SpaceX (Vol. 2)
Discussion
skwdenyer said:
hidetheelephants said:
They aren't any more intrinsically loud than any other jet engine. The prototype was loud as the tip jets used were originally designed for a rotodyne with an MTOW of approximately half the weight of the aircraft built; to compensate the fuel and air flow were increased greatly, which reduced efficiency and increased noise. Modern materials technology and CFD software would likely make tip jets and gyrodynes socially acceptable, or at least as much as the average gas turbine powered helicopter.
My Grandfather was a part of the Rotadyne design team. The noise was in part because the tip jets were going supersonic. At the time of cancellation, there was significant and productive work on noise reduction.What really annoyed the team was the Government, as the project’s funder, demanded that all work was completely destroyed. A pattern repeated elsewhere.
Sway said:
skwdenyer said:
hidetheelephants said:
Sorry, I meant the prototype Rotodyne. IIRC all that's left is part of the rotor pylon and some rotor blades.
It was very odd to destroy the prototype.The Rotodyne was a potentially very significant advance. Even if not for the intended civilian applications, as a military proposition it delivered a heavy lift capability otherwise unattainable. In original form, it could carry 8 tonnes of payload and cruise at 160kt for 2.5 hours. A Chinook today can manage 10 tonnes, and achieve a similar cruising speed and range.
The next generation of Rotadyne would have offered most of the Osprey's capability over 50 years earlier
From a reliability and availability perspective the Rotodyne was significantly ahead of the Chinook (especially early versions), without the gearbox issues which downed so many of them. It was of course a contemporary of the Chinook, which itself was heavily influenced by the earlier British Bristol Belvedere. The use case for heavy lift helicopters was becoming well-established.
As for the knowledge, the project itself wasn't a secret - it was highly-publicised at the time.
As so often, the big issue was a lack of imagination coupled with an unwillingness to follow through. The Government was looking for a single design followed by immediate commercial orders; when those didn't immediately come through, funding was pulled before further work could be completed.
skwdenyer said:
The next generation of Rotadyne would have offered most of the Osprey's capability over 50 years earlier
Very much that, heavy lift rotary wing prior to Chinook was a s
tshow of accidents from engine and gearbox failures. Even now I'm quite sure a rotodyne would be safer than a helicopter because the failure modes are so benign, it just didn't have someone absorbing the first mover costs. Given US airlines were signed up to buy the production model the decision by the UK govt to cancel it ranks alongside the V1000, TSR2 etc. in terms of self-inflicted wounds.skwdenyer said:
It was of course a contemporary of the Chinook, which itself was heavily influenced by the earlier British Bristol Belvedere. The use case for heavy lift helicopters was becoming well-established.
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The Chinook developed out of the work done by the Piasecki company - which had been bought by Boeing. Piasecki tandem rotor designs pre-dated the Belvedere..
"Starship Flight 4 in about 2 weeks" according to Elon.
"Primary goal is getting through max reentry heating.
Worth noting that no one has ever succeeded in creating a fully reusable heat shield. Shuttle required >6 months of rework."
And here it is:
"Primary goal is getting through max reentry heating.
Worth noting that no one has ever succeeded in creating a fully reusable heat shield. Shuttle required >6 months of rework."
And here it is:
Edited by Beati Dogu on Monday 20th May 20:53
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