G Forces, noise in Spitfire during dog fight

[tartare]

All - tried to Google this but not much insight.
Was watching the David Jason show on Battle of Britain last night.
Two things that aren't often mentioned in discussions about Spitfires are the G-forces, and the noise.
I remember Mark Hanna saying piston engined fighters will generate G-Forces that will rival a fast jet.
Does anyone have a sense of the sort of positive g's a Spitfire pilot might have pulled during a dogfight - I would have thought 4 to 5 at least in a tight turn or pullout (aware of the limit on negative g's due to the Merlin being starved of fuel). I guess they saw the beginning of G-LOC as a phenomena back then. What were the positive g limits on the airframe? And no speed jeans in 1940...!
Also the noise - I imagine 1100hp of Merlin, plus 8 .303's must have been absolutely bloody deafening for a 22 year old lad - yet surprisingly, a lot of the few who are now interviewed seem to have pretty good hearing for old blokes, as opposed to say, the Mitchell crews - many pilots of which were deafened by proximity to exhausts.
Only increases my admiration for them - sweat, noise, cordite, g-force and fear...

[500N]

Can't answer your questions but just wanted to say I thought it was a great program that showed more than just the pilots.

The behind the scenes observers, plotters, ground crew and others was as interesting as the rest.

I still remember my grand mother telling me about the massed formations of bombers in the sky and the criss cross of planes as they fought above England.

Anyway, great show.

[sisemen]

I seem to remember reading somewhere that the relatively high survival rate of BofB pilots was down to their inexperience and low hours on type.

On their first or second sorties with fear coursing through their veins any call to say that there was a 'bandit' on their tail caused them to look round over their shoulder trying to see the attacking aircraft. Sub consciously they were also pulling back on the stick while they did this (I know this happens 'cos I have to stop myself from doing it when flying). The result was, with high performance aircraft like the Hurricane and Spitfire, an instant stall and spin taking them out of the line of fire. The pilot then bales out (hopefully) and lands back on British soil thence to fight another day (and with a whole heap of combat experience under his belt).

[NutLoose]

I read one of the advantages Bader had, was with the lack of legs he had a higher tolerance to G forces than those he was flying against, due to not having to problem of blood pooling in them.

[Hydromet]

Can't help, but 'twas a great show.

[RedDragonFly]

Ive not flown in a Spitfire but have some hours in a P51. It was very loud, even with a headset on, can only imagine how it was with the old leather helmet on. We did aeros and I think pegged at +4.5 and -1G.

[John Eacott]

The G depends on what you do, I guess, but I (as a rotary driver) found it relatively benign. The noise was something else: the lovely Merlin howl is more akin to a Fergie tractor inside, and when the battery ran out on the DC ANR headset I found it very, very noisy. Far worse than a day of Helitak with the door off :eek:

But I wouldn't have swopped it for all the tea in China :ok:

Video and audio (http://gallery.me.com/johneacott#100559/DSCN3546) :cool:

[tartare]

Great video John.
See what you mean about the tractor sound.
Right.... That is another thing to put on the bucket list.... Fly a Spit...

[Skittles]

I imagine that the 'G' pulled depends on exactly how much you require. Probably an awful lot more than you might think.

[Evalu8ter]

Although a great experience, it's difficult to judge wartime performance on a preserved machine. Sensibly, owners will limit g and other stresses on the aircraft (such a power settings) to preserve fatigue life and maximise TBO. The P51 pulled enough g in wartime configuration to warrant a g-suit; many Mustang aces attribute the extra g they were able to sustain (and the K14 gunsight) as the reason they were successful. Mind you, the virtual cannon-fodder that the Luftwaffe were putting up in early 1945 probably helped....

[dat581]

G-suits did exist by the end of the war. Commander Crosley's book "They gave me a Sea Fire" describes the use of a water filled G-suits by the British Pacific Fleet after 1944. If the RN was using them the suits should have been avaliable to the RAF, USN, USAAF etc.

[Brian Abraham]

G limits. The specification (No. 7/30) for the prototype Spitfire called for the following,

5 Structural Strength

(a) The strength of the main structure when carrying the load specified in paragraph 3, plus 100 lb shall not be less than as specified hereunder ——

Load factor throughout the structure with the centre of pressure in its most forward position 9.0.

Load factor for wing structure with the centre of pressure in its most backward position in horizontal flight 6.0

Load factor in terminal nose dive 1.75

Inverted Flight

(1) Load factor at incidence corresponding to the inverted stall and with C.P. at 1/3 of chord 4.5

(2) Load factor at incidence appropriate to steady horizontal inverted flight and at the maximum speed of horizontal normal flight 4.5

(b) The alighting gear must be able to withstand an impact at a vertical velocity of 10 feet per second and at this velocity the load on the alighting gear must not exceed three times the fully loaded weight of the aircraft.

(c) When subject to the impact forces on alighting, as specified above, the load factor for the alighting gear must not be less than 1-1 /3, and for the remainder of the structure not less than 1-1/2. The load factor for the structure and the attachment fittings of the alighting gear must always be greater than that for the alighting gear itself by the margin indicated above.

(d) The maximum weight per wheel of the aircraft in pounds must not exceed 12 times the product of the wheel and tyre diameters in inches with the aircraft carrying the full load specified above.

(e) The above factors are to be determined by the approved official methods as published by the DTD and the detail requirements given in A.P.970 are also to be satisfied. With a view to minimising the risk of flutter, attention should be given to the recommendations of A.P.l 177, particularly as regards the static balance of ailerons.

(f`) The wing is to be sufficiently rigid to withstand satisfactorily any torsional or other loads which may be encountered during service operations.

(g) Ribs (both mainplane and tail unit) are required to develop, on test, factors 20% greater than those specified for the aircraft as a whole.Many a Spitfire was lost due to overstressing.

[lsh]

G-suits did exist by the end of the war. Commander Crosley's book "They gave me a Sea Fire" describes the use of a water filled G-suits by the British Pacific Fleet after 1944. If the RN was using them the suits should have been avaliable to the RAF, USN, USAAF etc.

Gill's uncle was given a water-filled one to trial in his Spitfire.
It kept leaking and led to lots of mickey taking from his mates;
"wet yourself when you saw the enemy did you Steve"?!

I talked to a Sea Fury pilot at Yeovilton, he had pulled 12g coming
off a target in Korea - it rippled the wings!
(The g-meter was for the maintainers and located in the wheel well).

lsh
:E

[Agaricus bisporus]

I was lucky enough to get a ride behind the late Lefty Gardner in his gorgeous P51 and though I then had little aviation experience to go on did not find it excessively loud. I was surprised at how smooth and deep the engine sounded (none of the Merlin crackle) and how regular - constant - the sound was. A loud Fergie tractor is actually a very good description. Integral cloth helmet so not much sound moderarion. It was much more mechanical noise and a lot less exhaust and prop than spectarors get. I recall lot of blower +gear whine and a whole gamut of noise from the mechanical parts which at first sounded a bit alarming as you never get that outisde - as with a car, but drive one stripped down and you hear every tappet, valve, camshaft and piston yammering away. Guns over all that? I'd guess more of the same, a deep mechanical drumming from the breech-blocks and little muzzle noise.
G? Sheesh! Six and then some I reckon. I had done a couple of aerobatic flights before and knew to stave off GLoC but it didn't work with Lefty. 350Kts on a knife edge between his house and garage looking up at the first floor windows (I swear it!) and pulling 3 or 4g was his way of saying "Honey I'm home". Then land on his short, very stony and rough strip, pause at the road to check for cars, taxi across, onto the grass and park by the pool.

[Halton Brat]

I have read somewhere (written by a WW2 fighter pilot) that the cockpit sound of x8 .303 Brownings being fired in anger was akin to the noise produced when a calico sheet is ripped.

The noises produced by the human body when these guns are fired in one's general direction are best left to the imagination..............

HB

[mmitch]

In Bob Stamford Tuck's bio 'Fly for your life' he mentions testing a captured 109 and found the pedals were much higher than his Spit.
He found he didn't black out so easily when pulling out of a dive.
He had his Spit pedals raised with the same effect.
mmitch.

[airsound]

During 1990 (BoB 50th anniversary year) I was lucky enough to do various radio and tv programmes about the Battle, mostly for the Beeb. For one of them, a 25min 'Outlook' programme for World Service, I managed to blag a ride in Charles Church's 2-seat T9 Spit, flown by the lovely Reg Hallam. The idea was to record the opening and closing of the programme.

At the time, I reckoned I could record my own voice over any sound, just using a normal reporting microphone. (Just turn the gain right down, then shout loud enough to make the needle kick.)

Well..... At any throttle setting other than the minimum for level flight, the noise was so humungous that I couldn't even get the tiniest quiver out of the needle. So I had to ask Reg to keep it at that minimum while I did the two pieces - and even then, the recorded result has me very obviously shouting at the microphone.

I agree with Agaricus that the noise is totally different to the sweet sound you get when you watch from the ground. John E's lovely recording captures it very well.

As a matter of interest, I have also flown in a P51, and I thought the noise was pretty much the same - but then, they are both Merlins, even if one was built by Packard!

I was perhaps even luckier later that year, when I got to fly in the Lanc over Buck House for the memorial flypast. I was reporting live for Radio 4 and pre-recorded for telly, with Raymond Baxter. So it was a very good year for this lover of anything aeronautical!

Happy days
airsound

[Tankertrashnav]

From time to time I bump into Geoffrey Wellum (author of First Light) who lives locally. At 91 there certainly seems to be nothing wrong with his hearing (or any other faculties for that matter) so he obviously coped with the noise levels very well.

[spannermonkey]

Also had the pleasure of meeting Geoffrey on a number of occasions and remember reading in his book that he used to put his feet on the top of the pedals so he could pull harder on the stick. Don’t recall the G he would hit but its in the book.

[AvMed.IN]

One of the earliest 'high G' aircraft was Sopwith Pup, a 1916 vintage, canvas wing bi-plane with wooden frames. This aircraft could do a controlled bunt, with structural limits of -5G! It could also make a U-turn in less than 200 yards, building up almost 8 G in the process…

G-LOC (http://www.avmed.in/2012/06/g-loc-then-and-now/) was known as early as 1919, then called as 'fainting in the air'. and the anti-G suits (http://www.avmed.in/2012/06/protection-against-the-g/), which are still in use, date back to mid-1940's, Cotton's was air-filled (like the present ones) and Frank's was water filled.

[DeepestSouth]

I asked my ex-Mk IX and Mk XVI (and P-51B, Beaufighter and Catalina) pilot neighbour - he was 90 last week! He has hearing loss but described the noises as not unbearable - you got used to it! One thing he DID mention was that under G the Spitfire 'creaked' as the wings and tail flexed - a bit worrying until you realised that it was perfectly normal. he gun noise was not siginificant on the Spitfire but certainly was in the Beaufighter.