Recurring Theme in WW2 Aviation

pbehn said:

Many things are easy with hind sight. Wiki history of ROTIOL says this
The Company was formed as Rotol Airscrews in 1937 by Rolls-Royce and Bristol Engines to take over both companies' propeller development,[1] the market being too small to support more than one company.

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De Havilland was in the Market too. The engine makers knew what was needed, it was the Air Ministry that had to dragged, kicking and screaming, out of the 1920s and into the 1930s in regards to propellers.

stona said:

Whether Fairey 'pushed' to build the P-51 I don't know off the top of my head, but given that it was a US built aircraft I rather doubt that it could ever have happened. The British tended to view the United States as a shop which could be raided to meet its needs, and the Americans could build as many P-51s as were needed.

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What may have been brought up in a meeting, or two, and what was seriously considered can two very different things. Anybody want to try to redraw ALL the drawings for the P-51 from 3rd angle projection to 1st angle (reverse of what was done to make the Merlin by Packard). It took 75 men 4 months to do the Merlin drawings. How many men, how long, to make the drawings for a British built Mustang? What else doesn't get done?

All manor of schemes were thought up and few actually acted upon (the long cable aerial mine and turbinlite are two that never should have made it) but obviously some ideas weren't really that good.

The structure of the Spitfire airframe was certainly not optimised for production. Having been originally built by hand in part of a small manufacturers works and mostly using hand tools by extremely skilled workmen. The wonder is that it was ever made in huge numbers but it was and very well. The Hurricane was made by a major manufacturer who could source and build machine tools for their production system. It is significant that the Spitfire was only made in the UK whereas factories were set up in Belgium, Yugoslavia and Canada as well as the UK for the Hurricane. The key item is specialised rolling machines for the spars etc. to be made from strip. Once you have these the Hurricane structure is more easily made with lesser skills.

The Hurricane was the right answer at the time it was introduced but was being overtaken by the next generation into 1940 as indeed Hawkers and the RAF expected it to be. For production optimising it might be better to compare the Typhoon as that was built as a next generation mass production aeroplane. I am not that familiar with the details of the Typhoon structure to comment myself. Hawkers expected the Hurricane to leave production in 1941 but their wonder machine, the Typhoon, was delayed and the Hurricane II & IV were the interim holding response. They never expected that the RAF would still have Hurricanes in service as fighter bombers into 1946 .

Ironically the hand made type of structure of the Spitfire made it easier for small restoration companies to restore Spitfires (almost from the name plate at times) and the need for specialised rolling machinery and strip made restoring Hurricanes near impossible until (IIRC) a set was found in South Africa just as Russia started coughing up abandoned Hurricanes.

The fixed pitch wooden prop was beloved of the Air Ministry I understand for it's lightness and optimised for the climb to interception. With it a Spitfire could still take off within existing UK airfields. The VP and CS types were much heavier I believe and required some attention to the CofG. Was this not the reason for the lead ballast in the tail of Spitfires? The engine manufacturers were not at all convinced that they could get their new heavy bomber designs off the ground in the same way thus Rolls Royce and Bristol were forced to set up a joint company Rotol to make CS units which were then fitted to fighters. The De Havilland licence made Hamilton Standard VP propellors came through the route of civil aviation and suited them better with take off and cruising settings. Lighter of course than the whole CS arrangement for optimum thrust for all revs.

Martin Bakers were champions at maintenance access having deduced that stiffness was not the same as strength in a structure and aerodynamic and structural design could cope with the lesser torsional stiffness for even a good steel tube spaceframe structure and then add removable metal panels allowing supreme access. The Swedish FFVS 22 fighter also had such an approach but with plywood panels.

The fixed pitch props on the Spitfire and Hurricane seem to have optimized for speed. at least there was only a minor improvement when fitted with 2 pitch or variable pitch/constant speed props.
Take-off and climb were severely comprised however as some of the trial reports show;
Spitfire Mk I K.9787 Trials Report
engine is held hundreds of rpm below max allowable (2600rpm for climb) which obviously affects power.
Same for Hurricane.
Hurricane K-5083 Trials Report
it even affected the top speed.
http://www.wwiiaircraftperformance.org/hurricane/k5083-level.jpg

Having a propeller that allowed 2600rpm and full boost to be used at ANY altitude for a long duration climb certainly helped.
As did being able to use 3000rpm and 6lbs boost at any altitude for high speed flight.

Please note that in combat it would have been possiable to use 3000rpm and 6lbs for climb at altitudes that allowed it .

Shortround6 said:

De Havilland was in the Market too. The engine makers knew what was needed, it was the Air Ministry that had to dragged, kicking and screaming, out of the 1920s and into the 1930s in regards to propellers.

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I have some sympathy for the Air Ministry, we now know what works and what doesnt, in the 1920s and 30s there were all sorts of ideas, early RADAR research was actually into the possibility of a death ray FFS. Telling the ministry in 1935 that special fuels and a better supercharger would be the best interim solution until an engine with one moving part makes the whole lot obsolete would have a lot of people laughing.

Cairncross in 'Planning in Wartime' makes the point that the Air Ministry had been 'backward' in propeller development.
When the need was finally identified 1,050 aircraft were fitted with variable pitch propellers and CSUs in just two months, starting in June 1940.
What makes this even more idiotic is that a variable pitch propeller with a primitive CSU had first been fitted to a British aircraft in 1928!
Cairncross' comment on the MAP is damning.
"The official attitude can be judged from the fact that the staff of MAP dealing with propellers at the end of 1940 consisted of two men and a young girl."
The patronising attitude towards this unfortunate young girl we may put down to the attitudes of the time

Remarkably the British only suffered one serious propeller shortage after 1940, of Rotol electric units, this led to 300 Wellingtons "accumulating propellerless on the beach at Blackpool."
There were less serious shortages of Rotol hydraulic propellers (effecting Halifax, Whitley production) and de Havilland hydraulic propellers (effecting Stirling, Beaufighter, Albermarle and Typhoon production) but the impact was ameliorated by the arrival of propellers from America.

What is even more remarkable is that in all the discussions, from 1930-36, from Bulldog to Spitfire, about the performance and armament of the new RAF fighters there is rarely a mention of propellers. The advantages of variable pitch propellers, in combination with a CSU, doesn't seem to have occurred to the decision makers of the time. It is a fact that the units fitted to the relatively low performance biplanes in the late 1920s did not much enhance their performance, but this is a poor excuse.

Cheers

Steve

stona said:

Remarkably the British only suffered one serious propeller shortage after 1940, of Rotol electric units, this led to 300 Wellingtons "accumulating propellerless on the beach at Blackpool."

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Where they equipped with anchors to stop them floating away at high tide

fastmongrel said:

Where they equipped with anchors to stop them floating away at high tide

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Now you see the cunningness of the geodesic system in being made up of lots of holes to let the water in and out freely.......

pbehn said:

I have some sympathy for the Air Ministry, we now know what works and what doesnt, in the 1920s and 30s there were all sorts of ideas, early RADAR research was actually into the possibility of a death ray FFS. Telling the ministry in 1935 that special fuels and a better supercharger would be the best interim solution until an engine with one moving part makes the whole lot obsolete would have a lot of people laughing.

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I have very little sympathy for the Air Ministry in this regard (although a lot in the areas you mention) as at the beginning of 1939 there were 21 airlines using fully feathering propellers on aircraft, not just variable pitch or constant speed. The improvement in aircraft safety was widely known to those who didn't have their heads firmly and deeply buried in the sand.

Shortround6 said:

The fixed pitch props on the Spitfire and Hurricane seem to have optimized for speed. at least there was only a minor improvement when fitted with 2 pitch or variable pitch/constant speed props.

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I stand corrected. Thank you Shortround.

IIRC the Blenheim VP propellors and engines fitted to Sea Gladiators in Malta gave a very marked improvement in the rate of climb.

fastmongrel said:

Where they equipped with anchors to stop them floating away at high tide

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I doubt that they were literally 'on the beach'. The aircraft would have been at the Squire's Gate and/or Stanley Park sites. It would be rather difficult to get them down onto that beach, one I know well as I have family in Blackburn. I think Cairncross was just making a point.

It was not unknown to fly aircraft away from the factories using 'slave' or substitute propellers, but presumably this did not happen in this case.

Cheers

Steve

some interesting stuff here

Stories of the Battle of Britain 1940 – Constant-Speed Propellers — Battle of Britain | 1940 | Reference | Spitfire Mk. I

stona said:

I think Cairncross was just making a point.

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I agree but taking something written as a throw away line in a book written for effect then becomes a fact. Author A asked Pilot Officer P about the Spitfire as a gun platform, "Oh it was a terrible fighter wandered all over the place compared to plane X and it cant climb as fast as plane Y" witten down for effect then taken out of context it becomes internet gospel truth that the Spitfire was a rotten aircraft. No one quotes the bit about Plane X was a P47D and Plane Y was a Gloster Meteor F8.

Fair enough, but even minimal investigation would reveal the impracticality of storing aircraft on Blackpool beach. It's not just the small matter of the Irish Sea, a sandy beach is hardly an ideal staging post for an 18,000lb aircraft, even if you can get it onto it
Cheers
Steve

the truly sad thing about it is... all of these outlandish and down right erroneous notions will end up prevailing in the end. in the not too distant future they will the historical facts and the youth of the day will not have one clue about the truth. all you have to do is peek in on a gaming forum where tomorrow's "experts" are already tutoring others in fantasy ww2. the way history is being rewritten has me wondering how much of most of what I do know is total BS. as each vet who was there passes so does our ability to correct the path which history is written. When the last one is gone...it will be a sad day.

bobbysocks said:

the truly sad thing about it is... all of these outlandish and down right erroneous notions will end up prevailing in the end. .

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They are already prevalent. However, the information to enable a more informed opinion is available.

The essential fact in Cairncross' statement is that 300 Wellingtons were without propellers due to a lack of foresight on the part of MAP. The number and type of the aircraft is most important. Whether they were on Blackpool beach, or at the two production sites I mentioned above, both within 2 or 3 miles of the beach, is not of primary importance.

Cheers

Steve

I think it is harsh to criticise the Spitfire for its performance in 1939/40 especially on the basis of its propeller. There was only one plane better and that was owned by the nation that fired the starting gun to re arm. The twin pitch propellers were available when conflict began and the constant speed props were installed before the height of the BoB. Things can always be done better, but how were the French Russians and US planes getting along at the same time?


The Spitfire was designed by Supermarine, the engine and propellers are down to other parties, same with the Hurricane. However bad they were they somehow managed to stop the LW.

fastmongrel said:

Where they equipped with anchors to stop them floating away at high tide

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Off topic, three times in my life I have had to explain what tides are and why they are dangerous. Working in China with Chinese who had never seen the sea they couldnt understand how the Morcambe Bay disaster happened, even those who had seen the sea presume all tides and seas are the same.
2004 Morecambe Bay cockling disaster - Wikipedia. The UK has some of the biggest tidal ranges in the world and the sea is cold enough to overcome those with no experience in minutes.

stona said:

The essential fact in Cairncross' statement is that 300 Wellingtons were without propellers due to a lack of foresight on the part of MAP. The number and type of the aircraft is most important. Whether they were on Blackpool beach, or at the two production sites I mentioned above, both within 2 or 3 miles of the beach, is not of primary importance.

Cheers

Steve

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Unfortunately the line about parking on the beach becomes the story. We both know thats not true nor even possible where the story originated was Blackpool Golf Club built in 1894 was taken over and became part of Squires Gate factory and airfield (now Blackpool Airport) planes were parked on what had once been the course. It had been a Links course and Links courses are usualy next to a beach.

My point was the beach story which was a local joke will probably turn up on something like warhistoryonline.com as proof that the Germans were so close to winning the RAF planes had no propellors and were parked on a beach.

I dont know if the MAP was responsible for the lack of props, maybe the prop factory was bombed or the ship they were on from the US was sunk or even something as simple as the clerk responsible sent them to the wrong Squires Gate I know there is one in Edinburgh.

Lack of foresight was probably an unfortunate phrase on my part. To quote Cairncross in full.

"When the heavy bomber programme was under discussion in September 1941 a review was undertaken of prospective shortages in key components, including propellers. The full calculation is not available and it is very doubtful whether it made any sense. For example, the only type of propeller that was expected to be in surplus in 1942 was the Rotol electric propeller - the shortage of which was so notorious three months later, with 300 Wellingtons accumulating propellerless on the beach at Blackpool."

There is a clue as to what went wrong in the next paragraph.

"Rotol hydraulic propellers were expected to be in rough balance; and the big shortage, intensified by the heavy bomber programme, looked like being in de Havilland hydromatic propellers. The mystery is how, without a production programme, any estimate was possible; but perhaps the two main firms were able to provide some indication of their likely output for the year as a whole."

Total British production of propellers (excluding fixed pitch) in 1942 was, Q1 2641, Q2 2992, Q3 3529, Q4 3908, a total of 13070.

The electric propellers were UK built. There were numerous factories and I don't know which built this particular type.
In any case the shortage soon eased.

"The Rotol electric shortage eased fairly rapidly. Production rose from 19 in the second quarter of 1941 to 481 in the second quarter of 1942 and reached a peak of 800 a month by May 1943. Meanwhile the propeller was denied new applications (the pitch change was slow), the Hercules engined Lancaster II, which was fitted with the Rotol electric propellers, was limited to 300 aeroplanes, and almost the sole requirement was thus for the Wellington III."

Cheers

Steve

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pbehn said:

I think it is harsh to criticise the Spitfire for its performance in 1939/40 especially on the basis of its propeller. There was only one plane better and that was owned by the nation that fired the starting gun to re arm. The twin pitch propellers were available when conflict began and the constant speed props were installed before the height of the BoB. Things can always be done better, but how were the French Russians and US planes getting along at the same time?

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The Hamilton Standard constant speed prop was introduced in 1935 and the full feathering prop in 1937.
See this website: Hamilton Standard Hydromatic Propeller History

American fighters were most certainly NOT using fixed pitch or 2 pitch props in the late 30s.
Hamilton Standard was part of the United Aircraft group (which included Pratt&Whitney). Curtiss Wright Corporation had their own propeller company but used electric operation rather than hydraulic. US fighters as far back as the consolidated P-30 had used variable pitch props of some sort. The P-26 used ground adjustable propellers.

The French flew the First Ms 405 prototype with a two pitch prop in 1935. Production planes may have had constant speed or variable pitch. The MB 150, when it did fly in October 1937 had a constant speed prop. While the D520 prototype fist flew with a fixed pitch prop it was soon changed to a constant speed prop.

The Macchi 200 seems to have had a variable pitch prop of some sort.

The Fiat CR 42 biplane used a licensed Hamilton Standard propeller of some sort. Variable pitch or constant speed I don't know.

Basically England was alone in 1938/39 using fixed pitch props on new fighters out of the major nations.
I wold say that using 2 pitch props on bombers at that time (Battle and Blenheim at least) was also behind the curve or world trends.