U.S. Navy Aircraft History

By Tommy H. Thomason

Tuesday, December 9, 2014

Aircraft Pictorial 7: F4U-1 Corsair Vol. 1

Dana Bell's long awaited monograph on the F4U-1 Corsair is finally available. There are many books and articles available on the F4U. I can say, because I have a goodly number of them in my collection, that none are quite as deeply researched or as sharply focused as this one is. It is a relatively slim volume, only 72 pages between the soft covers, but every page has a photo or illustration of interest, many of the former in color. I am very pleased to write that it contains information and facts about the Corsair of which I was previously unaware and should be taken as gospel, based on the depths that Dana has plumbed at the National Air and Space Museum and the National Archives. Most notable are these two: there was officially no F4U-1A and the cause for the Navy not deploying Corsairs on carriers initially was not due to unsatisfactory deck landing characteristics. (One proof Dana cites for the latter is an evaluation aboard Woverine that concluded it was very easy to land aboard; I may have missed Dana's mention of it but that carrier was one of the two converted side-wheeler excursion ships plying Lake Michigan as training carriers: it was not only short, it was slow.)

Some things this excellent volume is not: a compendium of war stories, list of squadron assignments, tables of performance attributes, or overall operational history. All that is available elsewhere. What it is: a detailed and well-illustrated document that describes the configuration, configuration changes, and color schemes (internal and external) of the so-called "Birdcage" Corsair during its initial flight test and operational usage, both U.S. and U. K. (Volume 2 will, Dana promises, cover the raised cockpit F4U-1, aka F4U-1A.) As such this work will not appeal to everyone, as fascinating as it is to me. If you are a Corsair fan, however, almost every page contains something of interest that you probably didn't know and likely is mentioned in no other Corsair reference.

For example, a picture of the early 20-gallon (your car's gas tank probably has less capacity) oil tank mentions that a larger tank was substituted to account for oil consumption on longer missions when greater endurance was provided by the addition of external tanks; however, a decal was placed on the larger tank to advise the ground crew not to fill it with more than 20 gallons of oil when external tanks weren't fitted in order to minimize weight. A revelation was the reason for the almost standard application of tape externally to the panel lines around the fuselage fuel tank. It turns out that it was to keep spilled gasoline out of the interior of the fuselage aft of the firewall when the tank was being filled because the result was sometimes a fire.

If Dana hadn't thoughtfully sent me a copy, I would have been first in line to purchase one based on his previous work and personal knowledge of his research diligence and insistence on the use of primary-source documents.

Sunday, November 30, 2014

Warpaint Series No. 99: McDonnell F3H Demon

From a detailed and illustrated Britmodeller review HERE

Tony Buttler, a well-known and prolific author, has written an excellent, well-illustrated monograph on the less-appreciated McDonnell F3H Demon. It is a very complete history in 48 pages plus softcover. There are lots of photographs, many in color, of the XF3H-1 prototypes, the J40-powered F3H-1N, and the J71-powered F3H-2 variants. Several pages of color profiles are provided as well as well as a large multi-view drawing at the centerfold. The paper quality is more than adequate for good reproduction of all the illustrations. See the link above for details.

Since this book deserves to be the cornerstone print reference, if not the only one, for the F3H in some libraries, I feel obligated to correct a few misstatements. First, the F3H wing did not have anhedral (page 22); see http://tailspintopics.blogspot.com/2014/03/anhedraldihedral-and-wing-sweep.html. I'm all but certain that the first Sparrow missile firings by a deployed squadron were accomplished by a VX-4 detachment of F7U-3Ms on Shangri-La in early 1957, not VF-64 F3Hs in December 1958 (page 35). A really minor correction is that the drawing of the F3H-2M is shown with the short beaver tail in the centerfold; all were built with the longer one and I doubt that any were retrofitted.

I'm pretty sure that the lineup of F3Hs on page 17 are four of the six involved in the Fleet Introduction Program described in the text with side numbers 10 through 15. Note that these, as well as some other early production Demons, have blue AERO stores pylons on the wings as the changeover to gray/white exterior paint had just occurred.

An oddity not mentioned or illustrated was one of the attempts at providing self-boarding (no separate ladder) on these big jets that set so nose high. See http://thanlont.blogspot.com/2009/06/self-boarding.html and http://thanlont.blogspot.com/2008/05/i-had-hoped-to-find-picture-like-this.html

Minor omissions and errors like these do not materially detract from the value of this book to the naval aviation enthusiast. I am very pleased to have been provided a copy by Tony.

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:



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:

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.