Martin XLB-4 explained

The Martin XLB-4 was a 1920s proposal for a light bomber by the Glenn L. Martin Company.

Design and development

The XLB-4 would have been a biplane bomber of all metal construction, powered by two Pratt & Whitney R-1690 Hornet radial engines. The United States Army Air Corps (USAAC) ordered a single prototype serialled 27-332, but the aircraft was cancelled because the USAAC leadership was lukewarm about experimenting with all-metal aircraft.^{[1] [2]}

Notes and References

1. Book: Wagner . Ray . American combat planes . 23 March 1982 . Doubleday . 9780385131209 . 3d, enl. . registration .
2. Web site: Baugher . Joe . Martin XLB-4 . www.joebaugher.com . 30 January 2019.