Very noisy "helicopter" last night - Cornwall

[clockworks]

A couple of extremely noisy helicopters flew over my house last night, first one drowned out the TV (which was quite loud at the time) and it felt like the house was shaking. We get used to low-flying jets and helicopters, living near to RNAS Culdrose, but this was the noisiest aircraft I've heard since the Vulcan visited.

A couple of posts on local Facebook groups this morning saying it was a pair of MV22 Ospreys from USS Iwo Jima, diverting to Culdrose because one had a technical isuue:

https://www.facebook.com/kaigreetphotography/

[normalbloke]

It wouldn’t have been BlueThunder.

[GliderRider]

V-22 Ospreys can be much noiser than an ordinary helicopter because in the hover and transition modes they are supporting their weight on much smaller rotors than an equivalent pure helicopter.

The downdraft from a V-22 is much more concentrated and powerful, as was demonstrated when some got sent to Nepal after the earthquake there. They were blowing the roofs off houses and demolishing what was left of already weakened buildings, hence them being withdrawn from that operation.

[egor110]

Ospreys - i live pretty much behind 40 commando and they've been buzzing around all week.

[hajaba123]

normalbloke said:

It wouldn’t have been BlueThunder.

Airwolf?

[anonymous-user]

Osprey does have a very distinctive sound. The first time one flew over us I went outside to look because I though to myself "that Chinook doesn't sound the same as usual" - and, of course, it wasn't.

Best bit of this link is the full "folding" process at 3 min 55 sec. Staggering. We must assume the propellers/rotors are "sacrificial" in the event of a forced landing from horizontal flight.
https://www.youtube.com/watch?v=57LfifvsTSg

[clockworks]

rockin said:

Osprey does have a very distinctive sound. The first time one flew over us I went outside to look because I though to myself "that Chinook doesn't sound the same as usual" - and, of course, it wasn't.

Best bit of this link is the full "folding" process at 3 min 55 sec. Staggering. We must assume the propellers/rotors are "sacrificial" in the event of a forced landing from horizontal flight.
https://www.youtube.com/watch?v=57LfifvsTSg

It did have a very unusual sound. A constant rumble/drone, no harmonics. I guess that's because of the relatively short rotors and common gearbox?

The last time I heard a noise like it was when my subwoofer's output transistors failed.

[56Lotus]

I live in West Devon and last week we had the pair of Ospreys fly directly over our house, very noisy.

Whilst out for a walk yesterday we had a Bell AH-1Z Viper and A N Other Heli fly directly over, very low and vey impressive. Wouldn't want to be on the wrong end of that.

I'm assuming it's all to do with the upcoming G7 conference.

[Terry Tibbs]

I live not too far from Hereford, I quite frequently have ‘their’ Osprey fly over my house, usually at night and very low - it makes the windows shake! The first time I wondered what the hell it was, it’s got a sound all of its own.

[Johnnytheboy]

There's a thread about these in which I reported two flying over my house in Dorset, like a week ago?

[anonymous-user]

clockworks said:

relatively short rotors and common gearbox?

It's an aspect of the thing that fascinates me. My simple engineering mind suggests one or more of these,

• They've got some very clever engine management system that keeps engine rpm exactly matched, or
• They've got a very good limited slip differential in the middle, or
• Both

But then I've never understood how Johnny American sends a quarter mile long diesel train on a 1,000 mile journey with four locomotives all playing the same tune. Is there some sort of magic torque equalisation process? I guess the same question much arise in a simple electric train with multiple motors...

[clockworks]

One has just flown overhead, heading into Culdrose. Ferrying in another load of spares for the broken one I guess.

An impressive sight

[GliderRider]

rockin said:

clockworks said:

relatively short rotors and common gearbox?

It's an aspect of the thing that fascinates me. My simple engineering mind suggests one or more of these,

• They've got some very clever engine management system that keeps engine rpm exactly matched, or
• They've got a very good limited slip differential in the middle, or
• Both

But then I've never understood how Johnny American sends a quarter mile long diesel train on a 1,000 mile journey with four locomotives all playing the same tune. Is there some sort of magic torque equalisation process? I guess the same question much arise in a simple electric train with multiple motors...

On the V-22 there is a transfer shaft which allow it to continue driving both rotors in the event of one engine failing. It can't generally hover on one engine though, nor feather the blades.
I imagine that there are torque sensing devices connected to the DECUs (Digital Engine Control Units) to ensure both sides remained balanced in normal operations.

Edited by GliderRider on Monday 19th April 15:48

[Pilotguy]

clockworks said:

One has just flown overhead, heading into Culdrose. Ferrying in another load of spares for the broken one I guess.

An impressive sight

I got some photos of it, passing over Breage, on appch to Rwy 11 I’ll upload a couple when I’ve walked my dog.

[clockworks]

Pilotguy said:

I got some photos of it, passing over Breage, on appch to Rwy 11 I’ll upload a couple when I’ve walked my dog.

I'm just up the road from Breage

[Pilotguy]

clockworks said:

Pilotguy said:

I got some photos of it, passing over Breage, on appch to Rwy 11 I’ll upload a couple when I’ve walked my dog.

I'm just up the road from Breage

[Pilotguy]

I was on the shadow side of this approach, some brilliant ones done by Kai Greet and Bob Sharples (on Facebook) the other evening and yesterday https://twitter.com/KaiGreet/status/13838048543641...

[clockworks]

Just spent an hour looking at Kai Greet's pics on Facebook. Some really interesting stuff there

[Harrison Bergeron]

Protip: Go on https://globe.adsbexchange.com/ and there should be 3 buttons at the top of the map - U H T
clicking U should hide all the civilian stuff and just leave you with Military.

[jonny142]

Oops ... Addenbrooke's Hospital Helipad today

https://www.youtube.com/watch?v=ObfdLy-QlsU