U.S. Navy Aircraft History

By Tommy H. Thomason

Monday, November 3, 2014

F-35C Finally Comes Aboard

At last, the end of the beginning...

3 November 2014, Nimitz, off San Diego (U.S. Navy photo by Mass Communications Specialist 3rd Class Kelly M. Agee)

Congratulations to all who persevered and made it happen.

For some previous posts on the workup to this milestone, see:

http://thanlont.blogspot.com/2013/12/f-35c-so-far-so-good.html

http://thanlont.blogspot.com/2011/12/brief-history-of-tailhook-design.html

Saturday, November 1, 2014

F-35C Unique Features

Lockheed Martin, which does great PR stuff like its Code One Magazine and makes excellent photos readily available, unlike some other aircraft companies, just released this:
http://lockheedmartin.com/us/news/features/2014/5-unique-f35c-carrier-variant-features.html

This release is almost certainly timed to build interest in and provide information about the carrier-based F-35 in advance of its at-sea trials this coming week.

However, it does appear to have been written (or edited) for the general public and some oversimplifications or downright errors have resulted. For one thing, the lead states that "For the first time in U.S. naval aviation history, radar-evading stealth capability will come to the carrier deck". I may be mistaken, but I thought the Boeing F-18E/F had some "radar-evading stealth" features, although certainly not to the same extent as the F-35. But in any event, there's more:

1 Larger wings: The lead picture in the release does some justice to the difference in planform with the F-35A and B but not the one used to illustrate this first feature. This crop of a photo on the Lockheed website is even better for that purpose.

"The aircraft lands at a high speed so that if they miss the hook when attempting to land they are still able to take off and try again."

The pilot actually approaches at a low speed consistent with stall margin, control power, thrust response, etc. What might be missed is one of the arresting cables, not the hook. Perhaps what the writer meant to convey was "miss the hook-on".

2 Wingtips that fold: "While a wide wingspan is essential on a carrier ship, it also takes up precious cargo space on the deck. To combat this, the F-35C's wingtips fold to allow for easy storage in tight quarters to create more room on the carrier's deck while deployed."

I understand what was meant, but "cargo space" isn't the usual term of art and "deployed" might not be good grammar or unambiguous in that it appears to refer to the wingtips, not the aircraft, and deployed could be taken to mean extended...

3 More robust landing gear: "The limited runway on the flight deck means there isn't much room to slow down after landing."

Strictly speaking, the landing area isn't a "runway" but I understand the need to use familiar words.

"Instead, the pilot has to perfectly time and aim the aircraft to hook the line on the carrier deck to bring the aircraft to a halt."

Well, sort of... Aim isn't too far off the mark but there is no timing involved since the pilot doesn't flare for a landing on a carrier. The word "line" doesn't do the justice to the steel wire that is usually known as the arresting cable or more nautically, cross-deck pendant.

4. Two wheels in front: "Stability is a priority and a necessity when landing on a naval carrier ship. While the robust landing gear takes care of the logistics of landing at a high capacity, the two wheels in the front of the aircraft provide stability, and absorb the shock of landing."

I was doing okay with the press release until I got to this paragraph; English appears to be a second language for its author. For starters, "naval carrier ship", "logistics", "at a high capacity"?  What's wrong with aircraft carrier, shock absorption, and high sink rate? And then there's the technical content. What do two wheels in front have to do with stability? The tailhook does a pretty good job of providing directional stability after landing on an aircraft carrier with a proper lineup before touchdown. Ideally, the main landing gear absorbs most of the shock of landing although the nose landing gear still has to be pretty robust. The necessity for two wheels in this case is the use of the nose-tow launch system. See http://thanlont.blogspot.com/2011/01/catapult-innovations.html

5. Greater internal fuel capacity: "The F-35C carries nearly 20,000 pounds of internal fuel for longer range and better persistence than any other fighter in a combat configuration."

Any other fighter? Maybe combat configuration, meaning no external tanks, makes this claim valid. I don't know offhand that it isn't incorrect. Maybe someone would like to comment?

Wednesday, October 29, 2014

Hard to Replace

The Douglas AD Skyraider proved hard to replace in the U.S. Navy. For decades, jets couldn't match its combination of size, endurance, and payload capability. It was eventually supplemented but not completely replaced in one of its missions, nuclear strike, since it was not as survivable as a jet.

The Douglas A4D Skyhawk was therefore specifically optimized for that particular mission, "one man, one bomb, one way". The Scooter, however, fell short of the Skyraider's range until the introduction of inflight refueling and buddy tanking.

The next mission for which a replacement was developed was all-weather attack, the province of the AD-5N.

This was accomplished with the bigger and more expensive, albeit more capable, Grumman A-6 Intruder.

However, because of its endurance and load-carrying capability the single-seat Skyraider continued to be a major part of the carrier strike force up through the first few years of the Vietnam War. At some point, it was given the nickname Spad, which was a World War I fighter. Some say it was to identify it as a Single Place AD, as opposed to the wide-body multi-place AD-5, for deck spotting purposes but my guess it was just to recognize it as an anachronism in what was otherwise an all-jet air wing.

The single-seat Navy ADs were finally replaced in the attack role with a jet of similar mission capability, the Vought A-7 Corsair II.

(The last ADs deployed on carriers were the EA-1Fs, which served through December 1968, providing electronic countermeasure; Skyraiders continued to be operated by the USAF and the Vietnamese Air Force up through the end of the Vietnam War.)

All those jets are long gone from the U.S. Navy, replaced by various McDonnell/Boeing F-18s. Two, the A-4 and the A-7, were also operated by foreign air forces. The last of the A-7s was just retired by Greece.
 Giovanni Colla Photo

The aircraft it replaced in the U.S. Navy, however, the A-4, continues to serve in Argentina as the A-4AR;
Jorge Alberto Leonardi Photo

in Brazil as the AF-1;

and for Singapore as an lead-in trainer, the A-4SU.

I doubt that the Scooter will outlast its replacement's replacement, the F-18, in a military air force but it's possible that they will still be flying as Warbirds after an F-18 lands for the last time.

Saturday, October 25, 2014

Tricycles Are For Kids

Although most airplanes now have a landing gear with a nose wheel, for many years after the Wright brothers' first flight almost all had a tail wheel instead. The tail wheel arrangement was lighter/cheaper, lower drag before landing gears began to be retractable, and more appropriate for landing on relatively unprepared surfaces (airfields were once actually fields, nephews). Its only drawback was a lack of directional stability on landing rollout, which would sometimes result in what was known as a ground loop, particularly if there was a crosswind.
Tricycle landing gears with nose wheels were directionally stable on landing roll out and therefore less likely to turn and bite the inattentive or clumsy pilot. Moreover, they provided an extra prospective benefit on takeoff for multi-engine airplanes. In the event of an engine failure in the takeoff roll before the pilot raised the nose to lift off, the nose landing gear provided increased directional control compared to a tail wheel, particularly if the tail wheel was off the ground for better acceleration. As a result, even before World War II, multi-engine bombers (e.g. the B-24) and fighters (e.g. the P-38) began to have nose landing gears.

The single-engine Bell Aircraft P-39 had a nose landing gear as well, in part because the engine was located behind the pilot, providing room for one.
However, when Bell proposed a variant of the P-39 to the Navy as a carrier-based fighter, one of the changes required by the Navy was to what was then known as a "conventional" landing gear.
Nevertheless, the Navy had evaluated a twin-engine airplane with a nose landing gear, the one-off XJO-3, at-sea in 1939 and all of its subsequent carrier-based multi-engine airplanes would have nose landing gears. (See http://thanlont.blogspot.com/2010/11/one-if-by-land-two-if-by-sea.html.)
The Navy also contracted with Douglas for two different single-engine torpedo bombers with nose landing gears during World War II, the BTD
and its humongous brother, the TB2D.
(BT meant that the airplane's primary mission was as a dive or level bomber and its secondary mission was as a torpedo bomber; TB meant that its primary mission was as a torpedo bomber - the TB2D was to carry as many as four torpedoes - and its secondary mission was as a level bomber.)

I haven't been able to find a Douglas justification for the nose-wheel landing gear arrangement. My guess is that it made loading of torpedoes and 2,000-lb bombs a little easier because of better ground clearance and they could be lifted into place more or less level, instead of having to be tilted nose up to fit in a bomb bay or be aligned with cruise-flight air flow.

The Blackburn Firebrand torpedo bomber featured a two-position torpedo mount that provide both level load/ground clearance and low-drag alignment once in flight.

The nose landing gear didn't seem to provide any benefit otherwise (a Douglas evaluation did note that that a bad landing was less likely to result in the airplane bouncing over the barriers). On a single-engine airplane it significantly restricted the space available for a bomb bay if low-drag carriage of bombs was desired.

Nose landing gears could also be at risk of collapse following an inflight arrestment.

In any event, the next Douglas design, the BT2D, had a tail wheel. It was subsequently redesignated as the AD when the carrier-based bomber designation system was simplified to one mission, attack.

In part as a result of its preference for tail-wheeled landing gear, the Navy lagged the Air Force in adopting trainers with nose landing gears, trading off a somewhat higher accident rate for an earlier and more thorough indoctrination in the art of landing a taildragger.

Sunday, July 27, 2014

Things Under Wings - Training Wheels

Before the advent of computer-aided bombing, it wasn't easy to hit a target with a bomb even if the intended target was not maneuvering. In order to account for the ballistic drop of the bomb after release, the bomb had to be dropped at a specific combination of airspeed, altitude, and dive/descent angle. Because of the degree of difficulty in having all three nailed at the same time as well as having the target centered in the sight (particularly while being shot at), the pilot had to drop at a higher altitude if he was a little fast and at lower a lower one if his dive was a little shallow. And if the drop was a fraction of a second late or early, the accuracy decreased. Not to mention the presence of wind aloft that would affect the fall of the bomb.

It was therefore necessary to practice. Since prewar carrier-based airplanes were intended to carry heavy bombs in order to do the most damage to an enemy ship or shore installation, only three bomb pylons were generally provided. To get the most effective training from a flight, practice bomb dispensers were therefore developed. These were the original Multiple Ejector Racks. The Mk 42 was a plate on which three practice bombs could be loaded. The more widely used Mk 47 was a streamlined dispenser that was about 40" long.


It contained compartments for eight miniature bomb-shaped weights.


The practice bombs were electrically dropped one at a time, separation aided by a spring. A small black-powder spotting charge was incorporated so the impact point could be easily seen. The bombs were also reusable. For more on them, see http://www.nebraskaaircrash.com/practicebombs/anmk43.html

Navy fighter planes have always been used for bombing as well. The number of aircraft that can be loaded on a carrier is finite so it is important that fighters can  drop bombs if necessary. Fighter pilots trained with the practice bomb dispensers as well (this one on an early Corsair looks like it might have only had six compartments).

Rockets were somewhat easier to aim, easier even than guns or cannon because they were propelled in flight and therefore did not go ballistic after being released. As a result, a pilot only needed to fire a few at the expected airspeed, altitude, and descent angle to be used in combat and note where they hit relative to his aiming point. Accuracy was affected of course by the wind, any sideslip (if the airplane wasn't heading the same way it was going, the rockets would tend to align themselves with the relative wind immediately after launch), and any damage to or misalignment of the fins. The Sub Caliber Aircraft Rocket (SCAR) was developed for training to reduce the cost of expended rockets.

It was 2.25 inches in diameter and about 29 inches long with a tail-fin span of 8.3". It could be configured to imitate either the 3.5 inch or 5.0 inch rocket with the result that some were about six inches longer. Adapters were provided for the different rocket pylons that were used.


A rather bulky camera could be mounted externally on the aircraft for training flights to provide feedback to the pilot on his technique and accuracy. This was particularly useful for torpedo bomber pilots who couldn't make multiple drops on their training flights (or any drops at all due to the expense of torpedoes).

Thanks to David Collier for suggesting the topic.

Thursday, July 17, 2014

Air Superiority Errata

No matter how hard an author tries, errors sometimes go unnoticed. New information often becomes available after a book goes to press. Here are some corrections and additions to my book, U.S. Naval Air Superiority.

Front inside dust cover: First paragraph, last line, “fee” should be “feet”.

Page 57: The wingspan of the XF9F-1, 55' 6", is missing.

Page 64: VMF(N)-542 was not the only operational squadron with F3D-2Ms. VMF(N)-513. operating out of NAS Atsugi, Japan, was also equipped with a few Sparrow-armed F3D-2Ms in 1957.

Page 71: The first paragraph in the left-hand column has been misread to mean that an unswept inboard section was added. For clarity, the first two sentences should have been: The wings were P-63 outer-wing panels mounted to sweep aft from the P-63's existing inboard-wing section. Retaining this unswept section was an attempt to correctly position the swept-wing's center of lift with respect to the aircraft's center of gravity without making major changes to the structure.

Page 72: The caption for the lower left picture refers the reader to Chapter 11, page 80, for a picture of the crash. The page is actually 180.

Chapter 7: The end-note numbers in Chapter 7 became incorrect for some reason. There is no "7" in the text, so "8" in the text is "7" in the end notes. After that, you have to subtract 1 from each end-note number in the text to obtain the correct number for the end note itself.

Page 119: At the end of the second full paragraph in the right-hand column, the implication is that the landing weight was limited to 23,500 pounds for the rest of the F7U-3M's operational career. In his book, The Wrong Stuff: Flying on the Edge of Disaster, John Moore apparently misremembered the results of the F7U-3M carrier-qualification testing. According to the F7U-3M Service Acceptance Trials dated 30 November 1956, the gross weight limit for axial deck landings (flat approach) was 23,000 pounds but for mirror approaches (descending to an angled deck), the limit was raised to 25,300 pounds.

Page 147: The caption for the upper picture incorrectly states that the original F4D tail hook arrangement did not survive to the prototype. It was in fact present on at least one of the prototypes. However, the Skyray that was used for the initial carrier evaluation had an A-frame type tail hook.

Page 154: In the fifth line from the bottom in the right column, add "pilot" after F-86D.

Page 191: The text does not mention the development of deck and approach lighting to provide better lineup visualization of short final in low-visibility conditions and at night as these were introduced at the end of the period covered buy the book. For example, the drop line or drop lights were added to the fan tail, along with the first sequenced-strobe flashers, in 1964.

Page 211: Figure 13.1 should include the label "Design 98".

Page 218: the picture caption states that the initial FJ-4 carrier qualifications were accomplished aboard Randolph in March 1956. According to the carrier-suitability test report that I was subsequently provided, landings and two launches were accomplished aboard Intrepid in January 1956. A final series was accomplished aboard Saratoga in December 1956.

Page 231: The caption for the two-position Crusader wing actuator picture states that "the center of lift was behind the pivot point." This was not true for all speed and g conditions but when there was a tension load, it was relatively low and well within the actuator capability. There were inflight structural failures where the Crusader wing came off, but the first component to fail was never the actuator itself.

Page 237: D'Oh! Two different months are given for the McDonnell AH letter of intent in adjacent columns. For the record, it was dated 18 October 1956.

Page 248: Fifth line in the left column, delete the word "but" so the sentence reads, "Not only was it positioned high on the vertical fin, but when it was generally accepted that..."

Page 258: I failed to mention that the F8U-2NE, F-8H, and F-8J could be armed with the AAM-N-7 Sidewinder IC (AIM-9C) semi-active radar homing (SARH) variant developed to provide true all-weather capability for the Crusader. According to the January 1969 Ault report, however, it added "only marginal Fleet capability...because of performance limitations at altitudes below 10,000 feet, lack of user confidence and interest, and deteriorating logistic support." It was subsequently withdrawn.

Page 267: In the first sentence of the second complete paragraph, the Lockheed/Vega PV-1 was the Ventura, not the Hudson. The Navy did operate a few Hudsons but they were designated PBO-1, signifying that they were produced by Lockheed Burbank. (Thanks to Lee Griffin for identifying that error.)

Chapter 13: After Air Superiority's publication, thanks to Jared A. Zichek, I became aware of a day-fighter proposition from North American, a General Electric J79-powered "FJ-5" derived from the F-107, a bigger and J75-powered USAF fighter-bomber.
Here's how it tied into the Vought F8U, Grumman F11F, and North American FJ-4 programs:

The Super Tiger (the real F12F; see http://thanlont.blogspot.com/2008/09/is-this-grummman-f12f.html) and the FJ-5 were attempts to compete with the F8U from a performance standpoint using the thrust-to-weight and SFC advances provided by the new J79 engine with variable inlet guide vanes. Once the F8U went supersonic on its first flight, neither proposition had any chance of being bought by the Navy. Grumman at least got to demonstrate what the F11F would do with the J79 because the Navy wanted some flight experience with the new engine before the F4H flew.

For a link to buy Jared's monograph on this airplane, click HERE.

Sunday, July 13, 2014

A Brief History of the F-111B Flight Test Program

I thought I had posted this before but I can't find it.

151970 Stricken Dec 1969.  Stored at the Naval Surface Weapons Center, Dahlgren VA for vulnerability testing. Transferred to Pax River for potential display at the museum. Subsequently sold to a scrap dealer in the Washington, D.C. area and destroyed in 2000.

151971 crashed Sept 11, 1968 off California coast, reportedly due to a component failure or disconnect in the rudder control system. Test pilots Barton Warren and Anthony Byland killed.

151972 Ferried to NAS Lakehurst NJ in late 1971. Stricken in Dec 1971.  At least the fuselage was shipped to China Lake for vulnerability testing and remains there in outdoor storage.

151973 crashed on takeoff at Calverton, Long Island Apr 21, 1967 due to an incorrect inlet cowl position switch setting—as a result, the translating inlet cowls closed when the landing gear retracted causing both engines to compressor stall. Test pilots Charles Wangeman and Ralph Donnell killed.

151974 transferred to NASA Ames for wind tunnel testing following at-sea carrier trials aboard Coral Sea  off the west coast, based at Point Mugu, CA. Ferried to Moffett Field from Point Mugu on Oct 10, 1968 and stricken the next day. Following the wind tunnel test, the wings were removed to be used as the test article for a jet/deflected flap concept. The fuselage was trucked to China Lake, where it was stripped of usable parts for the ongoing Hughes test program and the carcass eventually scrapped. 
152714 ferried to Davis-Monthan AFB from Hughes and stricken on 25 May 1971. It was shipped to McClellan AFB, California for potential use in battle-damage repair training. (McClellan was the Air Force repair depot for the F-111.) It was eventually sold to a scrap dealer and for several years the fuselage resided in a junkyard two miles east of Mohave, California. It was acquired by the Cactus Air Force museum and is now located at Silver Springs, Nevada near Reno.
152715 ferried to China Lake from Hughes in April 1971 for desert exposure testing and stricken in May 1971. It still resides today.