By Tommy H. Thomason

Friday, July 23, 2010

VX Squadrons

The history of Navy VX development/evaluation squadrons is complicated and inadequately documented but I've attempted to summarize it. An example of complication is VX-3. In its first (and brief) incarnation, it existed to evaluate helicopters and develop operational procedures for them.
The aircraft evaluated by the second VX-3 couldn't have been more different, although it even used the same tail code initially.

VX-3 was one of four new air development squadrons (VX) that the Navy formed in 1946 to develop and evaluate aircraft tactics and techniques as directed by a command that was a consolidation of fleet units doing development work. (In December 1947 this command was designated the Operational Development Force.) Other squadrons were subsequently added. In 1969, the surviving Air Development Squadrons became Air Test and Evaluation Squadrons.

The first VX squadrons had two-letter tail codes with the first letter being X. In 1957, the first letter of the east-coast-based VX squadrons was changed from X to J.

VX-1 (XA/JA) Anti-Submarine Warfare: VX-1 was originally an Aircraft Experimental and Development Squadron established at NAS Anacostia in Washington D.C. on 13 August 1942. A detachment for aircraft antisubmarine warfare development was established at NAS Quonset Point, Rhode Island on 1 April 1943. This detachment was the basis for the next VX-1, which was commissioned on 15 March 1946 and moved to Boca Chica Field, NAS Key West, Florida. VX-1 relocated to NAS Patuxent River in September 1973 and is the only one of the original four VX squadrons still in existence.

VX-2 (XB/JB) Drone Controller/Guided Missile Development: VX-2 was formed on 15 March 1946 from VJ-20, which existed for only a week having previously been XVJ-25, which was established on 16 June 1945 at NAS Brunswick, Maine to support XVF-200, an Experimental Development Squadron formed at the same time to evaluate and test Kamikaze defenses. VX-2 was based at NAS Chincoteague, Virginia until it was disestablished circa 1958.

VX-3 (XC) Helicopter Development: Established at NAS New York on 1 July 1946 and moved to NAS Lakehurst. It apparently didn't take long to sort things out because the first VX-3 was disestablished on 1 April 1948. Its personnel and aircraft were assigned to one of two utility helicopter squadrons HU-1 (UP) and HU-2 (UR) located on the west coast and east coast respectively.

VX-3 (XC/JC) was reincarnated in November 1948 at NAS Atlantic City to accomplish development and evaluation of jet fighter tactics and procedures. It was formed by merging VF-1L and VA-1L of Light Carrier Air Group 1L. VX-3 was relocated to NAS Oceana, Virginia before NAS Atlantic City was decommissioned in July 1958. It was disestablished on 1 March 1960.

VX-4 (XD) Airborne Early Warning Development was established with the personnel and aircraft of VPB-101 on 15 May 1946 at Floyd Bennett Field, New York, flying PB-1Ws (B-17Gs with APS-20 air search radar installed in place of the bomb bay). The squadron made the first hurricane surveillance flight using radar in September 1946. It relocated to NAS Quonset Point, Rhode Island, in September 1946. It subsequently moved to NAS Patuxent River in July 1948 and was reportedly redesignated as Airborne Early Warning Squadron 2 (VW-2) in June 1952.

VX-4 (XF) Air-Launched Guided-Missile Development: Established 15 September 1952 at Point Mugu, California. It was disestablished on 30 September 1994 as part of the consolidation with VX-5 to form VX-9.

VX-5 (XE) was commissioned on 18 June 1951 at NAS Moffett Field, California. The squadron was initially assigned the development and evaluation of aircraft tactics and techniques for delivery of special weapons (nukes) from AD Skyraiders in all-weather conditions. In July 1956 VX-5 moved to the Naval Air Facility, China Lake, CA, since much of their test effort had involved use of the ranges and instrumentation facilities there. Semi-permanent detachments were located at several other bases Over the years, VX-5 maintained detachments at other Navy bases, e.g. at NAS Whidbey Island, WA to monitor EA-6B developments. VX-5 was formally disestablished on 29 April 1994 as part of the consolidation with VX-4 to form VX-9.

VX-6 (XD/JD) Antarctic Program Support: Established at NAS Patuxent River, Maryland on 17 January 1955 and subsequently relocated to NAS Quonset Point from which it deployed to the Antarctic from October to February each year. It was redesignated as VXE-6 in January 1969. Before Quonset Point was closed in 1974, the squadron was relocated to Naval Air Weapons Stations Point Mugu, California, where it was disestablished on 27 March 1999. (At some point, possibly associated with the move to the west coast, the tail code became XD again.)

VX-7 I haven't found anything on a squadron operating as VX-7.

VX-8 (JB) The Oceanographic Airborne Survey Unit was established on 1 July 1965 at NAS Patuxent River. It was redesignated VX-8 on 1 July 1967 and became the Oceanographic Development Squadron, VXN-8, on 1 January 1969. It was disestablished on 1 October 1993.

VX-9 (XE) was formed at China Lake from the consolidation of VX-4 and VX-5 directed by the CNO in June 1993 as a cost reduction measure. It was established on 30 September 1994. It evaluates strike warfare airplanes, weapons, and tactics, to include electronic countermeasures, from an operational standpoint.

HMX-1 was established in on 1 December 1947 at MCAS Quantico, Virginia for the development of amphibious assault via vertical envelopment. In September 1957, it acquired the additional role of presidential transportation via helicopter.

In early 2002, only three "X" squadrons remained: VX-1, VX-9, and HMX-1. Five more were added on 1 May 2002 as a result of redesignations of existing units:

   The aircraft test and evaluation squadrons at Patuxent River were redesignated as VX squadrons;

      VX-20 (Force) Naval Force Warfare Aircraft Text Squadron (VP, VS, VAW, VX, VR, and VT aircraft)

      HX-21 Naval Rotary Wing Aircraft Test Squadron (for some reason, this squadron does not mark their aircraft with a tail code)

      VX-23 (SD) Naval Strike Aircraft Test Squadron

   Two existing Naval Weapons Test Squadrons were also redesignated:

      VX-30 (BH) Naval Weapons Test Squadron at Point Mugu

      VX-31 (DD) Naval Weapons Test Squadron at NWAS China Lake

Tuesday, July 20, 2010

Navy Research Aircraft Designations

In addition to its descriptive designation system for operational aircraft, the Navy had one for research aircraft, at least following World War II. It evolved to be the combination of the Navy’s letter for the manufacturer and the manufacturer’s internal design number for the project.

One of the first Navy research aircraft was the concept demonstrator for the Vought F5U program. The Navy designated it V-173, the Vought model number, and it was so marked along with the assigned Bureau Number (BuNo). The V-173 apparently predated the formal adoption of the research aircraft designation convention because U was the Navy’s letter for Vought, not V.

The Navy's next research aircraft program was initiated in 1945 with Douglas for high-speed research aircraft. This was intended to be a three-phase effort, with the first phase being design, manufacture. and flight test of a set of transonic jet airplanes; the second, modification of two of the six Phase 1 airplanes with auxiliary rocket engines for higher speed; and the third, a mockup of an operational jet fighter. Early on, Douglas and the Navy tore up the original plan. The first phase resulted in three D-558-1 identical straight-wing Skystreaks. The second phase was an all-new swept-wing aircraft. It received the designation D-558-2 and a different popular name, Skyrocket. Note that its Douglas model number was almost certainly not 558. The third phase of the contract was cancelled.*

The next Navy research aircraft program resulted in two Bell P-63s modified with swept wings in  early 1946. These were designated L-39-1 and L-39-2, with L being the Navy’s letter for Bell and 39 in this case being the Bell design number for the proposal. (Design numbers were assigned by Bell engineering independently of model numbers, which were assigned by management). As it happened, Bell never assigned a model number to the Navy’s L-39. However, at least one of Bell’s L-39 flight test reports began with 33, which was the model number of the early P-63s.

The Navy bought three of the Kaman synchropter model 225s for evaluation in 1950, assigned them BuNos, and gave them the designation K-225, which also was the Kaman designation.

In January 1951, Convair received a contract for two experimental jet fighter seaplanes, which the Navy designated Y2-2. This is the cleanest example of the convention, since Y was the Navy’s letter for Convair and 2-2 was Convair’s model number. These were redesignated XF2Y-1 later that year.

The Navy contracted with Kaman for a tiltwing STOL ground test article (half of the wing, one engine, nacelle, and prop) as the K-16 in 1956. In January 1958, this contract was amended to add the design and manufacture of the K-16B, which consisted of the K-16 wing and a Grumman JRF fuselage. It never flew but was tested in the NASA Ames 40X80 wind tunnel in late 1962. A K-16C proposal with a Kaman HU2K helicopter uselage and fixed wing aircraft empennage did not result in a contract.

The Goodyear Inflatoplane was evaluated at NATC circa 1959/1960 in an Office of Naval Research Program. Five Goodyear GA-468s were reportedly acquired by the Navy for test but I don’t know if it ever got a BuNo or a Navy designation.

* The cancellation of the third phase of the Navy/Douglas high-speed research program did not preclude the uninformed from subsequently applying the designation D-558-3 to a follow-on study accomplished by Douglas for the Navy, the Models 671, as well as to its proposal for the Air Force/NASA/Navy X-15 program, the Model 684. It was, in effect, a retroactive nickname, one not used by Douglas at the time, much less the Navy.
                                                                              D-671                                                  D-684

Monday, July 19, 2010

Index for Entries 1-99

For the hundredth post on this blog, I decided to create an index of blogs 1-99, since I have trouble remembering what I’ve done and some of the entry titles aren’t very helpful. I've added links for your convenience. Note that the titles here may differ from the blog entry.

For a more modeler-oriented blog, see Tailhook Topics.

   Real Men Don’t Need Catapults (F4D) 3 November 2008
   Hangar Deck Catapult 17 November 2008
   Hydraulic vs. Steam (F4D) 10 January 2009
   Nose Gear Launch Bar 27 April 2009
   Bridal Launch (F2H/A3J) 28 April 2009
   High Angle of Attack (F7U-1) 27 May 2009
   Davis Barrier Development 22 September 2008
   Davis Barrier Redux 1 October 2008
   Barrier Cable Pickup (XFJ-2) 26 September 2009
   Most Accurate Aviation Movie Ever? 10 November 2008
   Ramp Strikes 20 April 2009
   The Tail Hook (F11F) 20 September 2009
   Landing Stress (F8U) 3 October 2009
   The Tail Hook (FR-1/XF4D) 12 October 2009
   The Tail Hook (F7U-1) 14 October 2009
   Vertical Fin Markings 10 December 2009
   Beware of Propellers 21 January 2010
Spot Factor and Folding
   Wing Folding (F4F) 13 March 2010
   A-7 Vertical Fin Modification 18 June 2009
   A-6 Folding Horizontal Tail 19 June 2009
   Spot Factor Summary (V-383) 22 June 2009
   A4D Wing Span 28 June 2009
   XF3H Angled on Elevator 30 June 2009
   Hangar Deck Height
       AJ Savage 13 March 2010
       F9F Panther 21 March 2010
   Maximum Folded Wing Span 11 July 2010
   Folded Wing Span History 14 July 2010
   Hangar Deck Folded Width Constraint 2 July 2009
   SCB 27C Forward Elevator I 5 March 2010
   SCB 27C Forward Elevator II 9 March 2010
   Not Doing It Right (Idiot Loop) 5 June 2008
   Antiaircraft Bombs 20 June 2008
   Torpedo Attack Geometry 24 July 2008
   Torpedos (Tailhook Topics)
   TDN/TDR Control Plane 19 September 2008
   Folding Fin Air-to-Air Rockets
      XF4D/XF3H 12 June 2009
      F8U 20 December 2008
      A4D 11 June 2009
   AD-4N with torpedo 15 March 2009
   Nuclear Weapons (F2H) 4 November 2009
   Laser Guided Bombs 7 September 2009
Air Group Composition
   Saratoga (CV-3) 1930s 26 March 2009
   Midway August 1952 (F7U-3/XFJ-2) 26 February 2010
   Lake Champlain 1954/5 (VC squadrons) 29 November 2009
   Hornet 1957 23 March 2009
   Saratoga January 1958 4 December 2008
   Forrestal 1960 (F8U-2/A3J/F4H) 12 April 2009
   Area Rule (F11F/F8U) 15 February 2009
   Boundary Layer Control 12 December 2009
   Turboprop Fighters (A2D) 9 February 2009
   General Purpose Fighter (F3H) 2 June 2009
   Self Boarding
       XF3H 2 June 2009
      Production F3H 21 May 2008
   1946 Long Range Escort 20 April 2010
   1948 Jet Bomber Competition 24 December 2008
       F8U 26 January 2009
       XF4H 2 February 2009
   Akron and Macon 19 July 2009
   Strike from the Sea
      Errata I 31 July 2009
      Errata II 9 August 2009
   Unpainted Finish 20 December 2009
   V for Volplane? 4 April 2010
   Supercharging Makes a Difference 25 May 2008
   The Navy and Liquid Cooled Engines 10 June 2008
   Turbofan Engines (F-111B) 8 March 2009
Specific Airplanes
   Bell HSL Monograph Announcement 19 May 2008
   Bell XFL-1
      Carrier Suitability Evaluation 4 July 2008
      Monograph Announcement 6 September 2008
   Douglas “D-558-3” 20 May 2008
   Douglas AD Longevity 21 May 2008
   Douglas A4D
      With A3D Pathfinder 4 April 2009
      All-Weather (A4D-2N) 6 April 2009
      Book Announcement 27 June 2010
      Why 27 ft 6 inch Wing Span 11 July 2010
   General Dynamics A-12
      Lawsuit Status I 3 June 2009
      Lawsuit Status II 27 November 2009
      Lawsuit Status III 12 July 2010
   Grumman WF-2 Prototype 10 July 2008
   Grumman F10F
      Flight Controls 19 January 2009
      Variable Incidence Wing 14 July 2009
   Grumman Single Seat A-6 [VA(L) competition]
      Mockup 23 August 2008
      Artists Concept 14 June 2009
      A-6 Folding Horizontal Tail 19 June 2009
   Grumman F12F 16 September 2008
   Grumman F-111B
      Monograph Announcement 19 May 2008
      Carrier Trials 3 March 2009
      Engine Inlets 8 March 2009
   Martin Model 245 Long-Range Bomber 17 July 2008
   Martin Model 246 Attack Airplane 2 August 2008
   McDonnell F2H Banshee Misstatements 29 December 2008
   McDonnell F4H (F-4)
      Engine Selection 9 September 2009
      Lift Improvements 20 November 2008
   FJ-4/F8U (Navy Day Fighter Specification) 20 October 2008
   North American FJ-5 Monograph 6 December 2008
   Vought XF4U-1 (400 mph?) 10 October 2008
   Vought AU-1 20 March 2009
   Vought F7U-1 16 December 2008
   Vought General Purpose F8U 31 October 2008
   Vought F8U-3 15 December 2008
   Vought Attack Crusader (A-7) 17 August 2008
   Vought A-7 27 August 2009

Wednesday, July 14, 2010

Fitting In III

One of the interesting aspects of the maximum folded span of 27 feet six inches that set the wing span of the Skyhawk was that it was two feet less only a few years earlier.

I haven't made a complete review of folded spans but of the early jets, the biggest by far (not counting the FJ-1 and F6U that did not have folding wings but were to use a retractable nose gear feature to reduce the spot factor) was the Douglas F3D Skynight. Its mockup review was in April 1946 and the folded span appears to have been somewhat more than 26 feet. If this was a problem, it wasn't significant enough to be mentioned as a concern.  The folded span was measured on the XF3D-1 at 26 feet seven inches and shown on the F3D-2 SAC as 26 feet 10 inches.

The XA2D-1 folded span was 25 feet six inches from the September 1947 mockup review through the production aircraft. (The AD's folded span was 24 feet.)

The Navy's report on the F4D mockup review held in March 1949 mentions that the folding scheme had originally been to manually fold the outboard four feet of each wing downward. Assuming that the wing span at the time was the same as the XF4D's, that would have resulted in a folded width of 25 feet six inches. "However, in later design studies it became apparent that the wing break would have to run diagonally instead of fore and aft. This necessitates wing folding upward. It was thought that manual folding would be unsatisfactory from an operational viewpoint, therefore power folding is required." There is no concern expressed that the folded span would be 26 feet two inches with the slats open.

By the July 1949 mockup review of the McDonnell XF3H Demon, a limit has been established. "The Board requested the contractor to study the feasibility of providing manual instead of power wing folding. The unfolded span is not a limiting factor on carrier elevator and folding would be required primarily to permit passing of aircraft on CV-9 hangar decks. Since other operational considerations such as spotting on the flight deck did not appear to be seriously affected, the Board was of the opinion that the substantial weight saved by manual wing folding would be highly desirable in an interceptor. In addition, the contractor was asked to move the wing fold outboard, but under no circumstance is folded span to be greater than 25' 4" (max allowable to permit passing of aircraft on hangar deck)."

My current guess is that there were pressures to move the wing-fold joint outboard (lower loads on the fold joint and therefore somewhat reduced weight, for one thing). Since the pinch point on the hangar deck could be avoided by foresight in positioning aircraft, the new limit of 27 feet six inches was probably established in 1952 by the longer elevators being introduced on the Essex-class carriers modified in accordance with SCB 27A that were beginning to appear in 1950 and 1951. As shown in previous posts, this folded span permitted two airplanes to be loaded on the longer elevator at the same time.

How to explain the Navy approving a folded span of 28 feet five inches for the F5D at its mockup review in 1953? Perhaps because Douglas fit two in...

Monday, July 12, 2010

A-12, The Gift That Keeps On Giving III

Again, the gift is one to lawyers. When I last posted on this (27 November 2009), Boeing and General Dynamics had lost a request for a rehearing by the U.S. Court of Appeals for the Federal Circuit of its decision sustaining the government's default termination of the A-12 program. At that time, Boeing and GD announced that they would take the case to the Supreme Court.

As it turns out, you don't actually get to argue a case before the Supreme Court just because you want to. What you do is petition the Court to hear your case and the judges decide if it's worthy of their review. The Court turns down most petitions although there are reasons why it might find this one interesting, according to the contractors' lawyers anyway. (The Court might also not hear it but kick it back for the rehearing that Boeing and General Dynamics were denied.)

In Boeing's 2009 annual report, it said that it would file a Petition for Writ of Certiorari to the Court on or before March 24, 2010. As it turns out, you can look up the status of cases on the Court's docket. Boeing did file on 23 April. The United States government was to respond on 27 May. It did not however, requesting and receiving extensions on roughly a month-by-month basis. The latest response date is 20 August.

If the Supreme Court decides not to hear the case, Boeing and General Dynamics each have to pay about $1.5 billion in unliquidated progress payments and interest on the payments. On the other hand, if the Court does hear the case and decides that the U.S. Court of Federal Claims got it right in March 1998, then they each get almost $600 million.

If you want to follow all this excitement on your own, go Here.

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.

Why 27 feet 6 inches? Redux

In my 28 June 2009 post, I speculated that the A4D's span was set by the 58-ft length of the Essex-class forward elevator after the angled-deck conversion. Too conveniently, 27.5 feet times two plus one-foot clearance between the aircraft and the edge of the elevator equaled 58 feet. What I didn't realize was that the forward elevator was only open to the hangar deck on its aft side, the narrower one, so the Skyhawks loaded athwartships couldn't be moved unless the wheels were on dollies.

The correct loading is shown here and I've also revised the June post.
However, even before I realized my blunder with respect to access to the hangar, I had been bothered as to why the 58-foot long elevator was used as the criteria, since it was the biggest centerline elevator, introduced with the SCB 27A change. Most were smaller. The centerline elevators on the Essex before conversion were 48 feet by 44 feet; those on the Midway class before conversion had a maximum dimension of 54 feet. It turned out that the 27 feet 6 inches was consistent with the original Essex elevators when the aircraft were positioned athwartships and headed at each other. (This was probably established before the slats were reintroduced in the configuration, but since they were easily stowed, the lack of one-foot clearance with the slats extended was not a problem.)
Of course, the Skyhawks still had to be positioned fore and aft on the forward elevator and angled for loading and unloading, but they fit. Note that angling was undesirable because of the extra time it took for positioning and the added risk of a crunch...