By Tommy H. Thomason

Monday, December 29, 2008

Correcting Common Banshee Misstatements

The F2H-1 Banshee fuselage was not shorter than the -2. Only the three XF2H prototypes had the shorter fuselage. The stretch was made in belated recognition of the need for more fuel. The main difference between the -1 and the -2 is that the former did not have provisions for tip tanks. (Still not enough fuel.) As a result, the -2 wings could not be unfolded (or folded) with fuel in the tip tanks. Full tip tanks were also an overload condition with a lower g limit imposed.

Which leads me to the second and more serious canard. The F2H did not have "weak" wings. A Navy pilot pulled the wings off one at Patuxent River in May 1949 but that's because he exceeded the 6-g limit, which was the fighter standard for the time. The problem was that F2H was initially a bit light on the controls so overstressing it was too easy. That was fixed with a control system modification to add a bob-weight that increased stick force with increasing g.

The F9F Panther may have been stronger than specification-the incident at Pax when the rear fuselage came off on an arrested landing not withstanding-but the F2H was strong enough. It could also fly higher and longer than the F9F Panther, carry more ordnance, and may have been a bit easier to bring aboard on a dark and stormy night. The need to spread its wings to fill the tip tanks was an operational deficiency, however: too much space required in the spot for launch. (It may have also reinforced the reputation for "weak" wings.)

The top photo is from the National Archives, 80-G-406268, and is of a VF-171 F2H-1 aboard FDR on 8 August 1949, only a year after the first production F2H-1 flew. If I remember correctly, the bottom photo is from Bob Lawson's collection and is of VF-172 aircraft aboard Essex during the Korean War.

Wednesday, December 24, 2008

Just When I Thought I'd Seen Everything II

This is an amazing collection of the proposals for the competition won by Douglas with what became the A3D Skywarrior. As far as I know, at least 95% of the contents have never been published. Jared Zichek did a thorough job of documenting the Boeing F8B, and this is even more exceptional, not to mention welcome.

If you're interested in Naval aviation history, you won't need any more convincing. If you aren't sure, go here for a page-by-page thumbnail review.

Order here

Saturday, December 20, 2008

Missed It by That Much II

In the late 1940s and early 1950s, the Navy and the Air Force were looking for an air-to-air weapon more effective than guns in bringing down a big jet bomber. Guided missiles were in development but weren't ready for prime time and were going to be expensive in any event. The solution appeared to be unguided missiles, fired as a salvo. Since speed was critical to an intercept, they were housed internally or in pods, with the fins unfolding as they left the tubes. It was demonstrated at NOTS China Lake that a 2.75-inch rocket hit was devastating by firing them, one at a time, at a tied-down B-26. They planned 12 shots and even though four of the first nine missed, they had pretty much run out of B-26 at that point with three rockets left over.

The all-weather guys were to make an intercept on radar, flying a collision course and unleashing the rockets when in range. The F8U-1 Crusader, a day fighter, was also provided with an integral rocket pack with 16 tubes, two rockets to a tube. Unfortunately, the rockets proved to be even more inaccurate when aimed and launched in flight. One study indicated that 128 rockets, four Crusaders' worth, would have to be expended on one bomber for a 97% probability that it would be hit at least once. Given the accident rate of the F8U at the time, ramming would have been almost as effective a tactic. Moreover the rocket pack was somewhat unreliable in operation, with the pilots' enthusiasm for the weapon further diminished when a red light was added to the cockpit to inform them that there was a fire in the pack. As a result, the packs were locked up early on and deleted after F8U-2 production.

The photo of a VFAW-3 F8U-1 is from the files of the Vought Aircraft Heritage Foundation. The rocket pack, which is located just behind the nose wheel well, is extended (as is the emergency Ram Air Turbine on the side of the fuselage). Click on the photo for a bigger image.

For more on Crusader armament changes, see

Tuesday, December 16, 2008

Missed It By That Much

If Vought hadn't made the F7U-1 control system so complicated, underestimated the empty weight by so much, or realized that the visibility over the nose had to be a lot better than the existing specification on an airplane approaching at such a high angle of attack; Westinghouse had done as good a job initially on the J34 with afterburner as they did on the J30; and the Navy had figured out sooner that landing on an angled deck was a lot easier than an axial deck, then the F7U-1 would have been trolling for MiGs over Korea: It was faster than an F-86 with twice the rate of climb and a terrific rate of roll...

Two served briefly with the Blue Angels. The show was spectacular but the stars were failure prone so it was a short run. 

Monday, December 15, 2008

The F8U-3: The Best Airplane the Navy Didn't Buy

According to George Spangenberg, which is very meaningful coming from him since he was 1) the long-time director of BuAer's proposal evaluation division and 2) rarely (never?) that effusive about an aircraft. Later he wrote in Wings of Gold, comparing the F8U-3 which lost a fly-off to the F4H (Congess had decreed that there would be only one new Navy fighter): "The F8U-3 was faster, more maneuverable, had better flying qualities, cost 20% less, and had more range on internal fuel that the (F4H) did with a 600-gallon (external) tank."

Unfortunately, the F8U-3 was a single-seat fighter and the Navy had become convinced that a two-man crew would be at least slightly more likely to shoot down a Soviet bomber whose crew was intent on sinking an aircraft carrier. Given the unacceptability of even damage to a carrier, that advantage trumped faster, more maneuverable, etc. Following the cancellation of the program in December 1958 (and Merry Christmas!), Vought unsuccessfully proposed the Crusader III to the Air Force and the Canadians. NASA flew the prototypes for a year or two in a supersonic transport research program and then they were scrapped.

Pictured is the first production airplane and the last of three -3s to fly. A monograph on the F8U-3 is my winter project. I'd appreciate the loan of any unpublished pictures or documentation so it will be as complete and thorough as possible.

Saturday, December 6, 2008

Just When I Thought I'd Seen Everything

In 1955, Grumman and North American were at a disadvantage relative to Vought in the competition to furnish the Navy's next day fighter. The F8U Crusader was powered by the new P&W J57. Their candidates, the F11F and the FJ-4, had the less powerful Wright J65. The FJ-4 didn't even have an afterburner. Both proposed a J79 alternative, Grumman the Super Tiger and North American, the "FJ-5" which was similar to its F-107A but smaller. The Navy was interested enough in the Super Tiger to give it a new designation, F12F, and at least begin the production contract process but ultimately only bought two conversions of production Tigers as F11F-1Fs to provide early J79 in-flight experience before the XF4H first flight. North American's consolation prize was development and production of the FJ-4B.

For more information on Jared Zichek's excellent FJ-5 monograph and to order it, go here.

Thursday, December 4, 2008

Halcyon Days -1958

Once upon a time, specifically January 1958 aboard Saratoga. The picture was taken by Aviation Week's Pete Bulban. Two F8U-1 Crusaders are on the angled deck catapults, one with the wing up and the other with the wing down and folded. ADs are taxiing either to the bow catapults or for a deck run, with a widebody AD-5W at the far left. The airplane and tail in the foreground are F3H-2 Demons, a much maligned airplane but actually a relatively long-serving workhorse. The Crusader may have been capable of 1,000 mph, but on a dark and stormy night it was the Demon that would be aloft protecting the carrier from a bomber threat.

Thursday, November 20, 2008

It takes all the running you can do to stay in place...

Early in the F4H Phantom design, it was determined that more lift was needed to achieve the approach air speed required. The solution was the addition of an inboard leading edge flap and boundary layer control over the other leading edge flaps and the trailing edge flaps. This required postponing carrier trials from the 4th airplane to the 6th, since low rate production was already under way by the time the redesign was released.

Even more lift was required by the time the F-4J was ordered, which was accomplished by drooping the ailerons along with the flaps. The resulting increase in nose-down pitching moment proved too great for the existing stabilator. Locking up the inboard leading edge flap to increase stabilator effectiveness might have been enough but it was decided to also add a fixed slat to the leading edge of the elevator. The package of changes was made to F-4Bs then in production and retrofitted to surviving Bs.

Monday, November 17, 2008

Launching Athwartships

In 1928, catapults on the flight deck were considered obstructions by some but hangar deck catapults were of interest. Aircraft could be launched during recoveries and more aircraft could be launched during a shorter period of time. In order to maintain maximum freeboard at the bow and keep water out of the hangar deck, the launch had to be made sideways. or athwartships. One such catapult was installed on Yorktown. To provide enough length for the launch, the airplane was positioned on a outrigger on one side of the ship. like the early production Hellcat shown above, and then catapulted through the hangar deck and out the other side of the ship as shown here.

This concept and the installation of arresting gear forward for landings from the bow aft as well as from the stern forward were operationally evaluated and then removed as not being as worthwhile in practice as they had seemed in theory...

Monday, November 10, 2008

Most Accurate Aviation Movie Ever?

Faint praise perhaps, but The Bridges at Toko-Ri has to be in the top three. It was based on a slim novel by James Michener, who was embedded on aircraft carriers in action early in the Korean War.

The only major license taken in the book and repeated in the movie was the use of glamorous jets (Banshees in the book and Panthers in the movie) to drop the bridges. They and their puny bomb/rocket loads would have been used for anti-aircraft defense suppression instead, with Skyraiders doing the heavy lifting. Oh, and the F9F-5P shown here is an F9F-5 with a camera window painted on it - the real F9F-5P nose was 12 inches longer and didn't have four 20mm cannon sticking out the front of it.

Another is a very minor marking error on the actual F9F Panther used in the final scenes. The aircraft number is 209 but the number on the vertical fin is 4. It should be 9. (I checked the airborne footage before the crash landing; it doesn't appear that any number is on the fin of the aircraft being filmed.)

However, in this scene of CAG's crash in 21PP, they've taken the trouble to include Davis barrier straps being dragged as shown in the real barrier engagement of 109D shown above in black and white. In exterior closeups of the cockpits during the landing approach, the barrier engagement post in front of the canopy is extended. Compare it to the following picture, which is of an actual incident (the pilot caught one of the last wires and the barrier operator chose not to lower it).

It would appear that all of the scenes with airplanes were shot specifically for the movie, with no stock footage of the GB crash or other foolishness. It isn't immediately obvious that the scenes done with models weren't the real thing and they were good enough to win the 1955 Academy Award for Best Special Effects - no CGI back then. And I'm sure that most fighter pilots' wives look like Grace Kelly.

If you haven't seen it or seen it in a while and have any interest in carrier-based Naval aviation history, I suggest that you go buy the DVD from Amazon. Only $10. For men of a certain age, like me, it's also a great movie.

Monday, November 3, 2008

Real Men Don't Need Catapults

That is, if they are flying a fighter with a low wing-loading and a high thrust to weight like the F4D Skyray and they want to go back to home plate...

From the January 1958 issue of Naval Aviation News. The incident occurred in October 1957 during Operation Strikeback in the North Atlantic, with the takeoff on 13 October.

Friday, October 31, 2008

General Purpose F8U

Most of the Navy's jet fighters through the 1950s to a greater or lesser degree were general purpose, in that they could also drop bombs and fire rockets. The F8U was an exception for a few years. It was originally equipped with an integral rocket pack, but this may have been primarily intended as an air-to-air weapon. In any event, it was deleted after the F8U-2 (F-8C).

The F8U-2NE (F-8E) was to have a full air-to-ground mission capability including the ability to fire Bullpup A and B, as shown in this iconic display, as well as Shrike and Walleye. These and conventional bombs up to 2,000 lbs were to be carried on a stores pylon added on each wing. A hump was added over the wing to house the Bullpup avionics.

In September 1963, OpNav deleted the requirement for Bullpup, Shrike, and Walleye qualification from the F-8E "because of cost and mission reassignment," but retained the Zuni and 2,000-lb bomb delivery capability. It does not appear that the Bullpup qualification was ever reinstated. The hump was eventually used for defensive ECM avionics.

For more on F8U Crusader armament changes, see

Monday, October 20, 2008

1950s Navy Day Fighter Specification

In the early 1950s, BuAer was not of one mind with respect to the specification for a carrier-based day fighter. The class desk officer (equivalent to a program manager), an experienced fighter pilot, thought the best airplane for the mission was simple, light, and maneuverable. Supersonic speed, and therefore an afterburner, was not only unnecessary, but undesirable. He placed a contract with North American for the FJ-4, a substantial modification of the FJ-3 Fury, which was in turn a variation of the Air Force's F-86 Sabre Jet. This would provide the earliest availability of his vision of the optimum day fighter. At roughly the same time, a competition was initiated for a new day fighter, with supersonic speed explicitly not required, among other stipulations to reduce unit cost and complexity. As luck would have it, his tour of duty at BuAer ended shortly after the request for proposal was issued and he left for his next assignment. The RFP was immediately amended in accordance with different views on what was needed in the new fighter. The result was the 1,000 mph F8U Crusader. Both are shown here on Forrestal in 1956 during carrier qualifications. All the FJ-4s produced were assigned to the Marine Corps. A subsequent derivative, the FJ-4B, was procured as an attack airplane to provide a backup to the A4D Skyhawk.

Friday, October 10, 2008

400 MPH! (?)

"On 1 October 1940, the XF4U-1 made a flight from Stratford to Hartford with an average ground speed of 405 mph, the first U.S. fighter to fly faster than 400 mph."

If that was the actual wording of the Vought press release, that's not too misleading. It doesn't claim a world record (it wasn't). It implies that the course was not flown in both directions, a record requirement that would eliminate a beneficial tail wind component*. Moreover, it specifically states that it was a ground speed, not an air speed, which is what really counts in an apples-to-apples comparison of airplane performance. It doesn't describe how, much less how accurately, the beginning and end points of the speed run were determined from an altitude of over 20,000 feet. (At the time, speed records had to be set at a very low altitude. However, top speed for propeller-driven airplanes was attained at altitude. Click Here for examples.) It also doesn't state the engine rating or horsepower used. The distance, about 50 miles, does limit the amount of altitude that could be exchanged for speed and reduces the impact of an error in determining the beginning and end points.

The Navy's Service Acceptance Trials report provides a more accurate measurement of the XF4U's performance: 371 mph at rated power with the specified useful load. (Click the picture for a readable version.) The Navy did wind it up to 402 mph, but with the "radio mast and antenna not installed, the gun holes and handholds faired." There's no mention of what rpm and manifold pressure were used to attain that speed.

To be fair, the XF4U was powered by the X model of the Pratt & Whitney R-2800 engine. Later production models of the Corsair with more developed and powerful R-2800 engines were capable of exceeding 400 mph in level flight at altitudes above 20,000 feet.

Ron Lewis also notes that the Lockheed P-38 Lightning was the first fighter to exceed 400 mph in level flight, making the XF4U the first single-engine fighter to do so. In a quick interweb search, I didn't find a Lockheed or Army Air Forces claim that the sole XP-38—which first flew on 27 January 1939 and crashed about two weeks later at the end of an attempt to set a transcontinental speed record—reached 400 mph in its brief flight test career. It was reportedly capable of that (click HERE). The first YP-38 flew on 17 September 1940, about two weeks before the XF4U's "400 mph" flight, a second chance for the Lightning to have beaten the XF4U to that milestone. Again, I didn't find a report of a claim to that effect. Therefore, although the P-38 was appears to be the first U.S. fighter capable of 400 mph in level flight, Vought might have been correct with respect to the XF4U being the first to actually do it.

* At the same altitude both ways. There was a helicopter speed record set by taking advantage of a tail wind in both directions, but that's a story for another time...

Wednesday, October 1, 2008

Davis Barrier Redux

Blogdog asked about the difference between the Davis barrier and the barricade because he was aware that both involved straps. A detailed explanation is provided in my book, U.S.Naval Air Superiority, but the brief answer is that the Davis barrier was a modification of the existing barrier specifically to stop jet and twin-engine airplanes; the barricade was a subsequent addition to handle situations where the Davis barriers weren't effective. The upper photo is a fit check of an AJ-2 Savage and the barricade. The lower photo is of a fit check of an early version of the Davis barrier. The top strap is the "actuator" and is located where the steel cable was for stopping single-engine propeller-driven airplanes that didn't hook a wire. The steel cable is now lying on the deck. If the jet or twin-engine airplane arrived at the Davis barrier untrapped, the nose gear would snag the top strap. The vertical straps would then pull the cable up as the airplane continued forward, hopefully in time to engage the main landing gear struts and drag the airplane to a stop. A barrier actuator (a simple post, often extended by a spring when the tailhook was lowered) was provided in front of the windscreen to activate the barrier if the nose gear had collapsed.

There was a shortcoming. If the airplane was going too slowly when it hit the Davis barrier, the cable would fall back down before it caught the main landing gear. If the airplane was going too fast, the cable would not get up high enough, fast enough, and the airplane would roll right over it, unstopped. As it turned out, the combination of the Davis barrier and the barricade also proved to be what was needed to safely operate jet airplanes on axial decks, in terms of almost always keeping a crash from involving the people and planes forward of the barricade.

For other posts I've made on the Davis barrier and the barricade, see:

Monday, September 22, 2008

Development of the Davis Barrier

The Davis barrier was created by the Naval Aircraft Factory to replace the conventional barrier that was satisfactory for stopping single-engine propeller-driven airplanes that didn't pick up an arresting cable with the tail hook but not for twin-engine ones like the F7F Tigercat. The problem was that unlike the single-engine situation, where the propeller hit the barrier cable at a very shallow angle and wouldn't cut it, the nose gear of a twin-engine airplane would pull the cable out and forward, so when the propellers got to it, the cable might be at enough of an angle for it to be cut.

This wasn't exactly the situation here, but demonstrated the problem. In this test, the Davis barrier used a one-inch steel cable to actuate the retarding cable that was to snag the main landing gear. Fortunately the PBJ (U.S. Army Air Forces B-25) was unoccupied for the test, because a prop cut the actuating cable and flailed the cockpit with it. This resulted in the actuating cable becoming a canvas strap.

Friday, September 19, 2008

What's That?

It turns out to be an extendable radome housing an H2X radar. The TBM was a control plane for a TDN/TDR drone equipped with a transponder and a TV camera. In 1943. The controller in the TBM could guide the drone to the target using the radar and then dive it into the target using the TV image. Neither the drone nor the target needed to be within eyesight of the control plane.

Although it worked, the Navy fighting the war in the Pacific would have nothing to do with it. At the insistence of the Navy in Washington, the Special Unit involved was finally allowed a 30-day trial in late 1944 against Japanese targets on and near Bougainville and Rabaul that arguably demonstrated the effectiveness of the concept. It was then summarily withdrawn and disbanded. (It's not clear whether the beyond-visual range capability was utilized.)

For a good summary of the TDR (the very similar TDN wasn't used in combat), see

The photo is National Archives 80-G-387191.

Tuesday, September 16, 2008

Is This The Grumman F12F?

In a word, No. The F12F designation was assigned to a derivative of the F11F Tiger that was to be powered by the new General Electric J79 engine. It's not clear if a contract was ever issued but two Bureau Numbers were assigned. The program was canceled in January 1956.  The effort to evaluate the F11F with the J79 continued, however. The first of two F11F-1Fs flew in May 1956.

Pictured is the Grumman Design 118 proposed to the Navy in late 1955. It and a single J75-powered alternative were rejected in mid-1956 in favor of the Vought XF8U-3. It is unlikely that the Navy ever considered it seriously enough to assign it a designation since the McDonnell F4H was already on contract. Somebody subsequently and erroneously concluded, because of the concurrency of the projects, that it was the D 118 that received the F12F designation. Someone else has speculated that it would have received the popular name "Lion". Officially it never did and I've seen no evidence that Grumman referred to it internally as that.

Note that since enthusiasts continue to insist that it was the F12F,  I've updated this post with more information on the actual F12F program here:

Saturday, September 6, 2008

Bell XFL-1

I have this weakness for unappreciated "failures" (see Bell HSL and Grumman/GD F-111B below). My latest attempt to provide a nuanced and balanced account of a little known or notorious aircraft program is the one-off Bell XFL-1, a navalized version of the much more successful but frequently maligned P-39 Airacobra.

Order here: Ginter Books

Next, I plan to write a monograph on the XF8U-3, which actually enjoys a great reputation, possibly because it was canceled after initial envelope expansion and before its development was complete and operational evaluation had been accomplished.

Saturday, August 23, 2008

Single-Seat A-6

The Navy's VA(L) was to be a single-seat, single-engine attack airplane with an overload mission of 12 Mk 82 (500-lb) Snakeye bombs delivered at a radius of 600 nautical miles. Another key requirement was that it be "a modification of an airplane currently in the Navy inventory." The payload/range favored the use of the Navy's new TF30 engine.

Grumman considered proposing either a TF30-powered F11F or a single-seat modification of its A-6 Intruder with a single seat but the existing engines. The latter's size enabled it to easily exceed the payload/range requirement even though it did not have the fuel-efficient turbofan engine. (Although the A-6's size was a drawback from the spot factor standpoint, it could be mitigated by folding the horizontal tail; see Grumman decided to offer the A-6 derivative believing that the low development cost and commonality with an existing airplane in the air group would trump the somewhat higher unit cost.

It didn't.

Douglas proposed a supersized version of its A4D.

North American did the same with its FJ-4.

Vought won the VA(L) competition with an F8U Crusader derivative with an even more creative interpretation of the "modification" requirement than Douglas or North American proposed.

For a last minute change in the Vought proposal, see

Sunday, August 17, 2008

Attack Crusader

Vought went all out for the 1963 VA(L) competition. The Navy wanted six main stores stations. Vought decided to propose eight, plus the pylon on each side of the fuselage for Sidewinders. The Navy thought that eight was more than enough, too many in fact. Otherwise, Vought's proposal was exactly what the Navy wanted and superior overall to the ones from Douglas, Grumman, and North America.

Thanks to the Vought Aircraft Heritage Foundation for the photo.

Saturday, August 2, 2008

Little known (and unsuccessful) Proposals

In May 1949, Martin submitted a proposal to BuAer for a two-seat, twin-engine, carrier-based jet attack airplane with the Martin rotary bomb bay.

My guess is that it was an attempt to take advantage of the A2D troubles at the time. Douglas got a letter of intent for the T40 turboprop-engine-powered A2D in June 1947. It was supposed to fly in March 1949. Because of T40 engine problems, it didn't fly until May 1950.

Thanks to the Glenn L. Martin Maryland Aviation Museum for the illustration.

Thursday, July 24, 2008

Still not easy

The WWII problem - hit an aircraft carrier steaming at 33 knots with a torpedo that runs at 33 knots. This example is a drop roughly abeam the 800-ft long carrier at 2,000 feet, well inside the 1,000 yards usually cited as the maximum drop distance for accuracy. I've revised the calculation to roughly account for a drop from 200 feet (3.5 seconds of air time) and 200 knots, which increases the average speed of the torpedo significantly and therefore reduces the lead required. It's now obvious that the lead is sensitive to the drop speed and altitude, the ballistics (lift/drag) of the torpedo in the air, and the deceleration of the torpedo in the water until it is at its run speed of 33 knots. The good news is that the lead determination is less sensitive to the target speed, although it's still important, and the ship has less time to turn into or away from the torpedo track.

Thursday, July 17, 2008

Sticking With What You Know

In response to the U.S. Navy's need in the late 1940s for a carrier-based, long-range jet bomber, the Glenn L. Martin Company, the successful purveyor of large sea planes, proposed its Model 245, a hybrid that could fly to the carrier's operating area, refueling from submarines along the way, and then jettison the boat hull for operation from a carrier. It was apparently to be used only from staging from a carrier, because it did not have folding wings. The Navy went with the more conventional Douglas A3D Skywarrior instead.

Pictures and information courtesy of the Glenn L. Martin Maryland Aviation Museum.

Thursday, July 10, 2008

This Just Isn't Right

In looking up information to respond to a request, I was reminded of this unique Grumman. It was the cargo version of the venerable S2F ASW airplane, modified to be the aerodynamic prototype for the AEW version of the airplane. The addition of the big radome over the fuselage required the change shown here to the empennage and also a change to the wing fold arrangement. It did not have the stretched fuselage of the production airplane, however, as evidenced by the red propeller warning stripe being so close to the aft edge of the pilot's side window. After flight test, the dummy radome was removed and the airplane resumed its role as a transport.

The production airplane was originally the WF-2, redesignated in 1962 as the E-1B. Strictly speaking, there was a WF-1 but not an E-1A, since the WF-1 was cancelled at the mockup stage. It was to be an S2F airframe simply modified with an APS-20A mounted above the cockpit. This would have preserved the original empennage and wing fold arrangement, albeit with the addition of small fins on the horizontal stabilizer to maintain directional stability.

Friday, July 4, 2008

XFL-1 Carrier Suitability Evaluation

The Bell XFL-1 flunked its shore-based carrier suitability evaluation due to excessive tail rise on arrestment, not that it was being seriously considered for production after the XF4U reportedly exceeded 400 mph in level flight. Note that the pilot is not wearing a shoulder harness, which was surprisingly absent in all Navy carrier aircraft at the time given the abrupt stop involved in an arrested landing.

Friday, June 20, 2008

Antiaircraft Bombs

In the late 1930s, the Navy's Bureau of Ordnance developed a tactic to deal with large, heavily defended bomber formations. The fighters would fly above them and drop anti-aircraft bombs. These were small, with a light case containing two pounds of TNT, but would cause considerably more damage than a bullet. BuOrd designed small containers housing two bombs each for installation within the wings, five containers to a side. Twenty bombs were to be dropped at one time, covering an area 150 yards long and 50 yards wide. The pilot was to be provided with a downward vision window for aiming.

This was a requirement in the Navy's 1938 fighter procurement, so the Bell XFL-1 (shown here), Grumman XF5F, and Chance Vought XF4U were all built with the small bomb bays to house the BuOrd containers and a downward vision window. According to a BuOrd history published in 1953: "Although antiaircraft bombs gained a group of staunch advocates, their admirers were more numerous on the higher level of planning than on the lower one of actual combat." The bomb bays were deleted from the production F4U by BuAer although the window remained through at least some (most?) of the F4U-1As. Although BuOrd bought 200,000 anti-aircraft bombs, they were apparently only used as antipersonnel weapons.

Tuesday, June 10, 2008

The Navy and Liquid-Cooled Engines

Based on reading most accounts of the Naval aviation history, one would think that the U.S. Navy had no interest in liquid-cooled reciprocating engines for carrier-based airplanes after 1929. Certainly it only deployed ones powered by air-cooled engines thereafter. In fact, the Navy maintained an active role in liquid-cooled engine development into the early 1940s. One example was their selection for evaluation of a derivative of the Bell P-39 Airacobra, the XFL-1, in 1938. The Wright H-2120 was another such effort. It was a very unusual configuration - a twin-row radial engine, but with the six cylinders in the aft row lined up with those in the front row and each such pairing liquid-cooled. The objective was to minimize the frontal area of a radial engine and avoid potential problems with air cooling the aft row of cylinders. The Navy funded development of the H-2120 from about 1933 to 1936, when a 100-hour development test was run at 1,000 shp. At that point, both Wright and the Navy lost interest in pursuing this particular configuration, with the feasibility of air-cooling the second row of cylinders having been demonstrated.

Thursday, June 5, 2008

Not Doing It Right

This illustration is what the Air Force Museum is using to depict the "idiot loop" that the Air Force developed in 1952 to more or less safely deliver a nuclear weapon from a tactical aircraft. Safe in terms of both ingress and egress. The problem is, it's depicted as a loop and the actual maneuver is a half-Cuban eight. It starts as a loop (a loop is what you'd be doing on a Ferris wheel if the car you were riding in wasn't free to dangle) but after you go over the top, inverted, you do a half roll back to upright flight while diving back to treetop altitude to depart the premises as fast as possible back along the route you took to get to the target. A loop, as depicted, would keep you in the vicinity of the upcoming blast for too long...

After I wrote this, I discovered that there were proponents (at least one in the Navy, anyway) for the loop recovery from the over-the-shoulder mode and it was evaluated by him at China Lake in an F7U-3. There is a video of it somewhere on the interweb which I can't now find.

It was compatible with LABS since the pilot was free to recover from the inverted climb that he was in by any maneuver he wanted to use. However, in addition to probably not providing as much separation as the half-Cuban eight (I don't have any numbers to compare the two), completing the loop before encountering the ground was not entirely risk free, whereas the half-roll in a dive was. Remember that having enough altitude coming over the top to complete the loop was compromised by having to lug a heavy, draggy bomb a good part of the way up and a dive to build up loop entry airspeed was precluded by both the LABS computation and the need to make ingress at treetop level. The F7U-3 was probably better off from this standpoint because its engines were equipped with afterburners.

In any event, I haven't found any operational descriptions of the use of a loop on the interweb or in the literature other than this report.

This is an illustration of the three LABS alternatives from my book, Strike From the Sea.

Sunday, May 25, 2008

Supercharging Makes the Difference

Coming later this year from the Steve Ginter Naval Fighter series - my monograph on the Bell XFL-1 Airabonita. This little known pre-WWII Navy fighter prototype was based on the more successful Allison V-1710 powered P-39. Contemporaries were the XF5F and XF4U. It was one of several examples of U.S. Navy involvement in liquid-cooled engine projects after 1929. The chart shows the difference in airspeed at altitude due to supercharging. The XFL-1 was handicapped by not only by having less installed horsepower than its competitors, but also only having a single-stage supercharger. At altitudes below18,000 feet, it was significantly faster than the F4F-3, which had an engine of about the same horsepower, but then lost the advantage because the Wildcat's engine had a two-stage supercharger.

Wednesday, May 21, 2008

In contrast to the rapid development and replacement of carrier-based jet fighter types prior to the 1960s as described in my book, U.S. Naval Air Superiority, attack airplane types tended to stay on the front line for many more years. An example is the Douglas AD Skyraider, seen here in the late 1940s with the Grumman F8F Bearcat and the early 1960s as the A-1 with the McDonnell F-4 Phantom. Development of carrier-based Navy attack aircraft is the subject of my next book, Strike From the Sea, to be released in early 2009 by Specialty Press.

My thanks to Bob Lawson and Ed Barthelmes for the AD and A-1 photos respectively.

Tuesday, May 20, 2008

Self Boarding

I had hoped to find a picture like this for the fighter book - showing the lengths that the contractors went to to fulfill the "self-boarding" requirement for carrier-based aircraft. Ladders were anathema on a windy confines of a carrier flight deck. After a few aviators fell off airplanes with boarding provisions like this, accommodating ladders became less onerous...

Douglas D-558-3

For a short article on the D-558-3, click here

Monday, May 19, 2008

Bell HSL ASW Helicopter

The Bell HSL was to be the answer in 1950 to a major Navy requirement - find and kill Russian submarines. It was a major step forward in size and lift for a helicopter. Its development problems behind it and on the eve of a critical milestone, delivery for the fleet introduction program, one crashed, killing the Navy's program manager and subsequently the program itself. Its legacy is the Bell Helicopter plant in Fort Worth, built specifically to produce the HSL.

Now out of stock at Ginter Books; I still have some for sale.

Grumman F-111B

Little complimentary or even kind has been written about the F-111B. It deserved a more balanced assessment, because much of what was said about it before its cancellation was derogatory and bordering on misrepresentation, intended to both reflect badly on Robert McNamara's leadership of the Department of Defense and justify a very different type of fighter that the Navy had come to need. This is my attempt to provide a more nuanced analysis of the F-111B program.

Unfortunately, Steve Ginter has sold out his stock and doesn't plan to reprint it. However, there are several available from Amazon books.