by Tommy H. Thomason

Sunday, November 8, 2009

Early Phantom IIs

12 September 2011: Added stabilator changes
26 May 2011: Revised Configuration Matrix
23 November 2010: Added cockpit illustrations
10 November 2010: Added information on configuration differences between early and late F4H-1s
12 November 2009: Updated Configuration Matrix

Also see: http://tailspintopics.blogspot.com/2011/05/early-phantom-iis-redux.html

The F4H (F-4) Phantom II was originally intended to be a single-seat, supersonic attack airplane, the AH, powered by two afterburning Wright J65s. Because of an urgent need for a supersonic, two-seat, Sparrow-missile-armed fleet air defense capability, the fighter class desk at the Bureau of Aeronautics hijacked the program and repurposed it, substituting more powerful General Electric J79s for the Wrights. The second seat was crammed into the avionics bay of the AH.

During the course of development, a larger radar dish was deemed necessary to increase the detection range of incoming bombers, which resulted in a larger nose and raising the cockpit slightly. The engine inlets were also refined, in part due to higher than expected speeds being achieved with early uprating of the J79. As a result of these and other changes, there were detailed configuration differences among the first few dozen Phantoms. The first 47 were redesignated F4H-1F in May 1961, primarily to differentiate between airplanes with the J79-GE-2s and those with the -8s. In the 1962 DoD-directed redesignation exercise, the F4H-1Fs became F-4As and the F4H-1s, F-4Bs. (Click on this and any other image for a larger picture.)



The first F4H (not yet named Phantom II) first flight.
 
The larger radar dish required a larger radome, which resulted in raising the canopy line to restore visibility past the nose for the pilot's view of the carrier approach aids. As much of the original structure was retained as possible, reportedly up to the canopy sills.
As noted in the configuration matrix, not all F4Hs with big noses got the raised canopy. This is BuNo 145313.
The inlet change went through several iterations. The first XF4H, BuNo 142259, had a hooded inlet with a narrow fixed ramp and the external portion of the variable ramp was non-porous.

The next step appears to have been making the variable ramp porous. In some cases, the early porous variable ramp did not have the discharge chute at the bottom; in others, the chute was present at both the top and bottom of the ramp as on Skyburner and the second Sageburner.

The first F4H in early 1959 with a porous variable ramp and only the lower discharge chute; the "hood" on the top of inlet has been removed. Note that there is now a McDonnell ejection seat in the rear cockpit.

143389 (#4) on 4 December 1959 with the original hooded intake and no discharge chutes (note the addition of the infrared detector under the small nose and the different air inlet aft of that compared to NACA inlet in the picture above):

The second Sageburner. Note that this inlet has also been modified to remove the hood and the chutes are clearly scabbed on:

On the production inlet, there was both a lower and an upper discharge chute, but the latter was smaller. The fixed ramp was a much larger portion of the ramp area. The ramp angles were also changed during inlet development. The fixed ramp was originally set at an angle of 5 degrees and subsequently increased to 10 degrees. The variable ramp angle range was also increased.

The early Phantoms used a McDonnell-furnished seat:
Another major change, introduced with F4H #6, was the addition of Boundary Layer Control and inboard leading edge flaps in order to reduce the approach speed. My guess is that the cambered leading edge was also added to the stabilator as part of this redesign. The original stabilator had a symmetrical leading edge:

The cambered leading edge curved up to increase the down force from the stabilator at the same angle.

Interim stabilators had a zig-zag pattern at about 20% chord where the new leading edge was incorporated. Note that production stabilators integrated the camber as part of the basic structure so there is no zig-zag.

This redesign to increase lift and reduce approach speed delayed the carrier qualification trials.

Initially, the F4H had two emergency turbines, one in each wing under the inboard leading edge. When it was decided that the airplane needed inboard leading edge flaps, these were replaced by a single RAT in the upper left side of the fuselage. (For more on this installation, see http://tailhooktopics.blogspot.com/2012/12/early-f4h-rat.html)

The early F4Hs had perforated spoilers like the F3H as shown here on BuNO 143390. The holes were subsequently deleted, likely on the next airplane—which incorporated the inboard leading edge flaps—and probably to improve roll control effectiveness at approach speeds.
 This is the 6th F4H used for the initial at-sea evaluation on a subsequent visit to a carrier in different markings.


Thanks to Larry McCarley, I now have more illustrations of the cockpits of the early Phantoms.

The Airborne Missile Control System display was very different in the early F4Hs. Note that it wouldn't have been installed in the first aircraft.
The early aircraft probably had the area reserved for the pilot's radar indicator and missile controls filled with flight test unique instruments.

Contrary to speculation, some aircraft with the low canopy line did have a McDonnell ejection seat installed in the aft cockpit as shown in the picture of the first F4H above. However, the ejection seat was probably not installed in the aft cockpit of at least some of the early aircraft that didn't have the missile control system installed. It was likely filled instead with research instrumentation equipment. This is the rear seat equivalent of the pilot's early missile control system:
Note that the instrument panel in the aft cockpit was slightly different depending on the bureau number with the major change being the addition of an artificial horizon and airspeed indicator:

2 comments:

  1. The prototypes of the Phantom and the first Phantoms with short and little nose are among my favourites planes.

    Many more close-up photos of nose and cockpit, perhaps with pilots posing would be welcomed !

    Thank you very much !

    ReplyDelete
  2. Hello, i'm a French fanatic of US prototypes and experimental military planes of the late 40's and of the 50's.

    The prototypes of the Phantom, and also XF3H Demon, blue F3H-1N, and first F3H-2 with one-piece bubble windscreen are also among my favourite planes.

    I like very much photos of test pilot with flight gear and helmet posing in the cockpit of their plane.

    ReplyDelete