Lockheed P-38 Lightning I

In the spring of 1940, as France and Britain looked to American industry for aircraft their own factories could not deliver fast enough, the Anglo-French Purchasing Committee signed a contract with Lockheed for 667 examples of the Model 322, the export version of the P-38. Sources differ on the month (March in some, April in others) but agree on the scale of the deal, worth around US$100 million. For the Burbank company it was a major boost: until then, counting the prototype and the service-test machines, the Army Air Corps had ordered only eighty P-38s. The contract covered two sub-types: the 322-F (Model 322-61-03) for the Armée de l'Air, with French instruments, radio and armament and even throttles that worked in the opposite sense to American practice, and the 322-B (Model 322-61-04) for the Royal Air Force.

What set the Model 322 apart was its powerplant. Instead of the turbocharged Allisons of the Army P-38, it used two V-1710-C15s rated at about 1,090 hp at 14,000 ft, without turbosuperchargers and with both propellers turning to the right rather than in opposite directions. According to the notes in the Menzies collection, this was a deliberate choice by the committee: to share engines with the Curtiss H-81A, the P-40 Tomahawks both nations had ordered in large numbers, and to optimise the aircraft for the medium-altitude fighting then taking place over Europe. The Spanish and Italian encyclopedias instead attribute it to a US government ban on exporting the supercharging equipment. In this configuration Lockheed guaranteed 400 mph at 16,900 ft, about 644 km/h.

The fall of France in June 1940 left the entire contract in British hands, and it was then that the aircraft received its service name: Lightning. Lockheed, true to its habit of naming aircraft after mythological and celestial figures, had considered calling it Atalanta, but the British choice prevailed and passed to the whole P-38 family, so that the most lasting legacy of this order was, precisely, its name.

Lessons from the Battle of Britain and the Blitz led the British ministry to revise its specifications in June 1941, and dissatisfaction with the order surfaced in July. On 5 August 1941 the contract was amended: 143 aircraft would be delivered as ordered, with C15 engines, as the Lightning Mk I, carrying the military serials AE978 to AE999 and AF100 to AF220; the remaining 524 would be Lightning Mk IIs with turbocharged F-series engines and a guaranteed top speed of 415 mph at 20,000 ft.

That same summer an RAF test pilot posted to Burbank sent back an unfavourable report on tail flutter and other aerodynamic problems seen on the YP-38s, and London cancelled every Mk I except the first three, AE978, AE979 and AE980. Facing a loss of around US$15 million, Lockheed chose to hold the British to the original contract, and the talks turned bitter and stalled.

The Japanese attack of 7 December 1941 changed everything. The US government seized some 40 Model 322s for the defence of the West Coast, and all the British Mk Is were then sent to Dallas, Texas, to be modified and handed to the Army Air Forces from January 1942. The USAAF lent three of them to the RAF, shipped by sea in March 1942: AF105 went to Cunliffe-Owen Aircraft at Swaythling, Southampton; AF106 to the Aeroplane and Armament Experimental Establishment at Boscombe Down; and AF107 to the Royal Aircraft Establishment at Farnborough. None flew before May. The Boscombe Down machine, unarmed and lacking turbochargers, was restricted to 300 mph; the evaluators praised the undercarriage and found single-engine flight comfortable, but at low level and on low-octane British fuel its speed and manoeuvrability proved poor, and the verdict was a disappointment. One was returned to American hands in December 1942 and the other two in July 1943.

In the United States the Mk Is kept their British serials and were divided into two groups. Nineteen retained the C15 engines, known in Army service as the V-1710-33, and were designated RP-322-I, the R standing for restricted because propellers turning the same way were thought to make take-off more dangerous. The other 121 received counter-rotating V-1710-27 and -29 engines, still without turbosuperchargers, and became P-322-IIs. Most flew unarmed or with reduced armament as advanced or operational trainers: an ideal way to introduce new pilots to the P-38 without the added complication of the turbosupercharger, in an aircraft that was fairly fast below 16,000 ft and pleasant to handle. A few were still doing that job in 1945.

A handful of RP-322s also served as test beds, for instance for smoke-laying canisters; the Spanish encyclopedia adds the air-dropping of two torpedoes, trials that the Menzies collection links to the only Lightning II completed, AF221. AE979, photographed over California in December 1941 and never delivered to Britain, was scrapped at San Bernardino on 13 November 1945. As a curiosity, some of the fastest post-war racing P-38s were laid out almost exactly like the P-322-II.

The sources do not fully agree. Against the 19 RP-322-Is and 121 P-322-IIs given by the Menzies collection and the English encyclopedia, other accounts mention 22 P-322-Is, 146 Mk Is in the British order or 147 RP-322 trainers; the engine designation of the P-322-II also varies (V-1710-27/-29 or V-1710F-2).