Profile-Lockheed Lightning Pt II

The P-38s were all that stood between the Luftwaffe and the bombers, 500nm deep inside hostile airspace. Unescorted, the B-17s and B-24s suffered up to 30% attrition on some raids and the P-38s were the only aircraft with the radius equal to the task.

With nearly all Pacific and Med P-38 operations flown at medium to low altitudes, Lockheed and Allison had no operational experience with the aircraft at high altitude and low ambients and this was quickly revealed. The Allisons misbehaved quite consistently, ‘throwing rods, swallowing valves and fouling plugs’ while the intercoolers often ruptured under sustained high boost, and turbocharger regulators froze at lOin or 80in of boost, the latter quickly resulting in catastrophic failures. To aggravate these problems, inadequate cockpit heating resulted in severe pilot frostbite, while the Luftwaffe quickly learned about the compressibility problems in dives, with 109 pilots evading the P-38s by split-s-ing at high speed. The roll rate was not spectacular and the easily recognised planform provided the Luftwaffe with yet another advantage to play.

Poor serviceability and engine problems meant that initially 50 or less aircraft were available for such missions, including the first escorts over Berlin, and therefore the 55th and later also 20th FG usually fought the JGs outnumbered between three to one and five to one. The large number of engine failures deep inside enemy airspace exacerbated the problem, and the aggregate exchange rate, accidents inclusive, dropped to about l:l. 5in favour of the Lightning by 1944. Aircrew morale dropped, more so due to the large number of single engined landing accidents, thus further damaging the aircraft’s reputation. The technical problems were not resolved until the introduction of the P-38J, by which time the 8th had decided that the new Merlin powered P-518/C was a better choice for the mission.

In hindsight, while the P-38H may not have performed to expectations in the ETO, what is overlooked is that their presence alone allowed the daylight offensive to proceed at the most crucial phase of the battle, the last quarter of 1943, leading to eventual air superiority by the middle of 1944, when the P-518/C reached full strength. It is safe to say thatwere numbers of the P-38 available to offset Luftwaffe numbers, the overall result would have looked far better.

The Best of the Breed – the P-38J and L

The P-38J resolved the intercooler problems of the earlier subtypes via the use of a core type intercooler in the forward nacelle chin. While prototypes were being tested in early 1943, P-38H production continued. The new nacelle chin provided increased oil cooling capacity, and automatic control of the intercooler vent, resulting in the full availability of the l,600hp War Emergency rating of the F-17 powerplant. Other design changes were introduced, including enlarged glycol radiators in the tailbooms, in later build aircraft additional outboard leading edge tanks, and two major control system changes. These were hydraulically boosted ailerons which decreased control forces by a factor of six, and electrically actuated dive flaps under the wings which cured the dive compressibility problems. In addition, the windscreen was changed to flat armour glassplate, the control wheel was changed and proper cockpit heating and defrosting fitted. The electrical fuses were replaced with breakers.

The result was an aircraft which could match the Luftwaffe fighters in performance, while further extending the type’s radius performance. Deliveries commenced in August 1943, but the die had been cast in the ETO and the 8th began to phase in the P-518 and C from early 1944. The P -38s were gradually shifted to the ground attack and Flak suppression roles, where their superior payload radius performance easily outclassed the smgle engmed types.

Almost 3,000 were built and deployed to every theatre, with increasing numbers to the MTO with the 15th AF, the Pacific with the 5th, 7th, 11th and 13th AFs, and Burma/India with the lOth and 14th AFs.

In the Pacific, the 5th and 13th AFs used the P-38. J to its fullest. The invasion of the Phillipines saw redeployment from New Guinea to the Philippines, and the 475thFG, Satan’s Angels, with four squadrons of P-38s led the scoring contest, well ahead of the mixed FGs. The 475th was a late entry, formed at Ipswich in mid 1943 with a mixed force of G/H models. Many aces flew with this unit, and the two highest scoring US pilots of the war, Richard Bong (40) and Tommy McGuire (38), both flew the P-38 with the 475th. By the end of the war, the 475th had destroyed 551 for 56 losses, a ratio of 10:l. A much publicised event in the Pacific was the 1944 visit by Charles Lindbergh, who widely disseminated the knowledge of range performance improvement through optimal cruise control technique (discussed above), getting the message to pilots and unit commanders throughout the theatre.

In the Med, the P-38. Js flew from Italy on escort and fighter sweep missions into Southern and CentralEurope, attacking target sasfar north as Vienna and Prague, and repeatedly raiding the Rumanian oilfields at Ploesti. The Ploesti oilfields were the target of many a B-24 raid, with questionable results, P-38 strikes however reduced production to a fraction offull capacity. The P-38s became a familiar sight all over Europe, strafing railway locomotives and flak sites in areas once the inviolate domain of the Luftwaffe. With ability to carry two 2,000lb bombs to substantial radii the P-38 became a major battlefield interdiction asset, playing a key role in the 1944 invasion.

The P-38. J was followed by the P-38L, deliveries of which commenced in June, 1944, almost 4,000 were built by the end of hostilities. The P-38Lwas fitted with F-30 engines, delivering equal or better power to higher altitudes, and slightly larger fuel tanks, with booster pumpsin the wings. Detail changes included the first tail warning radar in a fighter.

By the end of 1944, the role of the P – 38, like that of most Allied fighters, had shifted to tactical ground support largely due to the absence of serious fighter opposition. As the Third Reich crumbled and the Japanese retreated into their final defensive perimeter, the operational career of the P-38 reached its final stage.

Expensive to maintain and fly, mostP-38s were phased out soon after the end of hostilities in the Pacific, the P-51 (later F-51) Mustang assuming its role. It is interesting to note that the haste with which the aircraft were disposed of prevented their use in the subsequent Korean War, an environment where the P-38 would doubtless have thrived in its tactical interdiction role, with better payload/radius, firepower and resilience to ground fire than the F-51. The last operational P -38s remained in service with several US aligned Third World countries, but spares availability and operating costs soon led to their demise.

Derivatives – the F-4, F-5, Droop Snoot, Pathfinder, P-38K andP-38M

The F-4 and F-5 photoreconnaissance derivatives of the P-38 were without doubt the most important reconnaissance aircraft in the USAAF inventory. After the difficulties the USAAF encountered with its prewar A-20 derivative F-3 recce platform, Lockheed exploited the opportunity with a proposal for a P-38E fitted with four K-17 cameras in a customised nose. In late 1941 the 116th production P-38E was converted to the new F-4 photoreconnaissance configuration, soon followed by new build F-4-1-LOs, which numbered one hundred. These were subsequently followed by twenty F-4A-1-LOs which were essentially P-38E airframes built concurrently with the P-38F

The speed and range of the F-4 ensured success and set the trend, with the later P-38G evolving into the F-5A, ofwhich no less than 60 were built. Later photorecce subtypes were created by converting fighter airframes rather than new build.

The P-38. J was the last subtype to provide for new built photorece airframes, with 200 built as F-5B-1 models, followed by 123F-5C-1 and an undisclosed number of F-5E-2 and F-5F conversions. The subsequent P-38L was only ever modified for this role, with 705rebuilt to E-3 configuration and many more to other subtypes, including the F-5G with the bulbous nose configuration.

Another important variant of the P-38 was the Droop Snoot. The P-38 could carry up to two 2,000lb bombs, or at more useful radii, one bomb and a 300 USG tank. This payload/radius capacity beg ged to be exploited and in mid-1943, USAAF Colonels Hough and Ostrander, capitalising on the pressure created by heavy losses in the B-17 and B-24 force, proposed the use of the P-38 as a level formation bomber, led by two seat pathfinding P-38s with bomb sights. By late February 1944, Lockheed’s facility at Langford Lodge in the UK rebuilt several P-38. Js to the proposed configuration. This involved removing the armament, installing a transparent perspex nose with an optical flat panel, fitting a Norden gyro stabilised bombsight and adding lead ballast and armour plate about the bombardier’s station. At least one aircraft is known to have had a flexibly mounted . 50 cal gun in the perspex nose, a field retrofit.

The Droop Snoots proved most successful, with over one hundred aircraft rebuilt, but the concept was in practice limited to tactical operations, largely due to the opposition of the heavy bomber commanders who rejected the idea. Droop Snoots were used extensively in Europe, the Mediterranean and India, and when not providing bomb aimingwere used as a anavigationallead aircraft.

A derivative of the Droop Snoot concept, in turn, the radar equipped P-38J and L Pathfinders were rebuilds from standard J/Lmodels. These aircraft had a dielectric nosecone covering an AN/ APS-15 navigation/attack radar, with the operator hidden in the forward fuselage compartment. No records exist on the number built, these aircraft were employed to lead P-38 level bombing formations under non visual conditions, eg bombing through an undercast.

The obscure P-38K was a one prototype of an optimised high altitude subtype, intended to resolve the problems found in the ETO with the P-38G/H models. Fitted with F-15 engines, chin intercoolers not unlike the later P -38. J, and Hamilton Standard Hydromatic propellers optimised for high altitude performance, the only P -38K-1-LO would outclimb (4,800fpm @ SL), outrun (375kt@alt)and out accelerate the P-38. J at altitude. However, the pressure to maintain production rates spelled doom for the P-38K, as the US Government was not prepared to accept a reduction in volumes resulting from the retooling required to accommodate the bigger props. In any event, the P -38. J had resolved most of the powerplant-related failings of the G/H series and was considered adequate to the task.

Somewhatmore successful, but equally obscure was the P-38M, a dedicated night fighter derivative of the P-38L. The P-38M Night Lightnings were a factory design which followed a number of successful field conversions in New Guinea and Guadalcanal, where P-38Fs were fitted with SCR-540 or APS-4 search radar. The P-38L to M rebuilds involved fitting a cramped ‘piggyback’ radar operator’s station aft of the cockpit, under a bubble canopy, and mounting an AN/APS-4 air intercept radar in a cylindrical pod under the nose, the mounting derived from the standard wing pylon. Seventy five P-38L-5-LOswere rebuilt to glossy black P-38M-6-LOs in late 1944, and deployed to the Pacific theatre in 1945, too late to score any kills. TheP-381-5/10-LO – A Technical Perspective

The P-38L will appear quaint to those familiar with modern combat fighter design, but includes many modern design features and was as densely packed as any contemporary tactical fighter. A measure of how well Lockheed engineers designed the aircraft is the fact that the airframe experienced only detail changes throughout its production history, that being the longest of any of the US wartime fighters.

The principal structural elements of the P-38 were the wing and the tailbooms, the latter housing engines, turbochargers and associated systems. The wing structure was of a cantilever type, comprised of a centre section assembly, outer sections and wingtips. The wing employed a single main spar at about 35% chord, with an auxiliary rear spar and a forward spar in the centre section. Torsion boxes were formed by skinning the wing with panels which were corrugated spanwise on the inner surface, in the centresection, these panels had an additional internal smooth skin to form true sandwich skins, which enclosed the main fuel tanks. The Fowler flaps were structurally attached to the rear spar. The wing leading edges formed a stiffened structure, which contained 62USG integral fuel cells. The 90USG main tanks were aft of the centre section main spar, with the cavity between the main and forward spars filled with the 60USG reserve tanks. Wet pylons provided for additional IB5 or 300USG drop tanks. While each engine had a separate fuel system, tanks could cross feed the engines with the exception of the reserve tanks.

The wing structurally supported the central nacelle and forward boom structure. The forward nacelle carried the nosewheel, gunsand magazines, andthe cockpit. The pilot was seated in front of the main spar, with a canopy built up from forward and aft sections, with a jettisonable top cover and downward cranked side windows. The windshield was a single slab of armour glass, with a single forward armour steel plate and multiple rear plates to provide comprehensive fore and aft aspect armour coverage. The tailboom turbochargers were contained in an armour ring to shield the pilot from disintegrating turbines. The nose wheel retracted underthe cockpit, with an entry ladder hinged at the end of the nacelle.

Avionics fit typically comprised an SCR-522A transceiver, an SCR-274N or BC1206 ranging receiver, an SCR-695A IFF transponder and an APS-13 tail warning radar, fitted to the left aft boom. F-5 photoreconnaissance aircraft often carried a DF receiver with a loop antenna under the forward nose.

Control was via a yoke on an inverted L shaped boom, with radio and gun buttons on the yoke, yoke aileron inputs were augmented by a hydraulic booster system. Engine controls were to the left of the cockpit, with pitch/RPM and throttles clustered, and a separate mixture control group forward of the throttles. The elevator trim wheel was below the throttles. Primary flight instruments occupied the left half of the panel, with engine instruments to the right, using dual indicator dials The gun fit was comprised of a centrally mounted AN-M2C 20mm cannon with up to 150rpg, about which were clustered four MG-53-2 . 50 cal (12. 7mm) machine guns with up to 500rpg. Bombs of up to 2,0001b weight were carried on the centre section pylons,and tree launchersfor ten 4. 5in rockets were optionally fitted to the outboard wing.

The low pressure oxygen system employed an A-12 demand regulator, fed from two F-1 bottles in the left aft boom and a single bottle in the right boom. Pressure drop below 100psi was typically signalled with a cockpit lamp. The aft boom mounted the coolant radiators and the detachable tail assembly, the forward boom housing the rearward retracting mainwheels under the turbochargers.

The two Allison V-1710F-30 V-12s had a 5. 5in bore and 6. 0in stroke, providing a compression ratio of 6. 5. These drove Curtiss Electric constant speed props via a 2:1 reduction gear, delivering l,475hp military and takeoff ratings at 3,000rpm,or l,612hp maximum rating at 3,000rpm and 60in of manifold pressure. Some later engines are described as delivering up to 1,725hp W EP rating. The engines required 100 octane or higher rated fuel,and had 13USG oil capacity. The oil was cooled in two outboard chin core radiators,vented via automatically controlled flaps on either side of the nacelle. Fuel consumption was 0. 65lb/hp. hr at l,lO0hp normal rating, at 2,600rpm.

The B-33turbochargers drew air from outboard scoops on the booms, feeding central chin core intercoolers with automatic temperature control, which in turn fed the carbs. The B-33 was redlined at 26,400rpm and exhausted upward,ejector hoods were not used due the the device’s intolerance of any significant backpressure.

The Strategic Perspective

Combat radius wins air wars. This simple observation sums up much of what distinguished the P-38from its contemporaries, and also why this aircraft must be considered the single most significant fighter in the US inventory in WW II. The critical air battles, when Allied strength was still building up and Axis strength was at its peak, were fought by the P-38 force, deep inside hostile airspace against a numerically superior enemy.

All other parameters being equal,it was the radius of the Lightning which allowed the ETO daylight bombing offensive to sueceed at a time when losses were high and long term success questionable. By the time Mustang numbers built up in the ETO, the Luftwaffe had already crossed the knee in the Lanchesterian attrition war curve and defeat was inevitable. While the much admired P-51 made an important contribution, it is worth noting that cumulative deployments of the Merlin powered P-51 matched the P-38 only as late as the end of 1944, which is clearly at odds with the established mythology.

In the Pacific,where land based air grappled with the Japanese, the Lightning was the foremost fighter, destroying more Japanese aircraft than any other Allied fighter. The air battles over New Guinea, the Solomons, the invasion of the Philippines and later Okinawa were all campaigns where the radius and performance of the P-38 were fundamental advantages over Japanese air assets.

The perception of the P-38 as a mediocre aircraft is clearly the result of wartime propaganda run unchecked. The historical record clearly indicates that the big twin was there when it really mattered and there can be no greatera compliment for its designers. The P-38 was without doubt one of the most important American

Special thanks to Warren Bodie, Keith Meggs, Dave Prossor and Lockheed Corporation for their assistance in the preparation of this article.