Northrop NS-41 Flying Wing

USAAF designations: YB-35 / YB-35A / YB-35B

Engines: 4 x 3,000 hp P&W R-4360 radials (takeoff power)

Significant date: ordered September 1942

In December 1944, some 6 months after the Martin B-35-MA production contract was nullified, modification requests began to alter the B-35 development contract. The AAF decided that Northrop would build the first 6 B-35 prototypes (YB-35s) on the XB-35's pattern, with certain exceptions affecting individual aircraft.

Another cost plus fixed fee contract issued on September 30, 1942 (W535-ac-33920) was approved on December 17. It called for the construction and testing of 13 service test models of the XB-35, designated YB-35s. Counting spare parts and the contractor's fee, the contract's cost was expected to reach $22.7 million. The AAF's approval of this YB-35 prototype contract followed by a few months the purchase of 2 additional N-9Ms, a fourth and last N-9M being ordered in mid 1943. Retained records did not itemize the costs of the additional N-9Ms. However, such costs were included in the XB-35 program's total amount.

The first eight YB-35s were built to late XB-35 specifications (including single-rotation propellers), but with certain individual differences. The first YB-35 (42-102366) flew on May 15, 1948, the only Flying Wing example actually fitted with defensive armament (the two XB-35s had carried only dummy turrets). This was destined to be the only one of the 13 YB-35s ordered that actually flew. and the YB-35 flight test program only lasted a few months in mid-1948. Soon afterward, Northrop was authorized to build 2 of the YB-35 prototypes as all-jet models, a change so important that it actually marked the beginning of a new program. Thus two YB-35s became YB-49s, and to replace the 2 earmarked for jet conversion, the AAF told Northrop to manufacture the remaining 5 airplanes to more advanced specifications, a directive that automatically entailed the aircraft's redesignation as YB-35A (42-102374/102378) (1 of which became YRB-49A). Of the original 13 YB-35s ordered, four had been scheduled to be used as sources of spare parts for the extensive flight test program that was planned; one YB-35s and three YB-35As were therefore designated YB-35B and stored for that very purpose.

One YB-35A (42-102378) was earmarked for static testing, and another jet-converted YB-35A was to be fitted out as a test-bed for the Turbodyne T37 turboshaft engine, which was then under development. This test aircraft was to have been designated YRB-35 (it was the last of the 13 prototypes) and would be capable of carrying two XT37 engines, although only one of these engines would actually be fitted initially. It was was however designated EB-35B (replacing XB-35 S/N 42-13603, originally scheduled for modification). In November 1949 , the Air Staff cancelled plans for further conversions of YB-35s and YB-35As to jet propulsion. The single flying YB-35 was in storage for about a year before being scrapped in 1949. Scrapping of the remaining YB-35 airframes started in December of 1949 and was completed by March of 1950. The disassembly of the EB-35B testbed began in that same month.

Population: YB-35: 1 [42-102366], YB-35A : 12 [42-102367/102378]

Specs:
Span: 172 ft. 0 in.
Length: 53 ft. 08 in.
Height: 20 ft. 0 in.
Wing area: 4,000.0 sq ft (371.5 sq m)
Gross weight: 162,000 lb (73,469 kg)
Maximum gross weight: 180,000 lbs.
Armament: Twenty .50-cal. plus 51,200 lbs. of bombs
Crew: 9 (plus space for 6 relief crewmen)

Performance:
Maximum speed: 391 mph. (629 km/h, 340 kt) at 35,000 ft.
Cruise Speed: 240 mph (386 km/h, 208 kt) (or 183 mph?)
Range: 7,500 miles 12,077 km
Range: 8,150 miles with 16,000 lbs. bomb load.
Service Ceiling: 39,700 ft. (or 40,000 ft, 12,191 m)

Crew/passengers: 9 (plus space for 6 relief crewmen)