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Supermarine Southampton II

PostPosted: Sun Feb 26, 2012 10:22 am
by schneiderman
Hi all,

I'm trying to establish a chronology for the early days of metal construction at Supermarine and have a couple of questions.
Does anyone know the registration date or first flight date for the prototype Southampton II, N218?
Also this aircraft is said to have been part of the Scandinavian capitals tour in Aug/Sept 1927 along with the Iris II, Singapore and Valkyrie but to have had a wooden hull. Was this actually N218 or another Southampton?

Any other info. on N218 and Supermarine early metal hulls would also be useful.


Re: Supermarine Southampton II

PostPosted: Thu Mar 22, 2012 5:02 pm
by dianariduna
I've been looking through my various books and 'Schneider Trophy to Spitfire by John Shelton talks about the first Southampton (the first name to leave the animal and bird theme in a wish for closer links to its host city)
It says that the specification for R18/24 in Aug 1924 was for a modified Swan and a modified experimental one for the Ministry N218 was fitted with a metal hull. It was streamlined and improved for military purposes rather than the previous pandering to passenger needs.

There is a photo of what the author describes as 'The Penultimate wooden hulled Southampton' though, (S1125)

Later it says that the Southampton1, 'appearing in early 1925......The hull can be supplied in either wood or metal.'

I hope that helps.
all the best
Diana :)

Re: Supermarine Southampton II

PostPosted: Thu Mar 22, 2012 10:52 pm
by schneiderman
Hi Diana,

Thanks for your reply. Unfortunately it was actually John's book that sparked my question as I do not believe that the timeline he presents, and which comes from the Supermarine Putnam volume, is correct. As I understand it the experimental 'N' registration numbers were allocated at the time the contract was awarded, and 1924 is just too early for N218 as they were still issuing numbers somewhere in the 180s.
The previous aircraft, N217, was the Parnall Perch, designed to spec. 5/24 but actually ordered much later and flown in Dec 1926. The following aircraft, N219, was the first Supermarine Napier S5, spec. 6/26, ordered in April 1926 and flown in May 1927. So I would hazard a guess that the Southampton II was ordered in late 1925, possible to spec. 11/25.


Re: Supermarine Southampton II

PostPosted: Fri Mar 30, 2012 7:34 pm
by Schneiderspit
I’m grateful for the above posts as it looks as if Putnam’s statement (p.357) that N218 was built with a metal hull to Spec. R.18/24 contains an error (typo?) with respect to the spec. number.

N218 was definitely metal hulled – see RAF Museum photo P9126.
It was also likely to have been on the Baltic cruise of 1927 as it was in the company of other manufacturers’ flying-boats showcasing the new metal hull approach. (Ominously for Supermarine, the flagship aircraft, carrying the Secretary of State for Air, Sir Samuel Hoare, to an Aero Exhibitiuon in Copenhagen, was the Blackburn Iris II.)

According to Putnam, the following aircraft were ordered as wooden hulled Mark Is:
N9896 to 9901 S1036 t0 1045 S1058 to 1059 S1121 to S1126 (making S1125 the penultimate MkI as stated in the post above). Building the Mk.Is began in 1925. But photos of the above might show metal hulls as these aircraft were retro-fitted with the more efficient units.

Putnam, p.100: "while all this activity was going on with the Southampton wooden-hulled MkIs in service, Supermarine was busy perfecting the light-alloy hull of N218".
Supermarine appointed their first metallurgist (Arthur Black) in 1926.

S1127 then became the first production metal hulled MkII. Putnam gives the Instructions to Proceed date as 6 March, 1926 .

It is interesting that in Jane’s for 1927, Supermarine announce that the Southampton hull can be "supplied either in wood or metal" – probably with an eye to selling the former to less technologically advanced countries.

The following extract from G.A. Cozens may also be of interest:

"Metal frames were becoming common on aircraft but it took a long time before there was an attempt to use metal for the skin, especially if there was the risk of contact with salt water and the danger of corrosion. However, the problem had to be faced and [the] Southampton was used for the experiment by the team at Woolston, because the design had already proved to be satisfactory and they were free to study the urgent question of metal hulls, thus avoiding the pitfall of a new design with a new method of construction at the same time. . .
Some wooden Southampton were fitted with stainless steel bottoms and some were built with stainless steel bottoms and duralumin hulls, and of course the expected corrosion did appear, and like other companies building flying boats, Supermarine set up a metallurgical section to try to overcome it."
Concerning the Aircraft Industry in South Hampshire (Unpublished MS., courtesy of Solent Sky Museum).

[I also have a query concerning the possible originality of the Southampton fuselage shape – see separate post:]

Re: Supermarine Southampton II

PostPosted: Fri Mar 30, 2012 10:36 pm
by schneiderman

There is no doubt that N218 was metal hulled, it carries the 'experimental' N registration for just that reason. The question is simply when it was ordered and built. I do not trust the Putnam Supermarine volume on this point, it is a good book but I have detected quite a few errors and this appears to be another. The order received from the Air Ministry on 6th March 1926 appears to be much more likely, it would fit the N218 number in the correct position with respect to N217 and N219.

I am trying to locate pictures of the Southampton on the Baltic cruise from contacts in Norway, I will let you know if I receive anything. By the way I don't see Hoare travelling out on the Iris as ominous for Supermarine, Blackburn only built 5 and there were many, many more Southamptons. I think Hoare returned on the Southampton anyway.

At the end of November 1926 'Flight' reported that metal hulls were being produced. Cozens is wrong to suggest that these hulls were to the same design as the wooden ones, they retained the same basic layout, planing surfaces, plan and elevation but have a different cross-section and are structurally quite distinct.


Re: Supermarine Southampton II

PostPosted: Sat Apr 07, 2012 5:32 pm
by Schneiderspit

Just a few notes with ref. to earlier posts.

1/. In a previous post I said that it was ominous that the Secretary for Air arrived at the Copenhagen Aero Exhibition in the Blackburn Iris. {Schneiderman says that Hoare returned on the Southampton although the Putnam book on Blackburn claims he also returned on the same aircraft on the 24th August; the Shorts book reports that the accompanying Saunders Valkyrie and a (wooden) Southampton crashed while taking off in rough seas on the return leg.]
However, I was making the point that the Sea Eagle and the Southampton had established Supermarine in the forefront of flying-boat technology but that the company was, thereafter, overtaken by larger multi-engined aircraft ordered from other companies.
The economic situation of the time did not allow many of the new aircraft to be produced and so, eventually, Supermarine was able to offer the very efficient (and cheaper) twin-engined Scapa and Stranraer, thanks to R.J. Mitchell’s thin-wing approach.
However, in the long run, when Imperial Airways was fully developed, Short’s scooped the field, as we all know – which must have been galling to the company which had been the early leader.

2/. Sea Eagle. Anyone wanting to read up about the Sea Eagle service to the Channel Islands, with details of the aircraft and incidents, might like to know about the folowing book:
From Sea Eagle to Flamingo by N. Doyle – The Self Publishing Association Ltd., Upton-upon-severn, 1991.
It may not feature in many bibliographies as it may not have been widely publicized when it came out but it’s very well researched from contemporary newspaper accounts.

Here’s a painting of the surviving Eagles which became part of the inaugural Imperial Airways outfit. I’ve followed the usual colour convention. Hope I’m right.

Supermarine Sea Eagles for Imperial Airways

3/. I think Cozens’ comments about Supermarine experiments with metal hulls were concerned with plating and his references to metal structures probably referred to wing components – his various entries are not always clear and should not be regarded as "gospel" but he was well acquainted with Supermarine in the early days and was a neighbour of their test pilot, Capt. Biard. His MS. is at least valuable as it gives a "feel" for the beginnings at Supermarine.
In respect of structural considerations, it would seem pretty obvious that the Linton Hope approach to wooden hulls, using close-spaced hoops on stringers, would not provide Mitchell with a model for his metal hulls but the advantages of the earlier hull being uncluttered by bracing etc. could not be ignored. The resultant Southampton II hull, basically still spherical in cross-section would thus seem to put Supermarine in the forefront of a metal fuselage technology that was not based upon more slab-sided precedents.

Are there any engineers out there who can support a claim for the Southampton II structure setting the precedent for much later (non-flying-boat) designs, in the U.K. and abroad?


Re: Supermarine Southampton II

PostPosted: Sat Apr 07, 2012 8:30 pm
by schneiderman

Flight for 18th Aug 1927 stated that Hoare was due to return by Southampton, then on 1st September they say he came back in the Iris. That's interesting, did the Southampton (and Valkyrie) crash? The weather was certainly extremely poor. The Putnam volume on Saunders says that the Valkyrie was dismantled at Cowes in 1929, so maybe they were just damaged rather than crashed.

I'm still not totally convinced about Supermarine being overtaken by others in the multi-engine 'boat market, they did quite well enough concentrating on the smaller sizes and my hunch is that this was a conscious management decision to focus on the market where they had proven their strengths, and in this they remained dominant. Was it, perhaps, Vickers policy not to pursue the passenger flying boat market, or indeed the airliner market, at this time? The cancelation of the Type 197 giant was no doubt a blow but this was always intended as a one-off for evaluation purposes and while there are Supermarine project numbers for several larger aircraft through the early '30s the only formal submission I can find is to R.2/33 (Sunderland). Of course by the mid '30s their works were pretty much at capacity with the Spitfire, Walrus, Stranraer and 316 bomber, not to mention that RJM was ailing fast.

The cross section of the Southampton I hull was basically egg-shaped, pointed end down and the planing surface was a separate structure attached to the exterior. For the Southampton II the hull section was broadened towards the bottom, sort of bell shaped, and the planing surface is an integral part of the structure, hence the internal volume is notably greater, albeit that the alloy bulkheads intruded more into the interior than the light wooden hoops in the Southampton I.