By Tommy H. Thomason

Friday, February 16, 2018

One More Time, The Grumman F12F

This is not the Grumman F12F:

It is the Grumman G118, proposed to the Navy in December 1955. The Navy rejected it because they didn't want a second development program of a fighter powered by two J79s (the McDonnell F4H was already under contract) but suggested that Grumman go back to the drawing board and propose a single-engine, Sparrow-missile armed fighter to compete with Vought's proposal for a Sparrow-armed "Super" F8U powered by the P&W J75. Grumman did but the Navy rejected it as well in favor of what became the F8U-3. Neither of the two Grumman proposals was ordered, much less received BuNos.

There was a Grumman F12F but it was a program to reengine the F11F with GE's J79. Grumman had proposed its G98J to the Navy in January 1955. The Navy prepared a purchase order and contract in August 1955 for two F12F prototypes, which were to be assigned BuNos 143401 and 143402. It's not clear that the contract was ever issued. In any event it was canceled in January 1956, probably due to the demonstrated performance of the Vought F8U-1 that first flew in March 1955. However, the Navy had contracted with Grumman in August 1955 to put the J79 in the last two F11Fs of the first production lot in parallel with this plan. These were designated F11F-1F.

This is the US Navy's F12F Characteristics Summary dated 15 August 1955. Although there is no drawing and it is somewhat bigger than the F11F, it is definitely smaller than the G118 and powered by a single J79 engine.
One or more aviation historians have inadvertently conflated the two programs and incorrectly concluded that the Navy contracted with Grumman for its twin-J79-powered G118 and designated it F12F. Another enthusiast even speculated that it was given the popular name Lion, which some have accepted as fact as well. It was not.

Saturday, February 10, 2018

The A-12 Avenger II Program - The Fat Lady Finally Sang

I'm embarrassed to say that I neglected to cap this story off when she did back on 24 January 2014. The settlement, according to a Reuters article, was:

"(T)he Navy will receive three EA-18G electronic attack aircraft from Boeing, and a $200 million credit from General Dynamics toward its work on a new DDG-1000 destroyer."

For the Aviation Week report (it may have still been a weekly back then), click here.

For my penultimate post, which has links to prior ones: http://thanlont.blogspot.com/2013/06/the-12-avenger-ii-program-end-is-near.html

Wednesday, January 3, 2018

Pre-war Downward-Vision Windows




One of the interesting features I noticed early on as I grew better acquainted with the history and development of U.S. Navy carrier-based airplanes was the presence of downward vision windows on most of the early monoplanes. My first guess was that they were incorporated to somewhat make up for the reduction in downward visibility resulting from the larger wing located more directly under the pilot. An example is the XF2F-1. As in most of the biplane fighters, the pilot sat just aft of the trailing edge of the lower wing.

The most significant benefit from restoring a view directly downward would be the ability to better judge drift from a crosswind, which would provide better accuracy for the dead reckoning necessary to find your way back to a carrier on an otherwise trackless ocean.

And that would appear to be the case for the downward vision windows in the Brewster F2A Buffalo and the Grumman F4F Wildcat.
Note that the F2A window is huge relative to the F4F's, indicative of a lack of specificity for the requirement. The F4F window was not intended to be used to determine whether the landing gear was down, as some have speculated. The pilot can't see the wheels through the window even when the shock struts are fully extended.
The windows are also of no use in landing. A pilot uses his peripheral vision to judge height above, and position over, the runway and the LSO's signals when landing on a carrier.

My original theory, even if correct, doesn't hold for the bombers since the pilot in the biplanes was generally located over the bottom wing. In any event, the earliest monoplane scout bombers like the BT-1 and SBA don't appear to have had downward-vision windows. The follow-on Brewster SB2A, Vought SB2U, and Douglas SBD Dauntless and its replacement, the Curtiss SB2C Helldiver, did. In this case, they were sometimes referred to as Bombing Approach Windows. Note that these were all dive bombers.

This is the Naval Aviation Museum's SB2A when it was conveniently hung from the ceiling. Note the channels on either side of the window for the struts of the bomb-displacement mechanism.

The SB2U's were located immediately aft of the cowl flaps.

The SBD's was located just aft of the post for the bomb-displacement mechanism and is hard to see even in this excellent Miles Lombard photo.
 The SB2C's is even more rarely remarked upon. It was ahead of the bomb bay and aft of the oil cooler flaps on the belly. It was covered by doors, which kept the window clean until needed.
 I have yet to see a picture with these doors open. The SB2C-3/4 pilots manual states that they were "removed from the SB2C-4 and replaced with an access panel". That was the end of the use of bombing approach windows.

The monoplane torpedo bombers beginning with the Douglas TBD Devastator had a downward vision window but in this case, it was for use by the bombardier although the pilot could see downward through it as well. The TBD was originally intended to function as a level bomber as well as a torpedo bomber. In fact, the Norden bomb sight made famous by the Army Air Force was initially a U.S. Navy project. The bombardier would crawl underneath the pilots seat from his seat in the center cockpit to use it.
 Two large doors kept the window clean until needed.

The Grumman TBF was originally designed for level bombing using the Norden bomb sight as well,

In the following picture, the window, located above the number "8636", is covered by a protective flap.

The Vought TBU's bombing window and sight were similarly located aft of the bomb bay as well.

The final variation of the downward-vision window was present in the Vought XF4U-1, Grumman XF5F-1, and Bell XFL-1. In this case it was again a bombing window, but for very specific armament, small antiaircraft bombs housed within compartments in the wings.

The requirement also mentioned another purpose for the window:

As it happened, the antiaircraft-bomb requirement was dropped for F4U production (also see http://thanlont.blogspot.com/2008/06/antiaircraft-bombs.html) but the window remained for a time.