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| L-193 Constellation II | |
|---|---|
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| General information | |
| Type | Jet airliner Aerial refuelling tanker |
| National origin | United States |
| Manufacturer | Lockheed |
| Status | Canceled |
| Number built | 0 |
TheLockheed L-193 Constellation II was ajet airliner design concept, designed between 1949 and 1953 with aswept wing and engines mounted at the tail. An airliner and tanker version were developed. The latter, in anaerial refueling competition initiated by theUnited States Air Force (USAF), won and was preferred over theBoeing KC-135 Stratotanker. Since the competing Boeing aircraft was ready to fly first, examples were ordered as an interim measure. They performed well enough that the L-193 was never ordered as a tanker, and airliner plans were dropped soon after.
The Lockheed L-193 jet was designed between 1949 and 1953. By comparison, Boeing started producing the prototype for theBoeing 707 after the design was completed in 1952. Lockheed sought input fromTrans World Airlines for the airliner's requirements[1] and several sub-variants were developed. It was a swept wing with the engines mounted at the tail. The same arrangement was later used by theLockheed JetStar (1957),Vickers VC-10 (1962), andIlyushin Il-62 (1963). It was designed to be slightly smaller than theBoeing 707 andDouglas DC-8 of the time.[2][3] Lockheed used features seen in its previous designs, including tip tanks similar to theLockheed Constellation and a double-deck fuselage similar to theLockheed Constitution.[4] The engines were also flush mounted to the fuselage, a feature dropped from most current jet designs.
In the wake of theKorean War, a competition was held in 1954 for a USAFaerial refueling tanker. A modified L-193 was chosen in 1955 to supplement the interim KC-135 tanker. The aircraft was designated "KCX-LO", and the first prototype would have been the XK-1.[citation needed] A prototype was ordered in February 1955.Air Force SecretaryHarold E. Talbott ordered 250 KC-135 interim tankers while the selection winner was manufactured. The KC-135 was able to be delivered two years earlier than the Lockheed, and was able to be put into squadron service four years earlier. The orders for the Lockheed tanker were eventually dropped so the USAF would not have to support two separate tanker designs.[5]
Lockheed never produced its jet airliner, instead producing the modestly-successful turboprop-poweredElectra. Lockheed also produced theC-141 Starlifter jet cargo transport and anSST design, but did not produce a jet airliner until theL-1011 wide-bodytrijet. By contrast, Boeing had beat Lockheed by producing its prototype first, at its own expense, rather than waiting for the military contract, and would eventually dominate the market with a family of airliners based on the 707 and KC-135.
General characteristics
Performance