Robinson attacks America
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Robinson attacks America
Yes, it’s true. A Robinson is leading the charge against the USA in revenge for the defeat of King Georges' troops in the war of 1776 (or there abouts). This is truly revenge because the Americans are going to be forced to absorb British mentality over and above Coronation Street and other British TV programs shown on Public Broadcasting stations. The Robinson I refer to is the Host of the UK program “The Weakest Link”. It starts sometimes next week on one of the commercial stations.
Just a bit of humo(u)r
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The Cat
Just a bit of humo(u)r
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The Cat
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To: Rameses III
Whisper mode was the first application on a large scale of Active Noise Cancellation. They measured the amplitude and frequency of the noise generated by the blades and engine and generated a sonic signal that was equal in amplitude and opposite in frequency. This was the same system used in the development of the “Cone of Silence” used in the program Get Smart.
Hughes Helicopters did some research for the Defense Advanced Research Projects Agency to isolate the noise generation on a Model 500. When they finished the modifications on the helicopter it could fly 500 feet overhead and you would only hear a soft whoosh. This was true whisper mode as it actually worked.
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The Cat
Whisper mode was the first application on a large scale of Active Noise Cancellation. They measured the amplitude and frequency of the noise generated by the blades and engine and generated a sonic signal that was equal in amplitude and opposite in frequency. This was the same system used in the development of the “Cone of Silence” used in the program Get Smart.
Hughes Helicopters did some research for the Defense Advanced Research Projects Agency to isolate the noise generation on a Model 500. When they finished the modifications on the helicopter it could fly 500 feet overhead and you would only hear a soft whoosh. This was true whisper mode as it actually worked.
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The Cat
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To: Rameses III
Which paragraph amazed you? Paragraph (1) was a joke. Paragraph (2) is true.
They built a special test stand that had several water brake dynamometers on it. The set up was such that they could attach the main rotor shaft to one of the dynamometers and operate the engine and the tail rotor. They would then disconnect the main rotor shaft from its’ dynamometer and re installed the head and blades. In this condition they would connect the tail rotor drive to its’ dynamometer. They took noise measurements under both conditions to determine the contribution to the overall noise emanating from the helicopter. They then hooked both rotor systems to their respective dynamometers and checked the noise emanating from the skin of the helicopter and at the same time checked the noise coming from the engine. With all this information they went back to the drawing board and redesigned the main and tail rotor. They made a five blade main rotor and an X tail rotor, which significantly cut down on the noise. They added foam padding to the internal structure to dampen the noise transmitted through the fuselage skin and the crowning glory was a silencer installed on the engine exhaust.
The consensus of those not involved in the program was that the helicopter or several like it would be employed in Vietnam but that was never proven to be true. Some time later, Hughes sold a bunch of helicopters to the Customs and DEA branches. These helicopters left the factory in black paint and no N-numbers but I don’t know if any were given the silent treatment.
In any case the government research financed the five-blade system on the 500-F series as it did for the X tail rotor used on the F and the Apache.
I do not know if an official report was ever generated or, if any material is available on the Internet.
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The Cat
Which paragraph amazed you? Paragraph (1) was a joke. Paragraph (2) is true.
They built a special test stand that had several water brake dynamometers on it. The set up was such that they could attach the main rotor shaft to one of the dynamometers and operate the engine and the tail rotor. They would then disconnect the main rotor shaft from its’ dynamometer and re installed the head and blades. In this condition they would connect the tail rotor drive to its’ dynamometer. They took noise measurements under both conditions to determine the contribution to the overall noise emanating from the helicopter. They then hooked both rotor systems to their respective dynamometers and checked the noise emanating from the skin of the helicopter and at the same time checked the noise coming from the engine. With all this information they went back to the drawing board and redesigned the main and tail rotor. They made a five blade main rotor and an X tail rotor, which significantly cut down on the noise. They added foam padding to the internal structure to dampen the noise transmitted through the fuselage skin and the crowning glory was a silencer installed on the engine exhaust.
The consensus of those not involved in the program was that the helicopter or several like it would be employed in Vietnam but that was never proven to be true. Some time later, Hughes sold a bunch of helicopters to the Customs and DEA branches. These helicopters left the factory in black paint and no N-numbers but I don’t know if any were given the silent treatment.
In any case the government research financed the five-blade system on the 500-F series as it did for the X tail rotor used on the F and the Apache.
I do not know if an official report was ever generated or, if any material is available on the Internet.
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The Cat
