How superior climb rate is used in air combat ?.

[Engineman]

Winkle Brown mentioned the 109's roll rate as effected by stick restrictions, when pulling max turns the stick was hard into his thighs limiting movement which is probably why Mitchell made the Spits control stick hinged.

Brown was short and probably needed the seat high, which would effect the thigh/stick relationship. The 109 has a small cockpit but, the stick throw would have been designed to match control movement. However, different aircraft types have different control throws, leverage, range of movement, ease of pilot effective operation and overall effect.

Eng

 

[Greg Boeser]

Found this.
The Spitfire HF Mk VI: Aspirations of High-Altitude Flight The Spitfire HF Mk VI: Aspirations of High-Altitude Flight

 

[Geoffrey Sinclair]

End August 1942, types in production at Supermarine, Spitfire Vc, VI, IX, Seafire IIc
Sept-42, end Vc production, Start VII production
Oct-42, start XII production
Nov-42, end VI production, start VIII production
Apr-43, end Seafire IIc production
Jun-43, end IX production
Sep-43, end XII production
Oct-43, start XIV production

XII Production, Oct to Dec-42 was 1,1,3. For Jan to Sep-43 it was 3, 5, 20, 17, 28, 6, 7, 4, 5. EN221 to 238, EN601 to 637, usually Griffon III, fixed tail wheel. MB794 to 895, MB829 to 863, MB875 to 882, Griffon III or IV, retractable tail wheel, hence reports of the EN Series based on mark IX and MB series mark VIII airframes. Essentially built in serial order. According to the online listings the EN serials were 41 Griffon III, 4 IV, the MB serials were 39 III and 16 IV (MB855 then MB857 on)

EN221 (regular), EN222 (clipped) wings sent for trails. No one has found evidence on what, if any, XII were built with clipped wings. The date for the photograph is reported as April 1944, easily 6 months after final manufacture. Broad chord rudders tended to be a later modification as well.

The British system usually had a change of mark with a change of engine and this applies across the board for Spitfires, including the mark V, but that version introduced a wing change considered significant enough to officially note.

While the official figures do not list any low altitude Merlin 40 or 50 series for Spitfires, apart from the 55M, it looks like the figures did not break them out from the regular versions, which were Merlin 45, 46, 47, 50, 55, 55M, 56, pointing out only 120 production Merlin 47 and 28 Merlin 56. The Merlin 60/70 series recorded were 60, 61, 62, 63, 64, 65, 66, 67, 70, 71c, 72, 73, 76, 77. Versions built in small numbers, 75 M60, 2 M65, 71 M67, 16 M71c.

No detailed break down prior to March 1942, during 1942 Crewe was producing at least 4 different Merlin versions a month, topping out at 6, and that went up in 1943. In 1942 Derby at least 5, topping out at 9, that went up in 1943 like at Crewe. Ford was stuck at 1 until July 1943 when it went to 2, Glasgow at 1 until April 1943 until it began an increase that reached 5 in November 1943 and 9 in October 1944. There was lots of activity in the Merlin family, plenty of detail changes along with new versions.

 

[Engineman]

While the official figures do not list any low altitude Merlin 40 or 50 series for Spitfires, apart from the 55M, it looks like the figures did not break them out from the regular versions, which were Merlin 45, 46, 47, 50, 55, 55M, 56, pointing out only 120 production Merlin 47 and 28 Merlin 56.

No detailed break down prior to March 1942, during 1942 Crewe was producing at least 4 different Merlin versions a month, topping out at 6, and that went up in 1943. In 1942 Derby at least 5, topping out at 9, that went up in 1943 like at Crewe. Ford was stuck at 1 until July 1943 when it went to 2, Glasgow at 1 until April 1943 until it began an increase that reached 5 in November 1943 and 9 in October 1944. There was lots of activity in the Merlin family, plenty of detail changes along with new versions.

Yes, a very convoluted period of Merlin evolution. I am not certain that the records of the Merlin 45 to 56 engines is well detailed. Certainly, there were several avenue's of development that overlapped and some series are listed as trials engines. Also,, the RR diaphragm carb was only in a very few engines, possibly the "28"?
Lumsden lists the Merlin 50 as "purely a Service Trials engine" with a production of 629 in 1943, which sounds a lot, and late!
All these Merlin 45 to 56 engines are listed by Lumsden as .477 reduction ratio, which is specific to Merlin Spitfire applications.

Eng

 

[Steamed_Banana]

Wasn't the 28 the license built XX from Packard?

 

[Engineman]

Wasn't the 28 the license built XX from Packard?

Yes, the Merlin Mk 28 was built by Packard for British contracts. The "28" I referred to were the total number of Merlin Mk 56 that are recorded as built (28 engines).

Eng

 

[ThomasP]

FWIW

I do not know the source of the data, but in my notes I have ~256x Spitfire Mk VB/C with Merlin 45M delivered from Factory to MU to Sqn.
May'41___ 2
Jun'41____8
Jul'41____11
Aug'41___13
Sep'41___30
Oct'41___19
Nov'41___16
Dec'41___24
Jan'42___15
Feb'42___30
Mar'42___21
Apr'42___32
May'42__ 26
Jun'42____8
Aug'42___ 1 (sent to Supermarine for fuel flow tests)

No idea how many had clipped wings, or when/where the ones with clipped wings were so modified.

 

[ThomasP]

FWIW

As above, I do not know the source of the data, but in my notes I have ~564x Spitfire Mk VC, Mk VC Trop, and Seafire Mk IIC with Merlin 50, delivered from Factory to MU to Sqn. Also included in the total are 2x Seafire Mk III delivered with the Merlin 50 for testing.
Apr'42_____3 (Spitfire Mk VBs for test of Bendix-Stromberg carburetters)
(No production due to lack of source for carburetters)
Jan'43_____5
Feb'43____71
Mar'43____85
Apr'43___149
May'43__ 170
Jun'43____69
Jul'43_____ 9
Aug'43____ 3

There were about 30x Merlin 50A in the mix.

 

[ThomasP]

FWIW

As above, I do not know the source of the data, but in my notes I have ~1298x Spitfire/Seafire with Merlin 55 produced, with 119x Spitfire Mk VC and Mk VC Trop, and 1179x Seafire Mk III, leaving out the few with Merlin 55M and 55MA built before May'43. The Spitfire airframes were from the Factory to MU to Sqn as above. The majority of the Seafire Mk III were assigned from the Factory to a pool from which aircraft were drawn and sent to wherever needed, but most to the PTO for the BPF.
Jun'41_____1 (Merlin 55MA in Spitfire Mk VB, for tests)
Nov'41____ 1 (Merlin 55M in Spitfire Mk VB, for field tests)
Feb'42_____1 (Merlin 55MA in Spitfire Mk VB, for tests)
May'42____ 2 (Merlin 55M field retrofit in Spitfire Mk VB)
Oct'42_____1 (Merlin 55 field retrofit in Spitfire Mk VB)
May'43____ 2 (All Spitfire Mk VC or Mk VC Trop May'43 thru Aug'43)
Jun'43____10
Jul'43____ 76
Aug'43___ 32
Sep'43___ 20 (All Seafire Mk III Sep'43 thru Jun'45, with a about 24x Seafire FR MK III)
Oct'43___ 18
Nov'43___ 29
Dec'43___ 30
Jan'44____39
Feb'44____51
Mar'44___ 58
Apr'44____63
May'44___ 62
Jun'44____71
Jul'44____ 74
Aug'44___ 52
Sep'44___ 99
Oct'44____97
Nov'44___ 82
Dec'44___ 95
Jan'45____62
Feb'45____86
Mar'45___ 13
Apr'45____40
May'45___ 17
Jun'45____21

I have 50x Seafire LF Mk III with Merlin 55M produced with all sent to the BPF
Jan'45____ 1
Feb'45____8
Mar'45___41

 

[ThomasP]

FWIW

As above, I do not know the source of the data, but in my notes I have ~17x Spitfire Mk VC and 1x Seafire Mk III w/Merlin 32, delivered from Factory to MU to Sqn.
Dec'42____17
Nov'44_____1 (Seafire Mk III)

I have ~24x Spitfire PR Mk XIII (conversions from Mk I and Mk VB), and ~12x Seafire LF Mk IIC (conversions from Seafire F Mk IIC) w/Merlin 32.
Jul'42______1 (PR)
Aug'42_____1 (Seafire)
Oct'42_____ 2 (PR)
Nov'42_____1 (Seafire)
Dec'42___2/4 (Seafire/PR)
Jan'43_____4 (PR Mk XIII)
Mar'43___1/5 (Seafire/PR)
Apr'43___ 3/3 (Seafire/PR)
May'43___3/3 (Seafire/PR)
Jun'43_____ 2 (PR)
Jul'43______1 (Seafire)
Aug'44_____1 (PR)

NOTE I thought there were supposed to be more Seafire LF Mk IIC conversions than listed above, but I have not been able to find any other numbers.

 

[J.D.]

I was just browsing Robert L. Shaw's book "Fighter Combat: Tactics and Maneuvering" and it seems to me that his opinion is that how you use rate of climb depends on energy state. Even though the book is largely around jets, it's certainly true that T/W is critical. Lower inertia means better acceleration, especially at lower airspeeds.

I came across something a while ago that referred to Mackie Steinhoff instructing his pilots to employ a climbing turn if they were dived on. While this tactic is more about energy states - the pilot of a diving aircraft with have to do more to manage it - a lighter aircraft with a good P/W will have a very significant advantage here.

Some aircraft climb at steeper angles than others and it isn't always indicative of their maximum climb performance. I can't remember reading of too many examples where pure climb was used. That said, if someone can climb at a steeper angle than you in a given energy state, you're going to have a hard time pulling any lead.

 

[ThomasP]

One example I can think of off hand is the Mosquito. If they were operating at low to medium altitude, and if the crew spotted the EA approaching from a lower altitude, they were usually able to use climb to draw away from the EA. If there was any knd of cloud cover they would excape by climbing into the clouds. This was in the recommended tactics after the AFDU got done with their tests, and was used to effect in operations. I have read several pilots reports where this was done.

Although it has to be kept in mind that, at least in the early operational days, the Mosquito was not too much slower than even the fastest EA.

Another example is the A6M2/3. Until the F6F & F4U came along the Zero was as fast pr faster than the F4F-3/-4, and had about 30%-60% higher ROC (depending on what figures you use) upto around 15,000 ft, after which the advantage slowly decreased until they were about equal at about 22,000 ft. Again, I have read several USN pilot and IJN pilot accounts where this happened. Kind of interesting, the Zero pilots tended to avoid pursuing the USN aircraft by diving if the altitudes were above 5,000-10,000 ft or so - above which the F4F could build up enough speed in a dive to outdistance the Zero - while the USN F4F pilots often commented being unable to follow the Zero in a climb, sometimes mentioning the steepness of the Zero's climb.

 

[Steamed_Banana]

One example I can think of off hand is the Mosquito. If they were operating at low to medium altitude, and if the crew spotted the EA approaching from a lower altitude, they were usually able to use climb to draw away from the EA. If there was any knd of cloud cover they would excape by climbing into the clouds. This was in the recommended tactics after the AFDU got done with their tests, and was used to effect in operations. I have read several pilots reports where this was done.

Although it has to be kept in mind that, at least in the early operational days, the Mosquito was not too much slower than even the fastest EA.

Another example is the A6M2/3. Until the F6F & F4U came along the Zero was as fast pr faster than the F4F-3/-4, and had about 30%-60% higher ROC (depending on what figures you use) upto around 15,000 ft, after which the advantage slowly decreased until they were about equal at about 22,000 ft. Again, I have read several USN pilot and IJN pilot accounts where this happened. Kind of interesting, the Zero pilots tended to avoid pursuing the USN aircraft by diving if the altitudes were above 5,000-10,000 ft or so - above which the F4F could build up enough speed in a dive to outdistance the Zero - while the USN F4F pilots often commented being unable to follow the Zero in a climb, sometimes mentioning the steepness of the Zero's climb.

And depending on the distances, which you might break down to 'engaged', 'combat distance', 'within sight' and 'preparatory' (i.e. not within sight but expecting contact, such as if notified by radio of a radar contact or a sighting from another unit) these aircraft would have different options. Depending on the distance, within sight or at combat distance the lone Mossie is probably doing a high speed climb at altitude, to keep up horizontal separation at the same time as raising the altitude. If the EA was closer, this might be done in a shallow high speed climb with a climbing turn to make it more difficult to sight them in. This is also what experienced P-38 pilots did in the Pacific. If altitude and / or horizontal distance is far enough, say just at the limits of sighting / identifying enemy aircraft, they may engage in a maximum climb rate climb, which would be very slow in terms of speed.

At altitude, the Mossie with it's (usually) two stage supercharger and the P-38 with it's turbo have a power advantage over most Axis fighters. Once there is enough (vertical and / or horizontal) separation, a fighter with an inferior ROC at that altitude is basically out of luck - if they try to chase in a climb they will lose power and become vulnerable to counterattack due to being in a lower E state, and will also be easily evaded if the aircraft they are pursuing wants to disengage.

Aircraft could climb at a steep angle for a short time, in many cases (depending on E state), but could not sustain it. So whether you could risk climbing at a steep angle would depend on how close the enemy aircraft were.

For the Wildcat, due to their (albeit not very efficient) two stage supercharger they had slightly more power than than the early (A6M2) Zero at 20,000+ ft, so at that altitude they may actually be able to out-climb it, but probably safest to try that with a high speed climb. The big flaw of the Wildcat was that it's climb rate at lower altitudes was abysmal, as little as 1,500 fpm when fully loaded with fuel, which caused major problems with getting them up to altitude after an enemy formation. So for preparatory situations the maximum climb rate was grossly insufficient. Once at altitude it was not as dire of a situation because they could zoom limb somewhat.

For the A6M2 conversely, being light and having a large wing, it's initial climb rate was quite good, and being well streamlined, it retained speed fairly well. So it was able to keep an E advantage up to around 20,000 feet if it had one.

When 'engaged', a slow climb was not an option and even a high speed climb was risky without some other element, a climbing turn or for example the famous Hinero Komi maneuver (a steep loop twisting back into an attack on the pursuer) or something like a hammerhead or Immelmann turn could be however.

Light aircraft like the Zero or Ki-43 could perform these turns very well, but so could heavier aircraft with sufficient power (and / or E) and good enough agility (roll rate, basically) and handling. Fw 190s performed such turns, as did P-39s (at low altitude) and many Soviet fighters like Yak -1/7/9, Yak 3, and La 5, P-40s could do these turns at low to medium altitude, and Corsairs could do them, as did P-51s.

 

[Steamed_Banana]

A6M3 was developed precisely to address some of these issues, with a two speed supercharger giving a bit better performance at altitude, and (depending on the subtype) clipped wings improving roll and dive performance somewhat. But they struggled to get the balance right with the A6M3 and the loss in fuel capacity was a big problem during a critical phase of the war.

 

[Geoffrey Sinclair]

A quote, "the Merlin 45 and 45M differed only in supercharger rotor size and so no modifications were necessary", which implies it was a simple parts change. Unlikely to trigger things like a new serial number.

The RAF Form 78 aircraft cards have the engine information as part of the header block, it is rare to find an entry dating an engine change, just the header altered, which in this case would add an M to Merlin 45.

First possibility, from January 1941 onwards the RAF was receiving low altitude Merlin 45M engines, Spitfire V so fitted were dispersed amongst the squadrons, only a few per unit per given time. This is when the RAF is desperate for altitude performance to counter the Bf109F then G and Fw190A, while still having lots of Hurricanes and the prospect of Typhoons for low level operations. These low level Spitfires seem to have gone unremarked, no mention by pilots, no special operations, no tactical instructions, until 1943.

Second possibility, people are faithfully transcribing the Form 78, so R6809, cannon armed mark I, converted to Vb in January 1941 with Merlin 45M. R6888 Write off in February 1941, but converted to Vb Merlin 45M then to 302 squadron. W3310 built in May 1941, Merlin 45M, a long range low altitude version. And so on.

The big assumption being the engine mentioned in the header was the one installed at build or conversion.

April 1943, W3228 trials with Merlin 50M, May 1943 W3228 and AB167 intensive flight trials with Merlin 45M. So why wait over 2 years for the trials?

Option 1, we have just discovered a hitherto ignored low altitude Spitfire force scattered amongst the line squadrons in 1941 and 1942.
Option 2, assumptions have been made about dates and/or types of engine fits. If you take a look at the aircraft with M45M they are survivors, lasting into 1943, with the observation made by pilots that older airfames were converted to low altitude.

The contract cards for the early mark V orders say Merlin 45 before simply saying Merlin.

Another check is a pair of production Merlin 50 in June 1942, then 729 built November 1942 to June 1943. No production Merlin 55 until May 1943, 55M from June, engines cannot be installed before these dates. Now to the archives.

AVIA 46/119 Spitfire Biography, I only have extracts.

"During early 1943 steps were taken to improve the performance of the Spitfire V still further following complaints from Middle East Command that the tropicalised Spitfire V could not catch the Fw190 at 2,000 feet. In particular cropped impellers and clipped wings were recommended by the Command as giving an increase of 20 mph at 2,000 feet. The question of clipped wings for all Spitfire V was discussed fully in April 1943 (File S.B. 45457 throughout). Briefly clipped wings were not suitable for high altitude but for sorties at medium and low altitude improved handling qualities outweighed small disadvantages from higher wing loading. For these reasons it was decided to clip the wings of some mark V aircraft to provide a special low flying version."

Mark XII summary, Griffon slowly progressing in the background, limited by efforts needed for Merlin, first suggestion in August 1942, as 100 planned mark IX would lack engines, order placed. Decision taken to fit all mark XII with clipped wings in October. Order strictly limited to 100 to concentrate on the mark VIII Merlin and the F.21 Griffon 2 speed 2 stage series. Original plan was 50 by end 1942, another 50 by end April 1943.

SUPP 9/1/3 part 3, amongst other data sheets, Spitfire VC: Low Altitude Fighter. (1944 Feb 22). "Spitfire low altitude" search string.

Wonder what the "Spitfire L.R.XXI: Long Range Fighter. (1944 Dec 8)" was

AIR 16/327 is long range tanks for Spitfires. AIR 23/5648 the super long range reinforcements for Malta.

There are the clipped wing reports as well.

AVIA 10/315 to 318 MAP production figures.
AIR 20/1918 engine production in 1942.

Rolls Royce heritage files are currently being catalogued, please ask again in January 2027.

Spitfire PR.XIII, all conversions from earlier versions done December 1942 to March 1943. Supermarine built 262 Seafire IIc June 1942 to April 1943. Westland built IIc December 1942 to September 1943, Seafire III from April to November 1943, June to September 1944, Seafire LF.III December 1943 to July 1945, Cunliffe Owen LF.III November 1943 to July 1945.

If you look at the engines mentioned in the online Spitfire listings 264 Spitfire Vb had M45M (261 Vb), 475 mark V had Merlin 50, 119 Merlin 55. The big user of the Merlin 55 is Seafire III with 1,132, compared with 485 M55 and 1,428 M55M reported built for 188 Seafire III (plus some Spitfire V) and 1,062 Seafire LF.III.

 

[Steamed_Banana]

Hurricanes were not going to help at all with Fw 190 flying Jabo strikes at low altitude. Which was becoming a problem in the Med by late 1942 early 1943 and had already been an issue in the Channel from mid 1942.

Clipped wing Spits were not necessarily low altitude fighters, my understanding is LF Spits represented cropped impeller, not necessarily clipped wings. Some had both but by no means all.

There was a small diminution of ceiling and slight rate of climb decrease from clipping wings (IIRC someone already posted some numbers on this upthread) but a clipped wing Spit was still viable up to 99% of it's rated altitude, per the engine and supercharger / impeller.

 

[mig-31bm]

Buy the book, it's worth it.

I just got it today, seem pretty interesting indeed

 

[bada]

Tell us what you think of it , if it was as refreshing for you as it was for me

 

[Holtzauge]

I just got it today, seem pretty interesting indeed

Tell us what you think of it , if it was as refreshing for you as it was for me

Well thanks for those kind words, and if you have any questions, please let me know.

Connected to climb, after having written the book, I came across what seems to have been a rpm limitation for the Merlin III that was in place at the time of the Battle of Britain:

In my book on page 225, I assume that the Spitfire could climb for more than 5 min at 3000 rpm, whereas the Pilot's Notes from the time seem to indicate that this was actually restricted to 5 min, and after that the rest of the climb should be done at 2600 rpm.

You can read more about it on my homepage here.

 

[Shortround6]

In my book on page 225, I assume that the Spitfire could climb for more than 5 min at 3000 rpm, whereas the Pilot's Notes from the time seem to indicate that this was actually restricted to 5 min, and after that the rest of the climb should be done at 2600 rpm.

You may, or may not, be using the American climb standards.
And we have standard climb and "combat" climb.
And we have the change in climb ratings for the Merlin III.
Standard climb was at 2600rpm and 6 or 6 1/4lbs boost, which could only be maintained to around 10,000ft.
Combat climb was at 3000rpm. Now if the plane was in combat I highly doubt the pilots throttled back to 2600rpm, at least if the temperature gauge was still OK.
At some point in summer of 1940 the British OKed the use of 2850rpm for standard climb in the Merlin IIIs but still at 6 lbs of boost.
In actual combat (shooting, trying to shoot or trying not be shot) the Spitfires could use 12lbs of boost assuming the correct height to get it and 3000rpm for climb.

The problem for these climb charts (American, British and German) is that they are sort of a tactical chart. I mean it will show the time it takes for a single fighter to get from ground level to a combat (intercept?) height and not abuse the engine doing so.
No pilot or group of pilots are going to use 3000 rpm to climb for 5 minutes and then throttle back to 2600rpm if the enemy bombers are still 3000ft above them.
British climb charts almost never used full throttle at time.
You can find a few charts where they used full throttle but most of the time they used the 30 minute rating (2600rpm for Merlin IIIs) for the entire climb.
You can find a few charts where they used 3000rpm # or 5 minute ratting) but in the notes it will say this was for test purposes only and was used to get the climb rates at altitude and not for time to altitude.
Americans may have been the only nation that used 5 minute rating for the first 5 minutes of climb and then dropped back to the 1 hour or max continuous rating for the rest of the climb.
British did not have a 1 hour rating. The Americans did not have a 30 minute or climb rating.