An F4U Corsair?

It's actually an AU-1, a close-air support variant of the F4U-5 developed specifically for the Marines Corps since AD Skyraiders were in short supply. It featured additional armor around the engine and accessories, a single-stage supercharger since only low altitude operation was required, and additional stores pylons. This is BuNo 129325 at Patuxent River in September 1952 making a field arrested landing. (AU-1s had been in combat in Korea since June.) However, the AU probably never flew operationally from an aircraft carrier, much less deployed.

 
In April 1954, 25 of the 111 built were transferred directly from a Marine Corps squadron to the French Aéronautique Navale to augment its fleet of F4U-7s in Indochina. After the fall of Dien Bien Phu and the withdrawal of French forces, the surviving Corsairs were ferried to NAS Sangley Point in the Philippine Islands and parked until a French carrier was available to transport them back to France. Another five were reportedly transferred to the French in the mid-1950s.
 The Marines swapped out AUs for ADs as soon as they could. However, at least a few survived as station hacks through the late 1950s as evidenced by a photo of a gray/white AU assigned to Quantico taxiing out past an early F8U-1, probably at NAS Los Alamitos, CA. (Note that the 'Navy" marking applied in overhaul has been painted over.) These were used to provide ground-based Marine Forward Air Controllers with airplanes to control for close air support training.

Strike From the Sea Update 3

My editor and I have completed the review of the layout proof: all 225+ pages, 300+ pictures/illustrations, and 80,000+ words. As with Naval Air Superiority, it will cover stillborn as well as successful programs, both aircraft and weaponry. The book is on schedule for release in July.

Over the next several weeks, I'll post pictures that didn't make the cut. For example, here is a VX-1 AD-4N loaded with a ring-tail Mk13 torpedo. (VX-1 is an anti-submarine warfare development squadron that can trace its history back to April 1943.)

It Seemed Like a Good Idea at the Time II

Turbofan engines, which add thrust by compressing more air than will go through the burners and turbine, provided more efficient thrust by increasing the mass flow for the same amount of fuel. The new Pratt & Whitney TF30 and the variable geometry wing were to be combined in the F-111 for far greater range than previously possible in a tactical fighter.

The turbofan had been introduced with commercial airliners so it was considered to be low risk. Unfortunately, in those pre-Concorde days, airliners did not need afterburner or fly at Mach 2. General Dynamics and its subcontractor, Grumman, quickly discovered how intolerant the turbofan was of flow conditions that the fully developed axial-flow jet engines took in stride.

There were three major inlet configurations on the seven F-111Bs that flew, two of which had two different inlets during the flight test program, and Grumman wasn't even the lead for inlet development. It just completed its F-111Bs with the most promising inlet that General Dynamics had defined at the time and retrofitted the carrier-trials prototype and the first pre-production aircraft with the subsequent one.

For a complete and more-balanced history on the F-111B, order my monograph on the F-111B here

F-111B Carrier Trials

One of the half-truths in the Navy's campaign to smear the F-111B was its poor performance in carrier trials accomplished aboard Coral Sea in July 1968. In fact, few new airplanes get much better than a barely passing grade from the NATC carrier suitability test pilots, with several deficiencies usually noted. In this case, the F-111B being evaluated was actually a prototype that did not have the carrier compatibility modifications like the raised cockpit and lowered forward windscreen interface with the nose shown here that were being incorporated- along with engine thrust, control system, and wing lift improvements- on the aircraft on the production line.

Although the F-111B would be 4,000 lbs heavier than the F-14 on landing (only 8%, far less than most people would guess based on the poor reputation of the "SeaPig"), it also approached 10 knots slower which meant it was actually easier on the arresting gear than the F-14 (ashore, landing ground roll was 21% less). It could come back aboard with all six big, expensive Phoenix missiles whereas the F-14 was limited to four. The F-111B also did not have as significant a directional control problem on a single-engine waveoff, since the engines were not as far from the centerline of the aircraft as they were on the F-14.

From the Coral Sea website: 

“Lt. Roy Buehler (from VF-33, we put six guys thru test pilot school in 2 ½ years) flew the carrier suitability trails. No one who flew the a/c was allowed to comment on the aircraft’s performance until the report was published. We almost got this one. Roy attempted a close-in wave-off. From the normal power setting for an approach (about 88% on each engine), the a/c landed, rolled out to the end of the wire, and the engines had not gotten to 100%. Not a real sharp performer. - Joel Jaudon”

“Here is a follow-up from someone who was there, Chuck Doughdrill:

Having served aboard the Coral Sea and witnessed the sea trials of the F-111, I can give you a bit more truthful evaluation of what occurred aboard Coral Sea. This trial was conducted as I understand it after the Navy had rejected the aircraft but because the money for the sea trial had nevertheless been appropriated. From a taxpayer's point of view, it was a waste of money. For us, it was a damned enjoyable afternoon. We were the open deck carrier available for that period off the California coast. The size of the aircraft was such that the JBD's could not be elevated but since we had no aircraft on board, save the COD, we just cleared the area aft for launch. We had the initial session of landings followed by a shutdown, while the pilots enjoyed a break, and then a start up and second session after which they left for home base. It was a welcome break from receiving cats and dogs from every persuasion who were trying to get in carquals on the open deck.

I had two Air Force officers from an inspection team visiting me onboard at the time and they probably are the only Air Force officers to witness the carrier trials by the F-111. As a naval aviator, not involved in the trial but only an observer, the aircraft operated magnificently and was a beauty to behold. I did not meet the pilots but understood they were former naval aviator test pilots for General Dynamics, not active naval aviators.* Whoever they were, their airwork was impressive. The airplane fairly leaped off the cats and came aboard gracefully, much like the A-6. It came aboard so slowly that it looked as if the pilot could have chosen which wire to engage. The general feeling among the flight deck handlers and officers was amazement although the aircraft was too large to ever have been used aboard Coral Sea.

As for the comments that the F-111 could not spool up sufficiently on wave off, etc., I never heard any of this at the time nor heard of anything but amazement by all the pilot types that were involved with direct support and who talked at length with the test pilots. The navy had already made up their minds and those comments may have been laundered to justify the decision. It's been done before but I really don't know.”

*Not correct; with rare exceptions, only active-duty Naval aviators accomplished carrier trials.


For a complete and more-balanced history on the F-111B, order my monograph on the F-111B from Ginter Books: Here

Also see http://thanlont.blogspot.com/2011/01/f-111b-versus-f-14a-one-more-time.html

Area Rule

The area rule for transonic drag minimization was postulated and demonstrated by NACA engineer Richard Whitcomb. The rule was that the total cross-sectional area of an airplane should smoothly increase and then decrease. The result was that the fuselage cross section needed to be reduced beginning at the point of attachment of the leading edge of the wing and indented as necessary to compensate for the cross sectional area of the wing at each successive fuselage station going aft. The theory was provided to U.S. aerospace contractors in a confidential Research Memorandum in September 1952.

As it happened, Grumman had already defined and proposed an area-ruled fighter design to the Navy in December 1951. The result was the sleek F11F Tiger. Grumman went so far as to design special area-ruled external wing tanks for the Tiger.

Unfortunately, the engine chosen, the license-built Armstrong-Siddeley Sapphire, did not meet specified thrust. Although supersonic, the airplane fell well short of the guaranteed top speed. Performance with the substituted engine, the General Electric J79, was excellent but the Navy chose to standardize on the 1,000 mph F8U Crusader. Tiger production ended with only 201 built. After a very brief operational career with a handful of carrier-based squadrons, most of these were relegated to a training role. It also served for several years as the mount for the Blue Angels flight-demonstration team.

Carrier-Based Jet Fighters: Plan B

After World War II, it was by no means clear to all Naval Aviators responsible for the development of future carrier-based aircraft that jets could be safely operated from aircraft carriers. The powerplant division and the attack class desk at the Bureau of Aeronautics teamed up with Douglas to promote a turboprop variant of the new Wright R-3350-powered AD Skyraider. It was "designed as a general purpose carrier attack airplane and as a fighter of conventional arrangement and construction." The Aircraft Characteristics & Performance (ACP) chart went on to state that it could "function as a fighter with better climb performance and maneuverability at high altitudes than most turbo jet fighters." (The very unusual insertion of an advocacy statement in an ACP was indicative of the infighting involved.) Fortunately, the earliest jets showed enough promise that the dead-end development of turboprop and mixed powerplant fighters was ended. The XAD-3 proposal was carried forward as the A2D, which was eventually terminated after its flight test was plagued by problems with its Allison T40 turboprop engine, including one fatality.

Thanks to Ryan Crierie for a copy of the April 1947 XAD-3 ACP chart, the forerunner of today's Standard Aircraft Characteristics chart.

RATs Too

All the prior stuff about RATs was foreshadowing and vamping while I tried (and failed) to find a better copy of this McDonnell XF4H picture, which is a scan from a tattered Aviation Week cover. Although the long-lost cover caption may have identified what those open doors were for on the leading edge of the wing, it was a mystery to me until I recently read a Vought competitive systems analysis of the F8U-3 and the F4H and discovered that the latter originally had two RATs, one in each wing as shown. When the leading edge slats had to be extended inboard for slower landing speeds, this arrangement was no longer viable. The F4H RAT that I was familiar with as a McDonnell flight test engineer extended from the left side of the upper mid fuselage.