Japanese Zero vs Spitfire vs FW 190

[pinsog]

The value of the constant speed prop and its governor are often not appreciated or understood by those who don't work with them regularly. Essentially, they constantly vary the pitch of the propeller to keep the load on the engine matched to its torque at the selected RPM and manifold pressure, thus keeping RPM constant. In combat or other acrobatic flight this is a godsend, as the pilot doesn't have to monitor the tach and jockey throttle to keep revs within limits. Throttle can be adjusted to desired thrust throughout maneuvers without worrying about revs, and the engine can be kept at its most efficient RPM through all changes of airspeed, attitude, and G load.
(Personal prejudice here), but IMO, double acting hydromatic-style props are the best there are. Fast acting, reliable, and relatively immune to cold induced sluggishness, as they are constantly pushing hot engine oil out into the dome. Good down to -40°C/F, where most lubricants start to fail, anyways.
Electric props are a bucket of worms, and the higher you go, the worse they get.
Cheers,
Wes

Does anyone know why the Spitfire and Hurricane weren't fitted with constant speed props from day 1? I know they cost more and are heavier but building a Spitfire or Hurricane with a fixed pitch prop is like buying a high powered sports car fitted with 4 space saver tires instead of high quality tires

 

[michael rauls]

The Spitfires life can be summed up by the phrase, ''good enough now is better than perfect later''. The desperate need for them meant it's development always took a second seat to production resulting in it never maturing into the fighter it should have been.

Agreed. This seems to be the story of many a ww2 aircraft.

 

[RCAFson]

Does anyone know why the Spitfire and Hurricane weren't fitted with constant speed props from day 1? I know they cost more and are heavier but building a Spitfire or Hurricane with a fixed pitch prop is like buying a high powered sports car fitted with 4 space saver tires instead of high quality tires

AIUI, the US had patent rights to CS prop technology and it took some time to negotiate a licensing deal and for a UK CS prop design to be developed. IIRC by 1939 most UK fighters (and the Skua/Roc) were using a UK designed VP (2) pitch prop which was somewhat superior to a fixed pitch prop, although the CS prop was still much preferred.

 

[tomo pauk]

Does anyone know why the Spitfire and Hurricane weren't fitted with constant speed props from day 1? I know they cost more and are heavier but building a Spitfire or Hurricane with a fixed pitch prop is like buying a high powered sports car fitted with 4 space saver tires instead of high quality tires

UK was trying to out-produce Germany in second hand of 1930s, something had to be sacrified to attain that goal. CS and 2-pitch props went to bombers; both Battle and Blenheim have had them, let alone bigger bombers.
By the time ww2 started, they indeed were out-producing Germany by a large margin (4:1 for whole 1939, if we believe Wikipedia; seems like that UK produced more aircraft in last 4 months of 1939 than Germans for all of 1939)*, even though a lot of that surplus were trainers and some combat types of questionable utility.

*UK was probably out-producing Germany, Japan and Italy combined from 1939 to 1942 in numbers of aircraft, and in weight of aircraf probably between 1939 and late 1943

 

[Schweik]

Agreed. This seems to be the sorry of many a ww2 aircraft.

Yeah that is what I think.

First of all thanks a lot to everyone who responded in the last several posts - very interesting stuff.

The question about the prop pitch finally rang a bell of clarity for me, it's something I hadn't even realized I'd been wondering about but had been for years. No amount of horsepower would really matter with out proper pitch. I have some followup questions on pitch settings for climb and dive and so forth (manual override?) and which aircraft had the best / most efficient prop pitch control (constant speed was the gold standard I gather, but what other options were there if any?), but I'll save that for later and maybe another thread.

As for the general build quality issues with the Spitfire V, that too is very interesting. This is another thing I'd noticed for a long time, not with Spitfires but with mostly American planes, and some German and Japanese, that I've seen at airshows and museums since I was a kid. The build quality is usually a little rough. The seams between the panels don't line up perfectly, the rivet heads stick out a bit, sometimes there are tiny gaps. I've noticed this with P-40s first and I thought it was just a problem with them, but since then I've seen this on just about every WW2 aircraft I've looked at up close. Nowhere near the kind of smooth surface finish you'd see on a modern car, or even a car from the 1950's.

In other threads we talked about the nightmarish build quality / production issues the Soviets dealt with, especially for the first year or so. I doubt Spitfire problems were anywhere near that scale. But I suspect it was a fairly universal issue to some extent or another. I know the Japanese and Italians had these kinds of problems, I know the Americans did too especially when expanding production to third or fourth party firms. Sometimes the subcontractors just couldn't pull it off. Some government outfits couldn't either like the torpedo manufacturing agency (I forgot what it was called) and some firms like Brewster and to some extent Curtiss (especially toward the end of the war) couldn't get their act together.

So it's interesting to learn that the Spitfire did have this issue as well. Did they Germans have any issues with build quality?


A WW2 fighter aircraft is a sort of a strange device. On the one hand, it probably has a useful service life measured in weeks or months, which may end suddenly at any point. So it's almost disposable from one point of view. Why put all that effort into the finer details for something which in the best possible world will probably be in combat for three months, used for training another six, and then be scrapped after a year? On the other hand it had to be tough enough to endure 5 and 6G turns, operate from sea level to up in the thin air and from temperatures ranging from Tropical to Arctic, and to even withstand a moderate pounding from heavy machine guns and keep going. So they were very strongly made, I think a lot more so than just about any car. This is why so many of them are still around flying 75 years after they were built. (Well, that and some very dedicated restorers).

The finer things like farings on a rearview mirror, the location of an antenna or a little putty to cover a tiny crack, seems trivial. The first time I read about sanding and putty and repainting for speed was in a book about the AVG. At the time I thought it was almost a superstitious gesture. But now I know better. These aircraft move only the air and they have only the bite of the propeller to pull them along. Everything that catches the air slows them down. The book itself said they improved speed by 10 mph by sanding and waxing, but I thought that was hyperbole. It really emphasizes the importance of good mechanics and also mechanics who can and will go a bit beyond standard practices of the time.

All in all very interesting folks, thanks. The knowledge in here is impressive.

 

[Schweik]

The P-40F and L were the versions with Packard Merlin V-1650-1.

I'm well aware but the V-1650-1 was an American version (so probably slightly different) of the Merlin XX right? So that is different from a Spit V which used a Merlin 45 or 46 or 45M right? I thought the Spit V had a higher critical altitude.

Advantages vs. plain vanilla Spitfire V might be: better carb, ram air intake (no ice guard) & exhausts, fit&finish (although the P-40 probably was not as good as P-51 in that regard - that's IMO), retractable tailwheel, possibly the windscreen. Not sure about cooling system, by 1942 neither was in world class.
Disadvantages: thicker wing, main U/C sticking out when retracted a bit.
(I've listed the stuff that should matter with drag, probably some other details can also be found)

Yes P-40s had the fared rearview mirror, internal instead of external armored glass, and a fully retractable tailwheel, but as you note, main wheels didn't fully retract and had the landing gear faring sticking out. Plus some had an IFF or nav radio stucking out too underneath. And that big scoop. Plus I think P-40 is thicker overall. Most P-40s had bomb shackles in the field and retained the ring and bead sight which surely also incurred drag.

P-40N received a new version of V-1710, with improved altitude power (still not up the V-1650-1 standard, though) , so it should be faster than P-40K and earlier. The P-40N that clocked 378 mph was a lighter & less draggy version, with 2 HMGs deleted (less weapon-related drag) and one fuel tank also removed, as well as other bits and pieces - weight can influence the speed a bit.

Right but all versions of the P-40 had lower and higher drag / weight configurations like that. P-40L was four guns out of the factory.

WRT speed - the Spitfire V and later P-40s (P-40M, N, plus F and L) were probably as evenly matched as one can imagine, typically between 360 to 370 mph. The P-39N/Q was faster than either, BTW, and P-51A was still faster.

Interesting. Yes on the P-39 though for some reason they seemed to struggle to get rated performance in the field (at least in American use) for reasons I never fully understood. Maybe that was another way the Russians got more out of them. P-51A was super fast but suffered from bad ailerons, fixed in later versions. The A version didn't seem to be a very good air to air combat aircraft.

Desire to have as many Spitfires as possible certainly meant that some corners were cut. That is not just a thing of fit&finish, but also some other choices that got to be made - BP glass is easier to fit and retrofit to the outside rather than to inside (corrected with Mk-VII and on, but not retroactively on previous examples), draggy undercarriage, no decision to copy exhausts from Bf 109E, no streamlined rearview mirror etc. Not having good carbs on Merlin already before the ww2 was an unfortunate oversight (impacted not just top speed, but also ceiling and negative-G use).
Spitfire VII and later corrected a lot of this (carb, exhausts, BP glass installation), meaning that Mk.IX was measured to have same Cd0 as the Mk.V, despite receiving much bigger radiators.

Spit VIII and IX seemed to be worlds better than everything else in the Allied inventory, at least for a while.

 

[Greyman]

So it's interesting to learn that the Spitfire did have this issue as well. Did they Germans have any issues with build quality?

The through line seems to be when you have factories/populations already under duress and crank production to emergency levels -- surprise surprise -- quality issues arise.

RE: Germany, from Mike Williams:

Conditions in Germany during the last year of the war, however, were not conducive to aircraft achieving maximum theoretical performance levels. Hans Knickrehm of I/JG 3 recalled the condition of new Me 109 G-14/AS's received by his group in October, 1944:

The machines that were delivered were technically obsolete and of considerably lowered quality. The engines proved prone to trouble after much too short a time, because the factories had had to sharply curtail test runs for lack of fuel. The surface finish of the outer skin also left much to be desired. The sprayed-on camouflage finish was rough and uneven. The result was a further reduction in speed. We often discovered clear cases of sabotage during our acceptance checks. Cables or wires were not secured, were improperly attached, scratched or had even been visibly cut....

At a conference in Berlin on 20 January 1945, with the Chief Engineer of the Luftwaffe, it was reported that the Me 109 airframe was extraordinarily bad and performance outrageously low. Daimler-Benz noted that there was no point in continually increasing engine power when the airframes were getting worse due to sloppy manufacturing. A comparison between the Me 109 and the Mustang was devastating....

It didn't help matters that ground crews, who might have ameliorated these problems to some degree, were being transferred to the infantry in significant numbers. The primitive conditions existing at Luftwaffe airfields was an additional complication. Bombing and strafing attacks further taxed the ground crew's ability to maintain the aircraft anywhere near the degree necessary to even approach theoretical performance levels.....

Here's an anecdote from an ADFU pilot when he first crossed paths with Faber's 190 (when German production was comparatively relaxed):

With some disappointment, I found that the 190 had already had its black crosses and swastikas replaced by British roundels and a hastily applied coat of RAF camouflage. In the few places that had been missed the beautifully smooth original finish could be felt. The 190 was a perfect example of precise German design and workmanship. Unlike our Spitfires, the panels were so well fitted that they looked like one piece.

 

[Admiral Beez]

Had several hundred modern fighters gone to Malaya in August 1940 as CIGS Dill had wanted, we might have seen the ultimate Zero vs. Spitfire engagement. Though most opposition would have been Oscars, not Zeros.

 

[slaterat]

Does anyone know why the Spitfire and Hurricane weren't fitted with constant speed props from day 1? I know they cost more and are heavier but building a Spitfire or Hurricane with a fixed pitch prop is like buying a high powered sports car fitted with 4 space saver tires instead of high quality tires

As I understand it all of the supplies of Constant speed props went to the bombers first, as they required them to take off with full loads.

Only the first 89 Spits produced had two blade propellers.

The first Hurricane flown with a two pitch three bladed prop was in Aug ,1938, the first with a constant speed prop was January , 1939.

Here's the breakdown on propeller development in fighter command for 1940. From "The Narrow Margin", Dempster and Wood, 1961.

By June 1940 all Hurricanes and Spitfires had three bladed, two pitch props.

By August 15, 1940 1051 Spitfires and Hurricanes in the field were equipped with constant speed propellers with automatic boost control. Production lines were also being converted to constant speed props.

Keep in mind that automatic boost control made the engines much easier to manage in flight and combat, this feature was lacking on many later American fighters such as the Brewster Buffalo, Tomahawk, Kittyhawk I, Martlet ect.

The RAF was at the forefront of propeller technology in 1940.

 

[Schweik]

Later mark Kittyhawks had automatic boost control (I think from K onward) but I know that this was in a way a mixed blessing, as they had to be tinkered with in order to do overboosting. Something about cutting a wire. I'm not certain about the Merlin engined ones (F and L) but I think they did too.

 

[nuuumannn]

The RAF was at the forefront of propeller technology in 1940.

It was, yes, although the DH props were of American origin - their 'Hydromatic' and counterweight props had appeared on bombers before fitting to fighters, but these were licence built Ham Std units. Rotol was the exception in Britain, but had limited application initially. The Rotol two position prop was first fitted to Spitfires with 54 Sqn in November/December 1939. This was initially limited to 54 Sqn however and the two position DH props were introduced in the Spring of 1940 - these were bracketed counter weight props. The DH and Rotol C/S props were fitted round about the same time as each other, from June/July 1940.

Bear in mind that the Bf 109 Emil, with a (pilot operated) variable pitch, not constant speed, prop entered service proper (apart from a limited number of E-Os in December 1938) in the Summer of 1939. VDM's first C/S props were designed in 1938. Later Bf 109Es had the awkwardly mounted pitch change lever on the instrument panel removed, formerly requiring the Bf 109 pilot to grow an extra hand to operate it during tight manoeuvring. British test pilots were surprised by this oddity of design when testing the type. The Friedrich had a C/S prop from the outset, work beginning in the Spring of 1940 on its development.

 

[slaterat]

Later Bf 109Es had the awkwardly mounted pitch change lever on the instrument panel removed, formerly requiring the Bf 109 pilot to grow an extra hand to operate it during tight manoeuvring

lol

 

[nuuumannn]

The Spitfires life can be summed up by the phrase, ''good enough now is better than perfect later''. The desperate need for them meant it's development always took a second seat to production resulting in it never maturing into the fighter it should have been.

I agree and disagree. Spitfire development was constantly evolving and the various marks and ease by which modifications could be made and hurried into production meant that it was very much given top priority, not to mention the considerable leaps in performance that expeditious measures such as the Sixty Series Merlins and the Griffons gave the type. Ironically, both the Spit IX and the Spitfire XIV that swung the Spitfire's performance ahead of its contemporaries were both stop-gaps.

As for the claim it never matured? Odd how it was one of the only WW2 fighters in production before the beginning and after the end of WW2 and produced in a large number of marks and sub-marks. Bear in mind that over 22,000 Spitfires were built. No US built fighter matches that number and of the best and greatest WW2 fighters, only the Bf 109 exceeds it. The Griffon engine gave the Spitfire a performance edge over its contemporaries. In Air Fighting Development Unit report No.117 dated 16 June 1944 the Spit XIV was evaluated against the Tempest, the P-51C, the Bf 109G and the Fw 190A. at height it was superior to all, although against the P-51C only marginally and the latter, not unexpectedly had a greater range, but the Spitfire held its own and proved superior in speed, rate of climb and dive. Against the Fw 190 it outperformed it in every aspect except rate of roll, against the Bf 109G, the Spitfire was superior in every way.

To claim it didn't mature into what it could have been is completely blind to its history.

 

[nuuumannn]

Let's also consider for a moment that the Mustang first entered service in january 1942 with the RAF, the design having taken advantage of the most current aerodynamic knowledge available to designers, so that by 1944 and the P-51C and 'D it was a world beater, yet, the Spitfire, the first of which first flew in 1936, in its 1944 incarnation, and structurally there wasn't much in it between the Mk.I and the Mk.XIV, only minor refienements, engine notwithstanding, could out perform the P-51.

 

[Shortround6]

The RAF was at the forefront of propeller technology in 1940.

ROFLMAO


The British Air Ministry (and a few others in Britain) had to dragged, kicking and screaming, to even get within rifle shot of current propeller technology in 1940.
The British may have been ahead of Lithuania

Roy Fedden of Bristol teamed up with RR to form Rotol in the teeth of opposition of both the air ministry and Bristols board of directors. The Bristol board was convinced the market for adjustable pitch (let alone constant speed) props was too small in England to be worth tooling up for and DH could easily supply the market.
Fedden and RR could see that the higher powered engines and faster planes would need something better than even two pitch props (all Bristol engines from the late 30s on had provisions, at least brackets and oil passages, sometimes plugged to fit variable pitch propellers, at least the export engines.

in 1938 there were something like 18 different airlines around the world using constant speed, fully feathering propellers in daily use on passenger carrying planes.
2 years later the British are just fitting constant speed props to their first line fighters and many of their bombers were still being fitted with 2 pitch props and the ones that got constant speed props weren't getting ones that would feather. They got a prop shaft brake, the dead or malfunctioning engine was put into coarse pitch and a brake was applied to keep the prop from turing. Please note that many of the early British 2 pitch props or constant speed props had a pitch change range of 20 degrees while many american planes (like Tomahawks) had a pitch change range of 30 degrees.

Too many British airmen flying bombers and maritime recconasance died due to crappy propellers for anyone to claim the British were at the forefront of propeller technology in 1940.

 

[slaterat]

Roy Fedden of Bristol teamed up with RR to form Rotol in the teeth of opposition of both the air ministry and Bristols board of directors. The Bristol board was convinced the market for adjustable pitch (let alone constant speed) props was too small in England to be worth tooling up for and DH could easily supply the market.
Fedden and RR could see that the higher powered engines and faster planes would need something better than even two pitch props (all Bristol engines from the late 30s on had provisions, at least brackets and oil passages, sometimes plugged to fit variable pitch propellers, at least the export engines.

Interesting history.

Rotol constant speed propellers installed on Hurricane Is in 1940 had a pitch range from 21 to 56 degrees, for a total range of 35 degrees.

Hurricane L-2026 Trials Report

These are the propellers that Hurricanes are flying with in Aug ,1940.

Over a year later, Kittyhawk Is, still didn't have automatic boost control.

Everyone who follows these things , knows that the Air Ministry made lots of very stupid decisions, fortunately there were many smart innovative and entrepreneurial people to compensate for this. Think of Hawker tooling up for 1000 Hurricanes , without an order, probably saved the free world.

 

[Greyman]

Automatic boost control doesn't really have much to do with prop development (for our purposes here, anyway). Curtiss had constant-speed props on their fighters before the P-36 even, did they not?

 

[PAT303]

To claim it didn't mature into what it could have been is completely blind to its history.

The Spitfire's development line went from the MkI then II then V and IX, if it had gone from the MkIII, a totally different aircraft we would have had the MkVIII and then the XIV instead. The MkIII air frame was a generation ahead of the MkII, two speed engine, shorter cleaner wings, retractable tail wheel, covered main gear and internal bullet proof windscreen. The MkIII gave the RAF an honest 385mph fighter with 650 mile range in 1941, 415 mph in 1942 accompanied by the Griffon powered XII and XIV from 1942 onwards. The interim models were good planes but they weren't a match for the ''production'' models.

 

[Glider]

See p648 and on, Chapter 11 'Aftermath' and various appendices.

Thanks for that

 

[tomo pauk]

...
The MkIII gave the RAF an honest 385mph fighter with 650 mile range in 1941
....

Already in 1940.