Remembering the Rotodyne

Author
Discussion

AnotherClarkey

3,602 posts

190 months

Sunday 14th February 2016
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010101 said:
Gyros don't have collective pitch on the rotor disc.
Some do.

010101

1,305 posts

149 months

Sunday 14th February 2016
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There isn't a windsock in the clip.
If there is a headwind a gyro can do what happened in the clip without collective on the disc.
They can also 'hover' if there is a headwind.
The American Post Office used to fly a gyro from tbe roof of their depot.
As it turned out, without enough airspeed you kill the pilots.

AnotherClarkey

3,602 posts

190 months

Sunday 14th February 2016
quotequote all
010101 said:
There isn't a windsock in the clip.
If there is a headwind a gyro can do what happened in the clip without collective on the disc.
They can also 'hover' if there is a headwind.
The American Post Office used to fly a gyro from tbe roof of their depot.
As it turned out, without enough airspeed you kill the pilots.
All true - but some could also do a jump take off in zero wind and used powerful pre-rotation and collective pitch control to achieve it.

010101

1,305 posts

149 months

Sunday 14th February 2016
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Alright you win.

HOGEPH

5,249 posts

187 months

Monday 15th February 2016
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AnotherClarkey said:
All true - but some could also do a jump take off in zero wind and used powerful pre-rotation and collective pitch control to achieve it.
I flew an Air & Space 18A which had this jump take off feature.
http://www.hmfriends.org.uk/airandspacegyro.htm

AnotherClarkey

3,602 posts

190 months

Monday 15th February 2016
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HOGEPH said:
I flew an Air & Space 18A which had this jump take off feature.
http://www.hmfriends.org.uk/airandspacegyro.htm
Oooh, interesting. With the jump take off, is the transition to forward flight a relatively relaxed affair or does the rotor rpm decay so quickly that it is a bit buttock-clenching?

Sorry for the thread drift.

HOGEPH

5,249 posts

187 months

Monday 15th February 2016
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This is going back 20 years, but what I can remember is spinning the rotor head up to where everything was shaking, pressing a button to cause the blade to increase pitch, (delta hinge?) And then slamming the throttle to the firewall to get some airspeed.

I don't recall screaming at any point...

AnotherClarkey

3,602 posts

190 months

Monday 15th February 2016
quotequote all
HOGEPH said:
This is going back 20 years, but what I can remember is spinning the rotor head up to where everything was shaking, pressing a button to cause the blade to increase pitch, (delta hinge?) And then slamming the throttle to the firewall to get some airspeed.

I don't recall screaming at any point...
Thanks, an interesting account. I am not surprised about the vibration - I seem to recall reading that the 'take off' rotor rpm is 350-370 while in normal flight it is more like 240.

williamp

19,264 posts

274 months

Tuesday 22nd November 2022
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Meanwhile, in a traditional Tuesday thread revival, the excellent @clark_aviation has found some bbc sound recordings

"Most people know that the Fairey Rotodyne was very LOUD!
Thanks to the BBC Sound Effects Library, you can now 'experience the noise' yourself!"

https://sound-effects.bbcrewind.co.uk/search?q=070...
https://sound-effects.bbcrewind.co.uk/search?q=070...

Certainly an interesting noise. And not one you'd want to be woken up to..l

Yertis

18,060 posts

267 months

Tuesday 22nd November 2022
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Thanks for finding that. I wonder whether, given time, they'd have been able to fix the noise issue? Volume if not nature of. All jets were a lot noisier back then.

Eric Mc

122,053 posts

266 months

Tuesday 22nd November 2022
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Small capacity jets are still pretty noisy. I doubt that they could have made them a lot quieter. Watch some remote control jet powered models to hear how load these smaller jet engines can be.

FourWheelDrift

88,551 posts

285 months

Tuesday 22nd November 2022
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Today the Tip jet main rotor would be replaced with an electric powered main rotor fed by hybrid energy recovery systems.

Ps. I bet the original is no noisier that the EC-135 Police helicopters flying low level over houses at night.

Eric Mc

122,053 posts

266 months

Tuesday 22nd November 2022
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Hard to tell how noisy they were in reality now because there are none around to listen to.

My theory is that it wasn't really the noise factor that doomed the Rotodyne. It was the fact that, under government decree, all helicopter projects were handed to Westland. As a result, Bristol, Saunders-Roe and Fairey all had to transfer their development work and projects to Westland. I just get the impression that Westland's ambitions were aimed more at getting licence work from other (overseas) manufacturers such as Sikorsky or Bell.

Huff

3,159 posts

192 months

Tuesday 22nd November 2022
quotequote all
williamp said:
Meanwhile, in a traditional Tuesday thread revival, the excellent @clark_aviation has found some bbc sound recordings

"Most people know that the Fairey Rotodyne was very LOUD!
Thanks to the BBC Sound Effects Library, you can now 'experience the noise' yourself!"

https://sound-effects.bbcrewind.co.uk/search?q=070...
https://sound-effects.bbcrewind.co.uk/search?q=070...

Certainly an interesting noise. And not one you'd want to be woken up to..l
Really interesting - thanks for posting that! : D

GliderRider

2,113 posts

82 months

Friday 25th November 2022
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My father was tasked with doing ground noise tests on the Rotodyne's predecessor, the Fairey Gyrodyne. Dad considered the Gyrodyne to be the principal cause of his deafness in later years. He was only given a leather flying helmet as personal noise protection.

The Rotodyne was also noisy and the scientists and engineers behind it knew that.
Fairey Rotodyne Development
Most jet aircraft of the time were also very noisy. As a result many millions have been spent on test facilities and research to reduce aircraft noise.

The National Gas Turbine Establishment at Pyestock, near Farnborough had an 80ft cubed anechoic chamber built for testing scale models of engine exhausts. I worked in there when the RB211-535E4 was being developed for the Boeing 757.

To suggest that because an aircraft sixty years ago was noisy and therefore if a similar aircraft if made today would have to be equally noisy is just ridiculous.

As an aside, the Rotodyne was one of the aircraft offered in competition for the US Army's heavy lift requirement which resulted in them buying the Chinook; still in production 61 years later.







Edited by GliderRider on Friday 25th November 10:29

Eric Mc

122,053 posts

266 months

Friday 25th November 2022
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Has anybody developed small but quiet turbofans yet?

andy97

4,703 posts

223 months

Friday 25th November 2022
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Eric Mc said:
Has anybody developed small but quiet turbofans yet?
Maybe for the defence UAV market?

The Global Hawk UAV is powered by an Allison Rolls-Royce AE3007H turbofan engine with 7,050 lbf (31.4 kN) thrust (credit Wiki!)

Edited by andy97 on Friday 25th November 16:51

Tony1963

4,786 posts

163 months

Friday 25th November 2022
quotequote all
andy97 said:
Maybe for the defence UAV market?

The Global Hawk UAV is powered by an Allison Rolls-Royce AE3007H turbofan engine with 7,050 lbf (31.4 kN) thrust (credit Wiki!)

Edited by andy97 on Friday 25th November 16:51
7,000lb of thrust is quite a lot, but the engine weighs 750kg.

Eric Mc

122,053 posts

266 months

Friday 25th November 2022
quotequote all
andy97 said:
Maybe for the defence UAV market?

The Global Hawk UAV is powered by an Allison Rolls-Royce AE3007H turbofan engine with 7,050 lbf (31.4 kN) thrust (credit Wiki!)

Edited by andy97 on Friday 25th November 16:51
The tip jets on the rotodyne were more like little ram jets. Would a modern rotodyne use this type of tip propulsion or an actual turbojet or turbofan?

FourWheelDrift

88,551 posts

285 months

Friday 25th November 2022
quotequote all
Eric Mc said:
The tip jets on the rotodyne were more like little ram jets. Would a modern rotodyne use this type of tip propulsion or an actual turbojet or turbofan?
With modern materials technology they could probably manufacturer lightweight carbon blade with a hollow tube running down inside to blow air down. Like the nose, tail and wingtip control nozzles on a harrier.