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Sting review F3F (26/12/01) |
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I first saw the Sting last year at an F3F race in Portugal. The model was being flown by the designer and builder, Vaclav Vojtisek, and he did rather well with it, a top ten placing if I remember correctly. The model generated a lot of interest and he could have sold the examples he had with him several times over. American, Charlie McMurray was the lucky punter who managed to obtain first refusal on Mr Vojtisek's own model and went away a very happy man at the end of the week. Espen Torp also managed to get hold of one and did rather well with it a few months later at the 2000 Welsh Open. He flew it for most of the competition, recorded a 35 second run on the second day and went on to win the competition. Our illustrious editor and I managed to have a fly of the original model in Portugal during one of the days we were waiting for the wind to blow. Unfortunately the conditions weren't particularly thermally while we had the transmitter in our possession so we were unable to really put the model through its paces. The time I did spend on the sticks left me suitably impressed, so when Kevin asked me a few months later if he could 'tempt me to the Dark Side' to do a review on a moulded model, I didn't need much persuading. |
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The Model The Sting is an out and out F3F machine. At 2.8 metres it is my ideal size for F3F, but it would now be considered too small for an F3B machine, as the current trend is for 3 metres and over. The layout is fairly conventional; a three-piece wing and a one piece V tail. The wing section is HN1038; a new one on me, so I had to go and look it up. It's a thin, low camber section, ideal for high-speed flight at 8.15% thick and 1.52% camber. |
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First Impressions The plane arrived in the biggest, sturdiest transit box I have ever seen. I was so impressed with the construction of the box I nearly took a photo of it but fortunately I managed to get my anorak off just in time. Ten minutes work with a screwdriver and I managed to gain entry and extract my new toy. The contents did not disappoint in any way. The fuselage is a beautiful moulding with a couple of unusual features. The most noticeable is the seam line, which is horizontal and runs along the side of the fuselage rather than the more usual vertical seam. This is a very practical idea as it means that the fiddly bits to mould, the wing seat and the V tail mounting, do not have a seam through the middle. This would suggest that the lay-up is that much simpler to do, which should result in a stronger, lighter final product. Also unusual is the inner nosecone, which is a complete moulding that has not had any radio access holes cut out, this job is left to the builder. The outer nosecone is a sturdy moulding that fits very well. Another pleasing feature was the use of the aluminium pushrods - I dislike snakes - which were already in situ, complete with ball joint connectors for the V tail torque rods. Next out of the box were the wing tips. The surface finish is absolutely superb, the trailing edges are very thin and completely straight, and the top hinged ailerons and their gap sealing wipers on the bottom are very neatly done. The control horn shroud is moulded into the back of the wing, rather than being part of the servo hatch cover and is very small; the model is designed to keep all of the linkages inside the wing. The centre panel finish is also excellent and features the word 'Sting' across the centre. The flaps are bottom hinged, a feature I like as it allows for a large amount of deflection for crow braking. Again, a small control horn shroud is moulded into the back of the wing. The centre panel has a small amount of dihedral built into it in the same way as the Pike, again a feature I like as it reduces the amount of dihedral where the tips join on to the centre panel. The torsional rigidity of the wing components is impressive to say the least and there is no sign of any give whatsoever; a rigid wing is a fast wing, in my opinion. Incorporated into the wing skin are indentations to take the servo covers, but the wing skin is intact and the holes for the servo wells have to be cut out prior to installing the servos. To compensate for this the holes in the wing roots for connecting up the aileron servos are already done and are very neatly finished. Finally the V tail and the accessory pack. The V tail is another beautiful moulding, very light and rigid with a superb finish. It's a one-piece unit held in place by two M3 bolts. The torque rods are ready installed, complete with balljoints. The accessory pack features clevises, brass control horns, brass servo arm connectors, wing and V tail bolts and servo covers. A particularly nice touch is the spare carbon wing joiner and spare bolts. Also included are a couple of instruction sheets showing details of the wing servo installation and the recommended control surface movements. These sheets are in German but are reasonably straightforward and easy to follow. The first important job is the initial assembly of the model to see what it looks like put together. The V tail was fitted to the fuselage, the ailerons and flaps taped in place and the wing put together and bolted on to the fuselage. The model really is pretty; sexy curved leading edges to the outer panels complete with the rather cute upturned wing tips. The V tail also features very racy tips. That initial assembly showed up a several points. Firstly the good ones; the join between the wing panels is excellent, very crisp with no gaps. The carbon wing joiners fit perfectly, no sanding required at all and absolutely no slop. The only minor flaw is the countersinking for the bolts in the V tail not being very neat and the holes are oversized, although this does not seem to affect the structural integrity. One thing which subsequently has come to annoy me is the use of two different size bolts to hold the wing on, structurally this is fine but it means I have to carry two different size drivers to put the wing on - there's just no pleasing some people! |
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