One of the strangest chapters in American aeronautics, the AV-4F was the product of the “Whiz Kids” of Robert S. McNamara’s Defense Department in the closing years of the Vietnam war.
The conflict had seen the birth of true vertical attack aircraft, in the form of helicopter gunships. The 1960s in general, however, had shown the promise of VTOL jet aircraft, such as the British Hawker-Siddeley Harrier…and a myriad of less successful prototypes and experimental designs from half a dozen nations.
Thus, to the Johnson administration, while the military situation in southeast Asia clearly demonstrated the need for a heavy (in comparison to heliborne, at least) strike/attack aircraft, a viable platform might be years away.
The concept of modifying an existing airframe into an interim VTOL design came from aircraft designer Kevin Altieri, a fixture at Douglas aircraft who had been “loaned” to Avro Canada in 1962 for assistance on the ground-attack variant of the CF-105 Arrow under maverick engineer T. S. McFarlane. In response to the open bid request from the DoD in 1969, Altieri’s team drafted a conversion plan for an A-4B airframe to a a “gyrodyne” (or “heliplane”) craft within 6 weeks; upon approval from McDonnell-Douglas brass, the first YAV-4F prototype was ready for flight testing in Santa Monica ten weeks later.
Although a seemingly radical (although not wholly unprecedented—combat autogyros had seen limited service with Germany and Japan in WWII), even outrageous departure from the current direction of aircraft evolution, the concept was solid. The A-4 Skyhawk had been designed from the outset for small size, weight, and a “future proof” expandability—as evidenced by the Skyhawk’s worldwide service well into the 21st century. And a hybrid gyrocopter design, with a rotor powered only by tip rockets during VTOL operations represented a relatively marginal weight cost compared to a dedicated second lift engine system, and contributed to overall low-speed performance, rather than simply adding dead weight during level flight.
93 of the AV-4Fs (which had garnered the nickname “Darwin’s Finch” from wags in the company press department) were deployed to Vietnam in the spring of 1971, operating in the roles later “jump jets” would be designed around. As a dedicated ground-support aircraft, the Finches flew not only from carriers and air bases, but also improvised landing strips and deep “in-country” fire support bases, usually a loadout of five 1000-lb Napalm canisters—or the experimental 300 gallon napalm pods hastily converted from Aero 1D drop tanks. (AV-4s operating out of Fire Base Crook gained no small share of infamy for this role when they participated in the famed napalm attack on Trang Brang in June, 1972.)
The “Finch” was much loved by it’s pilots and ground troops, but by very few others—thus, even though it was one of the last U.S. warplanes to leave Vietnam, the fairly conservative numbers built and deployed to action probably had little effect on the outcome of the war by the time fighting ultimately ended in 1976.
AV-4s briefly supplemented the Navy’s even shorter-lived FV-12 aboard it’s Toulgas-class Sea Control Ships in the 1970s, before the force was withdrawn from service after budget cuts and changing politico-military climate.
However, the “Finches” gained one more moment in the sun upon the coming of the Reagan administration, which saw the mothballed aircraft called back into service in the interim before the slated procurement of an AV-8B replacement force.
AV-4s flew out of the Beirut International Airport, and more notably off of the Interdiction Assault Ship USS Iowa (the hybrid “Battle Carrier” CVBB-61) during the multinational peacekeeping operation in Beirut in 1982. Their performance during the campaign was by all accounts superb, and might just have bought the Finches a new lease on life, but for one final adversary: time.
Routine maintenance evaluations in 1983-84 revealed metal fatigue and cracking in the wing boxes and rotor junctions of over 6/8ths of the AV-4 fleet—scars of overstress from pushing the nearly thirty year old airframes far beyond their design limits, often under combat conditions.
The final operational flight of the world’s only combat autogyro took place on February 3rd, 1985. Most of “Darwin’s Finches” were interred at Davis-Monthan AFB’s “boneyard,” or sold for scrap. A small number live on as museum exhibits, although few if any are kept airworthy.
), and I find I’m a little embarassed to bring them up, though most weren’t that bad. Maybe just a bit esoteric, or outright weird—I did do a couple of 