Recurring Theme in WW2 Aviation

[Shortround6]

In some cases fighters went for several years with the same engine. Spitfire was first flown in 1936 and while it didn't fly with a Merlin III the engine used wasn't far off. Production planes went into service in the summer of 1938 with Merlin II engines and the only difference between a II and a III was the prop shaft. Spitfire didn't get a higher powered engine until summer/fall of 1940 with the Merlin XII. Granted better fuel allowed the Merlin III to operate at higher boost for more power but that wasn't really a planned capability.
P-40s are ordered in April of 1939, First production planes are delivered in May of 1940. British order the equivalent of the P-40D about the same time. First P-40D doesn't fly until a year later with the "New" engine.
The First F4U production plane flew in June of 1942, the First F4U fitted with a water injection system on the production line was in Nov 1943, the 1551st Corsair built by Vought. Please note that both Brewster and Goodyear were building Corsairs at this point. There was no better performing R-2800 at this time except the turbo version in the P-47 and that required a LOT more volume inside the fuselage so it wasn't a "drop in" substitute. It wasn't even possible with out major redesign/modification.
Some planes seemed to get a new model engine every few months (exaggeration) like the 109 that went through 4 or more versions of the DB 601 from 1939 to 1942 and in 1942 switched to the DB 605 which went through at least 4 more versions by the spring of 1945. Spitfires after 1940 also seemed to be members of the engine of the month club (joke) with something like 18-19 different Merlins possibly fitted before you even get to the Griffons. Granted some had very small differences between them.
Fighters were usually designed with the best possible engine likely to be available when production was possible (often 1-2 years away, sometimes 3), sometimes engine development was slow or is some cases canceled which forced substitutions. Sometimes for the better and sometimes not.

 

[MiTasol]

My point - let's take a look at facts, not fiction, even the documentaries need to be taken with grain of salt.

Right on Tomo

 

[drgondog]

And virtually all of those same fighters also first flew with an engine developing less HP than the airframe was intended for. In most cases the engine was as much under development as the airframe.

I'm not quite in agreement. The airframe structure, while considering thrust and lateral inertia of the engine in a lateral G load condition (Brits ignored, we tended to use 1 1/2G), only sized the mount scheme. The dominant design loads were for max Angle of Attack loads (dive pullout, max instantaneous Turn rate). That is the reason why eventually other structure (like longerons/bulkhead/spar) in the empennage was beefed up when major increases in torque were introduced with engine/prop system upgrades.

 

[XBe02Drvr]

I'm not quite in agreement. The airframe structure, while considering thrust and lateral inertia of the engine in a lateral G load condition (Brits ignored, we tended to use 1 1/2G), only sized the mount scheme. The dominant design loads were for max Angle of Attack loads (dive pullout, max instantaneous Turn rate). That is the reason why eventually other structure (like longerons/bulkhead/spar) in the empennage was beefed up when major increases in torque were introduced with engine/prop system upgrades.

Quite true when viewed from a structural strength perspective only. But these aircraft were designed to PERFORM, and their designers had to make all of their design choices based on an assumed available thrust, usually for a more advanced version engine than existed at time of design or even first prototype flight. Engines were pushing the technology envelope and frequently didn't meet performance targets by promised date. So the prototype got to fly with a less powerful version. Production aircraft usually got something like the originally intended engine.

 

[XBe02Drvr]

Might be a case of semantics here. In some contexts "airframe" can be taken to mean the details of aircraft structure, while in others it refers to the entire aircraft for which the manufacturer is responsible, except powerplant and GSE stuff like armament and some of the electronics.
This latter is the context in which I was speaking.

 

[Glider]

As for the Spitfire it initially suffered from a poor climb rate. From Mk1 to Mk2 A 3 bladed prop was added as well as the engine being upgraded from a Merlin Mark II to III which was shortly again replaced with a Mark XII engine. Both engine replacements and the initial change from wood 2 bladed to metal 3 bladed propellor increased climb performance significantly. And these changes had been anticipated by its primary designer Mitchell who died of cancer in 1937. Yet the Mark 1 was delivered with neither change.

As I say an recurring theme...

You also have to judge the aircraft against its contemporaries. The Spitfire initially didn't have a poor climb, when first issued it could out climb almost everything. It was also faster, more agile and at least as easy to fly as any of its contemporaries.

Its almost unique ability was to absorb significant increases in power and payload with remarkably few alterations.

 

[buffnut453]

As for the Spitfire it initially suffered from a poor climb rate. From Mk1 to Mk2 A 3 bladed prop was added as well as the engine being upgraded from a Merlin Mark II to III which was shortly again replaced with a Mark XII engine. Both engine replacements and the initial change from wood 2 bladed to metal 3 bladed propellor increased climb performance significantly. And these changes had been anticipated by its primary designer Mitchell who died of cancer in 1937. Yet the Mark 1 was delivered with neither change.

As I say an recurring theme...

You can't deliver a system with updated components if those components aren't ready in sufficient quantity to equip and sustain the front line force.

I don't see it as blaming the companies, at least not all of them. I guess the point I was trying to make, and I believe is true to this day, is that typically speaking military equipment is always horrible when it comes to version 1. Often needlessly. Having served myself I can attest to time after time upon receiving new equipment we encountered difficulties that rendered it either useless or far less useful than intended. I cannot think of a single instance where this was necessary or could not have been avoided by simple reality checks of the requirements vs delivered specs. As far as blame, there was plenty of that to go around I am sure. It was unpatriotic to discuss war profiteering during and after the war but in the decades that followed it became readily apparent most manufacturers dined at that trough to some degree or another.

The problem is often a disconnect internal with the Govt between the front-line need and the requirements levied by the procuring organization. Also, the front-line often speaks with more than one voice. Different users place different priorities on needs, and those needs often don't reflect broader capability requirements like sustainability, training etc. Having worked both sides of the procurement fence, there's plenty of blame to go around and issues perceived by the front line are often not "needless" but result from people making the best decisions that they can in the circumstances.

 

[pbehn]

How did the spitfire ever suffer from a poor rate of climb? You can always improve rate of climb but it was never poor, it only had one contemporary that was possibly better as far as I know. Importantly the one that was better was its main adversary, improvements to the spit in terms of power output and propeller design closed the gap and possibly gave it an advantage in some conditions. Then everyone was pretty happy with the Spit until the Fw190 appeared. It is all purely relative to the opposition, all sides had to run flat out to maximise performance simply because they didnt know what the opposition would come up with. I am sure P51 pilots thought their planes were the dogs balls until they saw a Me262 introducing a new level in speed.

 

[drgondog]

Quite true when viewed from a structural strength perspective only. But these aircraft were designed to PERFORM, and their designers had to make all of their design choices based on an assumed available thrust, usually for a more advanced version engine than existed at time of design or even first prototype flight. Engines were pushing the technology envelope and frequently didn't meet performance targets by promised date. So the prototype got to fly with a less powerful version. Production aircraft usually got something like the originally intended engine.

I tend to disagree for this reason. The P-38, 39, 40, 47, P-61, P-63 and F4U, all started with the same engine as designed for, based on the best performance available at the time based on in-line or radial features. The engine manufacturers were able to keep pace to grow power and reliability without changing the envelope of the engine. The XF4F started with R-2600 delivering same power as the replacement R-2800 for the first production version.

The P-51B is the big exception and that wasn't a HP decision so much as it was altitude performance based on a different required mission than the original design spec. Others actually downgraded from original performance of selected engine - namely the XP-82 when NAA forced to accept Allison 1710 2 speed/2 stage that never could reliably perform to spec at WEP.


To your point there were many aircraft that began with an experimental engine (B-29, XP-47J, XP-75, etc) that took a long gestation period before becoming a reliable powerplant suitable for production reliability and performance as planned.

 

[Robert Porter]

How did the spitfire ever suffer from a poor rate of climb? You can always improve rate of climb but it was never poor, it only had one contemporary that was possibly better as far as I know. Importantly the one that was better was its main adversary, improvements to the spit in terms of power output and propeller design closed the gap and possibly gave it an advantage in some conditions. Then everyone was pretty happy with the Spit until the Fw190 appeared. It is all purely relative to the opposition, all sides had to run flat out to maximise performance simply because they didnt know what the opposition would come up with. I am sure P51 pilots thought their planes were the dogs balls until they saw a Me262 introducing a new level in speed.

The poor rate of climb I mentioned was in the official reports when the Mk I and II were being tested. I do not recall the actual rate of climb reported but it was much less than both desired and what contemporary german fighters were capable of, and it resulted in design changes and an engine and propellor change to compensate. Like I said not my observation this was right from the RAF.

 

[pbehn]

The poor rate of climb I mentioned was in the official reports when the Mk I and II were being tested. I do not recall the actual rate of climb reported but it was much less than both desired and what contemporary german fighters were capable of, and it resulted in design changes and an engine and propeller change to compensate. Like I said not my observation this was right from the RAF.

When the Spitfire was first tested it was actually slower than the Hurricane, it turned out that the propeller was wasting power. Later the twin blade props were replaced with 3 blade variable pitch and eventually constant speed propellers with 3,4 and 5 blades. When the MkII was introduced its improved performance was noted by the LW in combat making it a more dangerous adversary.

from wiki
K5054 was fitted with a new propeller, and Summers flew the aircraft on 10 March 1936; during this flight the undercarriage was retracted for the first time.[18] After the fourth flight, a new engine was fitted, and Summers left the test-flying to his assistants, Jeffrey Quill and George Pickering. They soon discovered that the Spitfire[nb 4][21] was a very good aircraft, but not perfect. The rudder was over-sensitive and the top speed was just 330 mph (528 km/h), little faster than Sydney Camm's new Merlin-powered Hurricane.[23] A new and better-shaped wooden propeller allowed the Spitfire to reach 348 mph (557 km/h) in level flight in mid-May, when Summers flew K5054 to RAF Martlesham Heath and handed the aircraft over to Squadron Leader Anderson of the Aeroplane & Armament Experimental Establishment (A&AEE). Here, Flight Lieutenant Humphrey Edwardes-Jones took over the prototype for the RAF.[24] He had been given orders to fly the aircraft and then to make his report to the Air Ministry on landing. Edwardes-Jones's report was positive; his only request was that the Spitfire be equipped with an undercarriage position indicator.[25] A week later, on 3 June 1936, the Air Ministry placed an order for 310 Spitfires,[26] before any formal report had been issued by the A&AEE; interim reports were later issued on a piecemeal basis.[27]

 

[tomo pauk]

The poor rate of climb I mentioned was in the official reports when the Mk I and II were being tested. I do not recall the actual rate of climb reported but it was much less than both desired and what contemporary german fighters were capable of, and it resulted in design changes and an engine and propellor change to compensate. Like I said not my observation this was right from the RAF.

I'm afraid that you'd need to be more specific on the Spit I and II flight tests. Like the date, condition and exact condition of the tested aircraft. And then compare with what contemporary (1936-1940) German fighters were doing.
I'd also like to see what were the 'design changes' in the early Spitfires, apart from prop and protection.

BTW - Robert, please don't take this personally, but since you've mistaken a big time about superchargers of ww2 aircraft, I believe you've mis-remembered other stuff.

 

[Robert Porter]

I'm afraid that you'd need to be more specific on the Spit I and II flight tests. Like the date, condition and exact condition of the tested aircraft. And then compare with what contemporary (1936-1940) German fighters were doing.
I'd also like to see what were the 'design changes' in the early Spitfires, apart from prop and protection.

BTW - Robert, please don't take this personally, but since you've mistaken a big time about superchargers of ww2 aircraft, I believe you've mis-remembered other stuff.

Well it is certainly possible, let me find the source documents and go from there.

 

[Robert Porter]

Okay as to my supposed mistake about aircraft being delivered without Super chargers here is just one reference of such. From the book "American Warplanes of WWII Pedia Press edited by Col John D Current.

Follow this link for an excerpt about the P-36 American Warplanes of WWII

I quote here: "It's lack of an engine Supercharger handicapped it at high altitudes as well."

 

[Robert Porter]

Per the poor rate of climb is best illustrated with this quote.

"The Spitfire was conceived about the time that the importance of speed and climb rate was being discovered. Subsequently, the early Spitfires were rather slow with poor climb rates, but (being very light weight) possessed excellent turn performance."

This is pretty well illustrated if you read the following RAF Reports. Spitfire Mk I K-5054 Handling Trials

The reports go model by model and compare all manner of handling characteristics and describe the exact equipment being tested.

I honestly do not believe I misremembered much but am still open to the possibilities.

Finally there is a great PDF Comparing the P-46, Spitfire and two german fighters and featuring prominently in the Spit coverage was its relative poor climb rate this document is available right here in these forums at: P-47 vs Fw-190,Spitfire,P-38,P-51

Hope this helps clarify where my opinion was developed.

 

[pbehn]

Per the poor rate of climb is best illustrated with this quote.

"The Spitfire was conceived about the time that the importance of speed and climb rate was being discovered. Subsequently, the early Spitfires were rather slow with poor climb rates, but (being very light weight) possessed excellent turn performance."

This is pretty well illustrated if you read the following RAF Reports. Spitfire Mk I K-5054 Handling Trials

The reports go model by model and compare all manner of handling characteristics and describe the exact equipment being tested.

I honestly do not believe I misremembered much but am still open to the possibilities.

Finally there is a great PDF Comparing the P-46, Spitfire and two german fighters and featuring prominently in the Spit coverage was its relative poor climb rate this document is available right here in these forums at: P-47 vs Fw-190,Spitfire,P-38,P-51

Hope this helps clarify where my opinion was developed.

Looked through the links and cant find anything saying the spitfire was poor in climb, only one link says the Spitfire could out turn the P47, turn performance is normally an indicator of climb performance. Climb performance had been sen as important as soon as planes were used in combat, the increasing speed of bombers made it more important

part of the report linked says this

Comparitive trials between the Me.109 and "Rotol" Spitfire.

1. The trial commenced with the two aircraft taking off together, with the Spitfire slightly behind and using +6 1/4 lb boost and 3,000 rpm.

2. When fully airborne, the pilot of the Spitfire reduced his revolutions to 2,650 rpm and was then able to overtake and outclimb the Me 109. At 4,000 ft, the Spitfire pilot was 1,000 feet above the Me 109, from which position he was able to get on its tail, and remain there within effective range despite all efforts of the pilot of the Me 109 to shake him off.

 

[Robert Porter]

Looked through the links and cant find anything saying the spitfire was poor in climb, only one link says the Spitfire could out turn the P47, turn performance is normally an indicator of climb performance. Climb performance had been sen as important as soon as planes were used in combat, the increasing speed of bombers made it more important

part of the report linked says this

Comparitive trials between the Me.109 and "Rotol" Spitfire.

1. The trial commenced with the two aircraft taking off together, with the Spitfire slightly behind and using +6 1/4 lb boost and 3,000 rpm.

2. When fully airborne, the pilot of the Spitfire reduced his revolutions to 2,650 rpm and was then able to overtake and outclimb the Me 109. At 4,000 ft, the Spitfire pilot was 1,000 feet above the Me 109, from which position he was able to get on its tail, and remain there within effective range despite all efforts of the pilot of the Me 109 to shake him off.

I do not know what to say, the phrase "poor climb rate" appears twice in conjunction with the Spitfire just in that one link but I am happy to find and share others. This issue was largely addressed by the Mark III and subsequent models but reappeared in the very last model built of which only 100 were made. However its climb rate at altitudes above 16,000 feet was poor throughout all models. Remember this is poor in comparison not saying it was overall.

 

[pbehn]

I do not know what to say, the phrase "poor climb rate" appears twice in conjunction with the Spitfire just in that one link but I am happy to find and share others. This issue was largely addressed by the Mark III and subsequent models but reappeared in the very last model built of which only 100 were made. However its climb rate at altitudes above 16,000 feet was poor throughout all models. Remember this is poor in comparison not saying it was overall.

from the link
The following table gives comparative times in minutes to reach various heights for the best climbing speed and the recommended climbing speed. Also included are the times to height for Spitfires with 2-Pitch and fixed pitch airscrews.

Airscrew Time to Height (Feet.)
10,000 15,000 20,000 25,000 30,000
Rotol Best Climb 3.4 5.3 7.7 11.1 16.1
Rotol Recommended 3.5 5.4 7.7 11.0 16.4
2-Pitch Metal 5.5 8 11.3 15.9 23.8
Wooden Fixed Pitch 4.4 6.6 9.4 13.8 22.4
Best climbing speed:- 140 m.p.h. A.S.I. to 12,000' thereafter
decreasing by 1 m.p.h. per 1000 feet.

the difference between best performance with Rotol prop on a Mk one and worst performance with two blade wooden prop is more than 6 minutes to 30,000 ft. The statement that the spitfire was poor in climb throughout all models above 16,000 ft is interesting, I dont agree.

 

[tomo pauk]

Okay as to my supposed mistake about aircraft being delivered without Super chargers here is just one reference of such. From the book "American Warplanes of WWII Pedia Press edited by Col John D Current.

Follow this link for an excerpt about the P-36 American Warplanes of WWII

I quote here: "It's lack of an engine Supercharger handicapped it at high altitudes as well."

One myth at time
The Bible on American fighter aircraft is the "America's hundred thousand". While not without a minor glitch or two, it is a vastly better resource than the copied Wikipedia aricles bundled in a book. Another excellent book is Ray Wagner's "American Combat Planes of the 20th Century", that I unfortunately don't own, unlike the 1st book.
The P-36 was outfitted with supercharged engines in all iterations, whether it was R-1820 or R-1830 in question. Red arrows are my contribution:

 

[tomo pauk]

Per the poor rate of climb is best illustrated with this quote.

"The Spitfire was conceived about the time that the importance of speed and climb rate was being discovered. Subsequently, the early Spitfires were rather slow with poor climb rates, but (being very light weight) possessed excellent turn performance."

This quote is an opinion. All fine and good with opinoins, they need to be backed by other informations - who is the person making an opinoin, what actual facts are used to form an opinion, what are the sources for those facts etc. Since there is no factual support for the opinion, I'll be so frank to discard it from a discussion where facts are required.

This is pretty well illustrated if you read the following RAF Reports. Spitfire Mk I K-5054 Handling Trials

The reports go model by model and compare all manner of handling characteristics and describe the exact equipment being tested.

I honestly do not believe I misremembered much but am still open to the possibilities.

Let's not move the goal post. You've described the Spitfire as unable to compete in rate of climb against German opposition, several times now. Please post data.

Finally there is a great PDF Comparing the P-46, Spitfire and two german fighters and featuring prominently in the Spit coverage was its relative poor climb rate this document is available right here in these forums at: P-47 vs Fw-190,Spitfire,P-38,P-51

Hope this helps clarify where my opinion was developed.

The comparison of rate of climb on that doc, involving a Spitfire, is the one between P-47 (not P-46, a typo I guess) and Spit IX, where is stated: