^ Jeez, that looks like a flying apartment building.
Maximum speed: 272 mph (237 kn, 438 km/h) at 13,000 ft (3,960 m)
Cruise speed: 230 mph (200 knots, 370 km/h)
Range: 1,350 mi (1,174 nmi, 2,174 km)
Service ceiling: 24,200 ft (7,378 m)
Armament
Guns: 12–18 × .50 in (12.7 mm) machine guns and 75 mm (2.95 in) T13E1 cannon
Hardpoints: 2,000 lb (900 kg) ventral shackles to hold one external Mark 13 torpedo[43]
Rockets: racks for eight 5 in (127 mm) high velocity aircraft rockets (HVAR)
Bombs: 3,000 lb (1,360 kg) bombs
Maximum speed: 355 mph (308 kn, 570 km/h)
Range: 1,400 mi (1,200 nmi, 2,300 km)
Service ceiling: 22,000 ft (6,700 m)
Armament
Guns:
6 or 8 0.50 in (12.7 mm) M2 Browning machine guns in solid, "all purpose" nose: or 2 0.50 in (12.7 mm) M2 machine guns in glass "bombardier" nose
Up to 8 0.50 in (12.7 mm) M2 machine guns paired in four optional under wing pods: or 3 0.50 in (12.7 mm) M2 machine guns in each outer wing panel
2 0.50 in (12.7 mm) M2 machine guns in remote-controlled dorsal turret
2 0.50 in (12.7 mm) M2 machine guns in remote-controlled ventral turret
Rockets: Up to 10 5-inch (12.7 cm) HVAR rockets on "zero length" launch pylons, five under each outer wing panel
Bombs: Up to 6,000 lb (2,700 kg) capacity - 4,000 lb (1,800 kg) in the bomb bay plus 2,000 lb (910 kg) carried externally on underwing hardpoints
Lockheed’s XC-35 was the world’s first aircraft specifically constructed with a pressurized passenger cabin and, as aerospace medical historian Douglas Robinson notes, is “the true ancestor of all modern pressurized airliners.” Credit for the cabin goes to structures experts Major Carl Greene and John Younger, both of whom worked for the Air Corps Engineering Division at Wright Field (now Wright-Patterson Air Force Base) in Ohio. They worked with Lockheed to redesign the fuselage of the Lockheed 10A Electra, adding two turbosuperchargers to its radial engines both to improve altitude performance and to feed air to the cabin. Designated XC-35 and delivered to Wright Field in May 1937, it began flight testing in July, flying up to 33,000 feet while maintaining a cabin pressure of 9.5 pounds per square inch. The XC-35 underwent an extensive series of high-altitude flight tests, proving the practicability of pressurizing the cabin. So confident were Army Air Corps leaders of its safety that they allowed it to be used as an executive transport for Louis Johnson, the assistant secretary of war. The XC-35 won the 1937 Collier Trophy for the Air Corps. But more significantly, it pointed the way for pressurized bombers and transports, the first of which were Boeing’s B-29 and Model 307.