The Grumman FF series marked the beginning of Grumman’s legacy as a premier builder of naval aircraft.
In 1931, the U.S. Navy approached Grumman to retrofit its Boeing F4B fighters with retractable landing gear.
Instead, Grumman proposed an entirely new aircraft—the FF-1—featuring a manually operated retractable undercarriage, enclosed cockpit, and all-metal fuselage with fabric-covered biplane wings.
The prototype XFF-1 (serial A8878) first flew on December 29, 1931, powered by a 616 hp Wright R-1820-E Cyclone.
Later upgraded to a 750 hp R-1820-F, it reached 201 mph—faster than any U.S. Navy fighter then in service.
U.S. Navy Service
FF-1
27 production aircraft were delivered starting in June 1933.
They served with Fighter Squadron VF-5B aboard USS Lexington.
The FF-1 was a two-seat fighter with forward-firing Browning machine guns and a flexible rear gun mount.
SF-1
A scout variant based on the XSF-1 prototype (serial A8940), 33 were built.
These served with VS-3B, also aboard Lexington, and featured revised internal equipment and a different engine model (Wright R-1820-84).
FF-2
25 FF-1s were converted into dual-control trainers by the Naval Aircraft Factory, extending their utility as frontline roles diminished.
XSF-2
A single SF-1 airframe fitted with a 650 hp Pratt & Whitney R-1535-72 Twin Wasp Junior engine and Hamilton Standard propeller, used for engine testing.
The FF series was retired from U.S. Navy service by 1940, but its retractable gear design influenced later Grumman fighters like the F2F, F3F, and F4F Wildcat.
GG-1 Demonstrator
Grumman built a hybrid demonstrator from FF-1 and SF-1 components, initially powered by a 450 hp Pratt & Whitney R-1340 Wasp.
It was later upgraded with an 890 hp Wright R-1820-F52 and featured full-span split flaps and modified ailerons.
Sold to American businessman Howard F. Klein, it was used to promote the design to Canadian Car & Foundry.
Canadian Goblin Mk I
Canada acquired 15 G-23s (licence-built FF derivatives) from Canadian Car & Foundry.
Originally intended for Spain, they were embargoed and instead taken on strength by the Royal Canadian Air Force as Goblin Mk I.
These aircraft served with No. 118 (Fighter) Squadron in training and coastal defence roles until 1941.
Spanish GE.23 Delfín
In 1938, 34 G-23s were delivered to the Spanish Republican Air Force during the Spanish Civil War.
Known as GE.23 Delfín, they were used in combat against Nationalist forces.
Despite their outdated design, they played a role in reconnaissance and light attack missions.
Japanese Evaluation
AXG1
A single G-23 was supplied to the Imperial Japanese Navy in 1935 for evaluation. Designated AXG1, it was tested but not adopted for service.
Legacy
The Grumman FF was a technological milestone—the first carrier-based fighter with retractable landing gear.
Though its combat career was brief, its design innovations shaped Grumman’s future aircraft and helped establish the company’s reputation for rugged, reliable naval fighters.
The Goblin and Delfín variants extended its legacy internationally, serving in training, coastal patrol, and combat roles across Canada, Spain, and Japan.
