BeermatGraham B, the reason the Whirlwind was not moved South to join the Battle of Britain was laid out by Dowding in September in a letter to the Ministry in September 1940, still available at TNA. He reasonably said that it wasn’t right to put it into a battle that was being fought at altitude when it was having all these problems at height.
It should be more than a footnote that it was a successful operational ground-attack aircraft for years afterwards, with no changes and few complaints.
BeermatTrumper, it wasn’t fitted to any other ‘production’ airframe at all. Just a Battle test-bed and a Gloster prototype twin. However, by another name.. essentially the Peregrine was a developed Kestrel. Another reason those decrying the engine as a design have it slightly wrong.
BeermatStephen, email on its way.
BeermatThanks folks. NII VVS that was greatly appreciated. I know it would be possible to run away with the idea of a world-beater held back by a single Achilies heel, and that things are never that simple.
I was really looking at the specific difference between the satisfactory performance of the Rotol-equipped prototype, claimed at the time of testing to be ‘identical to a squadron machine’ (and to be fair this was equivalent to a MkI Spitfire, so pretty good for the time) and the dH equipped aircraft that ran into RPM problems before they reached 30,000ft.
The lack of appreciation of prop compressibility is shown by the fact no-one thought a differently profiled prop meant the aircraft were far from identical.
All things being equal, hypothetically more powerful.engines, 2-stage superchargers etc would not have helped – the brick wall would have been run into with these props. In the real world the chances of selecting 9.6% RAF-section props again for the new engine would have been slim. These were unusual.
Nail in the coffin.. maybe more of a ‘last straw’. The early reports of RPM drop at height went straight to Dowding, and thence to Beaverbrook.
Whether production of any more Whirlwinds, and/or Peregrines, would have been a good idea anyway is another question.
There is an irony in that the wing root of the Whirlwind looks like it was designed very deliberately for a high Mach. I wish I could prove this was the work of JCM Frost, but so far it’s just a Wiki claim.
I am very interested in other examples of prop inefficiency sabotaging other types at the time. I am thinking about a book exploring both the beauty and limitations of design-by-eye in the thirties and forties.. the P-38 is another example.
BeermatIt has nothing in common with any part of the original thread. But it’s still recognisably a thread, and it may as well carry the same identity as it did when it began its service life. I would say that its useful service life is over, but there’s no reason it shouldn’t remain active for the edification of the masses (liked that, propstrike).
BeermatThat’s the classic ‘Just flown in a warbird’ grin at the end there! Thanks for posting.
BeermatIt was Graham who raised it as a possibility at high speeds, though I think we agree it isn’t directly causable by merely painting.
The oscillation of a control surface is bilateral, caused by a resonating dynamic ‘feed-back’ between varying aerodynamically and mechanically induced moments of inertia. This occurs at a specific harmonic frequency. Change the centre of mass relative to the pivot on one of the moving bodies and you change its fundamental frequency, such that you might get ‘constructive’ feedback causing oscillation, ie you hit a ‘harmonic’.
The vibration of a flap isn’t a bilateral oscillation as such, its a buffet. Moving the centre of mass of the flap might alter the buffet frequency, but as it’s a mechanically truncated, asymmetric and low-amplitude rattle not a smooth and symmetrical wave it is less likely to hit any kind of harmonic with the aerodynamic behaviour of the flying surface to which it is attached, however you paint it. I am struggling for an analogy, but when I get one I’ll write it 🙂
Is there any possibility the aim was to avoid any paint in hinge or actuator mechanisms?
BeermatI am not at all certain that flap-flutter is at all common, in the same way as control-surface flutter. A flap is held rigid against the airflow – in any given deployment it is meant to remain static relative to the airframe, regardless of any variation in force applied. An aileron, elevator or rudder can move freely on a pivot, it isn’t ‘propped’ in position, for want of a better phrase. It is this potential freedom of movement, combined with torsion when acted on by variable forces that can cause an oscillation of the control surface. So I am not convinced that not painting flaps was about avoiding flutter.
The other element of flutter, aeroelasticity, might cause flap-flutter, possibly as part of a larger wing flutter – but a bit of paint wouldn’t make a solid object held rigid against the airflow (or for that matter held flush to the wing) flutter, in the way it might affect a ‘balanced’ control surface.
BeermatSomebody is going to be very disappointed if they do a bit of research on this item:
Because I’ll guarantee it isn’t from a Do17 that was shot-down on 15th September 1940 during the Battle-of-Britain!
Trouble is no-one ever seems to own up to having been taken in, or surely he couldn’t continue defrauding punters. As that’s the only way eBay or the authorities will be moved ro deal with this crook it looks like he will continue to take the mickey.
BeermatRunning with the ship of Theseus philosophical model for a moment..
If that ship has every plank replaced, is it still the same ship..
The solution is to think of NH341 as a four-dimensional Spitfire. Obviously. https://en.m.wikipedia.org/wiki/Perdurantism
A bit like the famous “Schrodinger’s Burmese Cat”.
BeermatI had no idea that the dataplate / identity /FB’s Luton Minor discussion is an ancient one of Philosophy and Metaphysics that goes back to Plutarch in the first century AD and before.. https://en.m.wikipedia.org/wiki/Ship_of_Theseus
BeermatBig point, that. Consider the difference in quality between something put together by roped-in shift workers under time pressure and across multiple sites, and only expected to last a couple of years, and something lovingly and carefully hand built by a single team of type specialists.
Another point is you are putting your original material at risk if you fly it around, in the way you are not if you leave it in a museum and fly a new-build. Surely everyone wins?
BeermatDo we really have a grip on what we are discussing when we talk of ‘destroying’? If it really is just a dataplate being born aloft by a newly built aeroplane, what gets destroyed by removing it from the donor wreckage? Maybe a bit of drilling out of the rivets, at very worst? If it’s a copied stencil, then there is NO net effect on ‘historic material’.
Of course, the ethical aspect of telling punters they are flying in an original without qualifying that description, if that is what anyone’s doing, is an entirely different question.
I suspect from my own limited exposure to it that the world of ‘original’ statics being ‘restored’ to museum standard destroys far more ‘historic’ material (as in my previous example of reskinning) than the use of a convenient dataplate for a flying aircraft. Those paying to put something for us all to enjoy in the air and doing what they have to do to make it possible are probably the wrong target, if you need a target at all.
BeermatYes. And as long as the unused parts are preserved where necessary, appropriate and possible. In truth if you have ever tried removing tangled and torn metal skinning from a useable structural component you will know you are a) making knackered scrap more so in the process while b) making the ‘good’ part useable again, even as a reference, at the very same time. In this case the ‘scrap’ alloy sheet says very little to posterity.
As for identities, if that troubles one, there is no real harm or cause for confusion in both the flying dataplate and the rusty lumps co-existing. The lumps are just previously-used components of the flying thing.
BeermatLet’s step back and look at this without recrimination – very few of us here are in a position to criticise anyway.
What we have is a regulatory reason to use a dataplate. Nothing more. No one is trying to deceive or destroy.
You want an original? Fine. Go dig up your own. You will have what to the uneducated is a pile of corroded metal. Often a very worthy excercise, and very far from scrap. I have some myself.
It is not a flying machine. To remain flying the machine frequently needs new parts. It is no less that type of machine – the parts must work as a part of a mechanical and aerodynamic ‘whole’ and that ‘whole’ is called ‘Spitfire’, ‘Cub’ or B-17. That’s just the way it is. The rest is bureaucracy.
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