Talk:Supermarine Spitfire variants: specifications, performance and armament/Archive 1

Archive 1

Necessity of this article

Is this article really needed? The name is too long! And I think all the variant and performance info should go in 1 page. --Fireaxe888 (talk) 17:20, 11 September 2008 (UTC)

How many articles are "really needed" in Wikipedia? If you can think of a better title for the article then, by all means, discuss your thoughts with those of us who have spent hours working on it :). The reason the information is in more than on page is that it would be near impossible to present all of the data on one page, given the limitations of the Wikitable format; things would be so squeezed in that it would be impossible to read.Minorhistorian (talk) 10:49, 12 September 2008 (UTC)

I removed this eulogy as it is pointless and totally untrue:

It is notable that throughout the entire development process, which took place over twelve years, from 1935 through to 1948, there were no outstanding failures of the basic design: this is a real testament to the original genius of Reginald J. Mitchell, his successor Joseph Smith, and the design teams they led.

The reference to Mr McKinstry's book ignores the problems with the Mark 5 that led to the use of the heavier engine to help restore longitudinal balance. He cited Jeffrey Quill as deciding the reason for (at least 25) frame failures being slight errors in loading the airframe, yet the initial project for the Seafires was tried out on the same badly stressed marque. that had blown at least one pilot through the roof, parachute included.

I'd like to hear the results of the enquiries following those. That's how many articles this free and unbiased website needs But sabotage was covered up in the emergency. So how come the eulogist missed all that?

The same reason that he missed the point McKinstry made about the shambles of it's design team causing World War 2?

Weatherlawyer (talk) 13:16, 4 September 2015 (UTC)

The in-flight breakups were caused by incorrect loading by some squadrons leading to a too far aft CofG causing longitudinal instability. This, if the pilot relaxed his pressure on the control column momentarily, caused the aircraft to 'flick' nose-up or nose-down during high speed dives or to suddenly tighten into or out of high speed turns, causing over-stressing of the wings. Some squadrons had added additional operational equipment in the rear fuselage aft of the CofG, such as dinghies, new wireless equipment, etc., which led the aircraft's CofG to move rearwards out of its safe range.

The problem was cured by introducing a bob weight into the elevator control cable circuit and by enforcing correct loading standards on the squadrons. The bob weight modified the 'stick free' stability of the aeroplane by adding some damping to the elevator control. Once this had been done the problem 'disappeared'. IIRC, some Mosquitoes also had a bob weight so-fitted.

It was because 'flick manoeuvres' cause sudden greatly-increased loads (and therefore, stress) on an airframe that such manoeuvres were forbidden for many RAF aircraft of the period. At normal speeds an aeroplane will usually stall, but at high speeds, the sudden application of large amounts of lift before the wing has a chance to stall can fold the wings up.

BTW, in high speed dives, or tight, high speed turns, the aircraft's mass and apparent weight, and thus the load on the wings and other surfaces when attempting to change direction, is increased by inertia. — Preceding unsigned comment added by 2.29.18.221 (talk) 13:11, 22 November 2015 (UTC)

Clearly Weatherlawyer doesn't have have properly referenced material that will back up his claims about "problems with the Mark 5 that led to the use of the heavier engine to help restore longitudinal balance" (in itself is a completely erroneous assertion about why the Mk V used the Merlin 45 series). He might not like the so-called "eulogy" but with nothing to prove the basic statement wrong, there is no reason to remove it. ◆Min✪rhist✪rian◆MTalk 23:59, 22 November 2015 (UTC)

Quite so. IIRC, the Merlin 45 introduced the two-speed supercharger and it was for this reason the engine was heavier. Similarly the Merlin 60-series introduced a two-stage supercharger, and this engine was even heavier than the 45.

It was for reasons of CofG position and longitudinal stability that it was not possible to install a rear fuselage fuel tank in the Spitfire like was done with the Mustang III and later, as with any additional weight aft it would have made the aircraft unsafe to fly. The additional weight aft in the Mustang also affected stability but the tank was only full at the start of a mission, and provided the flying was restricted to straight-and-level with no violent manoeuvres until the rear tank was nearly empty the Mustang was still reasonably safe for the average pilot to fly - as fuel in the rear tank was used so the CofG moved slowly forwards until it was back within the normal range. IIRC the addition of an elevator bob weight on the Spitfire did allow the safe CofG to be moved aft to some extent, but not enough for a fuel tank.

BTW it was because flying with a too far aft CofG is so dangerous that airline passengers are now by law made to be in their seats strapped-in before landing. With an incorrectly loaded aeroplane with a too far aft CofG a passenger or two walking towards the rear of the cabin, e.g., to use the lavatory, while on the approach or landing can shift the CofG just sufficiently rearwards to cause the aircraft's nose to suddenly rise with a resultant stall of the aircraft. — Preceding unsigned comment added by 2.29.18.221 (talk) 11:38, 23 November 2015 (UTC)

References

Corrections to the information on Supercharging

There are some errors in regards to the effects of altitude on air mass and density. While air density decreases with altitude the fundamental change is that the weight of air decreases as a ratio of altitude; as a result an engine will have to draw in three times the volume of air at 30,000 feet as it does at S/L to create the same amount of power. I find a really useful book to have is an old one I found in a book store some years ago; Aircraft Power Plants by the Northrop Aeronautical Institute published in 1955 by McGraw Hill Books. I would recommend this to anyone who is interested in aeronautics because it describes everything related to WW 2 aero engines like the Merlin without being too scientific. It does turn up on the likes of Amazon from time to time http://www.amazon.com/s?ie=UTF8&applicationContextPath=%2Fgp%2Fsearch%2Fconstruct-application-context.mi&index=books&field-keywords=Northrop%20aircraft&page=1 plus most libraries would probably have a copy.Circlingsky (talk) —Preceding undated comment was added at 00:53, 20 September 2008 (UTC).

Image copyright problem with File:303 plane picture.jpg

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Beatrice Shilling's Contribution

The statement that "The remedy, invented by Beatrice "Tilly" Shilling, was to fit a metal diaphragm with a hole in it was fitted across the float chambers. It partly cured the problem of fuel starvation in a dive." is wrong. This story must be in hundreds, perhaps thousands of books; but it is inaccurate. Miss Shilling's contribution was to solve the problem of flooding of the carburettor by the fuel pump, which followed after the initial fuel starvation, as under negative g the float was pushed down by the fuel on top. Her solution was to install a diaphragm in the fuel line (not the carburettor) to restrict the fuel flow to the maximum the engine could consume. (A reasonably complete account can be found in Aeroplane Monthly of February 1997; see also 'British Piston Aero-Engines' by Alec Lumsden.) Mutatis Mutandis (talk) 19:40, 28 August 2010 (UTC) Weatherlawyer (talk) 13:39, 4 September 2015 (UTC)

Normal atmospheric pressure

The article has this as 14.5 but the International Standard Atmosphere is 14.7 at sea level. (1 bar = 1000 millibars and these do equal 14.5 psi, but this is not normal pressure!)

86.176.165.167 (talk) 22:59, 17 December 2011 (UTC)

Yup, the precise measurement and calculations have varied over several decades so that the current standard is 14.6959 or 14.696 psi, depending on the source; eg: [1]. During the 1940s the standard atmosphere was often rounded to 14.5 psi, again depending on the source. ◆Min✪rhist✪rian◆MTalk 09:23, 18 December 2011 (UTC)

Suggestions for improving this article (and others come to that)

To kick this off I have a couple of suggestions. The first is that in the useful table of data there should be dates of production and into general service. This information is actually very important and tends to be lacking, or difficult to find, in many Wiki articles on WW2 planes, putting it in the table would make it easy to find. I actually think whenever any specifications for any plane are given (on any page) the dates should be included otherwise it`s a bit meaningless reading performance specs about a plane which may bear no relation to how it was at the time in history that you`re interested in. Secondly any acronym (e.g. F.S) should be explained, if necessary by means of a link. Using the example given I`ve no idea what F.S. means and couldn`t (by skim reading the whole article, why should one have to do that anyway ? ) find out either. Always bear in mind many people don`t actually read the whole article they may just read the section they`re interested in.--JustinSmith (talk) 08:55, 2 June 2012 (UTC)

Hi Justin, Re: your first suggestion about dates of production etc: the problem here is that this would involve some intensive research particularly when different marks or sub-types were being built at the same time - eg; The Spitfire V and IX series, both of which were produced in very large numbers, overlapped in production and in serial number allocations, and many Mk Is were converted to Mk Vs, so determining, for example, when the first and last Mk Vs were built could be tricky - your suggestion about a general in service date is more practicable.

F.S = "Full Supercharger" M.S = Moderate Supercharger and was descriptive of the gear ratio used to drive the supercharger's impellors - this is now in the second paragraph of a new section on the two-stage, two-speed superchargers. If you have any other thoughts on improvements don't hesitate to add. ◆Min✪rhist✪rian◆MTalk 11:57, 2 June 2012 (UTC)

That`s better !--JustinSmith (talk) 09:34, 3 June 2012 (UTC)

No problem; I've also had a look at your other thoughts on the Supermarine Spitfire talk page Cheers ◆Min✪rhist✪rian◆MTalk 12:45, 3 June 2012 (UTC)

Just to further confuse everyone, Full Supercharge (FS) and Moderate Supercharge (MS) are also sometimes described as "S ratio" or "High blower gear", and "M ratio" or "Low blower gear", or more simply "High gear" and "Low gear" respectively. — Preceding unsigned comment added by 2.29.18.221 (talk) 13:35, 22 November 2015 (UTC)

Ram jet assisted Spitfire

I would like to propose the following addition to this article after boost pressure. Can anyone think of anywhere better to insert it?

Ram jet assisted Spitfire

In an attempt to boost the performance of the Spitfire Mk1 in May 1940, RAe scientists (including Hayne Constant) developed a 'propulsive duct'. This was in essence a simple ram jet, fed by petrol, utilizing the Meredith effect. It was housed in a 48"x30"x15" deep duct mounted on the fuselage centre line and resembled a third radiator. Bench tests showed that the increase in speed was not significant and the device was not flight tested.

In 1943 the idea was reconsidered as a counter to the threat of the V1. Aircraft such as the Hawker Tempest and Gloster Meteor were not widely available and the Spitfire would only be able to intercept in a diving attack. A.D Baxter and C.W.R Smith at Farnborough reviewed the 1940 work and concluded that it was practical. However, problems with drag and pressure loss were encountered and the V1 had been beaten before they were solved.

Perhaps someone would like to add a new section on experimental variants such as the World Record attempt "Speed Spitfire", the proposed Crecy Spitfire, as well as the one mentioned above. — Preceding unsigned comment added by 2.29.18.221 (talk) 13:45, 22 November 2015 (UTC)

References

Footnote 3 error

This has 'the second stage starting' &c. but (as explained some years ago) the second stage was always in circuit and did not 'start'.

What caused the jolt was the change in boost due to the change in engine/supercharger gear ratio. 109.145.109.71 (talk) 22:19, 5 May 2016 (UTC)

Boost pressure measurements

Reference 13 does not support the claim made in this paragraph that there was ' a problem with the British system of measuring boost '

A reference for the 'problem' is required - else deletion!

109.145.109.71 (talk) 12:03, 8 May 2016 (UTC)

Mk. 24 engine model

The current specification listing for the Spitfire Mk. 24 on this page states that it uses a Griffon 85 engine. However, according to Alfred Price's "The Spitfire Story" (and another page on Wikipedia itself) the Mk. 24 was identical to the Mk. 22 except for the addition of rear fuel tanks and mounting for zero-length rocket stubs. Additionally, this document states that the Griffon 85 engine had fittings for contra-rotating propellers. These were tested experimentally on the late mark Spitfires with the new wing, but only made it into production usage with the Seafire 47 on, if I remember correctly, the Griffon 88. The Spitfire Mk 21 and onward used a Griffon 61 engine, similar to the Griffon 65 in use on the Mks XIV and XVIII but with a slightly slower-spinning propeller shaft to prevent the tips of the Mk 21 and later models' larger propellers from traveling too quickly. (Some sources state that later Mk 21s used a Griffon 65 as well but I can't find their original information, and based off the paragraph at the end of this document as well as typical aircraft design principles I'm assuming all Spitfires with the redesigned wing used the Griffon 61.) Should the engine model be corrected as such? Fsend (talk) 16:22, 12 January 2021 (UTC)

Merge this article and the other variants article?

https://en.wikipedia.org/wiki/Supermarine_Spitfire_(early_Merlin-powered_variants)

The above article covers the early variants, this one covers the late ones. I feel like merging the two would be good, seeing as they cover essentially the same topic. It might be too long though.