Lockheed L-188 Electra
In the 1950s jet transport aircraft were introduced but they were not (yet) considered suitable for short to medium ranges. Turboprops were better suited for that. Hence Lockheed saw the need for a hundred seat turboprop aircraft to compete with the Vickers Viscount. Using the experience gathered with the development of the Hercules tactical transport aircraft the L-188 Electra was born. It has low mounted wing with the four engines in the wing's leading edge. The intakes are above the prop spinners and the exhausts near the trailing edge, at the top of the wings. The conventional horizontal stabilisers have dihedral while the vertical stabiliser is nicely curved from the dorsal fin until the trailing edge. The fuselage is circular and has nearly squared cabin windows with rounded corners. The nose is very round, typical for the Electra.
The nose of the Lockheed Electra is almost perfectly round, one of the key features of the aircraft. Note the flat cockpit windows with one triangular eyebrow window above. Behind are the square cabin windows with rounded corners.
The Electra has the same engines as the Hercules, but then upside down: the air intakes are above the spinners and the nacelles are largely above the wings. The two wheel main gear retracts in the inner nacelles.
The different versions of the Lockheed Electra can externally be distinguish by the presence of a cargo door in the left front or rear fuselage.
L-188A & L-188C
There are two main passenger version of the Electra, designated L-188A and L-188C. The C model is the longer range version, but externally the same as the A model. Both have many cabin windows and cabin doors in the left side of the fuselage, before and after the wing.
L-188AF & L-188CF
Many Electras were converted to cargo aircraft, after jets took over the short to medium range routes. These received designations L-188AF and L-188CF, based on the L-188A and L-188C respectively. Both models cannot be externally distinguished. Strangly some converted aircrfat have a cargo door in the left front fuselage, some in the rear front fuselage and some both (see photo at the top)!
Few Electras got a cargo door in the left front fuselage but retained the passenger cabin (and cabin windows) at the back. These aircraft are known as L-188PF. Later some aircraft were converted to full freighter, but the designation was not changed, so beware.
Confusion possible with
The Orion is a maritime patrol aircraft derived from the Electra, which is clearly visible in the curved vertical stabiliser, wings and engine nacelles. The fuselage is shorter than that of the Electra, Additionally, the nose is less rounded and the cockpit windows are slightly different. Finally, the Orion has an extended tail cone, often with a long boom.
The Vickers Vanguard is about the same size as Lockheed Electra, but has a trapezium vertical stabiliser with straight edges. Also the Vanguard has more pointed nose, large oval cabin windows and nacelles circular air intakes, around the prop spinners.
The Viscount was the main competitor of the Electra and has a similar basic configuration, including the curved vertical stabiliser. The Viscount has oval cabin windows though, and nacelles with ring shaped air intakes. Contrary to the Electra it has a less streamlined, more pointed nose, with the cockpit popping out.
The Soviet counterpart of the Electra and Vanguard can best be recognised by the round cabin windows, two cockpit eyebrow windows on each side and four wheels on the main landing gear, apart from other differences. The fuselage is round.