P-40 the RAF in 1940/41

[Mike Williams]

Do you have anything for the P-40 performance above 15,000ft?

It would be interesting to see how it dropped off.

Hi Wuzak,

Check the P-40 Performance chart

Level speeds:
340 mph at 25,000 ft.
322 mph at 30,000 ft.

Climb:

880 fpm at 25,000 ft.
360 fpm at 30,000 ft.

Time to climb
25,000 ft. - 12.53 minutes
30,000 ft. - 21.03 minutes

The Spitfire I for comparison from A. & A.E.E.:

Level speeds:
345 mph at 25,000 ft.
319 mph at 30,000 ft.

Climb (1/2 hour rating):
1,250 ft/min at 25,000 ft.
660 ft/min at 30,000 ft.

Time to climb:
25,000 ft. - 10.9 minutes
30,000 ft. - 16.4 minutes

Closer that I expected. Surprised me.

 

[Shortround6]

Trouble is this is for the the very, very early P-40.

From your website.
http://www.wwiiaircraftperformance.org/P-40/P-40_Official_Summary_of_Characteristics.pdf

at a gross weight of 6780lbs (give or take a few)
The P-40 gained weight faster than the Spitfire.

http://www.wwiiaircraftperformance.org/P-40/P-40B_Official_Summary_of_Characteristics.jpg

shows that while normal gross weight had gone to 7326lbs performace was still being calculated or based on a weight of 6835lbs.

They needed to dump a lot of guns/ammo/ fuel to get down to the design weight and since design weight and the 7326lb weight was with 120 US gallons (100 imp) dumping a lot of fuel wasn't a good option.

adding about 500lbs is what hurt the climb performance at altitude. The even heavier P-40C suffered more.

I would also note that the real difference show up in times between 25,000ft and 30,000ft.
5.5 minutes for the Spitfire and 8.5 minutes for the P-40.

Edit: The US Army flight manual shows 12 minutes to 25,000ft at 7000lbs and 18 minutes to 25,000ft at 7750lbs. This is, as usual, cutting back from 3000rpm/37.2" to 2600rpm/33.7in after the first 5 minutes.
rate of climb at max continuous at 25,000ft is given as 800fpm (chart is hard to read '6's and '8's look a lot alike.)

 

[stona]

Even given a two or three month time warp to allow the participation of early P-40s in the BoB I have yet to see any evidence that this would have been of any advantage to Fighter Command. The aircraft would have to perform better than the readily available Spitfires and Hurricanes, including in the hands of relatively inexperienced pilots, and this, even in its non battle ready form it did not.

The Spitfire I could compete well with the Bf 109 E. The Hurricane maybe not so well, it is a less clear cut case, and the same or worse would have been the case for the P-40, particularly at the ever increasing altitudes at which combat was taking place.

The premise originally advanced that having the P-40 available in numbers in the summer of 1940 would have given Fighter Command a significant advantage by being more potent than the fighters it already operated as the sharp end of a coordinated air defence system, is, and remains, nonsense.

Cheers

Steve

 

[Shortround6]

There are reasons the RAF shuffled the Tomahawks off to the mid-east or sent them on to the Russians (in many cases straight from the docks in US ports) and it wasn't stupidity or not invented here. The British were perfectly happy to use Lockheed Hudsons, Douglas A-20s, Grumman Wildcats/Martlets, Martin Marylanders and other US aircraft at this time that they were paying for with gold.

 

[Glider]

When considering the testing of weapons pre war its worth remembering that the targets didn't have armour or self sealing fuel tanks. In that scenario an LMG is very effective and eight of them was a massive amount of firepower.

 

[Shortround6]

Primary Fighters during the BoB were the MK I Spitfire and MK I Hurricane because they already existed in large numbers, The Spitfire MK II started to be introduced during the summer and the MK II Hurricane started to trickle into squadrons in Sept/Oct. It took until Spring 1941 to replace most of the MK Is but the Tomahawks certainly offered very little to warrant changing changing the replacement schedule to anything but what was done.

 

[Shortround6]

When considering the testing of weapons pre war its worth remembering that the targets didn't have armour or self sealing fuel tanks. In that scenario an LMG is very effective and eight of them was a massive amount of firepower.

Well, this is from Wiki and referenced to Bungay, Stephen. The Most Dangerous Enemy. London: Aurum Press, 2000.

"From 10 July to 11 August 1940, RAF fighters fired at 114 German bombers and shot down 80, a destruction ratio of 70%. Against the Bf 109, the RAF fighters attacked 70 and shot down 54 of these, a ratio of 77%. Part of the success of the British fighters was possibly due to the use of the de Wilde Incendiary Ammunition"

Other sources may very well differ but until somebody can really show some statistics showing large numbers (0ver 50% say?) of German aircraft escaping after taking hits the idea that eight .303s were near useless needs to be put away. Less than ideal yes, but there is a lot of room between the two positions. And 20mm cannon were being introduced (or at least trialed) during the BoB.

 

[buffnut453]

As to the P-40's 0.50" HMGs, were the RAF using the 0.50" Browning anywhere in 1940? Or teh British in general? What does that do for the supply of rounds - do they all have to be imported from the US?

The US 50 cal was not a viable weapon in 1940 for wing installations. Every major US operational type with wing installations had issues with the 50 cal thru Q3 of 1942 due to ammunition shifting during combat manoeuvres. Aircraft affected included the early P-51s, the P-40s in the Philippines, F4Fs and F2As, with wing gun stoppages a not uncommon occurrence...hardly a good thing in a combat environment. Yes, the problems might have been fixed sooner had the RAF shown incredible foresight by adopting the 50 cal in 1939 but by 1940 they needed a reliable weapon that could be used in multiple fighter types...and the 50 cal just wasn't that weapon during that timeframe.

 

[Greyman]

The US 50 cal was not a viable weapon in 1940 for wing installations. Every major US operational type with wing installations had issues with the 50 cal thru Q3 of 1942 due to ammunition shifting during combat manoeuvres. Aircraft affected included the early P-51s, the P-40s in the Philippines, F4Fs and F2As, with wing gun stoppages a not uncommon occurrence...hardly a good thing in a combat environment. Yes, the problems might have been fixed sooner had the RAF shown incredible foresight by adopting the 50 cal in 1939 but by 1940 they needed a reliable weapon that could be used in multiple fighter types...and the 50 cal just wasn't that weapon during that timeframe.

Interesting about the stoppages. I didn't know it was that widespread of a problem. I quoted James Edwards earlier - he's got another bit on this issue;

"All Kittyhawks I flew had six .50 guns, excellent for strafing or blowing up a target. However, one very annoying feature was gun stoppages in the desert. In ground strafing one could count on firing all the ammo without problems, but when it came to dog-fighting and excessive 'G' forces came into play, the guns most always packed up after a few bursts, leaving the fighter in a most perilous position. The 109s never appeared to have any problem with the nose cannon ..."

It must have been maddening. Reading the accounts of his dogfights - many 109s escaped his (and many others obviously) grasp because of this.

 

[MIflyer]

The RAF got its first Tomahawk during 7-14 Sep 1940.

By that time it had received 12 Brewster Buffalos, 54 Curtiss Hawk 75's, and 5 Grumman Martlets.

And even without drop tanks the Tomahawk and Hawk 75 had considerably longer range than the Spitfire, Hurricane, BF-109, and BF-110.

 

[Shortround6]

They did and they didn't have a lot more range. Yes they had a lot more range IF the fuselage tank was full (or nearly full) How ever the Fuselage tank was an overload tank or ferry tank. The performance figures for the Hawk 75 and the Tomahawk are with the tank either empty or drawn down to about 19 US gallons. I am not sure how well they handled with the rear tank full or even if combat maneuvers were allowed with the tank full.
There were a number of items relocated from the Hawk 75 to the Hawk 81 (Tomahawk) to keep the center of gravity in place with the longer engine, Oil tank being one of them for instance.
A P-40B held 33 Imp gallons in the front wing tank, 51 Imp gallons in the rear wing tank and had 16 Imp gallons reserve in the fuselage tank. total 100 imp gallons. it really isn't going to get you a whole lot further than the 97 imp gallons in a Hurricane. You could add another 32 Imp gallons to the rear fuselage tank and get your extra range but adding another 230lbs behind the Pilot's seat might not be good idea for either climb or trying to pull 6 G turns.

A P-40B on a summer day with full fuel tanks could take 600yds or more to clear a 50ft obstacle on take off. It needed about the same for landing.

 

[pbehn]

If the Tomahawk had considerably longer range than the Bf110 it was carrying too much fuel, the Bf110 could escort bombers across the North Sea

 

[Shortround6]

question there is which Bf 110?

There is no magic to range. Similar planes ( near the same top speed on close to the same power) will have similar cruising speeds and similar ranges on the same amount of fuel. Many times the ranges listed in online sources or in some books are best case ranges or calculated ranges. If a range looks too good to be true it probably is.

 

[pbehn]

Posting pictures of an aeroplane giving birth is the sign of a sick mind, what on earth was that bulge for?

I was really just discussing the run of the mill 1940 Bf110 which did escort bombers across the North Sea with no great mods.

 

[Shortround6]

Gentlemen, the pilots manual for the P-40B and P-40C is here on this site.
Can't find it at the moment but I have down loaded it. It is just the performance charts (range, climb, take-off and landing) but will answer a lot the questions in this thread.

 

[Shortround6]

Posting pictures of an aeroplane giving birth is the sign of a sick mind, what on earth was that bulge for?

I was really just discussing the run of the mill 1940 Bf110 which did escort bombers across the North Sea with no great mods.

Bugle was a fuel tank. The go trid of it in a hurry as they either couldn't jettison it or the jettison mechanism often failed. In either case it lit up pretty good when full of fumes.

 

[wuzak]

Bugle was a fuel tank. The go trid of it in a hurry as they either couldn't jettison it or the jettison mechanism often failed. In either case it lit up pretty good when full of fumes.

Looks like it wasn't at all jettisonable!

 

[Shortround6]

It may not have been, I didn't take the trouble to look it up. I do remember that it was less than successful as an escort due to the lower performance and rather alarming tendency to catch fire with relatively few hits. I believe the use of the tank also meant the two 20mm guns were taken out which rather hurt the firepower.

 

[stona]

The tank ('dackelbauch') was not jettisonable.
The 20mm cannon remained in place and usable, there was a space within the 'dackebauch' to collect the spent cartridges.
The Bf 110s that flew across the North Sea from Norway on 15th August 1940 were all dackelbauch equipped Bf 110 Ds of I./ZG 76. They were badly mauled by Fighter Command and it was the only time they flew against Britain during the BoB.
Cheers
Steve

 

[MiTasol]

Posting pictures of an aeroplane giving birth is the sign of a sick mind, what on earth was that bulge for?

I was really just discussing the run of the mill 1940 Bf110 which did escort bombers across the North Sea with no great mods.

Pregnant Bf110s had fuel and oil in the belly and there were multiple reports of them exploding in flight when the fumes from the tank got ignited by the guns firing and/or the hot spent brass which was stored inside the fairing.
They also had a CofG problem when almost empty because the tanks had insufficient baffles
cockpitinstruments.de has the manual for the BF 110 D installation and a discussion on the problems if you are interested. I think it was called flugzeugmutter or something similar - been a while