While the North American B-25 Mitchell is an iconic U.S. W.W. II medium bomber
less well remembered are some of the concepts it spawned.
This version of the famous B-25 was designed as a more heavily-armed close-support platform taking advantage of the new gun nose developed by Major 'Pappy' Gunn.
The original design was heavily armed with four 35 m.m. cannons and four .50 caliber machine guns in the nose along with two more .50s in the rear turret. It featured a bubble canopy and was converted to a tail-dragger because the guns took up too much space in the nose for landing gear.
The entire project was put under the supervision of chief engineer Throckmorton Twitchell whose experience was seen as key to overcoming any development hurdles.
Of course it was natural this new version of the Mitchell would be called the Twitchell.
The fact that the heavier nose took a strong hand at the stick and fatigued pilots often developed a twitch had nothing at all to do with the nomenclature. North American and the U.S. Army Air Forces however were working under the exigencies of war and such petty concerns as pilot fatigue did not factor into things as the aircraft completed flight tests.
By this time, the new B-25G was entering service and the performance advantage of the Twitchell was only marginal so the project was cancelled. The prototype was instead modified to carry the largest, most powerful airborne radar available and re-designated XNF(R)-25B for Experimental Night Fighter-Radar.
The aircraft was armed with four .50 caliber machine guns in blisters on the sides of the nose and four 20 m.m. Smith & Wesson Aero-Killer auto cannons. Two of these fast-firing guns were located in blisters under the nose and the other two in a remote-controlled Sperry turret. The auto-cannons were usually aimed upwards at an angle in a Yankee imitation of the famous German Schräge Musik.
The XNF(R)-25B sure looked every bit the bomber killer but tests revealed firing the nose guns often put the radar out of whack and the 20 m.m. cannon took it off-line completely until it could be re-booted on the ground. Hence the Twitchell's most potent weapons were in the turret and the nose guns would only be used in extremities.
After being thoroughly put through its paces, the XNF(R)-25B was briefly used for training night bomber crews in defensive tactics. The aircraft was then trialed in new U.S. national test markings before it was ignominiously tasked with providing night fighter defense over western Pennsylvania's vital Moon-Mars air corridor to counter reports of unknown aircraft over-flying the area.
The press of the day followed events closely.
The locals were certainly no strangers to strange things in the sky.
The Graf Zeppelin dirigible had cruised above them on its world tour a decade before.
But this was different and the Army Air Force and its lone Twitchell were called to action against a mysterious enemy.
The XNF(R)-25B was often alerted by ground spotter reports and by the time it came on the scene, the intruder was long gone. But on the night of March 9th, the Twitchell was finally able to engage this amorphous foe. While this air action would prove inconclusive, it did provide the only documentary evidence of these unidentified flying objects.
Just as suddenly as they'd started, the over-flights stopped. And soon the XNF(R)-25B stopped being in front-line service when it was replaced by the far more capable P-61 Black Widow. The Twitchell ended its career as a destructional airframe and nothing remains of it today except this inaccurate replica of the manufacturer's desktop model.
Still, for one brief moment this prototype night fighter was the only defense against the phantom foe even if it was a shot in the dark that missed.
Brian da Basher