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Lockheed P-38 Lightning

locp-38
P-38J


The first aeroplane developed from the start as a military type by Lockheed, the P-38 was designed to meet an Air Corps specification issued in 1936. The XP-38 prototype flew for the first time on 27 January 1939 and the first YP-38 service-evaluation aircraft of a limited procurement order for 13 was delivered to the USAAF in March 1941.

It utilised a unique fuel system with separate fuel tanks for each engine. Each tank was divided into three cells, all self-sealing. Two main tanks were in the centre fuselage and one tank was in each leading wing edge. The entire system was interconnected so that fuel from any tank, except the outer wing tanks, could be routed to either engine.The Lightning’s armament included one 20mm cannon and four .50-caliber machine guns in the nose along with racks to carry up to 1,600 pounds of bombs.

P-38D in US service differed from the original P-38 by introducing self-sealing tanks and tail-unit revisions to overcome buffeting. The P-38D was the first version of the Lightning to go into service in the war - an aircraft of this mark was the first American fighter to shoot down an enemy aeroplane, flying over Iceland a few minutes after the US declared war on Germany.

 

Loc-P38


The RAF received only three of 143 aircraft similar to the P-38D which followed the P-38 into production - their performance being unacceptable to the RAF. This resulted from the fact that Lockheed were not permitted to export aircraft with turbocharged engines, making it necessary to install the unsupercharged 775kW Allison V-1710-33 engines which had proved to be underpowered in the XP-38 prototype.

The P-38E had armament changes and were followed by the P-38F with more powerful engines and underwing racks (between engines and fuselage nacelle) for drop-tanks or weapons: late production examples introduced Fowler-type flaps which had a 'droop' setting to enhance manoeuvrability.

Production of the P-38 Lightning accelerated steadily at Lockheed's principal plant in Burbank, California, rising from 207 in 1941 to 1,478 in 1942, the year in which the P-38 entered service in the European and Pacific arenas. Lockheed also modified 200 P-38Fs, providing a pair of 165-US gal (625-lt) drop tanks for each aircraft plus two pairs for each for initial combat use.

While the Lightning had been receiving its combat initiation in Europe, North Africa and the Pacific, Lockheed had been at work to overcome the remaining basic flaws in the P-38 design - the inadequate engine cooling and the compressibility "tuck” problem. The first of these was attributable to the fixed space available in the wing leading edges for the intercoolers; sized to cope with the engines first used in the P-38, these were inadequate for the uprated V-1710s that had been introduced in successive models of the fighter to take advantage of Allison's own development work. The intercoolers received supercharged air from the turbo-compressors in the tailbooms and reduced its temperature before supplying it to the carburettor; however, the inlet temperature actually achieved at the carburettor imposed restrictions on usable manifold pressures, in turn reducing the maximum power that could be extracted from the engines, particularly in the P-38H. The only solution to this was to move the intercoolers to a chin position in each engine nacelle, where they could be sized for the engine powers now available.

Using substantially the same nacelle shape that was already flying on the Curtiss P-40F Warhawk, a P-38E was tested in the summer of 1942 with the new cooling system, which was found to bestow major improvements on the high altitude performance of the Lightning, without any adverse effects. To establish a production standard, this prototype was subsequently fitted with redesigned air intakes for the Prestone coolant radiators on each side of the tailbooms, which although wider than the original type had less drag. Coupled with the use of the same V-1710-89/91 engines already powering the P-38H, these modifications marked the P-38J model of the Lightning - the first to differ significantly in outward appearance from the YP-38. Thanks to the new cooling system, the engines could now be cruised at 1,100 hp at 32,500 ft (9 906 m) and deliver a war emergency rating of 1,600 hp at 26,500 ft (8 077 m). Flying at a combat weight of 16,450 lb (7 468 kg), without drop tanks, the P-38J achieved 413 mph (665 km/h) at 30,000 ft (9 145 m), to become the fastest of all Lightning service versions, and with the big 300 US gal (1136 1) drop tanks, it could cruise for more than 2,000 mls (3 218 km).

Production up to the end of 1942 had been entirely of the earlier P-38 versions, and some 1,400 P-38Gs and Hs were still on order at the beginning of 1943. To handle an increased volume of output, a mechanised moving production line was put in at Burbank, and a major modification centre was established at Dallas, Texas, to prevent constant interruption in the main production progress to accommodate small changes. As a result of these measures, and the use of 22 major sub-contractors to feed components to the Burbank line, the production rate eventually peaked at 432 a month in January 1945.

 

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Production of the P-38J itself totalled 2,970. With effect from the P-38J-15-LO the space in the leading edges previously occupied by the inter-coolers was taken up by two bladder fuel tanks, increasing overall capacity by 110 US gal (416 lt); all but the earliest aircraft also introduced a flat-panel front windshield, and the P-38J-25 and subsequent blocks incorporated the electrically-operated dive flaps that finally cured the compressibility problem. These small flaps, just outboard of the tailbooms, had a span of 4ft 10 in (1,47 m) each, and could be deflected 35 deg in 1 sec; they changed the wing airflow characteristics in such a way as to make recovery from the steepest dive possible. A further contribution to the fighting capability of the P-38J was made by the adoption of hydraulic boosters in the aileron circuits, making the Lightning the first fighter in the world to feature powered flight controls.

The final stage in the evolution of the P-38 was the introduction of Allison V-1710-111/113 engines, with similar ratings to the engines of the P-38J but potential for further development. This model was produced as the P-38L. Lockheed built 3,810 at Burbank and a second production source for Lightning manufacture was established at Nashville under the direction of Consolidated-Vultee, this unit turning out 113 P-38Ls up to V-J Day, of 2,000 on order, the balance being cancelled.

The P-38L was the last fighter version to see combat service, which took in the final stages of the Pacific War. Two P-38L Lightnings escorting a Boeing Fortress were actually the first Allied fighters to land on Japanese soil after the surrender.

More than 700 P-38J/L Lightnings were converted at Dallas to F-5E photo reconnaissance configuration; the F-5F and F-5G were similar apart from the camera installations. The P-38K designation had been intended for another variant with more powerful V-171075/77 engines and Hamilton Standard high-activity paddle-bladed propellers, but to accommodate the latter the engine thrust line needed to be raised one degree and this would have caused a major interruption in the production flow, so the P38K was abandoned after one prototype had been flown.

Experimentally, Lockheed had tested a P-38G with retractable Federal skis at Ladd Field, Alaska, in 1943/44 and USAAF then ordered the conversion of one of the first P-38Js for similar testing in March 1944. The need for a ski-equipped operational variant did not materialise, however. Among trial armament installations made on P-38Ls at Wright Field were three machine guns of 0.60-in (15,24-mm) calibre, with long barrels projecting out of the nose, and eight of the standard 0.50-in (12,7-mm) guns in the nose plus a twin-gun pod beneath each wing, outboard of the engines. Of more importance operationally was the addition of rockets to the Lightning's armament. In 1943, the early "bazooka" launching tubes were attached to P-38Fs and P-38Gs, in triple packs beneath the outboard wings or close in alongside the fuselage. With the advent of the zero-length launcher, Lockheed tried a 14-rocket installation, seven under each outer wing, but the final standard on the P-38L was a five-rocket "Christmas Tree" pack under each wing.

Lockheed built 2,497 P-38s in 1943, of which about 1,000 were the new P-38Js, with the first P-38J-10s coming off the line in October.

The P-38 groups became involved in bombing missions, aided by the P-38J Droop Snoot variant evolved in Britain to serve as a navigation bomb-aiming lead ship. The conversions, engineered by Lockheed Overseas Corporation at Langford Lodge, near Belfast, comprised a Plexiglas nose fairing, replacing all the Lightning's armament, in which was located a seat for the navigator/bombardier, plus a Norden bombsight and a navigation table, with necessary instruments and controls. With an empty weight of 14,206 lb (6 450 kg) and grossing 19,291 lb (8 758 kg) with two 165-US gal (625-1) drop tanks, the first P-38J Droop Snoot flew at Belfast in late February 1944, and about 25 are believed to have been converted for the Eighth Air Force P-38 groups.

Also during 1944, Lockheed developed a two-seat P-38 variant with AN/APS-15 radar bombsight in a lengthened nose together with an operator. The bomb-through-overcast (BTO) radar was usually known as Mickey and small numbers of P-38Ls were converted, seeing service in both the European and CBI theatres.

The most numerous model was the P-38L (3,923 built) powered by the same 1,425-hp engine as the P-38H, but with improved performance ratings. When needed, the engine could produce a “war emergency” 1,600 hp. A bulletproof window was installed, the radiators in the twin tailbooms were increased in capacity, and fuel tanks were placed in the leading-wing edges.

The ability of the P-38L to carry rocket projectiles (10, beneath the centre section), gave these units an added punch during the last year of the war, and some Lightnings were also adapted to carry the early-style rocket launching tubes alongside the fuselage nose, leaving the wing pylons available for fuel tanks.

The P-38s continued operating in this theatre right up to the end of the war, and these units included among their pilots two of the leading USAAF fighter aces - Richard Bong, with 40 confirmed victories, and Tommy MeGuire, with 38.

 

 


Adaptation of the Lightning as a night fighter, to fill the gap in the USAAF inventory caused by late delivery of the Northrop P-61, accounted for the last-designated variant of the Lockheed twin, the P-38M, although the use of Lightnings in the nocturnal role actually originated at squadron level rather than as a factory-designed innovation. Detachments of the 6th Fighter Squadron flying Douglas P-70s in New Guinea and at Guadalcanal, both operated P-38Gs in this role, and the New Guinea detachment actually converted two Lightnings to two-seaters, carrying SCR-540 radar in a drop tank; the unit was, however, disbanded before these aircraft could be tested in combat.

To permit rapid evacuation of casualties from forward bases, this modified fuel tank was developed in Hawaii, for carriage by the P-38. It had portholes, air vents and earphones, and could accommodate a standard stretcher.
While these operational innovations had been going on, a P-38J had been adapted at Wright Field to serve as a test-bed for AN/APS-4 radar, installed in the first instance in a pod under the fuselage behind the nose wheel. As it was struck by cartridges ejected when the nose guns were fired, this pod was later moved to an underwing position, outboard of the starboard engine. Several similar radar conversions of P-38Js, including "piggy-back" two-seaters (known, probably unofficially, as TP-38Js) were then made for the 481st NF Operational Training Group, which conducted field trials, and the USAAF then contracted with Lockheed, in late 1944, to convert a P-38L as a night fighter, carrying a radar operator in a second cockpit behind and above the pilot, and radar in a long pod under the nose ahead of the nosewheel doors. The first flight with all modifications in place was made on 5 February 1945, and although only six flights were made before this aircraft was destroyed, the USAAF then ordered 75 similar P-38L conversions, to be redesignated P-38Ms. Testing of the first P-38Ms began in July 1945, and five of these aircraft arrived at the training establishment at Hammer Field, California, in the same month. Found to have a better overall performance than the P-61B but to suffer some operational limitations, the P-38M saw brief service in Japan in late 1945 and early 1946, being flown by the 418th and 421st Night Fighter Squadrons.

Some P-38J were converted to serve as two-seat 'Pathfinders'; some P-38L as TP-38L two-seat trainers; and other versions included F-4 and F-5 photo-reconnaissance aircraft.

After the end of the war, the P-38 was rapidly withdrawn from USAF service, and as a consequence it did not see such wide use in other air forces as did its principal contemporaries. A small number of P-38Ls was supplied to Honduras in 1947 as part of American aid under the terms of the Rio Pact, but the only significant quantity of Lightnings delivered overseas after 1945 comprised a batch of 50 P-38Js for Italy. These were supplied in 1949 immediately following Italy's signature of the North Atlantic Pact, but were used only briefly, pending the introduction of the AMI's first jet equipment in the shape of the de Havilland Vampire.

In the USAF itself, a few Lightnings survived long enough to be redesignated F-38J and F-38L when the "fighter" category replaced "pursuit" in 1948; the type was finally declared surplus in 1949.

The Lightning is remembered for the long-range interception and destruction of the Mitsubishi G4M1 (Betty) bomber carrying Japan's Admiral Isoroku Yamamoto.

 

Gallery

 

 


Replica: Treadwell P-38

XP-38 prototype
Engines: 2 x unsupercharged 775kW Allison V-1710-33

YP-38

P-38D

P-38 (RAF)
Engines: 2 x unsupercharged 775kW Allison V-1710-33

P-38E

P-38F

P-38G

P-38H
Engines: 2 x Allison V-1710-89/91, 1,100 hp at 32,500 ft (9 906 m) / emergency 1,600 hp at 26,500 ft (8 077 m)

P-38J
Engines: 2 x Allison V-1710-89/91, 1,100 hp at 32,500 ft (9 906 m) / emergency 1,600 hp at 26,500 ft (8 077 m)
Length: 37.828 ft / 11.53 m
Height: 9.843 ft / 3.0 m
Wingspan: 52.001 ft / 15.85 m
Wing area: 327.441 sq.ft / 30.42 sq.m
Max take off weight: 21604.6 lb / 9798.0 kg
Weight empty: 12782.4 lb / 5797.0 kg
Combat weight: 16,450 lb (7 468 kg)
Max speed: 360 kts / 413 mph / 665 km/h at 30,000 ft (9 145 m)
Cruising speed: 252 kts / 467 km/h
Service ceiling: 43996 ft / 13410 m
Wing loading: 66.01 lb/sq.ft / 322.0 kg/sq.m
Range: 413 nm / 764 km
Range 300 US gal (1136 1) drop tanks: 2,000 mls (3 218 km).
Crew: 1
Armament: 4x .50 MG (12,7mm), 1x 20mm MG, 1451kg Bomb

P-38J-10

P-38J-15-LO
Increased fuel capacity by 110 US gal (416 lt)  

P-38J-25-LO
Engines: 2 x Allison V-1710-89/91, 1,425 hp for take-off at sea level; military rating, 1,425 hp at 26,500 ft (8 077 m); war emergency rating, 1,600 hp at 26,500 ft (8 077 m); continuous rating, 1,100 hp at 32,500 ft (9 906 m).
Curtiss Electric three-bladed fully-feathering propellers, diameter 11 ft 6 in (3,51 m).
Fuel capacity, 300 US gal (1136 lt) in two main and two reserve wing tanks plus 110 US gal (416 lt) in two leading edge tanks; two 75-, 150-, 165- or 300-US gal (284-, 568-, 625- or 1136-lt) drop tanks.
Max speeds (clean), 360 mph (579 km/h) at 5,000 ft (1525 m), 390 mph (628 km/h) at 15,000 ft (4 575 m) and 414 mph (666 km/h) at 25,000 ft (7 625 m)
Rate of climb, 3,670 ft/min (18,6 m/sec) at 5,000 ft (1525 m)
Time to climb to 30,000 ft (9 150 m), 12 min
Range (clean) at max cruise at 25,000 ft (7 625 m), 840 mls (1352 km)
Range (max fuel) at max cruise at 25,000 ft (7 625 m), 1,880 mls (3 025 km)
Range with two 1,600-1b (726-kg) bombs, 725 mls (1167 km).
Basic weight, 14,100 lb (6401 kg)
Combat weight (clean), 17,500 lb (7 945 kg)
Max take-off weight (max fuel), 21,600 lb (9 806 kg).
Wing span, 52 ft 0 in (15,85 m)
Length, 37 ft 10 in (11,53 m)
Height, 12 ft 10 in (3,91 m)
Undercarriage track, 16 ft 6 in (5,03 m)
Wing area, 328 sq ft (30,5sq.m)
Armament: One 20-mm Type AN-M2 "C" 20-mm cannon with 150 rounds and four 0.50-in (12,7-mm) machine guns, with 500 rpg, all in nose. Provision for two bombs of up to 1,600 lb (726 kg) each under wing centre section.
Dive flap span: 4ft 10 in (1,47 m)
Dive flap deflection: 35 deg in 1 sec

P-38J Droop Snoot
Empty weight: 14,206 lb (6 450 kg)
Gross weight: 19,291 lb (8 758 kg) with two 165-US gal (625-1) drop tanks
Armament: none. Seats: 2.
Equipment: Navigator/bombardier, Norden bombsight and a navigation table
Fuel cap: + 2 x 165-US gal (625-lt) drop tanks.

TP-38J
Crew: 2

P-38K
Engines: 2 x Allison V-171075/77
Props: Hamilton Standard high-activity paddle-bladed

P-38L
Engines: 2 x Allison V-1710-111/113 , 1,100 hp at 32,500 ft (9 906 m) / emergency 1,600 hp at 26,500 ft (8 077 m)
Max take-off weight: 9798 kg / 21601 lb
Empty weight: 5806 kg / 12800 lb
Wingspan: 15.85 m / 52 ft 0 in
Length: 11.53 m / 37 ft 10 in
Height: 3.91 m / 12 ft 10 in
Wing area: 30.47 sq.m / 327.98 sq ft
Max. speed: 666 km/h / 414 mph
Ceiling: 13410 m / 44000 ft
Range: 724 km / 450 miles
Range w/max.fuel: 3640 km / 2262 miles
Armament: 1 x 20mm cannon, 4 x 12.7mm machine-guns, 1451kg of bombs
Crew: 1

TP-38L
Engines: 2 x Allison V-1710-111/113 , 1,100 hp at 32,500 ft (9 906 m) / emergency 1,600 hp at 26,500 ft (8 077 m)
Wingspan: 15.85 m / 52 ft 0 in
Length: 11.53 m / 37 ft 10 in
Height: 3.91 m / 12 ft 10 in
Wing area: 30.47 sq.m / 327.98 sq ft
Crew: 2

P-38M
Engines: 2 x Allison V-1710-111/113 , 1,100 hp at 32,500 ft (9 906 m) / emergency 1,600 hp at 26,500 ft (8 077 m)
Crew: 2

F-5E
Engines: 2 x Allison V-1710-111/113 , 1,100 hp at 32,500 ft (9 906 m) / emergency 1,600 hp at 26,500 ft (8 077 m)

F-5F
Engines: 2 x Allison V-1710-111/113 , 1,100 hp at 32,500 ft (9 906 m) / emergency 1,600 hp at 26,500 ft (8 077 m)

F-5G
Engines: 2 x Allison V-1710-111/113 , 1,100 hp at 32,500 ft (9 906 m) / emergency 1,600 hp at 26,500 ft (8 077 m)

locp-38ld

 

Lockheed P-38 Lightning

 

 

 


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