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Aviation History
1963
1963 - 2325.PDF
Air-Cushion Vehicles FLIGHT International supplement, 21 November 1963 VA-2 ON THE ORESUND . . . view were much more arduous than a straight trip to Copenhagen. They involved manoeuvres and 180° turns into, down, and across the wind; thus the full problems of control of hover craft were exposed; so, too, were the hardy Swedes enjoying their Sauna bath. Naturally the Press were disappointed, as the impact of five return trips to Copenhagen in one day, taking half the time of the fastest existing means of transport, would have made the head lines. It was disappointing to the hover craft team also, but VA-2 is a compara tively small craft and the limiting opera tions conditions must be more stringent. A hovercraft of the size of VA-3, with a wave clearance flexibility of 2-3ft, would have been able to operate without any such problems. After the trouble encountered on the first attempt, the ascent of the slipway at Kockums shipyard was made without any fuss on all subsequent occasions. Speed of approach was judged so that the craft just got to the top of the slip way at almost zero forward speed. Here the wheels were selected down and the VA-2 was manoeuvred within a very confined space ready for the next trip. Dual for the Navy Following an almost English per- verseness of climatic conditions, the day scheduled for demonstrations to the Swedish Navy dawned windless, with a flat calm sea. Rough conditions to test VA-2's seaworthiness and steadi ness as a weapons platform had been the main aim of the Navy. However, a great deal of dual instruction was given during the day which proved that in these ideal hovercraft conditions people can quite quickly grasp the fundament als of hovercraft controls. Two admir als, a captain and a commander all showed excellent promise. Following the demonstration to the Navy, a rapid dash to Copenhagen was made. Dash is the correct word, for the return journey time was only 36min, five minutes less than a single journey in the hydrofoil. There can be no doubt that if this schedule could be maintained, commuting between Sweden and Den mark would increase, but the stewards would be hard pressed to sell the duty free beer and cigarettes! For the first time since VA-2 had been at Malmo it was possible to give chase to a hydrofoil. Its captain accepted the challenge at first and obviously had the throttles pushed wide open. When he realized that even at this emergency rating the VA-2 was gaining ground he apparently decided to throttle back to his normal cruise condition and VA-2 shot ahead. This was a moment of justifiable elation. There can be little doubt that hovercraft will always be faster than hydrofoils and the ride will be more comfortable. Several people at Malmo had direct evidence of this. On the Press day—when conditions were fairly rough—there were a number who, after their experience on VA-2, went on the hydrofoil. They all thought that the motion of the hovercraft was more acceptable; the craft was much more stable in roll, and wave impacts were obviously softened by the air cushion. Pouring a glass of beer in the hydrofoil in these conditions was a wet business. Unfortunately beer was not served in VA-2, so a direct comparison along these lines could not be made. High Seas Throughout the remainder of the Scandinavian programme only one further trip to Copenhagen was possible. This was in seas reported as 2-3ft high with wind-blown crests, and a wind strength of 14-18kt. The outward run from Malmo was downwind and down sea. This was not a comfortable experi ence, as in these conditions VA-2 tended to bury her nose into the oncoming waves. This phenomenon succeeded in bruising the shins of an eminent Swedish financier who was the passenger of honour. Despite this discomfort he was most impressed by the ride; and, being a very experienced seaman, he realized that with a longer hovercraft this sort of impacting would not occur. These conditions also underlined the short comings of aerodynamic rudders for directional control, as there was not enough airflow over them to get ade quate response. On the return journey, into the wind and sea, VA-2 behaved very well. There was only a little pitching motion and all the wave impacts occurred on the flexible rubber skirts. Though this gave a slightly jerky motion the effect was not of sufficient amplitude to cause any worry or distress. Unfortunately the last four days were "blown off." Quite contrary to expecta tions, the equinoxes were a little early this year. That at least would be one reason, but from Thursday until Mon day the wind blew at 18-20kt with gusts ofupto35kt. It was doubly unfortunate that the direction was towards the shore for once outside the breakwater waves of 3-4ft were encountered. VA-2 was not built for such conditions. One attempt was made on the Thurs day afternoon with a Swedish admiral on board, but once clear of the yard wall it was obvious that VA-2 should have remained on the slipway. With cushion-pressure on, and into wind, VA-2 coped extremely well, but it was quite impossible to achieve "hump" speed. Moreover, an excess of spray stopped the propulsion engine which, with the wind blowing directly on the sea wall, created a situation fraught with danger. Luckily the engine re-started immediately, but in order to give it a better chance it was decided to keep the lift engines throttled back and return to shelter as a displacement vessel. The craft was turned downwind with some difficulty and steady progress made towards the yard. However, just off the yard-basin entrance, local eddying effects of the wind made directional control impossible and assistance was requested. This took the form of a Dowty speedboat, and great praise is due to the crew. When it came out of the yard into the sea it might have been a submarine! However, it came alongside and took VA-2's tow line, and, with this assistance, the hovercraft's bow was turned downwind. It was fortunate, though, that the tow was for only about 100yd. Much more and it was conceivable that VA-2 would have been rescuing the nearly swamped Dowty boat! Far from damping the admiral's enthusiasm, it apparently strengthened his faith. He had experi enced for himself the seaworthy charac teristics of hovercraft and was most impressed. Well Worth While The experience did, however, prove that VA-2 was not really suitable for such conditions. Remaining demonstra tions were, therefore, confined to the top of the slipway. This was very dis appointing for all concerned, but some consolation was gained from the ft*ct that the regular-service hydrofoils also were locked safely in the harbour. It may be asked, was it all worth it • The answer, of course, is that it was. A new set of conditions was experience;d and new people were introduced to this latest concept of transport. It is belief that they all were favourably impressed; and, given a larger hovercraft, even the worst conditions encountered in the Oresund could have been mastered. 74
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