MAY/JUNE
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RC MODEL WORLD ( DECEMBER 2000) |
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RC MODEL
WORLD [PAGE 1] |
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Initial operation experience was disappointing following the adoption of bad combat techniques. The first reported combat being an even 6 against 6, where the new F2A was up against experienced Albatross DIlls of Jagdstaffel Manfred Von Richtofen. Only 2 Bristol F2As returned for no loss to the Albatross. However, full advantage of the aircraft was taken with a combination of improved combat techniques and the introduction of the F2B commencing with the 51st machine. |
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| The primary combat issue of using the aircraft as a gunnery platform for the rear gunner was addressed when the pilots adopting single seater tactics, using the forward firing Vickers as the main offensive armament. The Bristfit became one of the most effective allied fighters of the war. At the end of W. W.I, the newly formed RAF adopted the F2B as the standard army co-operation machine. Extensive refurbishment saw the creation of Mk II and Mk III versions. The production line was reopened in 1928, with 50 Mk Ills being produced. In 1928, all surviving aircraft were converted to Mk IV standard. Between 1917 and 1932 the Brisfit served in some 44 squadrons. All of the literature, along with the web site information, indicates the that model being shipped is 8084, which represents an F2B of No 139 Squadron based in Italy 1918. This model is based upon the full size and airworthy machine which can be seen flying regularly at the Shuttleworth Collection, Old Warden, Bedfordshire. The review model is registered 8096, again this is the Shuttleworth machine, but as painted in around 1980. ..in fact the very machine in my Brisfit photo collection. I think 8084, is the prettier of the two, with multiple white identification' markings around the fuselage and a large white central bar running along the wing. I have to admit to being slightly disappointed on receiving the 8096 finished version. This also led to a small problem repairing Solartex later on. The documentation refers to the aircraft being finished with PCI0 Solartex. My review model was covered in Olive Drab tex. Unfortunately, I did not realise this until I had applied some PCI0 paint! |
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Construction. ..or assembly
Construction is possibly the wrong word. At first views, the F2B is no more than a fairly simple, but large assembly job. Having started, I found the instructions to be a little thin on detail and certainly lacking step detail (in fact, the Adobe download is the instruction booklet). One could argue that this range of air craft is aimed at the more experienced modeller (I have been at it for around 30 years!), therefore step to step is over the top -but it would been useful to have a little more detail here and there. More of this later. Cowling The aluminium pressed cowl is in 3 parts. A single sheet over the engine bay and exhaust stubs. This is removed by unscrewing the 5 off, 1/2 inch self tap screws. Once removed, full access is available to the large engine bay. To remove the remaining 2 cowl halves, the top wing centre section must first be removed. This is achieved by removing 4 Allen screws that bolt the section to the centre section struts. Having removed the wing section, each remaining half of cowl can be released by removal of the 1/4 and 1/2 inch self taps and windscreen. Access is now available to the upper side of the servo tray. Additional access is achieved by removing the two screws that hold the hatch in place on the fuselage underside. This gives access to the underside of the servo tray. |
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| Engine installation | |
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The instruction booklet refers to an 120FS as the proven prototype
power plant. My Laser 120 was a little to wide for the (substantial)
ply mount. This was widened using Permagrit tools. The Laser bolted in
place using captive nuts. The engine compartment was given a good fuel
proofing using Tuffcoat. Unfortunately, the lower cowling is not
removable, therefore only the top of the engine bay - which is more
susceptible to fuel penetration, unprotected. One of the additional options for the F2B us working exhaust stacks. my standard model came with a solid wooden exhaust. I therefore drilled a large hole between 2 of the exhaust manifolds. This lined up nicely with the Quiet Pipe on my Laser along with a 1" length silicone tube extension. As a result, the engine vents into the gap between the 'ali' cowl where it covers the exhaust stack Not quiet scale, but totally invisible. A 16 ounce ( Black ) SLEC tank was mounted on a plinth at carburettor height to v\give a problem free fuel pipe was attached to a brass tube and mounting. This sits exactly inline with the 'ali' cowl / exhaust cover, enabling the prop wash to give a degree of presure feed. ( recommended by NEIL TIDY ) |
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| Upto this time, all had gone well. It was easy! However, I now come to the part that NO kit reviewer should do -the mods! | |
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Mod 1 -Cooling
I was not convinced that the engine would have sufficient airflow and hence cooling. Over 30 square inches of air goes through the front cowling, with only 16 or so square inches for efflux. The engine is totally cowled, with the airflow effectively split into two by the ply mount. The lower half has 3 louvers and a 1" diameter hole each side of the fuselage. The top half of the engine bay again has a 1" hole and a 6" vent for the exhaust cover, but the exhaust stack largely restricts this. I decided to add some additional ventilation. As I did not want to spoil the scale lines, I cut two one inch holes through the substantial ply firewall. This allows the airflow to vent directly into the open cockpit.
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Mod 2 -Servo mounting
Mod 2 came about when I attempted to install the elevator, rudder and throttle servos. The airframe comes complete with a 1/4 inch ply servo tray. The instructions indicate that the elevator and rudder servos should be mounted inverted. This I tried, but the access panel on the bottom of the fuselage was too small for my fingers. More importantly the servo arms were some 1.5 inches adrift in height from the premounted bellcrank. I played around with Z linkages for a while, but could not find a happy fit. This is a £700 and very large model. I refuse to risk it for a sloppy linkage. Therefore, I constructed a new mount and lowered it such that the servo arms were inline with the bell cranks. The rudder and elevator servos (2 x 1/4 scale Hitec 615MG 7.5 kg/cm) now have direct links to the bell cranks with zero slop. I cut down and reused part of the original mount to house the throttle servo. The original position was exactly correct for this. Mod 3 -Aileron servos Having completed the engine and primary servo controls, I moved to the servo installation within the lower wings. Each lower wing has a servo hatch. This is released by removing 4 x 1/4" screws. Easy. I then attempted to position the servo into the mounting. Hard! There is no way on this earth you can get a servo to fit! The servo should be screwed to two mounting blocks already located within the wing. Due to the servo leads, the servo cannot fit between the blocks. Even if it did, you could not access the servo leads which would be hidden under the Solartex covering. So having fiddled with poor servo access in the past, I took the scalpel and cut the Solartex back one panel. |
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| Full access is now available, with the servo easily installed. A new, double sized hatch cover was knocked up using some thin ply from the scrap box. Having positioned the servo, it was then a question of how to hook up to the 14 SWG pushrod. I made up a small rod/clevis in a 'V' shape. This was wire bound to the push rod. All of the wire parts were well cleaned, fluxed and then carefully soldered to ensure a good joint. A positive, slop free linkage being the result. Having completed one wing, the second wing was completed much quicker. Again, care was taken to ensure servo throws were 'handed' (i.e. 1 up, 1 down , obvious, but yes we have all done it!). | |
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RC MODEL
WORLD [PAGE 1] |
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So that's all the primary systems and controls. |
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