By Tommy H. Thomason

Sunday, July 11, 2010

Fitting In II

I still haven't found out what set the maximum folded span at 27' 6" in the early 1950s. Before then, folded spans for the jets varied somewhat but were almost always less than 27 feet. Exceptions were the big strategic bombers (the AJ, A2J, A3D, and A3J) as well as the Douglas F5D, which had a folded span of 28' 5". I had thought that it might have been set by a pinch point in the middle bay of the Essex-class carrier hangar deck:
However, if that pinch point dictated the width that allowed an airplane to be towed past another one that was parked to one side there, then the maximum folded span would be about 25 feet—which perhaps not coincidentally, was the wing span of the first predesign sketch of what became the A4D—not 27' 6".

The Navy's contractors paid close attention to the size constraints. As previously noted, the McDonnell XF3H-1 was 59' 4" long, which maximized its fineness ratio but required it to be carefully positioned at an angle on the forward elevator of the Essex-class carrier. The Navy did not like that.
As a result, the F4H was initially 56 feet long, giving 1 foot of clearance at the nose and tail so it did not have to be angled. (Note that the folded span is 27' 6" inches!)
Of course, the F4H nose got two feet longer with the introduction of the bigger radar dish during development but it turned out not to matter, because the Phantom was never deployed on the Essex-class carriers.

As an indication of the attention that the contractors paid to spotting in predesign, here are two pages from Vought's 1952 proposal for what became the F8U Crusader. The V-383, which was powered by the Pratt & Whitney J57, has a folded span of only 22' 6", but was more than 54 feet long, so only 25 could be accommodated on the forward or aft 200 feet of an Essex-class carrier compared to 27 of the slightly smaller and lighter V-384s, which was powered by the Wright J65. Note that two V-383s can be positioned on the forward elevator without being angled.

For some reason, the shorter V-384 had a greater folded span. However, because it was slightly smaller overall, a slightly different spotting arrangement (three versus four abreast) resulted in an increase of two airplanes that could be parked in the 200 foot by 96 foot area. The greater folded span did require the V-384 to be angled on the elevator if two were to ride it at the same time.

2 comments:

Erik said...

In other related news, do you have any indication as to how these notional spotting diagrams compare to the maximum spot densities regularly achieved in service? I assume the latter would be somewhat lower (that is, less aircraft per deck area). I've grown up looking at angled decks with tails hanging off both beams, so these look foreign to me from the get-go, but I've done a quick search of Navsource and I (think) I haven't seen densities this high in practice. I don't recall any mention of the issue from Friedman in his Carriers book.

The densest I've seemingly found is USN-1036055 ( http://www.navsource.org/archives/01/013926b.jpg ), with this picture of Kearsage ( http://www.navsource.org/archives/02/023334.jpg) seeming more typical.

Tailspin said...

No idea. Wasn't there. And bear in mind that the pack consisted of different airplanes, not 25 of one kind, so we wouldn't be likely to find a picture matching the theoretical spot. But they packed them in pretty tight. See http://thanlont.blogspot.com/2009/03/air-group-in-transition.html. There are 22 airplanes in roughly the first 200 feet. Note that they could get almost three Cougars side by side compared to only two Furies.