By Tommy H. Thomason

Tuesday, March 26, 2013

F4H-1, F4H-1F, F-4A?

This shouldn't be that confusing but I was momentarily discomfited by a poorly worded description of the transition recently so herewith an summary illustrated history.

The F4H-1 (F for Fighter, H for McDonnell Aircraft, 4 for the fourth fighter that the Navy was serious about having McDonnell develop) first flew in 1958. It was powered by two J79-GE-2 engines.

Early in the F4H production program, the Navy decided to change to the more powerful J79-GE-8 engine. As a result, the designation of the first 47 F4H-1s that had the early production inlet was changed to F4H-1F in May 1961 when the last one was accepted. (A retroactive redesignation without a configuration change was unusual but not unknown; at least if you give me time, I might think of another one.) The F suffix denoted an engine change. Subsequent production with the -8 engine were still F4H-1s for a short while.

In November 1962 the airplane designations of the Army, Navy, and Air Force were changed to be common and consistent. As a result, the F4H-1F became the F-4A and the F4H-1 became the F-4B, which I have to admit is a more straightforward way of identifying the production configuration change.

The main external difference between the standard production F-4A and F-4B was the engine inlet.*

Based on a review of pictures looking at the position of the leading edge of the fixed ramp relative to access doors and the lower-right kick-in step, I had concluded that the F-4B ramp extended slightly more forward than the F-4A ramp, by perhaps an inch. This difference was also evident on McDonnell lines drawings but it is so small that it could easily be within the accuracy of those particular drawings. However, I recently confirmed this on a visit to the Quonset Air Museum, hosted by Larry Webster, because there are examples of both the A and B fuselages there. That particular difference, is of course, insignificant in model scales: the only difference likely to be noticed on very close examination is that the right side of the A's lower-right kick-in step is vertical whereas the B's is angled forward.

 In addition to the changes shown in the illustration above, the inlet boundary layer discharge system was modified as well: the major difference was in the shape and size of the exhaust vents on the upper side of the nacelle aft of the inlet. The original outlets on the inboard side of the variable ramp were probably deleted.

Most of the F-4As were assigned to training squadrons VF-101 (Oceana, Virginia) and VF-121 (Miramar, California).

Five were used in project LANA to compete for the Bendix Trophy in May 1961, celebrating the 50th anniversary of U.S. Naval aviation (L for 50 + ANA for Anniversary of Naval Aviation). It was a cross-country time-trial race from Ontario International Airport, California to NAS New York. The fastest Phantom averaged 870 mph for two hours and 47 minutes. Three subsonic in-flight refuelings were required.


The last F-4A built, BuNo 148275, was retired in April 1968. It has been on display at the U.S. Naval Academy at  Annapolis, Maryland since 1969. It is periodically repainted by the midshipmen in a different squadron's markings.
Robert F. Dorr Collection

*The flush canopy and small radome, which is what most people associate with the early F4H, was only on the first 18 of a total of 47 F4H-1Fs. The remaining 29 had the raised canopy and at least two of the first 18 had the bigger radome. For more on the configurations of the early F4Hs, see http://tailspintopics.blogspot.com/2009/11/early-phantom-iis.html

Sunday, March 24, 2013

A Brief History of F8U Crusader Armament

The Navy originally bought the F8U Crusader as a carrier-based "day fighter". That basically meant that it didn't also need to be capable of finding and shooting down another aircraft in low visibility conditions, e.g. cloud, or at night. It turned out to be the last of the pure gunfighters in the Navy.

For a summary of F-8 (F8U-1/2) Crusader configurations by suffix letter , see http://tailspintopics.blogspot.com/2009/10/f8u-crusader-variations.html

The F8U-1 (F-8A) did have a small radar that the gun sight used for automatic ranging but did not provide visual assistance to the pilot. It was armed with four 20 mm cannon and 2.75-inch rockets.

 The rocket pack tilted down when the rockets were to be fired:

The rockets proved to be not only not effective except as an area suppression weapon due to inaccuracy but also downright dangerous. To maximize the number carried versus the frontal area of the pack, one set of 16 was loaded ahead of another. If a rocket in the forward set did not fire, the one behind it, when fired, might stay in the pack, still burning. Rockets occasionally did not clear the pack, which meant that it could not be retracted and could potentially keep one of the nose gear doors from opening, which meant the nose gear would not extend.
 The combination of useless and hazardous resulted in them being deactivated in the fleet. For a bit more on the rocket pack, see http://thanlont.blogspot.com/2008/12/missed-it-by-that-much-ii.html

For various reasons, the Navy didn't shut off production of F8Us with the rocket pack for a while, resulting in the Controller General telling Congress in July 1964 that the Navy could have eliminated them and saved about $4 million in 1958 (about $31 million now) instead of having Vought build 306 F8Us with that capability.

Far more effective than the rocket pack, at least from an air-to-air standpoint, was the addition of heat-seeking Sidewinder missiles, first two, one on each side of the fuselage:
If two Sidewinders was good, four would be better. This capability was introduced with the F8U-2 (F-8C) but there were a couple of extendable legacy things that had to be avoided, the inflight refueling probe on the left side of the fuselage:
And the ram air turbine (RAT) on the right side:
(Also see http://thanlont.blogspot.com/2009/01/rats.html)

As a result, the two-Sidewinder pylon on the right was not a mirror image of the one on the left and no two missiles were oriented exactly the same:
Note that these illustrations include the wing pylons added with the F8U-2NE (F-8E).

Visual-assist radar was added to the F8U beginning with the F8U-1E (F-8B). However, it wasn't going to be much of an all-weather fighter if it wasn't armed with an all-weather missile. A radar-guided Sidewinder, the AIM-9C, was developed, qualified, and deployed. It was, however, subsequently withdrawn reportedly because its envelope was too restricted and it wasn't very reliable. (I don't know why the Sparrow III capability was never incorporated.)

The AIM-9C is on the upper rail and the 9D on the lower.
 U.S. Navy via Gary Verver

Since a carrier air group can only carry so many airplanes, general-purpose fighters that had a strike capability were preferred to one-trick ponies like a day fighter. As a result, wing pylons with a stores capability of 2,000 lbs were introduced with the F8U-2NE (F-8E) and retrofitted to the F-8Cs and F-8Ds that were remanufactured to be F-8Ks and F-8Hs respectively:
Note that although qualification of the Bullpup on the F8U began, it wasn't completed and no squadron deployed with the capability. For a bit more on that, see http://thanlont.blogspot.com/2008/10/general-purpose-f8u.html

It was apparently intended that the pylons also be used to carry external fuel tanks. Vought flight tested them but for some reason that capability was also never used in the fleet as far as I know.
For one thing, the F8U already had great endurance for a jet and for another, the likelihood of the tank hitting the horizontal stabilizer may have been off-putting. (If this was a concern, it was overcome during Vought A-7 development.)

However, the F8U was qualified to carry bombs on the pylons and two-shot Zuni rocket pods on the two-station Sidewinder pylons, four Zunis to a side.
Although carrier-based F8U squadrons fired Zunis and dropped bombs, primarily on air defense suppression missions, the shore-based Marine squadrons probably employed it in the ground-attack role to a greater degree, dropping whatever was at hand: