Shorts Stirling, Wingspan, Hangar Doors?

[Load Toad]

It is often recounted that the Stirling had to have <100 Ft wingspan due to the RAF insisting it fitted through existing hangar doors.

I've found nothing with internet searches to prove this.

Mostly the reason for the wingspan being restricted was to save weight and other aspects of the design were so it could ferry troops, then provide bomber support around the Empire and operate from unprepared (short) runways & clear obstructions quickly after getting airborne.

Internet searches also show that RAF hangar doors varied and some were greater than 100ft, also it would seem strange for only one aircraft to be restricted in wingspan due to the width of doors...

Would anyone have any information to confirm whether the rumor of hangar doors being the reason for the Stirlings wing span is true or not?

[Harley Quinn]

Worth a look at this PhD thesis (https://www.google.com/url?sa=t&source=web&rct=j&url=https://kclpure.kcl.ac.uk/portal/files/2936079/266156.pdf&ved=2ahUKEwinlcmks8nfAhVJxoUKHT9CAFw4FBAWMAF6BAgBEAE&usg=AOvVaw3JglCqVWruKNNC3OCeRkNF)

[Load Toad]

Worth a look at this PhD thesis (https://www.google.com/url?sa=t&source=web&rct=j&url=https://kclpure.kcl.ac.uk/portal/files/2936079/266156.pdf&ved=2ahUKEwinlcmks8nfAhVJxoUKHT9CAFw4FBAWMAF6BAgBEAE&usg=AOvVaw3JglCqVWruKNNC3OCeRkNF)

- Can not get it to load. What is it about?

[Haraka]

Some Halifax variants also had a 99ft wingspan.

[Harley Quinn]

Don't know why it won't load, I managed to get it up on my phone.

Anyway, I googled 'RAF bomber specification B12/36' and it comes up about halfway down on the 3rd page as a PDF. The thesis is entitled 'RAF operational requirements 1923-1939' by Colin Sydney Sinnott submitted in 1998 and is archived by KCL. As you would expect the author has used PRO documents as references. He points out that some contemporary RAF hangars had door openings well in excess of 100ft, and some were considerably shorter, and posits the theory that any limitation imposed in size was due to the forthcoming treaty limitations.

I searched the document using 'hangar' it turns out that earlier, in 1932 Salmond had expressed concern regarding allowing designers free reign that may result in 'these machines may become so large that we cannot get them into any of our sheds; e. g., the bomber transport machine will not fit into any shed we have at home or abroad. "

It is actually quite an interesting read and certainly gives a lot of context as to why the Air Ministry specified requirements as it did.

I've appended the link again here just in case I didn't do it right earlier. LINK (https://kclpure.kcl.ac.uk/portal/files/2936079/266156.pdf)

[iskanderian]

Colin Sinnott's thesis has in fact been published in expanded form by Routledge. The title is 'The Royal Air Force and Aircraft Design 1923-1939' subtitled 'Air Staff Operational Requirements' . Paperback ISBN 978-0-415-76130-7. A very interesting read. The 'wingspan restricted by hanger door width' myth is shown to be just that - mythical.

[DaveReidUK]

Mostly the reason for the wingspan being restricted was to save weight

That doesn't tend to work very well, as a rule, and it clearly didn't in the case of the Stirling. :O

Most authoritative sources, including Barnes and Thetford, quote the 100 ft limit as being imposed on Shorts by the 1936 specification.

[Harley Quinn]

Most authoritative sources, including Barnes and Thetford, quote the 100 ft limit as being imposed on Shorts by the 1936 specification.

The limit was suggested by the head of the Operational Requirements section (Gp Capt Oxland). This was not directly related to hangarage of the aircraft, but to minimise weight whilst having a structure strong enough to be catapulted with an acceleration of 2.5g at the end of a launch. Previously specifications had limited span to 100ft citing hangar doors as the reason, but not apparently B12/36.

Interestingly in 1934 one AT Harris, then in charge of Plans wrote on 6 Mar 34 "Hangars are already proved an unessential luxury, except for repair purposes & in wartime hangars will be the last place in which to keep aircraft."

[megan]

Always treated the Stirling wing span story with scepticism, so thanks to you who have provided background.

https://cimg0.ibsrv.net/gimg/pprune.org-vbulletin/960x1280/british_ww2_bombers_comparison_13afa37b50e32609fa90d81ae0bd3 714f57e0ccb.png

[Fris B. Fairing]

Megan
That's a nifty drawing. May I suggest one small improvement that will make it easier to follow?
Increase the width of the coloured bars and put the relevant text on the coloured background.
Rgds

[Quemerford]

Megan,

Really impressed with that graphic: I hadn't realised the similarity in wingspan between the heavies but how much longer the Stirling fuselage is. Many thanks for posting.

[PDR1]

The sterling was a bigger aeroplane all-round - 10,000lbs (~25%) more structure weight for the same MTOW and rated payload (ie 14,000lbs, although as we all know the Lanc was later cleared to over 22,000lbs) and giving it a much shorter range with decent-sized payloads. The lower aspect ratio for the same span gave 150sqft extra wing area, making the aircraft manoeuverable but at the expense of higher induced drag and frontal area. The two aircraft had similar installed power giving similar sea-level speeds, but the Hercules had a less effective supercharger than the Merlin, so it became a bit asthmatic at altitude and I suspect that's what really limited the Stirling's effectiveness (well that and the silly split bomb-bay design).

PDR

[DaveReidUK]

The sterling was a bigger aeroplane all-round - 10,000lbs (~25%) more structure weight for the same MTOW

The Stirling, while it was clearly never destined to be as light as the Lancaster, reportedly suffered from more-than-average weight creep during its development, with the above-mentionen impact on payload/range.

Not the first, nor last, time that Shorts built an aircraft like a brick outhouse. :O

[staircase]

I always suspected that the Stirling wing was a copy of the Empire Flying Boat wing, and that Shorts used that wing to either reduce development time and or costs.

Mind you i could be talking 'Bull***t'!!!

[treadigraph]

Staircase, seem to recall that the Short Belfast used Britannia wings...

'Bull***t' Bullshort?

[staircase]

Sorry but one * extra needed for Short - smell the cows mate, smell the cows.

[Harley Quinn]

I was always curious about the undercarriage. I realise it was modified to provide a better angle of attack for take off and landing, but it must have been very delicate, with lots of extra articulations in the structure.

[pax britanica]

Looking t that diagram it certainly illustrates how much extra weight the Sterling had to carry a round to deliver fewer bombs -a large part of it in the wheels alone which look enormous and of course it does look extremely ungainly on the ground and must have been a nightmare to land with that extreme deck angle. The Lanc and Halifax look almost exactly the same so where does the Lancs advantage come in there-I think there we some Merlin Halifaxes so perhaps it was structural weight for same bomb load ?

With their Provincial city naming scheme its a shame they didnt find a way to give one an extremely Welsh name so that German fighter controllers couldnt say it perhaps a Vickers Llanelli

[meleagertoo]

That door-width rumour has been around for a long time. I specifically recall it - and being highly amused by the ridiculousness of it, from the background info in an Airfix kit in - what? 1968-70 perhaps?

[Harley Quinn]

That door-width rumour has been around for a long time. I specifically recall it - and being highly amused by the ridiculousness of it, from the background info in an Airfix kit in - what? 1968-70 perhaps?

I agree, I remember reading something in the early 70s in a library book, along with a restriction on individual component size so they would fit inside a 'standard packing case' whatever one of those is. Maybe sized to fit a Queen Mary or its predecessor perhaps?

[Pontius Navigator]

​​​​​Valiant 114
Vulcan 2 111
Vulcan 1 99
Victor 2 120
Victor 1 114

[b1lanc]

It is often recounted that the Stirling had to have <100 Ft wingspan due to the RAF insisting it fitted through existing hangar doors.

I've found nothing with internet searches to prove this.


This was the reason cited by Murray Peden from 214 Sqdn who at least believed that to be true in his book "A Thousand Shall Fall" so at least that story was circulating during the war amongst crew - probably as they flew misions 8,000 feet below the Lancs. However, there are some interesting write-ups from PFF crew citations of the maneuverability of the Stirling in fending off German night-fighters.

[b1lanc]

Looking t that diagram it certainly illustrates how much extra weight the Sterling had to carry a round to deliver fewer bombs -a large part of it in the wheels alone which look enormous and of course it does look extremely ungainly on the ground and must have been a nightmare to land with that extreme deck angle. The Lanc and Halifax look almost exactly the same so where does the Lancs advantage come in there-I think there we some Merlin Halifaxes so perhaps it was structural weight for same bomb load ?

Max weights have been cited as Stirling 71,000 lbs - Lancaster 63,000 - Halifax 65,000 (with Hercs). Stirling had rigid partitions lengthwise in the bomb bay (couldn't carry a cookie), not sure what the Mk 1 Halifax could carry. As I recall, the early Halifax's had some loss of control issues until redesign of the vertical fins. Interesting that it too ws originally designed as a twin with RR Vulture engines, but Handley Page converted earlier then Avro to 4 Merlins. According to Harris, the max altitude in 1942 for the Halifax was 18,000 feet, or lower than the Lanc albeit higher than the Stirling.

But I think Harris' preference for the Lancaster was what ultimately swayed the dynamic. Quoting from his book Bomber Offensive on page 103:
"The Lancaster far surpassed all the other types of heavy bomber. Not only could it take heavier bomb loads, not only was it easier to handle, and not only were there fewer accidents with this than with other types; throughout the war the casualty rates of Lancasters was also consistently below that of other types." Interesting follow-up to explain the last statement:"It is true that in 1944 the wastage of Lancasters from casualties became equal to, and at times even greater than, the wastage of Halifaxes, but this was the exception that proved the rule; at that time I invariably used Lancasters alone for those attacks which involved the deepest penetration into Germany and were consequently the most dangerous."

I'd suggest that to Harris, a casualty was an aircraft not necessarily crew (and I don't mean that in a derogatory sense). By most accounts I've read, the Halifax was not as difficult to abandon in distress as the Lancaster and Stirling, the Lancaster being particularly cramped and hard to bail out from. He goes on to say he was willing to lose a years production of the Halifax to convert the factories into Lancaster production (he did not win that battle).

Kind of interesting that the PFF started with 12 H2S Stirlings and 12 H2S Halifaxes.

[rolling20]

Don't forget the Hallibag and the Manchester were built to P13/36 and were supposed to be twin engine bombers powered by the RR Vulture. The Lanc obviously came about after the failure of the Manchester, the Halibag being changed to 4 engines at the design stage The Stirling was the only bomber built to the original 4 engined spec. A Centaurus powered Super Stirling was planned: Top speed over 300mph, 29,000 ft ceiling and bomb load in excess of 20,000lb. However it was decided to continue with current types and Shorts were told to cease work in mid 42.

[peterperfect]

I visited RAF Luqa in Malta as a keen young lad and asked our host why there were narrow railway tracks in and out of the main hangar. The answer related to the need to shuffle aircraft (prob Shackletons at that time, maybe Stirlings, Lincolns or Lancasters earlier ?) at a diagonal angle to fit through the main doors. Is this related to the thread ? Can anyone explain background or show photos of the trolley contraption involved ? pp Happy New Year

[Hipper]

I presume aerodynamics was the reason for having the tail wheel raised in flight but was it worth the extra complication/weight? I can't recall any other tail wheeled aircraft having this facility.

I also note in the Wiki article that the crewing of the Stirling was different from the other four engine bombers. The Stirling had two pilots and a Flight Engineer, as well as a Navigator/Bomb Aimer, compared to the others having one pilot, a Flight Engineer, Navigator and Air Bomber/Gunner. Unless this was later changed, would this have been another reason for preferring Halifaxes and Lancasters?

[b1lanc]

Don't forget the Hallibag and the Manchester were built to P13/36 and were supposed to be twin engine bombers powered by the RR Vulture. The Lanc obviously came about after the failure of the Manchester, the Halibag being changed to 4 engines at the design stage The Stirling was the only bomber built to the original 4 engined spec. A Centaurus powered Super Stirling was planned: Top speed over 300mph, 29,000 ft ceiling and bomb load in excess of 20,000lb. However it was decided to continue with current types and Shorts were told to cease work in mid 42.

Good point - two different specifications. Supermarine and later Short were invited to bid on B.12/36 which was the 4 engine bomber and troop transport.

[rolling20]

I also note in the Wiki article that the crewing of the Stirling was different from the other four engine bombers. The Stirling had two pilots and a Flight Engineer, as well as a Navigator/Bomb Aimer, compared to the others having one pilot, a Flight Engineer, Navigator and Air Bomber/Gunner. Unless this was later changed, would this have been another reason for preferring Halifaxes and Lancasters?
Pre war and until early 42, bombers carried 2 pilots. Even Wellingtons and Whitleys had 2 pilots. The 2nd pilot would usually do other duties to assist the crew. The decision was taken ,to allow the force to grow, to do away with 2nd pilots and the specialist trade of Flight Engineer was introduced as the 4 engined bombers came more to the fore. Air Bombers also became a specialist trade, relieving the Observer, who now became a Navigator. A number of Bomb Aimers were failed pilots and they or the Flight Engineer would assist the pilot, especially if he was incapacitated. There were a number of cases of Bomb Aimers flying and landing a bomber home after the pilot was incapacitated.

[Harley Quinn]

I presume aerodynamics was the reason for having the tail wheel raised in flight but was it worth the extra complication/weight? I can't recall any other tail wheeled aircraft having this facility.


Off the top of my shiny bald head: B17, Mosquito, P51, Later marks of Spitfire, FW190 (semi retractable), Typhoon all had retractable tailwheels. Drag affects speed and range.

[oxenos]

I can't recall any other tail wheeled aircraft having this facility.

When I scratch built a flying model Wellington, I was surprised to find that it too had a retracting tailwheel.

[longer ron]

Pre war and until early 42, bombers carried 2 pilots. Even Wellingtons and Whitleys had 2 pilots. The 2nd pilot would usually do other duties to assist the crew. The decision was taken ,to allow the force to grow, to do away with 2nd pilots and the specialist trade of Flight Engineer was introduced as the 4 engined bombers came more to the fore. Air Bombers also became a specialist trade, relieving the Observer, who now became a Navigator. A number of Bomb Aimers were failed pilots and they or the Flight Engineer would assist the pilot, especially if he was incapacitated. There were a number of cases of Bomb Aimers flying and landing a bomber home after the pilot was incapacitated.

On many Aircraft - the 2nd Pilot was the Navigator,the RAF did not have many Observers/Navigators between the Wars.

A number of Bomb Aimers were failed pilots and they or the Flight Engineer would assist the pilot, especially if he was incapacitated. There were a number of cases of Bomb Aimers flying and landing a bomber home after the pilot was incapacitated.

Sqn Ldr Ian Blair DFM
John Ian Blair was a prewar Boy Entrant Armourer/Air Gunner - in 1940 as a Corporal (Acting Sergeant) Air Gunner and volunteer Observer on a 113 sqn Blenheim - he was flying as the Observer during an operational sortie,his pilot was killed in action and Blair managed to get the A/C under control and landed safely back at base - he had always closely watched the Pilots actions and had a good idea of what to do.He was awarded the DFM and also given a Pilots course.

From 113 sqn website - http://113squadron.com/id191.htm


From my observations of my skipper's flying , we had done many hours together,. I knew that I had to, change pitch of the propeller, engage rich mixture control, and when the wheels went down there would be a lot of vibration, and loss of speed which I would have to compensate for with increased revs, all of these actions were carried out on the down wind leg , and on the final approach I kept at about 85 mph, knowing that there would be a marked change of aircraft attitude when the flaps were lowered, I trimmed the aircraft tail heavy, (too much,) as it happened, because I had to exert forward stick pressure on the control column in order to maintain my approach path and speed, being aware of the telephone poles and lines at the touch down end of the strip. As soon as I passed over the telephone lines, I throttled back and because the tail trim was tail heavy, the aircraft flared out nicely and sat on the ground. I kept the stick hard backwards with all my strength and eventually the aircraft came to a halt in a cloud of dust.

[rolling20]

On many Aircraft - the 2nd Pilot was the Navigator,the RAF did not have many Observers/Navigators between the Wars.

IIRC Air Observer was introduced in 1934, but it wasn't until 37/8 that they were primarily concerned with navigation.

[Fareastdriver]

It's possible that had the RAF gone for two pilots from the beginning with four engine heavies the carnage that killed an enormous number of crews during their training might have been tempered. The initial crewing with one pilot because for no other reason they felt they would get on together OK meant that there was no experience to draw on during their training. Should there have been two pilots then the junior one would have advanced to getting his own crew and having a good idea of what it was all about.

The USAAC seem to cope with two pilots as would have the RAF because their training system was churning out more pilots than they could use.

[longer ron]

IIRC Air Observer was introduced in 1934, but it wasn't until 37/8 that they were primarily concerned with navigation.

Yes but at the outbreak of WW2 - the RAF did not have many observers and therefore we were short of navigators for multi crew aircraft,also partly why I posted the link about Ian Blair - his sqn were so short of Observer/Navs that an Air Gunner was acting as a volunteer Nav/Bomb Aimer,the pre war Air Gunners did sometimes act as Observer on the Biplanes etc but they were not given much (if any) formal training in that role.

[rolling20]

Yes but at the outbreak of WW2 - the RAF did not have many observers and therefore we were short of navigators for multi crew aircraft,also partly why I posted the link about Ian Blair - his sqn were so short of Observer/Navs that an Air Gunner was acting as a volunteer Nav/Bomb Aimer,the pre war Air Gunners did sometimes act as Observer on the Biplanes etc but they were not given much (if any) formal training in that role.
I think you'll find most pre war and early war air gunners were ground crew who could volunteer for aircrew duties for extra pay. They had little if any formal training. Most were ordinary aircraftsmen.

[longer ron]

Yes R20 - I know ;)
I was merely explaining why the prewar/early wartime 2nd Pilot was often the Navigator on multi crew aircraft - because the RAF was extremely short of qualified Observers/Navigators.
Ian Blair was included for interest and to reinforce the idea of the shortage of trained/qualified Observers/Navigators.
After 1941/42 large numbers of Observers/Navs became available as the training schools got into gear.

[rolling20]

It's possible that had the RAF gone for two pilots from the beginning with four engine heavies the carnage that killed an enormous number of crews during their training might have been tempered. The initial crewing with one pilot because for no other reason they felt they would get on together OK meant that there was no experience to draw on during their training. Should there have been two pilots then the junior one would have advanced to getting his own crew and having a good idea of what it was all about.

The USAAC seem to cope with two pilots as would have the RAF because their training system was churning out more pilots than they could use.
​​​​​​It wasn't until early 42 that 2 pilots were no longer the norm. The heavies were just starting to come in greater numbers and did use 2 pilots. Most training losses occurred at OTUs, some 1600 aircraft, the majority Wellingtons. 8000 aircrew being killed. 4 engined flying didn't take place until they reached conversion flights or Heavy Conversion Units later in the war. The RAF didn't have the USAAC manpower.

[Load Toad]

Thank you, everyone, for their input - it's been very informative and interesting (as usual) - Cheers.

[Hipper]

Also thanks to all.

However, I'm still not clear if Stirling's retained the two pilot set up or also later changed to one pilot and flight engineer, seeing as they had a different crewing arrangement then the other two heavy bombers. Then later of course it was used for towing gliders, perhaps leading to another arrangement. The only pictures I've seen on the internet show two sets of control gear in the cockpit.

http://www.dailymail.co.uk/news/article-3498578/Military-buff-building-World-War-Two-Stirling-bomber-SHED-using-parts-30-different-aircrafts-bought-eBay-Haynes-manual.html

[longer ron]

Yes I doubt there is an easy answer to your question Hipper,I have seen crew photos with either 1 or 2 Pilots included.
I was under the impression that some crews used the Bomb Aimer in the cockpit for T/O and Landing and also when not req'd to assist with Navigation.
The Flight Eng would perhaps be busy down in the bilges with his man sized controls.
Of course most Bomber Pilots did 1 or 2 'Stooge' trips with an experienced skipper before being declared operational.

[rolling20]

The Stirling was the only 4 engined bomber originally designed for 2 pilot operation. I believe that it maintained that set up throughout production, but stand to be corrected. Stirling squadrons in Bomber Command switched to single pilot operation along with other types in early 42.

[longer ron]

Looking through some of the casualty lists - by late 1942/early 1943 most Stirling crews seemed to be single pilot.
Some of the earlier casualty lists with 2 Pilots listed had a navigator/observer,some did not have a navigator/observer listed.
Also as I posted above most Bomber Pilots did 1 or 2 'stooge' trips with an experienced skipper which woulkd show in a proportion of the losses.

[b1lanc]

Looking through some of the casualty lists - by late 1942/early 1943 most Stirling crews seemed to be single pilot.
Some of the earlier casualty lists with 2 Pilots listed had a navigator/observer,some did not have a navigator/observer listed.
Also as I posted above most Bomber Pilots did 1 or 2 'stooge' trips with an experienced skipper which woulkd show in a proportion of the losses.

Here's the 214 Sqdn Stirling loss site that pretty much verifies what you stated above. Most had one pilot and an FE even with the dual controls.

No. 214 (FMS) Squadron RAF - Crews and Losses - Stirling (http://www.214squadron.org.uk/Crews_and_losses_Stirling.htm)

Harris stated that his grand plan was to move the Stirlings and Halifaxes to Heavy Conversion Units (with crews completing a short Lancaster finishing school). However, in the 1942- early 43 timeframe, Lancasters were in short supply so he felt compelled to send them along on Ops (also including the Hampdens, Whitleys, and Wimpys still operational).

Should note that the Stirling could and did raid Italy as did Lancasters. Not sure about the Halifax.

Regarding the high number of OTU losses, the condition of the Wimpy's used in the OTUs were less than desirable with de-rated engines that, again form Peden's book, would give a foot and a half of altitude every 100 miles with undercart down and full flaps on overshoot. These same aircraft were sent on Ops.

[rolling20]

Halibags did raid Italy, their ceiling was also higher than the Stirling. OTU Wimpys were usually earlier marks that were 'op expired' they did not receive the same maintenance as front line aircraft. They rarely carried out ops, aside of the Thousand Bomber raids, Nickels and a few other usually not to distant targets as a diversion. Aside of giving crews op experience, it wasn't sound economics to send newly trained crews out on ops in worn out aircraft. Harris once said of the Stirling: 'I can't send my crews/ young men out to die in an aircraft like that'. Unfortunately he had no choice until losses became prohibitive in late 43.

[Haraka]

Interesting that Chris Barnes states in his 1967 Putnam that Shorts originally submitted a 112ft (Sunderland type) wing for their B.12/36 tender. which would have given a more capable performance:
" Unfortunately before ordering any prototypes ,the Air Ministry stipulated that the span must not exceed 100ft in order to conform to exiting hangar dimensions.; even this limitation was accepted by (Arthur) Gouge who increased the flap chord to 48 % of the wing chord and hoped to obtain Hercules VI engines in time for production."
This comment is repeated almost verbatim in Air Enthusiast No.10 in 1979, along with the " fitting in crates " story.
Later on in August 02 Aeroplane Monthly states that the 100ft span was an attempt to limit overall size and weight limitations for the then airfield capacities.

[Hipper]

Thanks again all.

I can confirm that Halifaxes flew to Italy. For example 158 Squadron attacked Genoa on the 23 October 1942.

[Load Toad]

I found the Short Stirling Airfix instructions online that may have been the promotion of the hangar door rumour:
https://cimg3.ibsrv.net/gimg/pprune.org-vbulletin/1170x736/ssairfixplan_87b9154b1736c67b59d5151fb7e8f696e740d6fc.jpg

[Prangster]

My stepfather did a tour on 7 Squadron on the early Stirlings, he was convinced they were better performers than subsequent batches possibly as a result of the raid on Rochester disrupting the production line. He though that there might have been a change in wing incidence leading to a loss of performance. He hated the undercart and throttle management systems calling them a pilots nightmare.

[ancientaviator62]

Later in the war they were used on supply missions to drop kit to the resistance in France. Several were lost this way

[VX275]

Later in the war they were used on supply missions to drop kit to the resistance in France. Several were lost this way
Not just supply missions. The Stirling Mk IV could stake a claim to being the best allied airborne forces aircraft. It could carry more stores both internally and externally, drop more parachutists and tow heavier gliders than the Dakota. The Dakota only won on numbers available.