550hp P&W SR-1340
The following is from Peter M Bowers' book, Boeing Aircraft since 1916
The XF7B-1 was designed to a Navy specification issued on December 6, 1932, and a contract for its construction was signed on March 20, 1933. Model 273 was selected for construction and test from four monoplane proposals submitted and incorporated several notable 'firsts', both for Boeing and the Navy. It was the first Boeing to be fitted with a controllable-pitch propeller before initial testing and the first to have flaps fitted, and was the first low-wing cantilever monoplane ever submitted to the Navy as a carrier fighter.
The first flight was made on September 14, 1933.
After preliminary demonstration flights for Navy officers in Seattle, the XF7B-1 was flown to Hartford, Conn, for engine and cowling modifications by Pratt & Whitney. It was delivered to the Navy test centre at Anacostia, Maryland, on November 11, 1933. As the result of Navy criticism of high landing speed and the lack of downward visibility, the XF7B-1 was returned to the factory for conversion to a standard open cockpit design and the addition of a split flap along the trailing edge of the centre section.
While other characteristics of the aeroplane compared favourably with new Army monoplane fighters then under test, the Navy still felt that its needs were best met by the biplanes. Compared to them, the average 357.2 ft take-off run of the Boeing monoplane was excessive for carrier operation, the landing speed of 70 mph was too high, the manoeuvrability was inferior, and the low position of the thick wing obsured the horizontal tail surfaces from the vision of the Landing Signal Officer on the carrier deck and made it difficult for him to judge the approach speed. These monoplane characteristics did not become acceptable to the Navy until 1938, when the first production orders for monoplane shipboard fighters were placed, and the XF7B-1 became an example of a gamble that lost because the product was too far ahead of its market.
The XF7B-1 was scrapped after extensive in-flight damage was incurred during a 415 mph dive in March 1935. The centre panel of the windshield collapsed during the dive, and this apparently caused the pilot to make too abrupt a pull-out, for the measured 'g' load was 12.1 while the design load factor was only 9.0. The structure was seriously sprung, but the Navy pilot was able to fly the aeroplane home and land it safely. The cost of repair could not be justified in view of the fact that the Navy had already decided against production of the F7B-1 design. Total cost of the X7FB-1 to the Navy was $70,014.
Aeroplane Photo Supply No. 3217
Aeroplane Photo Supply No. 5015
Aeroplane Photo Supply No. 5016
Aeroplane Photo Supply No. 2316
