The XF5X Skyrocket

What were they thinking?

The U.S. Navy Grumman XF5F-1 Skyrocket experimental fighter.


The XF5F Skyrocket was a prototype, carrier-borne interceptor built for the U.S. Navy in 1940. Predecessor to the Tigercat, it was built by Grumman in competition with Vought’s XF4U, the first prototype of the Corsair. It’s hardly surprising that Vought won when you look at this bizarre looking bird.


What is surprising though is that the Skyrocket was aptly named. It really did rocket into the sky with a superb climb rate of 4,000 ft/min, leaving the Corsair prototype in its wake with a comparatively slow climb rate of 2,660 ft/min. The existing Spitfire was also left behind with its max speed of 369 mph vs the XF5F’s 382 mph, and climb rate 1,334 ft/min slower.


“I remember testing the XF5F against the XF4U on climb to the 10,000 foot level. I pulled away from the Corsair so fast I thought he was having engine trouble.” - LCDR Crommelin


Powered by two 1,200 hp (895 kW) Wright XR-1820-40 and -42 engines driving three-bladed counter-rotating propellers, it was the first Grumman aircraft with folding wings.


Appropriately, it’s first flight was on April Fools Day, 1940. It had good flight characteristics, the counter rotating blades eliminated torque effect, it performed aerobatic maneuvers well and provided good pilot visibility.

Colourised photo showing the Skyrocket paint scheme.


Speed obviously wasn’t the problem, so what was? The Navy wasn’t sure about some of the Skyrockets ‘radical’ features and there was an issue with parts availability for this completely new design. In addition - engine cooling was problematic, there was some instability in certain flight conditions, the aircraft had excessive drag, the landing gear doors didn’t close properly, and the pilots forward view during carrier landings was obstructed by the weird wing position. After 70 flights to test corrections before delivery on February 22, 1941, the Vought XF4U-1, producing speeds up to 404 mph (650 km/h), had won the race.


Despite losing against the Corsair, the Skyrocket became incredibly well known for a plane that never went into production. The weird looking failure went on to have a 50 year career as the aircraft of choice for the WWII Fighter Aces of the Blackhawks - a comic book.


The one and only XF5F Skyrocket completed 211 test flights before being cancelled in early 1941. It continued to be used in various tests until it’s ongoing landing gear problems caused a belly landing and ended it’s short life as a flying machine in December 1944.


We'll likely never see another plane quite like it - probably not a bad thing.