Merlin negative G cutout too quick?

[VO101_Tom]

Originally Posted by Crumpp

It is a cut scene from a movie that has nothing to do with reality.

Why? As far as I know, the aircraft were original, and there was no CG in 1969...

[Crumpp]

Why? As far as I know, the aircraft were original, and there was no CG in 1969...

So what?

Many original aircraft have been used in movies. These are real aircraft AND plenty of cut scenes with no CG either....

http://www.youtube.com/watch?v=l8wmyCcbnX0&NR=1

[klem]

Originally Posted by Crumpp

I did watch the video. It is a cut scene from a movie that has nothing to do with reality.


I just checked the Mk I Operating Notes. Flying inverted is normal provided the engine is set up not to foul the aircraft with glycol and oil. It is done at high speed with the throttle closed and the pilot is instructed not to reopen the throttle until oil pressure is restored.

Crumpp, are you dure you're talking about the same movie? We've been discussing the film of Alex Henshaw flying an early MkVa:
http://forum.1cpublishing.eu/showpos...&postcount=152

[winny]

Originally Posted by Crumpp

I did watch the video. It is a cut scene from a movie that has nothing to do with reality.

It's Alex Henshaw, one of the chief Spitfire test pilots, flying a MkV in early 1941, at the Spitfire factory in Castle Bromwich. It's real.
It was filmed for the Americans to show how 'well' the British were getting on with the war. That's why the American guy is in it.

The flying is real, the Mk V has the 'orifice' fitted. If you listen carefully you'll notice that the engine does over-rev when the power comes back on.

[41Sqn_Banks]

Originally Posted by winny

The flying is real, the Mk V has the 'orifice' fitted. If you listen carefully you'll notice that the engine does over-rev when the power comes back on.

Not sure about that. The RAE restrictor only works at full throttle.

To me it sounds like the pilot closes the throttle during the inverted flying and quickly opens it after it (which causes a slight overrev). There is no RAE restrictor needed in this conditions.

[Crumpp]

We've been discussing the film of Alex Henshaw flying an early MkVa

I did watch the video. It is a cut scene from a movie that has nothing to do with reality.

[Osprey]

Originally Posted by Crumpp

I did watch the video. It is a cut scene from a movie that has nothing to do with reality.

Was it a CGI flypast then?

[CaptainDoggles]

You guys know there was lots of Hollywood trickery going on before computers were invented, right?

Doesn't have to be CG to be inaccurate.

[Fenrir]

There is nothing more sinister going on here than crummps partisanship. For some reason there's a selection of people with an axe to grind against the Spitfire and Crummp falls particularly into this particular sorry species.

The fact is if he had done ANY research on ANY of the readily available tomes of the Spitfire (the volumes by Alex Henshaw and Jeffrey Quill for one, both Spitfire pilots and people with a far more qualifed opinion on practical aerodynamics than Crummp I am sure) he will know that the various quotes he has selected are, as typical, cherry picked examples of well known and quickly corrected faults with the Spitfire.

1) Spitfire Stability in Pitch: The Spitfire was certainly not UNSTABLE in pitch but the stablity it did have was MARGINAL. Big difference. as long as the CofG was kept within limits then the a/c was perfectly safe. The issues that affected only Mk.V aircraft of vicious spin characteristics and some strcutural failures were as a result of Squadron a/c being poorly loaded and supermarine directives not being followed at squadron level regarding the loading of new equipment and pushing the CofG out of limits. Bob weights and eventually a redesigned elevator mass balance actually cured this. See Quills book.

2) I suggest he actually reads Henshaws description of his fairly standard aerobatic routine that he was regularly called on to display and is accurately described in his book, Sigh for a Merlin:

p.54, Sigh for a Merlin, Testing the Spitfire by Alex Henshaw

On the pull out from the flick roll, sometimes I would open the engine flat out in another vertical climb and at approximately 1200ft push the nose over forward and with engine closed complete the half of an outside loop, usually in those days called a bunt. I never really liked this manoeuvre either; it was easy but required heavy pressure forward on the control column and you could not afford to misjudge at 1200ft: with the nose going over down towards the ground the speed built up at such an alarming rate that it left no room to change your mind until it was too late. A the bottom of the inverted dive I would usually round-off to a few feet above the ground and then with as much pressure as I would dare on the control column - I say dare because I found it more disconcerting and frightening to black out from excessive negative g than I did from high loads in the postive position - I would push the machine into an almost vertical climb and then as it lost momentum from the negative g position pull the control gently over to form a half loop hoping as I did that the engine would burst into life as I opened the throttle. This it usually did with a spectacular sheet of flame pluming from the exhaust stubs caused by the unused fuel which had accumulated during the inverted manouevres.

Though according to Crummp that couldn't possibly have happened could it?

Agenda boi much!?!?!

[robtek]

Originally Posted by Fenrir

There is nothing more sinister going on here than crummps partisanship. For some reason there's a selection of people with an axe to grind against the Spitfire and Crummp falls particularly into this particular sorry species.

The fact is if he had done ANY research on ANY of the readily available tomes of the Spitfire (the volumes by Alex Henshaw and Jeffrey Quill for one, both Spitfire pilots and people with a far more qualifed opinion on practical aerodynamics than Crummp I am sure) he will know that the various quotes he has selected are, as typical, cherry picked examples of well known and quickly corrected faults with the Spitfire.

1) Spitfire Stability in Pitch: The Spitfire was certainly not UNSTABLE in pitch but the stablity it did have was MARGINAL. Big difference. as long as the CofG was kept within limits then the a/c was perfectly safe. The issues that affected only Mk.V aircraft of vicious spin characteristics and some strcutural failures were as a result of Squadron a/c being poorly loaded and supermarine directives not being followed at squadron level regarding the loading of new equipment and pushing the CofG out of limits. Bob weights and eventually a redesigned elevator mass balance actually cured this. See Quills book.

2) I suggest he actually reads Henshaws description of his fairly standard aerobatic routine that he was regularly called on to display and is accurately described in his book, Sigh for a Merlin:



Though according to Crummp that couldn't possibly have happened could it?

Agenda boi much!?!?!

I, at least, see your agenda, Fenrir.

Crummp says that the spits/hurris are not outfitted for inverted flight!

That is 100% correct!

That doesn't say that said aircraft cannot endure inverted flight for a very limited time.

To be outfitted for inverted (neg g) flight the engine must get metered fuel AND oil-pressure during the inversion.

Afaik all piston drive AC during that time only could endure neg-g, some better than the others.