P-38 vs P-47

[jmcalli2]

Don't quote me on this without corroboration, but basically from what I could readily gather on the two aircraft would be the following advantages and disadvantages

1. P-38
   • Advantages
     • It was available earlier (late 1941 versus some point during 1942).
     • It had a superior rate of climb and level acceleration off the bat, which remained until water injection and paddle-props were added to the P-47
     • It had a superior rate of turn with our without maneuvering flaps once stabilized in the turn
     • The gun armament, all centered in the nose, basically meant that it could hit more reliably at greater distances
     • The presence of a nose-gear provided greatly improved landing characteristics, likely improved takeoff acceleration, and probably improved forward visibility while taxiing.
     • The shape of the nose, nose-gear, and canopy probably also improved forward visibility
     • It had the provision for drop-tanks fairly early on, which allowed the range to be better extended.
     • Once the P-38J/L came around, it would appear that the use of powered ailerons might have given it a superior roll-rate under some conditions (probably high speed, and lower angle of attack).
   • Disadvantages
     • It could not dive as good as the P-47: While it might very well have been able to accelerate faster in a dive (unsure about that), it was limited by mach number. The P-38E and on would start running into mach-effects at around 0.68, and by 0.74 controllability would be lost.
     • The lower critical mach-number also discouraged higher boost-levels (something done with other aircraft using the V-1710), particularly in the case of the P-38J, as the aircraft would be very close to or actually within transonic range and you'd be only a shallow-dive away from mach tuck.
     • Roll-control seemed to be slower than the P-47 under most conditions, and because of that: Even though it could turn faster, it took longer to get stabilized in the turn, and all that time meant that the P-47 would usually be able to do, either a 180 or 360 (something that is now known as torsional agility), faster. When maneuvering flaps out, this might have changed.
     • The aircraft seemed to have a lower critical altitude than the P-47 in level flight (ironically it seemed sometimes higher in the climb-configuration, the P-38's critical altitude in climb seemed to be around 14000-15000 feet; the P-47's was all over the place from as low as 10000-12000 to 23400-25000 with the P-47B/C/D).
     • Though the P-38J/L had powered ailerons: They didn't seem to have much variation (all or nothing), and the time from initiation of the roll to full roll-speed was probably slower than P-47's.
     • The earlier P-38's had intercoolers in the wings, which proved to be prone to battle-damage; the later versions had them under the engine with the carburetor and oil-cooler. In that case it did too good a job at cooling things off, sometimes the oil would turn into sludge and the turbo would runaway, and you'd get backfiring and stuff. They had to restrict airflow to the coolers and possibly the engine, and use some special high octane fuel for it.
     • While it might have been able to carry a heavier air-to-ground load, it might not have been as survivable, despite having two-engines.
2. P-47
   • Advantages
     • It was faster in earlier variants: I don't think a single variant of the P-47 was under 400 mph in top-speed; the earliest operational P-38's were doing around 390 (still respectable).
     • It could dive to higher mach numbers: The airspeed limitations at higher altitudes basically correlate to a placard limit mach number of 0.745. There were cases where 0.78 was reached on the P-47C. The later versions would see 0.82 or so come up, potentially requiring from dive-recovery flaps.
     • It had a superior roll-rate under a number of conditions: Particularly at higher angles of attack, at around 300 mph it and the Hawker Tempest were about similar, with the Tempest taking over above that.
     • The aircraft seemed able to absorb an unusually massive amount of damage: Part of this seemed to be the result of the radial-engine, but part of it also happened to do with the remarkable engineering job Republic's designers managed to do.
     • The engine and supercharger controls appeared to be better arranged, and easier to use.
     • The cockpit seemed to not be quite as cold as the P-38 owing to the engine and superior air conditioning system: Not that I'd expect it to be toasty.
     • It proved greatly more effective in the air-to-ground role, despite being designed as a high-altitude fighter, mostly owing to the engine design.
     • The P-47N, actually managed the longest combat radius (1125 miles to 1310 nm) and range (2250 miles to 2620 nm) of other operational escort fighters, though it was not representative of most Jugs.
   • Disadvantages
     • Rate of climb was rather poor initially, somewhere between 2500 and 3000 feet a minute. As time would go on, the increase in engine power, bigger propellers, and water-methanol injection would bump the climb rate somewhat over 3000 feet a minute. While the P47M might have bested the P-38J's, it seemed to be a rare variant.
     • Rate of turn appeared to be inferior to the Lightning, particularly when the maneuvering flaps were hung out.
     • Visibility ahead was inferior to the P-38 owing to the radial engine and lack of nose-gear; the visibility to the rear was inferior until the late P-47D's came around.
     • The range of the aircraft might have been inferior to the P-38 under some conditions: It was not as quickly adapted to carry effective drop-tanks; while it could carry a ferry tank, it could not be jettisoned, and could not work above 10,000-14,000' AMSL.

There might be a few errors in that, but I think that's a decent summary, though you'd probably want more experienced members here.

This may give you some insight on the U.S. Army Air Force's direct comparison: http://www.wwiiaircraftperformance.org/mustang/Performance_Data_on_Fighter_Aircraft.pdf

Both aircraft suffered from teething problems due to the maturing of their turbosupercharger technology. Only the U.S. applied turbos to significant combat aircraft in WWII; the B-17, B-24, B-29 and B-32, as well as the P-38 and P-47. Only the P-38 and P-47 were single engine aircraft, and only the P-38 used an inline liquid cooled engine; the bombers and P-47 used air cooled radial engines.
Another factor was cost; the P-38 was more expensive than most single engined fighters.

Late models of the P-38 had special flaps to allow pull-out from dives at speeds causing compressability issues, as well as power-boosted ailerons and maneuvering flaps. These later features made the P-38 one of the most manueverable Allied fighters in WWII. And engine refinements gave them a lot of speed too, closer to 440mph than the 414 so often quoted.
The P-38G executed the longest range interception of WWII, shooting down Japanese Admiral Yamamoto after a 600 mile flight.
P-38s were used extensively as phot recon aircraft, with cameras replacing their guns.
P-38J and L models were modified into night fighters as well as lead 'pthfinder' bombers. The former has an extra seat behind the pilot and a radar pod under the nose, while the later had its guns replaced with a bombardier's station in a plexiglass nose cone.
The P-38s were armed with four .50cal machine guns and one 20mm cannon in the central pod, and could carry two bombs of up to 1,600lbs or a torpedo, and up to fourteen 5 inch rockets.

Later models of the P-47 included the M and N models; the P-47M was designed to be lighter and much more powerful, and was among the fastest WWII fighters reaching over 470mph, while the P-47N combined the P-47M's uprated engine with larger wings holding more fuel to produce an escort fighter with over a 2,000 mile range. P-47M models were successful in combating V-1 buzz-bombs over England and ME-262s over europe.
The P-47D and N models could carry two 1,000 lb bombs, one 500 lb bomb, and ten 5 inch rockets in addition to eight .50cal machine guns mounted in the wings.

The highest scoring U.S. WWII ace was Major Richard Bong, with 40 kills. Major Thomas McQuire was the second highest U.S. ace with 38. Both flew P-38s in the South Pacific.
The leading U.S. P-47 aces were Colonel Frances 'Gabby" Gabreski with 28 kills in Europe and Major Robert Johnson with 27.
The P-38 was not kept in the U.S. inventory long after WWII. The P-47 was assigned to some ANG units, but did not see combat during the Korean War. Both suffered from turbo/overheating issues that were eventually resolved.

Hope that helps!

 

[Navalwarrior]

The RAF equipped one squadron of Tomahawks and used them as fighters, yes 29 sorties. The other 12 went to army co-operation squadrons. All those early Mustang I's went to army co-operation squadrons. So yes you can use them for strafing too, but they weren't suitable for fighter combat as over the English Channel this usually started at 20000 feet. Hurricanes were used at Dieppe as fighter bombers, Sptifires and Typhoons as fighters. You could use Mustangs as escorts for fighter-bombers and bombers but they still need a top cover. Bet you they didn't score a single aerial victory over Dieppe though.

The RAF equipped one squadron of Tomahawks and used them as fighters, yes 29 sorties. The other 12 went to army co-operation squadrons. All those early Mustang I's went to army co-operation squadrons. So yes you can use them for strafing too, but they weren't suitable for fighter combat as over the English Channel this usually started at 20000 feet. Hurricanes were used at Dieppe as fighter bombers, Sptifires and Typhoons as fighters. You could use Mustangs as escorts for fighter-bombers and bombers but they still need a top cover. Bet you they didn't score a single aerial victory over Dieppe though.

Resp:
Dieppe is where an RAF Mustang MkI (or IA) scored its first air-to-air victory. However, it was also where the Luftwaffe scored its first Mustang kill by an FW-190. One for one.

 

[fubar57]

An American pilot by the name of Pilot Officer Hollis Hills flying in 414 Sqn (RCAF)

 

[drgondog]

This may give you some insight on the U.S. Army Air Force's direct comparison: http://www.wwiiaircraftperformance.org/mustang/Performance_Data_on_Fighter_Aircraft.pdf

Both aircraft suffered from teething problems due to the maturing of their turbosupercharger technology. Only the U.S. applied turbos to significant combat aircraft in WWII; the B-17, B-24, B-29 and B-32, as well as the P-38 and P-47. Only the P-38 and P-47 were single engine aircraft, and only the P-38 used an inline liquid cooled engine; the bombers and P-47 used air cooled radial engines.
Another factor was cost; the P-38 was more expensive than most single engined fighters.

A mild understatement - perhaps 2-3X over P-51, P-39 and P-40

Late models of the P-38 had special flaps to allow pull-out from dives at speeds causing compressability issues, as well as power-boosted ailerons and maneuvering flaps. These later features made the P-38 one of the most manueverable Allied fighters in WWII. And engine refinements gave them a lot of speed too, closer to 440mph than the 414 so often quoted.

The wing and the wing centerbody design caused the low speed (relative to P-47 and P-51) compressibility issues, but both the P-38 and P-47 had dive flaps to assist in recovery - the 51 didn't need them.

Unfortunately, it took until mid 1944 to solve the myriad and serious issues associated with the turbos and the aftercoolers which greatly limited reliability at high altitudes. As to speed, yes the P-38J-25 and P-38L series with 2950 BHP could finally reach speed capability of the early P-51B-1 at 29000 w/1300 HP - which tells you a lot about how draggy the P-38 airframe was in comparison - about the same parasite drag as the F6F and F4U w/radials.
The P-38G executed the longest range interception of WWII, shooting down Japanese Admiral Yamamoto after a 600 mile flight.
The P-51B was 'intercepting' German fighters over Posnan Poland 740 miles away as an early example of the use of external 108 gallon tanks

P-38s were used extensively as phot recon aircraft, with cameras replacing their guns.

P-38J and L models were modified into night fighters as well as lead 'pthfinder' bombers. The former has an extra seat behind the pilot and a radar pod under the nose, while the later had its guns replaced with a bombardier's station in a plexiglass nose cone.
The P-38s were armed with four .50cal machine guns and one 20mm cannon in the central pod, and could carry two bombs of up to 1,600lbs or a torpedo, and up to fourteen 5 inch rockets.

Later models of the P-47 included the M and N models; the P-47M was designed to be lighter and much more powerful, and was among the fastest WWII fighters reaching over 470mph, while the P-47N combined the P-47M's uprated engine with larger wings holding more fuel to produce an escort fighter with over a 2,000 mile range. P-47M models were successful in combating V-1 buzz-bombs over England and ME-262s over europe.
The P-47D and N models could carry two 1,000 lb bombs, one 500 lb bomb, and ten 5 inch rockets in addition to eight .50cal machine guns mounted in the wings.

The highest scoring U.S. WWII ace was Major Richard Bong, with 40 kills. Major Thomas McQuire was the second highest U.S. ace with 38. Both flew P-38s in the South Pacific.
The leading U.S. P-47 aces were Colonel Frances 'Gabby" Gabreski with 28 kills in Europe and Major Robert Johnson with 27.
The P-38 was not kept in the U.S. inventory long after WWII. The P-47 was assigned to some ANG units, but did not see combat during the Korean War. Both suffered from turbo/overheating issues that were eventually resolved.

Hope that helps!

It may have escaped your attention that somebody wanted to 'beef up' the P-38J statistics by taking off at approximately 2600 pounds under full internal combat load (15000 vs 17699 w/full ammo and internal fuel). By contrast the P-51B took off at 9000 pounds - approximately 600 pounds under full internal combat load.

So the 38J in the AAF test report was tested with a reduction in W/L of 15%. The P-51B was tested with a reduction of 7% on W/L. That translates to a ~ 7% improvement to rate of turn for the P-38J vs 3% for the P-51B when compared to testing both at full combat gross weight and 15% vs 7% for Climb.

IIRC the highest scoring P-38 aces in MTO and ETO respectively were 12 (Dixie Sloan) and 7.33 (James Morris). Comparing Bong to Gabreski, Johnson, Preddy, Meyer, Gentile is apples and oranges. Bong had a potential 100 mph speed advantage as well as altitude advantage when he took off. He also did not have to enter any fights freezing to death at 25000 while flying a 38 whose engines might blow up if he spooled up MP before moving to auto rich, then RPM before boost - while someone is shooting at him.

It was a good airplane and needed by AAF in all theatres but at the end of the day it was #3 in comparison to a.) ease of training, b.) complexity of operation, c.) cost of maintenance, d.) cost of operation and last, e.) effectiveness against the axis. The single major advantage over 51 and 47 was having twin engines for long over water operations where intermediate interception/combat was not a factor.

 

[Simon Thomas]

P-38s were used extensively as phot recon aircraft, with cameras replacing their guns.

True, however the RAAF were totally underwhelmed by them.

the Lightnings were beset with unserviceabilities and this is reflected in an exasperated signal from 1PRU to RAAF HQ on 22nd March 1943, less than a week after the replacement aircraft had arrived: "Lightning A55-3 intercooler system unserviceable. After only 16 hours flying. Modifications unsuitable this climate." In August, another signal advised that: "It is seldom possible to have both Lightnings serviceable at the same time."

RAAF LIGHTNINGS 1PRU - The Lockheed File

 

[wuzak]

Late models of the P-38 had special flaps to allow pull-out from dives at speeds causing compressability issues, as well as power-boosted ailerons and maneuvering flaps. These later features made the P-38 one of the most manueverable Allied fighters in WWII. And engine refinements gave them a lot of speed too, closer to 440mph than the 414 so often quoted.
The P-38G executed the longest range interception of WWII, shooting down Japanese Admiral Yamamoto after a 600 mile flight.
P-38s were used extensively as phot recon aircraft, with cameras replacing their guns.
P-38J and L models were modified into night fighters as well as lead 'pthfinder' bombers. The former has an extra seat behind the pilot and a radar pod under the nose, while the later had its guns replaced with a bombardier's station in a plexiglass nose cone.
The P-38s were armed with four .50cal machine guns and one 20mm cannon in the central pod, and could carry two bombs of up to 1,600lbs or a torpedo, and up to fourteen 5 inch rockets.

The night-fighter version was the P-38M, but that only appeared in early 1945. The Mosquito XXX was operating for about a year at that time.

 

[chuter]

The P-38 propellers rotated in opposite directions but both rotated in the wrong direction. Loss of one engine on takeoff caused the plane to roll into the dead engine (flip over). Had the rotation been reversed the loss of an engine on takeoff would have been less difficult since the torque of the engine would have caused the plane to try to roll into the good engine minimizing the roll and stabilizing the plane. The propellers rotating in the correct direction supposedly caused flutter so they were reversed.

The primary reason for the selected prop rotation was to have the spiral slipstream from the props oriented in a way that made high AoA, high power flight easily controllable. With the props turning outboard the inboard wing panels have a higher AoA than nominal (ambient?) and the outboard wing panels have a lower than nominal AoA. When the plane gets close to critical AoA the inboard wing sections begin buffeting with minimal roll deviation and if the wing section does stall that stall is limited to the inboard section unless the AoA is increased further. A good case of prop slipstream induced AoA variation was the Corsair which could stall the left inboard wing section at near critical AoA with some throttle hence the stall strip added to the right wing outboard of the propwash (which then went on to sabotage the Corsair's turning ability) to make the stall a straight ahead and level one. The main reason for inboard turning props is a resulting inboard P Factor, in other words single engine performance, so basically it helps lower power airplanes.

 

[drgondog]

True, however the RAAF were totally underwhelmed by them.

the Lightnings were beset with unserviceabilities and this is reflected in an exasperated signal from 1PRU to RAAF HQ on 22nd March 1943, less than a week after the replacement aircraft had arrived: "Lightning A55-3 intercooler system unserviceable. After only 16 hours flying. Modifications unsuitable this climate." In August, another signal advised that: "It is seldom possible to have both Lightnings serviceable at the same time."

RAAF LIGHTNINGS 1PRU - The Lockheed File

In fairness the F5 and subsequent modified P-38H/J were far more reliable, but still tender due to overcooling the oil and poor operating procedures. For AAF it remained the high altitude recon ship of choice. That said, the mosquito would have replaced them if available. The NAA F-6A/B/C/D remained Tactical recon ship of choice.

 

[wuzak]

In fairness the F5 and subsequent modified P-38H/J were far more reliable, but still tender due to overcooling the oil and poor operating procedures. For AAF it remained the high altitude recon ship of choice. That said, the mosquito would have replaced them if available. The NAA F-6A/B/C/D remained Tactical recon ship of choice.

Not forgetting the Spitfire XI, which was used by a couple of PR groups and, in some cases, replaced F5 Lightnings.

 

[Barrett]

Ref. Fubar's comment: Youbetcha. I was acquainted with "Holly" Hills because after RCAF he went USN and flew with my dad's high school friend (whose mother taught Dad the piano) in VF-32, Dick May (5 victories). Hills added four Japanese to his 190 to qualify as a really rara avis. His second victory came just about 2 years after Dieppe.