e. leading edge, centre rib, tip ribs and trailing edge. Obviously it is very important to ensure it is straight and true. When that is complete, ribs can be added along with gussets for a little extra strength. That gets us to the picture below, where I have just added sheeting to the underside leading edge.
The leading edge is 10mm square balsa with a reinforcing strip of ply. The trailing edge is 5mm strip spruce. Centre and tip ribs are half an inch, and I think I used 3mm balsa for the ribs and gussets.
Close up of centre section, you can just about see the ply reinforcement on the leading edge. I don't think the wing would last 2 minutes without this!
The top sheeting attached using ordinary wood glue and held in place with pins.
When the sheeting has been applied, there is obviously a step up, from the rib to the sheeting as can be seen on the left above. This can be corrected by having the ribs notched to accept the sheeting flush or to add rib caps made from the same thickness balsa as the sheeting. I prefer this method, as although a little fiddlier, I think it helps to strengthen the ribs and their attachment to the trailing edge.
This picture shows the sheeting added between the centre and first rib. This helps greatly when covering and also adds rigidity to the wing. You can also see the balsa support struts that have been added between the upper and lower sheeting. This helps prevent the sheeting from being crushed. In conventional models, this duty would be performed by wing spars, but I wanted to be sparless for simplicity and weight saving reasons.
Wing construction completed, all in all, very simple!
Go to part 2
This article was first published: 22/09/2008
This article was last updated: 22/09/2008