Fairey Rotodyne

[rickshaw]

Are there any three-view drawings of the "Type-Z" Rotodyne?

[Hobbes]

I can't find if the 'dyne had a rotor brake or not, but I imagine that it must have at that period of chopper history.

I wonder if a rotor brake is feasible at all. With the drive torque coming from the rotor tips, you'd stress the blades quite severely if you used a rotor brake.

[Mossie]

Are there any three-view drawings of the "Type-Z" Rotodyne?

Here you go, scanned from Derek Wood's Project Canceled.  The mock up in the book differs slightly, it had two small inner fins mounted on the tail, rather than the single fuselage mounted fin.  The tip jets would have been different too, it's likely that there wold have been nine smaller jets (fitted with square silencers) on each blade rather than a single large jet.  This was part of the noise reduction programme.



Rotodyne Y for comparison:

[rickshaw]

Thanks.  Now I can see the difference.  I've often wondered how the Rotodyne compares to the V-22 as far as noise goes.  I suspect the V-22 is as noisy, if not more so.  Which rather makes IMHO the noise problem for the Rotodyne a bit of a furphy.

[Mossie]

The V-22 is a pretty noisy beast, although it's not as big a problem as it is a purely military aircraft.  A civil market was originally intended but once the development problems set the unit cost rocketing, that put an end to that.

To be honest the noise issue was never really a problem for the Rotodyne.  Fairey, then Westland were well aware of it & took steps to reduce it, see the comments I made on tip jets & silencers in the above post.  Contemporary reports say it was quieter than the DC-8.  By the time the project was canceled, the work done had reduced the noise levels to well within limits set by the CAA.  The high noise level of the early prototype led to the Rotodynes detractors jumping on the problem & they continued to pointed it out, even after the problem had been solved, this is why it continues to persist today.

[kitnut617]

Reading a book on Westland, I get the impression that Fairey was more or less forced on them.  They had just taken over Bristol too so had three projects all aimed at the same thing, Westland had it's Westminster, then they had Bristol's Belvedere and then the Rotordyne. On top of that the book says that Westland was under pressure to get the Wessex into production.  I can see that one or two would have to be cancelled.

[PR19_Kit]

To be honest the noise issue was never really a problem for the Rotodyne. 

Sorry, can you speak up please?

A noisy helicopter-cum-aeroplane deafened me in the lare 50s.........

[Mossie]

You need to tell us more Kit!

[jcf]

Another 3-view of the Type Z, from Fairey Aircraft since 1915, H A Taylor, Putnam 1974 (1984 NIP reprint).

Taylor has the following to say about the Z and noise levels:
"With the power planned for the production Rotodyne the noise level for the existing
tip-jets would have been about 113 db. To achieve the necessary 17-db reduction in
noise level a complete redesign fo the pressure jet was planned. This would have been
in two-dimensional form, occupying the last 48 inches of each blade, with nine circular
flame-tubes in a combustion chamber submerged within the blade profile."


Jon

[jcf]

Just for fun, the original Tyne Rotodyne proposal from Project Cancelled (Second edition, 1990 printing).
I think this would be a doable conversion.

Jon

[Captain Canada]

  I can see that one or two would have to be cancelled.

Very interesting, Robert...I never who have thought of that end of things !

I'm loving this thread...one of those aeroplanes I've always wanted to build. One of these days !

[Mossie]

Another 3-view of the Type Z, from Fairey Aircraft since 1915, H A Taylor, Putnam 1974 (1984 NIP reprint).

That's the one in the Gibbings book.  The mock up was only a fuselage, but it had a sharper beaver-tail.  I'd scan some pictures, but I guess we'll have some copyright issues.

[PR19_Kit]

You need to tell us more Kit!

Mossie,

I thought I'd done that already, but for the record the 'dyne flew some of its test flights from RAF Benson where I was living at the time. Then we were told that it was because the noise level was so high that the Joe Publics who lived near White Waltham, its main base, had complained and the MoD decreed that RAF families' hearing was considered expendable! After reading the Gibbigns book I suspect this was wrong, the real reason being Benson's much larger approach area as they were doing single engine landing tests at the time.

I spent some time perched up on 'My Tree' at Benson (they planted a handy tree right against the airfield boundary fence from which it was possible to get excellent views of the flying etc. I almost lived in it for about 1.5 years  ) The 'dyne would come in from White Waltham and spend all day sitting on the ground with the tip jets running, then lift off and fly away to the west before returning down the 'Benson Slope' to land. The noise level was EXCRUCIATING, and you could hear the tip jets start up when it was on the approach from some miles away.

I presume this was before the effective silencers were introduced but there's a lack of exact dates in the book to check.

[Mossie]

Ouch!  I don't remember you mentioning that tale, I probably missed it or my memory is paying tricks on me again!

I'm guessing that even with the silencers fitted, it would still be damn noisy in the immediate viccinity of the aircraft.  The ground crew will probably have been given ear defenders, but sitting in your tree you'll have got the full brunt of it!

[rickshaw]

I remember how loud the Darts were on the F.27 Friendship. I used to hang around the civil airport a lot and the Australian airlines used to operate them on short-haul routes.  They were, to me as a child extremely loud.  I wonder though, how they do in comparison to the Rotodyne?