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BRABAZON AND ON (Part IV)
Improving the Freighter Part of my time as a student apprentice was spent in the Experi-mental Dept at Filton. To be let loose in a place like this was abso-lute paradise to an aviation enthusiast. Not only was the full-scale mock-up of the Brabazon being meticulously constructed but the prototypes of the Brigand Torpedo Bomber and Freighter aircraft were undergoing final assembly. |
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In addition there were many relics in odd corners of some of the more bizarre experimental war-time installations. This department was in effect a factory within a factory, with machine shops, as well as manufacturing, fitting and assembly areas. I graduated to the electrical section, which was being run by Frank York, a man way ahead of his time in my estimation. He later emigrated to Australia where he managed a major factory. His ambition was to manufacture the electrical installation for the freighter as a complete prefabricated kit. Knowing my design office aspirations he soon acquired a drawing board and set me to putting his ideas on paper. The length of every loom was carefully measured and after the attached panels had been carefully checked for access to their various locations in wings, nacelles etc, and the whole assembly was completed away from the aircraft. On a given night G-ABPV was allocated to Frank York, and in the early hours of the morning a huge octopus of electronics (the body being the main distribution panel) was lifted by a Coles crane and lowered through the top hatch of the flight deck. It was a great success and I was pleased to have played a small part in it. As the freighter took shape one got occasional reminders of its Bombay ancestry. I felt some concern about the length and apparent fragility of the naked undercarriage legs, but once they had their trousers on they made a lot more sense. The final ritual was the “guess-the-weight” competition, the winner taking all the tanners from the entry fees following the official weighing. I was to get to know this aircraft very well subsequently in the Flight Research Dept. At the outset its performance and handling qualities were marginal to say the least. One of the first shortcomings to show up was known as rudder tramping. In certain manoeuvres, when large rudder deflection was applied, it would slam over to its stops and would stay there until eventually forced back by the pilot, an alarming situation. The aerodynamicists’ first solution was to suggest special moveable stops. Two of us spent an entire weekend designing these, which comprised adjustable stops with the spindles extended forward through the bulkhead into the cabin, where two hand wheels could be rotated to “back off” the rudder to its central position. This idea was not much favoured by the pilots as of course at given times the travel of the rudder in one direction would be severely inhibited, so the idea was abandoned. Now the Freighter/Wayfarer flew initially with sharply square-cut wing and tail plane tips and it was decided to round these off and at the same time incorporate a simple dorsal fin to improve handling. My boss Austin J Randell – “A.J.”, was a past master at designing wooden structures, so this was the construction chosen for these extensions. (He had been engaged by the firm to design the wooden wings for the Bristol 138 high-altitude monoplane.) Time was of the essence so the lines were quickly laid out, partly on the office floor in chalk and crayon, and very soon construction was under way. There was a great deal of shuttling back and forward to the flight shed to check every stage of the construction, filling in with sketches where necessary. As I was leaving the office to check on the start of the skinning stage I received yet another cryptic warning from A.J., who unfortunately suffered from a terrible stutter. “Make sure the chippies (woodworkers) shake the brass pins up in a tin of resin before use. They will then scr… scr… screech as they go in, but they’ll stay! And make sure everything is covered finally in Madapolin before spraying.” I wasn’t prepared to admit that I didn’t know what Madapolin was so hurried en route to the technical library to find out that it was a type of fine mutton-cloth. This was pasted like wallpaper over wooden structures to provide a harder surface and a key for the paint finish. The flight-tests were a great success, in the words of one pilot the aircraft handling was “transformed”, but there shortly followed a regrettable, but I must say (afterwards!) amusing incident. We had a “rough diamond” working in the office that was not renowned for his accuracy. On more than one occasion his calculations seemed to provide a satisfactory answer but on checking they sometimes contained two mistakes which cancelled each other out! On this occasion the ’phone rang (and was answered by you’ve guessed who) from Aerodynamics Dept. “We are compiling our report on the dorsal fin flights for the Officials. Can you please tell us the exact area of the extra fin?” Extracting the General Arrangement drawing from a pile with one hand and a six-inch rule from his pocket with the other a rapid calculation was made (the geometry of the dorsal fin could be broken down into two triangles). “Let’s see – half the base times the height + half the base times the height. Say sixty two square feet”. Over succeeding days this apparently happened twice more. Next requiring the area of the fin was our boss Mr. Barry Laight, Head of Flight Research (who went on to become our chief engineer at Blackburn’s responsible for the Buccaneer) and then Mr. Pegg himself for the Flight Test Dept report. Apparently the same gentleman answered the ’phone on each occasion. A few days later A.J. emerged from his office, visibly shaking and white with anger, waving a lengthy pink note (i.e. internal memo) jointly at me and the other person who had shared the design work. It was from Barry Laight, listing the saga of the telephone enquiries in detail which had resulted in three entirely different areas for the same dorsal fin being quoted to the officials by different departments in their separate reports! The letter concluded on a conciliatory note, employing a phrase which I had not heard before or since. “However, lest anyone should think that this job is all kicks and no ha’pennies I must say that the design of this installation was excellent and carried out in record time. It has improved the aircraft out of all recognition. The two people mainly concerned should report to my Office on Monday morning.” We both received a warm hand-shake and an instantaneous rise of 2/6 per annum, a unique experience as increases were invariably awarded only at Christmas. Improving the handling of the aircraft was one thing. The take-off and single-engine climb performance was really not acceptable. With my limited experience I could not see how this could be improved without more engine power, which was not forthcoming, but I reckoned without the skill, experience and perseverance of my more seasoned colleagues. A team of various specialists examined the aircraft and a list of about a dozen items was prepared for action. Individually these could surely have had little effect, but collectively they provided the margin of improvement necessary for certifications. The mudguards were removed completely from the wheels and the chunky (mountain bike type) tread on the tyres deleted and replaced by peripheral grooves. Round-head rivets in some limited areas were replaced by countersunk or mush-room heads. The rain water deflector was deleted from above the main cabin door. The cabin door leaked anyway so you were already wet before you left the aircraft! The external hinges on the nose freight doors were carefully shrouded. The seals and fairings were improved where control rods emerged from the wings, fin and tail plane to operate surfaces. No major modifications were made, but neither was any detail neglected. The required improvement in performance was readily achieved by all this attention to detail design. In spite of the appalling tragedy which befell G-AIFF (described elsewhere) the freighter turned out to be a considerable commercial success. It was heart warming to see them being regularly dispatched from the assembly line on the hill at Filton down to the flight sheds in their many different airline liveries, each milestone aircraft (e.g. No. 50, 100 etc.) being liberally decorated with balloons and streamers. Many which were sold to Pakistan were finished in a sinister grey camouflage with bomb-aimers position installed. The whole gambit of development was covered; winter trials in Canada, Tropical Tests in Khartoum, overseas tours etc., and these were not without incident. In Canada apparently the aircraft sustained a burst tyre on landing at a major airport, but the jack carried would only go under an axle with an inflated tyre! The digging of a small hole in the runway caused considerable embarrassment to the crew! Another aircraft had been fully instrumented for winter trials and was taking off for its final “shake-down” flight before departure. It had been fitted with a new system called “auto-coarsening” causing the propeller on a failed engine to feather instantly automatically. On take off the aircraft sustained engine failure on one side at about 100 ft and the second engine became shut down also. A touch down was made on the remaining length of runway but the aircraft ran off the end into soft ground. Superficially it looked undamaged but the violent deceleration had pulled just about every rivet in the airframe and I believe it was a write off. On another famous occasion a freighter was approaching the coast of USA and contacted Air Traffic Control with its call sign. ATC replied with “What type are you?” which elicited the reply “Bristol 170 Freighter.” A long pause from ATC and then “Did you make it yourself?” Incidentally the new price of early Freighters was quoted at £70,000 and the Sycamore Helicopter around £30,000. It’s a big jump to the recent contract of £1 million plus for replacement Concord rudders! The late Tony Wilkey |
