It was a big target though. The biggest trouble I have with comparisons is the era they were in, Spitfires, Hurricanes, Me109's and FW190's all fought each other at the beginning of the war when both sides were equal as far as skill of the pilots and strength of the opposing forces was concerned, move forward to late '43 onwards when the P47 and P51 really came into being the Luftwaffe was a different animal, same could be said for the Pacific, the Wildcat fought a much tougher fight than the Hellcat, Corsair and P38 ever did.
Effectiveness of the P-38 (1 Viewer)
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ThomasP
Chief Master Sergeant
For the Corsair and Hellcat maybe, but the early-war P-38 pilots in the Pacific flew against the same highly trained IJN pilots or the same somewhat less highly selective IJA pilots.
It needs to be kept in mind that when the P-38s in 1942-43 encountered aircraft during the island hopping campaign, any A6Ms they ran into were flown by the same quality IJN pilots as the USN Wildcat pilots fought against. This is true for the IJA pilots in their Ki-43s.
The more recent research into the actual kill:loss ratios (as opposed to the post-WWII origin rah-rah USA numbers) is evidence of this.
It needs to be kept in mind that when the P-38s in 1942-43 encountered aircraft during the island hopping campaign, any A6Ms they ran into were flown by the same quality IJN pilots as the USN Wildcat pilots fought against. This is true for the IJA pilots in their Ki-43s.
The more recent research into the actual kill:loss ratios (as opposed to the post-WWII origin rah-rah USA numbers) is evidence of this.
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Geoffrey Sinclair
Staff Sergeant
- 1,268
- Sep 30, 2021
The Mosquito and Spitfire had the advantage the Germans provided lots of publicity, for US fighters more about their range as a group. The Mosquito was not used much as a day fighter where it could encounter single engine fighters, at low level it was significantly faster than the Fw190A when it comes to anti shipping work. The P-38 had troubles in the Mediterranean and even more at altitude operating out of Britain, it did not shoot down a lot of European Axis fighters, more preventing them shooing down allied bombers. The 8th Air Force preferred Mosquito to F4/5. In Europe the allies used the Mosquito to its strengths, the P-38 pure fighter usage exposed weaknesses.
By the time the power ailerons and dive recovery flaps were around the P-38 were on the way out of the 8th Air Force and seeing little air combat in the 15th Air Force.
What happened in the USAAF between 1938 and 1940 has all sorts of inputs, changing theory, the reality of what the new designs delivered, initial war experience, even the cost of larger airfields. As of 1938 the theoretical enemy was attacking the US with unescorted bombers, as of end 1939 the US entering a European war was possible. As noted the initial US interest was ferry ranges but remember as of April 1940 Greenland and Iceland were neutral and flying the Atlantic was something only done by highly experienced crews and the all time number of crossings was low, only recently were there scheduled services. As of May 1940 fighter bases could be close to the German border, well able to cover much of Germany. As of July 1940, expect to be at war with Germany and Italy "soon", expect Greenland and Iceland to be available but not France. Once the tripartite pact was signed add Japan, but that was going to be a mostly naval war, Manila is about 1,860 miles from Tokyo.
Without radar long range is useful to enable standing patrols or a weight penalty when trying for fast climb after minimal warning.
The P-36C had 1 heavy and 3 rifle calibre machine guns. As first flown the XP-38 and XP-39 were similar in performance and mission. No idea on promised ranges Francis Dean credits the P-38J with an ideal range of over 1,000 miles with 410 gallons, that gets you to Berlin from eastern France. The P-39 was built around the 37mm gun, which made it a bomber destroyer, then came the decision to remove the turbo, a more modern lower altitude design with more firepower compared with the evolution of P-36 to P-40. All waiting the move to 2,000 HP engines, the P-47 and B-29.
In many ways the Luftwaffe did the same thing in 1943/44, build up a twin engine fighter force which could carry heavier firepower plus give the single engine types heavier firepower with the 30mm cannon.
The 1938/39 USAAF fighters, if given drop tanks, could match the 1938/39 USAF bombers range wise, or close enough to impose few operational limits, but of course the peace time ruling against carrying external fuel was in place, escorting the B-17 class was another matter, then came the optimism of arrival times for the B-29/32 with their even greater range and you arrive at the 1,500 mile fighter idea. With the restrictions on carrying external fuel but also the amount needed to fight, have a reserve and fly home a new design with greater internal fuel was needed and development time said make it B-29 escort capable. Compared with the P-36 the XP-38 and XP-39 had around 25% more fuel for their more powerful engines, until they suddenly had less thanks to self sealing requirements. When war came the restrictions on carrying external fuel were removed.
P-39D, 50% power, 120 gallons internal fuel, radius of action 151 miles at 10,000 feet, 141 miles at 15,000 feet, 128 miles at 20,000 feet, 109 miles at 25,000 feet, P-38E, 300 gallons of fuel, radius of action for the same heights 343, 338, 336, 333 miles. The P-38 supercharging advantage is clear.
If enough external fuel could be carried to get the aircraft from engine start to operational height, under 40 gallons for the P-39 its radius of action figures become 244, 244, 241, 222 miles, for the P-38E, under 70 gallons of external fuel, 425, 441, 456, 476 miles.
P-38F fuel US gallons. US Archives Record Group 342 Entry P26 Box 2237. Decimal hours 0.333 = 20 minutes
290 gallons internal,
1. Warm up taxi, take off to 100 feet 12 gallons,
2. 100 to 15,000 feet 30 gallons, 0.1 hours,
3. cruise 2,280 RPM full throttle, 280 mph, 110 gallons per hour, 0.754 hours, 83 gallons, 210 air miles flown,
4. combat full military power for 10 minutes, 42 gallons,
5. return cruise as per outgoing 83 gallons, 0.754 hours, 210 miles,
6. Reserve 40 gallons 0.333 hours.
290 gallons internal, 150 gallons external fuel,
1. Warm up taxi, take off to 100 feet 12 gallons main tanks,
2. 100 to 15,000 feet 34 gallons, 0.16 hours, belly tank
3. cruise 2,280 RPM full throttle, 250 mph, 55 gallons per hour, 1.055 hours, 116 gallons, 265 air miles flown, belly tank,
4. Drop belly tank, main tank 2,280 RPM full throttle, 280 mph, 110 gallons per hour 0.41 hours, 45 gallons, 115 miles,
5. combat full military power for 10 minutes 42 gallons,
6. return cruise as per outgoing but at 280 mph, 151 gallons, 1.37 hours, 384 miles,
7. Reserve 40 gallons 0.333 hours. 380 miles out, 384 miles in.
290 gallons internal, 300 gallons external fuel,
1. Warm up taxi, take off to 100 feet 12 gallons main tanks,
2. 100 to 15,000 feet 34 gallons, 0.16 hours, belly tank
3. cruise 2,280 RPM full throttle, 250 mph, 110 gallons per hour, 2.0 hours, 220 gallons, 500 air miles flown, belly tank,
4. Drop belly tank, with 46 gallons still in it (or use the fuel but stay within 500 miles of base)
5. combat full military power for 10 minutes, 42 gallons,
6. return cruise as per outgoing but at 280 mph, 196 gallons, 1.8 hours, 500 miles,
7. Reserve 40 gallons 0.333 hours.
drgondog
Major
Nice summary Geoffrey.
FWIIW, the last 8th AF P-38 FG, the 479th, had two P-38J-25 arriving for orientation in early September 1944. The 479th however also had the first of many transfers of P-5B/D from other fighter groups for full conversion September 28th.
Most of the P-38J-10 and J-15 from 20th, 55th and 364th were sent to 15th AF to serve as replacements for attrition of 1, 14 and 82 FG. Most of the ETO inbound J-25s went to 9th AF, Ditto the P-47D-25s after D-Day. I haven't been able to confirm J-25s to MTO but the 367 and 370th FG converted to P-47 in Feb 1945. Suspect their ships went to 470th FG which remained as P-38FG through VE-Day.
FWIIW, the last 8th AF P-38 FG, the 479th, had two P-38J-25 arriving for orientation in early September 1944. The 479th however also had the first of many transfers of P-5B/D from other fighter groups for full conversion September 28th.
Most of the P-38J-10 and J-15 from 20th, 55th and 364th were sent to 15th AF to serve as replacements for attrition of 1, 14 and 82 FG. Most of the ETO inbound J-25s went to 9th AF, Ditto the P-47D-25s after D-Day. I haven't been able to confirm J-25s to MTO but the 367 and 370th FG converted to P-47 in Feb 1945. Suspect their ships went to 470th FG which remained as P-38FG through VE-Day.
I personally don't rate the A6M or Ki 43 after 1942, yes they could be dangerous at low speeds but neither were air superiority aircraft.
wuzak
Captain
Was the Mosquito actually used as a day fighter operationally?
Certainly performance trials for the Mosquito as a day fighter concluded that it was not a good idea.
Didn't the 8th AF prefer the Spitfire PR.XI for photo-reconnaissance and the Mosquito for various other tasks, such as weather reconnaissance?
wuzak
Captain
The Mosquito was designed as an high speed unarmed light bomber.
The P-38 was designed as an interceptor/fighter.
It's not a shock that the P-38 did better as a day fighter than the Mosquito. I'm not even sure that the Mosquito was even deployed as a day fighter.
Only a few Mosquitoes were built as F.IIs, quite a few were built as NF.IIs.
There was still some lag between input and the roll beginning.
Thumpalumpacus
Colonel
Which rather skates the point that @ThomasP was making, that pilot-quality mattered.
Geoffrey Sinclair
Staff Sergeant
- 1,268
- Sep 30, 2021
Yes.
Yes, the way I would describe it from the anti shipping operations was the Mosquito did not go looking for enemy fighters but were willing to engage the fighters that found them, certainly at low level where the Mosquito VI was faster.
Bomber Command sent 123 Mosquito sorties what it calls escort missions 4 August to 4 October 1944, mostly to shallow targets in France but also to Bergen, plus another 2 sorties on 12 January 1945. It also flew 117 sorties on Day Ranger patrols 15 June to 23 November 1944 plus a final 2 on 2 February 1945, there could be more as 100 Group tends to report its operations separate to Bomber Command.
Fighter Command flew a steady number of Day Ranger patrols from 1943 onwards, usually Mosquito, sort of the equivalent of night intruder sorties, plenty of cloud was usually a prerequisite, the Bay of Biscay patrols from late 1942 tended to be called Instep operations.
No details on Coastal Command operations beyond reports some anti shipping missions had the Mosquito as escorts to Beaufighter, until P-51 became available.
Probably mostly, I do not have a breakdown of 8th Air Force reconnaissance sorties specific mission and aircraft type. Only that 7th PR group flew 4,593 photo and mapping sorties, 4,247 credit, 3,354 effective, with 53 aircraft MIA, 15 Category E, 9 aircrew KIA, 46 MIA, with the 25th Bomb/Reconnaissance group weather and reconnaissance sorties were 3,795 total, 3,610 credit, 3,469 successful, with 17 aircraft MIA, 16 category E and 1 missing, 20 aircrew KIA, 40 MIA, the aircrew figures give away which group had what sort of aircraft. The 25th group figures include the provisional unit operations.
As of mid September 1944, 7th PRG (mixed a/c, 13, 14, 22, 27 sqns), 25th BG (Reconnaissance) (652 (B-17), 653 (Mosquito), 654 (mixed) sqns). The 25th Group entry notes used various aircraft, including B-17's, B-24's, B-25's, B-26's, P-38's, and L-5's, what eventually became the 25th Group were all originally provisional units, (April 1944, 802nd PRG (8th PHWR (B-17), [LWR (Mosquito)] and SWR (mixed?) sqns), makes it harder to track them.
Using USAAF Combat squadrons,
the 13th had P-38/F-5 during its wartime existence, L-4 1942/43, Spitfire in 1943, P-51 in 1945
the 14th had P-38/F-4 in 1942, P-38/F-5 1942/44, Spitfire in 1943/45, P-51 in 1945
the 22nd had P-38/F-5 during its wartime existence, Spitfire in 1943/44, P-51 in 1945
the 27th had P-38/F-4 in 1943, P-38/F-5 1943/45, P-51 in 1945
Bomber Command reports doing 106 day and 104 night weather reconnaissance sorties for Pinetree/8th AF/USAAF from 1 May 1943 to 11 August 1944.
The Mosquito Mk.II all rolled off the production line as radarless F.II. Radar or other role specific equipment that was then on the secret list was then fitted at Maintenance Units.
The first Mosquito day combat took place on 30 Sept 1942 when a 157 Mosquito II was directed to shoot down a Ju 88 off the Dutch coast. Other daylight operations around that time by Fighter Command Mosquito squadrons included attempts to intercept Luftwaffe daylight raiders and convoy patrols.
On 10 Dec 1942 Air Marshall Leigh Mallory visited Hatfield to inform DH that it had been decided that the Mosquito NF squadrons should undertake a more offensive role with daylight missions under cloud cover. To that end Hatfield undertook conversion of 6 aircraft from each of 5 squadrons in Dec 1942 / Jan 1943 to make them ready for those operations. That involved removal of the radar set, fitting of GEE for navigation and long range fuel tanks and increasing the 20mm ammunition load in the Mk.II used by these squadrons.
While Coastal Command use of the Mosquito began in May 1943 with a flight of Mk.II in 333 (Norwegian) squadron and Sept 1943 with the Tse-Tse flight in 248 squadron (detached from 618), it was Dec 1943 before 248 converted onto the Mosquito FB.VI. But this ignores the support provided to CC during its operations over the Bay of Biscay by Mosquito squadrons from Fighter Command from Dec 1942.
V/KG 40 had been formed in July 1942 with JU 88C-6 in the heavy fighter role to intercept CC aircraft operating over the Bay of Biscay. The two CC Beaufighter squadrons operating in the long range fighter role over the Bay proved inadequate to counter the threat, so Fighter Command Mosquito squadrons were added to the mix from Dec 1942 starting with 264 squadron, flying in daylight in the long range fighter role. These were known as Instep patrols. Flights of Mosquitos would be detached to operate over the Bay from airfields in Cornwall with operations consisting of flights of 3 Mosquitos being dispatched on an operation. At least 8 Fighter Command Mosquito squadrons were involved in these operations at some time in 1943/44.
Definition of types of operation in 1943:-
Intruder - held at readiness to be dispatched to target definite enemy activity, known or anticipated. They were always in communication with home stations.
Ranger - these flights left at pre-determined intervals to roam freely over enemy territory, out of communication with home base. Mosquitos would fly Day Ranger operations when cloud cover permitted. Night Rangers could be flown in any weather but against ground targets only if the moonlight was right.
There was something like 10 Mosquito squadrons involved in these operations in 1943/44, all with some radarless Mk.II on their books. It was May 1943 before the first FB.VI started to arrive with the two dedicated intruder squadrons in Fighter Command (418 & 605) but they also continued to use Mk.II until Sept 1943. In the NF squadrons the FB.VI started to become available for them to use for non night fighter operations from mid-1943 to slowly replace their Mk.II.
I don't think anyone has an accurate figure for the split of radar equipped NF.II and radarless F.II especially considering how aircraft could be easily switched between roles by equipment changes at MU level. Four Mk.II were also converted to the PR role for a while during their RAF careers.
GregP
Major
By the time the power ailerons and dive flaps were in use, the P-51 was around and there was little point in having two logistics chains for airplanes with the same missions. So, P-38s were sent elsewhere. The twin engines were very useful over long water, and the Pacific made sense. P-51s took over mostly in the ETO.
As for how good a fighter the P-38 was, it could be useful to remember that the two top USAAF Aces of all time flew P-38s, and the P-38 was flown by 3 of the top 10 Aces in USAAF service (Bong, McGuire, and MacDonald).
The F6F was flown by 1 of the top 10 (McCampbell).
The P-47 was flown by 2 of the top 10 (Gabreski, Johnson).
The F4F was flown by 2 of the top 10 (Foss, Harris).
The F4U was flown by 2 of the top 10 (Hanson, Boyington).
The P-51 was flown by 1 of the top 10 (Preddy).
I think the P-38 is rather well-represented in the top ten of Aces of the USAAF.
When the P-38 went to war, it had 4 main shortcomings:
1) Fuel issue: The British fuels had 20% aromatics and the US fuels, for whicj the ALlison carbs were jettedm used 2% aromatics. Once they figured this out (9 months) it was corrected. They could never duplicate the issue on the test stand until someone sent home a somple of British fuel! Duhhhhhh .....
2) Intake issue: The intakes were so smooth, the fuela nd air were separating, causing lean running. Took 6 months to figure it out. Turbulators were designed to fit inside the intakes to keep the mixture mixed. The "fix" also took a bit of time. Once fixed, it wasn't an issue. But when they first got tyhere, it was the main culprit for the "Allison Time Bomb" monicker, coupled with the early fuel issue.
3) The early P-38 pilots had no combat training. They'd fly into a combat zone in cruise power settings. If they were attacked, the'd have to go to high rpm, throttle back, move the mixture to rich, throttle up, and turn the gunsight on. By that time, they might have been shot down. Later, they entered the combat area alread configured for combat, with suitable settings and gunsight on.
4) The original cockpit heater was abysmal. The eventual "fix" was to fit an electric cockpit heater!
After the four above were addressed, there was very lttle the P-38 could not do well enough to be quite effective. Included in the "not do well" was the compressability issue with high speed dives, but the dive brakes made that much less of an issue, when they were fitted.
The P-38 display at Yank's Air Museum in Chino, California has the dive brakes fitted. Neat little things.
SaparotRob
Unter Gemeine Geschwader Murmeltier XIII
A very insightful post. It does put things into perspective.
special ed
1st Lieutenant
- 7,073
- May 13, 2018
Somewhere on the forum is an account of a Mosquito and Me 262 in turning combat. Surprising to me was the 262 victory over the Mossie.
Shortround6
Lieutenant General
Going back to the original.............
Effectiveness of the P-38 ?
Like many planes the P-38 went through a number of modifications over a number of years.
As did it's opponents and it's stablemates.
At a number of different points in time the P-38 was either the most effect US fighter or at least the most effective on offer (available) for the next 3-6 months. In late 1943 and beginning of 1944 this was no longer the case. The mid 1944 P-38s were better than the late 1943 P-38s but the bar had moved. P-47s had gotten a lot better and the Mustangs showed up relegating the P-47 and P-38s to 2nd and 3rd place. But was the early or mid 1944 P-38s not effective at all or just not as effective as P-51s?
Actual effectiveness might have been different due to training, quality control and maintenance.
Actual combat use was also not what had been anticipated in some theaters for a few different reasons.
Evaluating combat effectiveness is hard. In the long-range escort role, the goal was to prevent bomber losses, not to shoot down enemy fighters. Shooting down interceptors was just part of the goal. Keeping the interceptors busy or making them use up fuel/ammo dealing the escorts instead of shooting at the bombers was part of the defense even if hard to measure. Just the appearance of the P-38s with their distinctive size/shape might cause the interceptors to change tactics or attack plan. How to measure that?
P-38 was also suffering from a number of self-inflected wounds, from both the right hand (USAAC) and the left (Lockheed) and perhaps a few right leg kicking it's own butt.
The P-47 may have (?) had a few problems fixed before seeing much service and the P-51 had a few more fixed before seeing service?
Assigning blame for a number of the P-38s problems is hard. Like the lack of generator capacity. Was a single generator enough to keep up with the electrical load with the engines running at cruising RPM? How many electrical devices had to operated when enemy planes were spotted? P-38s used electric propellers. P-38s had the best power to weight and best climb of any USAAC fighters just about all of the time? why didn't they have a better response time from enemy sighted to combat capable? Why did it take so long to fix the cockpit heat problem? Were there problems with the gun heating system/s?
Effectiveness of the P-38 ?
Like many planes the P-38 went through a number of modifications over a number of years.
As did it's opponents and it's stablemates.
At a number of different points in time the P-38 was either the most effect US fighter or at least the most effective on offer (available) for the next 3-6 months. In late 1943 and beginning of 1944 this was no longer the case. The mid 1944 P-38s were better than the late 1943 P-38s but the bar had moved. P-47s had gotten a lot better and the Mustangs showed up relegating the P-47 and P-38s to 2nd and 3rd place. But was the early or mid 1944 P-38s not effective at all or just not as effective as P-51s?
Actual effectiveness might have been different due to training, quality control and maintenance.
Actual combat use was also not what had been anticipated in some theaters for a few different reasons.
Evaluating combat effectiveness is hard. In the long-range escort role, the goal was to prevent bomber losses, not to shoot down enemy fighters. Shooting down interceptors was just part of the goal. Keeping the interceptors busy or making them use up fuel/ammo dealing the escorts instead of shooting at the bombers was part of the defense even if hard to measure. Just the appearance of the P-38s with their distinctive size/shape might cause the interceptors to change tactics or attack plan. How to measure that?
P-38 was also suffering from a number of self-inflected wounds, from both the right hand (USAAC) and the left (Lockheed) and perhaps a few right leg kicking it's own butt.
The P-47 may have (?) had a few problems fixed before seeing much service and the P-51 had a few more fixed before seeing service?
Assigning blame for a number of the P-38s problems is hard. Like the lack of generator capacity. Was a single generator enough to keep up with the electrical load with the engines running at cruising RPM? How many electrical devices had to operated when enemy planes were spotted? P-38s used electric propellers. P-38s had the best power to weight and best climb of any USAAC fighters just about all of the time? why didn't they have a better response time from enemy sighted to combat capable? Why did it take so long to fix the cockpit heat problem? Were there problems with the gun heating system/s?
- Thread starter
- #175
Not this myth again.
Shortround6
Lieutenant General
You and I have been arguing over this for 10-15 years.
Anybody who even looked at the fuel specs should have been able to figure this one out without a sample of "British" fuel which was actually coming from either US refineries or refineries in Trinidad/Tobago. You can't make 100/120 or 100/125 or 100/130 fuel in large quantities without 15-20% aromatics. You can make 100/100 with little or no aromatics but you need an ungodly amount of lead in the fuel to get to the 120 range. Like very quickly lead fouling quantities. The very first joint British/American fuel spec called for 100/125 fuel and 3 ccs of lead per gallon, quicky changed to 100/130. Later specifications called for 3.6cc of lead and a later specification called for not only 4.3cc max but different allowable limits of certain aromatics to increase production. This was late 1942? and it was a joint specification. It was also about 1 1/2 years after the US had stopped asking for less than 2% aromatics.
20% aromatics had serious problems with US fuel systems. The aromatics tended to dissolve gaskets and rubber components in the fuel systems and also tended to dissolve the early self-sealing fuel tank liners which resulted in clogged fuel filters/pumps/lines. This was found out in a number of US planes used by the British in 1940-41 before the P-38s ever showed up in Europe.
There was a problem with this 1942/43 specification fuel but not all batches had the same amounts of the same aromatics. Each refinery was allowed to use what they had on hand, subject to allowable limits, to meet the required performance specifications. Refineries often changed exact 'recipes' a number of times per month in order to maximize production based on available base stock fuel, available additives (aromatics) and desired performance. You can't use too much aromatics as the fuel has to have 18,700lbs per pound and most (all?) aromatics have less BTUs per pound. Each aromatic has a slightly different number of BTUs per pound and different densities and vaporization temperatures.
even if somebody in England had shipped a drum of 100/130 fuel back the US there is no telling which 100/130 fuel he shipped back without a very good analysis. A drum of fuel delivered to an airfield 50 miles away or 3-4 weeks before or after could give different results.
pinehilljoe
Staff Sergeant
I'll go so far as to say the P-38 was the only pre-1939 designed fighter that could perform all missions required of a 1945 fighter; long range escort, interceptor, fighter, fighter bomber, and do them equally well to newer designs.
GregP
Major
The Mosquito is a very neat airplane. We have one that visits regularly at the Planes of Fame. But it isn't a small airplane and the bomber heritage is evident. The Me 262 is smaller than a Mosquito and the jet engines are lighter. Not the engines themselves (about the same as a Merlin), but there are no radiators and associated hardware and, particularly, no neavy propellers.
So, the Mosquito has a gross weight around 18,000 pounds while the Me 262 has a gross weight around 6,400 pounds.
No surprise it turns better.
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wuzak
Captain
Wasn't that related to the new intercoolers on the J overcooling the mixture?
Geoffrey Sinclair
Staff Sergeant
- 1,268
- Sep 30, 2021
The short answer is no, the P-51 was longer ranged, more effective in air to air combat, and lower maintenance. Only a shortage of P-51 delayed the 8th Air Force transition from P-47 and P-38 to P-51, plus probably the need for maximum effort mid 1944.
The early J models actually had more cooling than was required at altitude. The J-15 had the wing leading edge fuel tanks as standard (December 1943), the J-25 and later had the dive recovery flap which pitched the nose up (not a brake) and also the boosted ailerons (June 1944). The recovery flaps had little effect on maximum safe dive speed. The Luftwaffe fighter pilots continued to worry more about P-38 below than above them.
Dive Recovery Flaps on P-38
Did the dive recovery flaps on the P-38 slow add enough drag to keep the aircraft below the compressibility threshold, or did they raise the compressibility threshold?
ww2aircraft.net
P-38F production ended October 1942, P-38G production was from June 1942 to April 1943, P-38H from May to August 1943, P-38J from August 1943 to June 1944, P-38L from June 44 to August 1945, 15th Air Force, table is date, number of F, G, H, J, L models, 1st, 14th and 82nd Fighter groups.
| Date | P-38F | P-38G | P-38H | P-38J | P-38L | Total |
31-Oct-43 | 20 | 189 | 0 | 0 | 0 | 209 |
28-Nov-43 | 14 | 179 | 0 | 0 | 0 | 193 |
26-Dec-43 | 19 | 143 | 0 | 0 | 0 | 162 |
30-Jan-44 | 14 | 95 | 0 | 0 | 0 | 109 |
6-Feb-44 | 10 | 94 | 0 | 0 | 0 | 104 |
27-Feb-44 | 7 | 85 | 38 | 0 | 0 | 130 |
1-Apr-44 | 8 | 85 | 25 | 38 | 0 | 156 |
29-Apr-44 | 7 | 73 | 24 | 159 | 0 | 263 |
3-Jun-44 | 2 | 44 | 4 | 211 | 0 | 261 |
24-Jun-44 | 2 | 42 | 3 | 222 | 0 | 269 |
1-Jul-44 | 2 | 41 | 4 | 228 | 0 | 275 |
27-Jul-44 | 0 | 36 | 3 | 191 | 0 | 230 |
2-Sep-44 | 0 | 0 | 0 | 119 | 5 | 124 |
30-Sep-44 | 0 | 0 | 0 | 167 | 73 | 240 |
21-Oct-44 | 0 | 0 | 0 | 116 | 119 | 235 |
20-Nov-44 | 0 | 0 | 0 | 110 | 144 | 254 |
10-Dec-44 | 0 | 0 | 0 | 106 | 165 | 271 |
10-Jan-45 | 0 | 0 | 0 | 102 | 158 | 260 |
10-Feb-45 | 0 | 0 | 0 | 80 | 156 | 236 |
10-Mar-45 | 0 | 0 | 0 | 78 | 187 | 265 |
31-Mar-45 | 0 | 0 | 0 | 69 | 194 | 263 |
30-Apr-45 | 0 | 0 | 0 | 58 | 201 | 259 |
Notes, 27-Feb-44 1st FG has the H models, 1-Apr-44 1st has the H, 14th and 82nd the J, 30-Sep-44 All groups have J and L models.
So some 10 months between H model production start and the first models in the groups, then around 8 months between production start and the arrival of J models but only 3 months for the L models to arrive, partly due to the decision to use the P-51 instead of the P-38 in the 8th Air Force. The groups were almost always equipped with at least 2 different P-38 models.
From a very incomplete 8th Air Force loss list, P-38H lost in 1943, P-38J-5 first loss 4 January 1944, they entered production in August 1943, J-10 on 5 January 1943 (October 1943), J-15 on 15 April 1944 (December 1943), J-20 on 4 July 1944 (May 1944)
8th Air Force P-38 groups, 55th FG 15 October 1943 (P-51 16 July 1944), 364th FG 3 March 1944 (P-51 31 July 1944), 20th FG 28 December 1943 (P-51 20 July 1944), 479th FG 26 May 1944 (P-51 27 September 1944).
The 8th Air Force decided to go from 10 operational P-47 groups in late February 1944 to 4 in mid May 1944, P-51 groups from 0 to 7 mostly via conversion from P-47, in July 1944 3 P-38 groups converted to P-51, then the final P-38 group in September, the October 1943 to early January 1945, another 3 P-47 groups converted to P-51. Which indicates the P-38 range was initially considered more valuable in preventing bomber losses versus the P-47 better combat record, then that changed.
15th Air Force, air combat record, claims, losses by cause, rates.
| Type | Airborne | Early return | Credit | Effective |
| P-38 | 44,296 | 3,814 | 40,482 | 37,026 |
| P-51 | 43,844 | 3,841 | 40,003 | 37,761 |
| Type | encounters | Destroyed | Probable | Damaged | To Flak | To E/A | To Mech/Oth | Unknown cause | Victory Rate | Loss Rate |
| P-38 | 4,004 | 608 | 123 | 343 | 155 | 131 | 166 | 62 | 15.2 | 3.3 |
| P-51 | 3,804 | 976 | 88 | 247 | 78 | 51 | 165 | 116 | 25.7 | 1.3 |
Loss rate is number reported shot down by enemy aircraft times 100 divided by encounters
If you assume all unknown losses were to enemy aircraft loss rates are about the same, if you allocate the unknowns in the ratios of the knowns the loss rates move to about 2 to 1 in favour of the P-51.
9th AF P-38 units,
474th FG from 25-Apr-44 to 31-May-45
370th FG from 1-May-44 to 9-Mar-45 then P-51 to 31-May-45
367th FG from 9-May-44 to 20-Feb-45 then P-47 to 31-May-45
The 9th Air Force P-38 units claims 266 enemy aircraft destroyed from 31,862 effective sorties, P-47 1,127.5 destroyed from 190,450 effective sorties, P-51 750 destroyed from 23,932 effective sorties.
No one is disputing the USAAF in the Pacific liked the P-38, meantime thanks to the 9th AF and 1st TAF the P-47 remained about half the USAAF ETO fighter strength.
Yes, but factor in opportunity, how many combat sorties the pilots flew, plus how often they encountered enemy aircraft. Sticking to aircraft the above highlights the F4F given its limited time in combat with a mention to the F6F since it was mostly a carrier based aircraft and see how often the USN carriers were actually in action, given their fuel and magazine restrictions.
The short answer is no.
Aviation fuel in the ETO mostly came from American and Caribbean sources and went into a common pool, there was no separate British supply either from refineries or to the RAF, indeed the US complained that US sourced Lend Lease fuel was put into the pool only for the US to be billed when they used it. The system was changed. The RAF was operating Allison Mustangs well into 1944. And all the other engine types running the 100 octane reported no problems with the fuel.
Note how many of the P-38 complains came from the ETO, the MTO was more likely to have "British" fuel given how close the Middle East refineries were, how many 12th/15th Air Force complaints about the P-38 problems the 8th Air Force were encountering?
Unfortunately the following is from a long ago message and the URL quoted no longer work.
"The -25 mainly fixed Lockheed's flight control issues. Allegedly the intake problem overstressed Allison's small engineering team. The behavior of liquid / gas mixtures under extreme conditions is the core of "rocket science" and it was very rare knowledge back then, before computers enabled Computational Fluid Dynamics.
To be more specific, the foremost problem was the temperature of the compressed air from the turbosupercharger entering the carburetor. High carburetor air temperature (CAT for short) can cause all kinds of engine problems including detonation, which can lead to catastrophic engine failure. Allison recommended a CAT of no more than 45 degrees C.
As it turned out high CAT was one of the major problems limiting P-38 performance through the P-38H. The root cause was, of course, the limited cooling ability of the wing leading edge intercoolers found in all early P-38s. They were a very clever design, inducing almost no aerodynamic drag, but they were designed for the 1000 hp Allisons of the late 1930s. By 1943 Military power was up to 1425 bhp and War Emergency Power was 1600 bhp. The increased power required higher induction pressure, which through compression by the superchargers heated the air by several hundred degrees. There is no way that the simple intercoolers could keep CAT below 45 degrees C. when operating at high power at altitude.
CAT wasn't the only problem though. The centrifuge effect of the compressor and the temperature variations in the plumbing could separate out the heavier octane enhancing additives and worsen the destructive detonation. The scientists who really understood this stuff were elsewhere separating Uranium.
A lot of this had to do with its poor intake manifold design, something that Gen. Jimmy Doolittle, who had a PhD in aviation science from MIT, pointed out in a report on the P-38's problems, written to Carl Spaatz in the spring of 1944.
Doolittle specifically singled out the intake system of the V-1710 as a problem - the tetraethyl lead was somehow separating out with the uneven distribution which caused repeated problems with detonation in certain cylinders in the V-1710s (i.e., they would blow up and catch fire in flight - kinda nasty for the pilots, eh?).
***"Doolittle's letter to Spaatz is about as clear cut of an explanation of the problems of the V-1710 - turbosupercharger combo at high altitude in Europe as any I've ever found. It's the smoking gun that answers the question of why the P-38 was pulled from almost all combat duty in Europe, remaining only as a photo-reconnaissance plane."***
Fred Colvin's writing on war production illuminates the difficulty of finding the proper curvature for efficient turbocharger and jet engine compressor blades. Unable to calculate it, the scientists were demanding that the shop produce a variety of exotic and difficult-to-machine mathematical spirals to determine by experiment what was best.
However the Archimedean spiral is used in a variety of applications. One such interesting application is in scroll compressors."
End quoted message
Lots of early USAAF fighter pilots had similar problems, tactics and training.
Yet there seems to have been few complaints about the heating until the 8th Air Force operations from late 1943.
In the ETO the P-38 was phased out of being an air superiority fighter, so was the P-47 even though it had a better combat record than the P-38, in the MTO the P-38 groups retained their air superiority role to the end, same in the Pacific At the same time the US was moving to phase it out, the 20th Air Force was receiving P-47 and P-51.
Also preventing own losses is important, but if you do not inflict enough casualties on the enemy long term then the average enemy becomes more experienced and so more lethal, while your losses send average experience down. Bomber Command versus the Luftwaffe night fighters, U-boats versus allied escorts are good examples.
