V-366 Landing Gear Studies

 Additional design study work was requested by the BuAer for the F7U development program. The V-366A/B/C had listed "undesirable catapult take-off characteristics, unprotected fuel tanks, insufficient vision over the nose and insufficient strength to meet current Bureau strength requirements." The V-366, (improved F7U-1) with Westinghouse 24C jet engines (J46) and improved radar, armament combination.

The BuAer requested the contractor to study landing gear arrangements other than the conventional tricycle gear for application in the design. It was an attempt at solutions to the "problems associated with operating a swept wing airplane off an aircraft carrier."

The conventional tail wheel was "not satisfactory due to high bearing loads in the strut and the adverse effect on airplane balance."

Tricycle gear with addition of a small tail wheel was evaluated next. This arrangement allowed the airplane to rock back on the tail wheel as the bridle and holdback are tensioned. The catapult bridle was planned to maintain the airplane on the main and tail wheel after the catapult was fired. This study with others led to a better solution of an extensible nose wheel strut removing dependency on the catapult bridle maintaining take-off attitude.

The third arrangement was a bicycle arrangement which was more difficult to implement due to fuselage space arrangements and weight. The fuselage would need reinforcement for the landing gear loads, the out riggers had to be heavy due to barrier crash loads.

In the end it was concluded that none of the configurations considered offered improvement over the conventional tricycle landing gear of the V-366 proposal

V-433 Low Cost Light Attack

 

 In 1959 Chance Vought internal studies identified a need for a low cost, versatile light attack aircraft to serve the needs of the US Navy and Marine Corps. They created an unsolicited proposal for a turboprop attack aircraft with tricycle landing gear. 

The concept was for a an aircraft optimized for close support and versatility to perform the Navy attack mission. A selling point for the aircraft would be a unit cost with Government Furnished Equipment to be under $400,000 each if the order was for 500 aircraft.

The aircraft was touted to be "all-weather" with instrument flight equipment and a ground controlled all weather bombing system. It was also mentioned that provisions would be provided for pylon mounted electronic equipment to support full all weather attack missions.

The V-433 was originally to be powered by the General Electric T-64-GE-4 engine with a three bladed propeller. However, delays with that powerplant led to the selection of the Allison T-56-A-8 turning a four bladed propeller. Maximum speed at 25,000ft was projected to be .74 Mach. 

The aircraft was to have six external pylons for the carriage of weapons, ECM pods, or radar pods. In addition to conventional bombs, Bullpup and Sidewinder missiles could be carried. Normal bomb load of 3,500lbs with an short range load of 4,410lbs. The V-433 could also carry 2,000lbs of special weapons instead of conventional ordinance. 

One of the envisioned missions was helicopter escort to support the Marine Corps and supporting a vertical envelopment for approximately 3 hours with a normal external weapons load.

The V-433 was to be 35' 10" long with a wingspan of 37'.

Models by Jay Frank Dial, general arrangement courtesy of Mark N.

Chance Vought V-369 High Speed Target

Developed under Chance Vought Project number V-369 was a high speed target for the US Navy known first as X-27A and later as the production version X-28A. It was designed to be operated at speeds approaching 450 mph. 

CV-25391-X-27A-General-Arrangement-Starboard-View-19470121

 

CV-25393-X-27A-General-Arrangement-Port-View-19470121

NOTE: I am still researching the program so all that follows may turn out to not be factually correct. 

At least 35 examples were built with the first being designated X-27A and is illustrated in these contract photos from NARA 72AC files. 

CV-25394-X-27A-General-Arrangement-Front-View-19470121

I have found a part number drawing for the X-27 and all the production drawings started with the prefix CV5-. I also found one drawing for the X-28A that in configuration is the same "V" tailed design as the X-27A photos.

The construction of the fuselage of the target was fairly simple as this interior shot illustrates.

CV-25412-X-27A Upper-Shell-Assembly-Interior-View-19470121

If you happen to have any more details about the V-369/X-27/28 I would like to hear from you.

V-507 The F-14 That Wasn't Part Three

     After the visitors had passed the various information panels the pathway eventually led to the main event, the full size mock up. The mock up was placed in an open, well lit area for viewing and showing off the designs features.

     With the V-507, space was given to show the wing sweep design for it's aerodynamic and ship board handling qualities. The mock up also allows a full size representation of height of the aircraft along with the presentation of where the major components are housed in the airframe. 

     With the AN/AWG-9 Phoenix weapons system being central to the future F-14, the V-507 mock up was able to show the antenna installation along with the ease of access to the avionics boxes used for the system.

All photos courtesy VAHF

V-507 The F-14 That Wasn't Part Two

The V-507 Mock Up is Born

As was common practice in the industry since the 1930's, an Operations Specification, Request for Proposal or other documents were submitted to industry and brochures, reports were generated on the company's proposal. The proposals were evaluated and the top one or top two were selected to go further into the development stage with more detailed engineering being accomplished and a mock up built.The V-507 is was selected to continue on to the mock up phase. 

The visitor to the V-507 mock up was treated to a series of informational panels along the way to the actual mock up. These panels helped to tell the story of the V-507 and why it was the right choice for the US Navy. Although incomplete, the photos do give signifigant insight into the development of the V-507.

A configuration display was presented with models showing the evolution from the F8U-3 to the V-484, V-505 and eventually the final V-507 configuration.

The threat that needed to be countered was illustrated. This showed that the engineering team understood the challenges facing the new design.

The technical alliance of Vought, Dassault, and Lockheed shown with the contributions of each highlighted.

Vought

• Navy Fighter Design
• Movable Wing Technology

Dassault

• Inlet Design
• TF-30 Operational Experience (Mirage F2, Mirage G)
• Swing Wing Experience

Lockheed

• Air Force Fighter Design
• Titanium Manufacturing Technology

To further illustrate the technical alliance a display of the inlet design was presented along with the metals used in the manufacture of the aircraft along with what components were using titanium.

Finally in the photos that were uncovered for this post are the spotting diagrams. As this was an aircraft for the US Navy the ability to move and store the design aboard ship is critical to the success.

The display shows different spotting arrangements and compares the V-507 to the F-4 that was the current shipboard fighter. It also shows the V-507 in the hangar with the various other types then on board ship.

That concludes this walk through of the V-507 information boards. As can bee seen in the photos there are other panels and places where the confidential information has been covered over. These were the only photos uncovered thus far of this display, which is amazing that they still exist!  

In the next installment of this series the mock up will be revealed.

V-507 The F-14 That Wasn't

The V-507 was Vought's entry into the VFX competition to replace the unsuccessful F-111B aircraft. Unfortunately, the V-507 lost out to the Grumman 303 design that was designated F-14 Tomcat and went into US Navy and Iranian service.

The design featured swing wings, twin engines with a single vertical tail along with a tandem seating arrangement for the crew. Missile load for the V-507 included the AIM-7 Sparrow, AIM-9 Sidewinder, AIM-54 Phoenix and M61 cannon.

In addition to the AWG-9 fire control system the V-507 also had a provision for a retractable IRST/TV under the nose of the aircraft.

Unfortunately, there was not a fly off and nothing more than a mock up was ever built.

 Drawings from the VAHF Archives.

V-389 More Details

     Continuing with V-389 information is a look at the actual J57-P-4 engine installation into the A2U-1 airframe. This installation drawing shows the placement of the engine and afterburner assembly into the A2U fuselage. 

     Basically aft of fuselage station 265.1 a structural production break the fuselage is new. One major internal change is the changing from a central shear panel (formerly between the two engines) to two shear panels (one on either side of the engine) to absorb fuselage bending loads and fuel inertial loads. 

     All the changes to the fuselage still enable the same wing root rib to be used with the slight exception at the tail cone.

Clip from CVS-37356 V-389 Engine Installation Profile View

Clip from CVS-37356 V-389 Engine Installation Plan View

     Changes to the wing center section was fairly mild. The center-section pylons are moved 9.7 inches aft of the A2U location. The pylons attached to the main wing beam and aft beam instead of the front beam and main beam. 

CVS-37358 V-389 Comparison of V-389 and A2U-1 Plan View

     In addition to the pylons the aft end of the wing root was to be changed to adapt to the new aft fuselage cone for the single exhaust.

CVS-37358 V-389 Comparison of V-389 and A2U-1 Plan View

     Under the skin lighter electrical and hydraulic systems were incorporated. The electrical system would incorporate a separate AC and DC circuits with AC generation taking place by a bleed air turbine generator. Weight would be saved by removing one DC generator, internal battery, and two inverters.

     The hydraulic system incorporated an emergency ram-air-turbine driven hydraulic pump and alternator. The utility system reservoir was redesigned to accommodate the lower fluid volume requirements. One utility system pump was eliminated due to a new higher efficiency pump and the hydraulic oil cooler was eliminated.

     Another subtle change was the installation of only two MK12 guns above the right-hand inlet duct with provisions for a second set over the left-hand inlet duct. 

CVS-37360 V-389 Gun Installation Profile View

The gun muzzles are staggered and located aft of the duct lip instead of in the air duct lip like the A2U-1.

CVS-37360 V-389 Gun Installation Plan View

Source Chance Vought Engineering Report 8847 V-389 Attack Airplane Design Report, NARA II

V-389 Attack Aircraft

  

     A January 1954 Chance Vought V-389 proposal was for an improved performance attack aircraft based upon the A2U-1 Cutlass. The proposal featured a single Pratt and Whitney J57-P-4 engine replacing the twin Westinghouse J46 engines. A new fuselage section from the inlets aft would be required to house the single engine. The V-389 would share major components of the A2U-1 including wings, vertical tails, landing gear and forward fuselage.

The powerplant change caused a significant increase in radius of action, 280 nautical miles for a total radius of 605 NM while using only internal fuel and carrying two 2,000 lb bombs. 

The V-389 equipped with external fuel and a “special weapon*” had a radius of 815 NM.

AIRPLANE	V-389		A2U-1
ENGINE	J57-P-4		TWO J46-WE-18
Loading	Two 2,000 lb Bombs	3,500 lb Store, 300 Gallon Drop Tank and 220 Gallon Fuel Pack	Two 2,000 lb Bombs	3,500 lb Store, 300 Gallon Drop Tank and 220 Gallon Fuel Pack
Gross Weight	34,830 lbs.	38,170 lbs.	33,950 lbs.	37,330 lbs.
Combat Radius (NM)	605	815	325	500
Max Speed, Sea Level Clean Configuration (kts)	598	598	593	593

There appeared to be little official interest in the proposal and eventually the entire A2U-1 program was canceled. The V-389 is left as another interesting “what if”.

Data from Vought Report 8846 NARA II 

*The F7U-3 was cleared in separation tests to carry the Mk 7, 8, 11, and 12 stores.

The A2U-1 cancellation occurred November 19, 1954

Other A2U related posts: (here) (and here)

Type Spec 149 and the V-416 Vigilante Part II

     Continuing with the post started in June 2014, V-416 Vigilante

     The V-416A was a design for a minimum size, all weather attack airplane, with short take-off and landing capabilities. The aircraft was to be equipped with two J52 non-after-burning turbojet engines mounted in nacelles on the wings.

     Looking at the performance summary a 1,000 mile radius of action will only yield 2,200lbs of bombs to deliver on that distant target. Maximum speeds of Mach .915 with stores on at sea level and Mach .94 at 35,000 ft are impressive.

     The V-416 had a straight high wing, a unit horizontal tail 
(Vought preferred terminology) and a vertical tail with a large rudder. Short take offs were to be accomplished using double slotted flaps, leading edge droops and thrust deflectors that were to be located behind each engine.

     The attack and navigation track and search antennas were to be located in the nose with the system components installed under the cockpit accessible through access panels on the fuselage side.

     An additional avionics compartment was to be located in the rear fuselage to house communication equipment and computers for the attack-navigation system. 

     Here is the drawing of the avionics installations in the V-416A:

     This is the list of the numbered call outs for the drawing:

     Another important aspect for a carrier based aircraft was spotting arrangements. It did no good to create a great aircraft that could not be accommodated on deck in sufficient numbers to make it useful. 

     Therefore spotting diagrams were an important part of any carrier based proposal. In the typical 96' x 200' spotting area 20 aircraft could be parked. In an arrangement was use with tails overhanging the deck then 28 aircraft could share the same space.

This is a typical spotting diagram:

This is a spotting diagram for a CVA-41 style aircraft carrier:

     With straight spotting 56 V-416s could be spotted on deck, if deck overhang was use the number increased to 83.

Finally, below is a diagram showing the width of the V-416 with the wings folded that was used in creating the spotting diagrams.

V-519 The Great White Whale Part II

     An addition to the V-519 White Whale posts are these images of 156801. These are some scans of some older negatives that were not in the best shape of the V-519. These appear to be taken prior to the first flight. A couple of items of interest: the designation is still A-7E and most visibly the gold stripe is not painted on the vertical fin.

A nice image of the nose with the canopy open. VAHF Archives

 Side view of the V-519 after being towed from the hangar.  The gold fin stripe has not been added yet. VAHF Archive

Close up of the tail markings on 156801. VAHF Archives

A little better image of the aircraft with the A-7E designation painted on the fuselage above the Bureau number. VAHF Archives.

The White Whale, a fixture around the Vought plant for many, many years, was used in a number of test programs. Further posts will illustrate more of the different paint schemes carried by the aircraft over it's service life with Vought.

V-519 The Great White Whale

Artists concept of the the V-519 modified from A-7E 156801. VAHF Archives

     With each of the aircraft that Vought sold the US Navy since the F4U Corsair there has been an offering for a two seat trainer version. The first that nearly achieved production conversion status was the F4U, A mock-up was build from a surplus F4U-1 and money was actually budgeted at one time. Sadly the project was killed by a number of things, the main reason being budget cuts.

Vought also developed "paper planes" of a two seat F6U Pirate and a two seat F7U Cutlass. The F8U came close to having a production conversion line for the F8U-1T, but once again it did not happen. 

With the successful introduction of the A-7 into the fleet, once again Vought proposed a training version of the A-7A the TA-7A without gaining much traction towards a contract. Keeping with the tradition Vought proposed the V-519 two seat version of the A-7E.

Early photo of the White Whale while the test probe was fitted to the nose. VAHF Archive

The Navy and Vought agreed upon a project to take an A-7E and convert it into a two seat configuration.

The aircraft bailed to Vought was A-7E 156801 (VAC No 68). The aircraft was to be fitted with equipment to support the flight test program developed for the program. 

The conversion consisted of adding a 16-inch extension and a second cockpit to the forward fuselage section along with an 18-inch extension between the mid and aft fuselage sections.
The refueling probe and M-61A1 gun system were removed along with the ECM system. The rest of the A-7E avionics suite was retained. The TF41-A-2 engine remained unchanged. 

The last major change was the addition of a single side opening canopy that utilized a "through the glass" ejection system. 

Head on image of 156801 shows the side hinging canopy to advantage. VAHF Archive

The forward cockpit basically stayed the same as the A-7E from which it was derived. The rear cockpit had primary flight controls and a limited set of instruments fitted. Vought bestowed the company designation of V-519 on the modified aircraft.

Taxi shot of the White Whale during the early testing program. VAHF Archive

The first flight was made on August 29, 1972 by John Konrad and the aircraft flew for one hour. The White Whale went on to perform many test and demonstration functions with Vought along with having a number of designation changes during its life. More later.......................

Here is a later image of 156801 after the test probe was removed but the aircraft still retains the gold fin band. This view also shows the large speed brake in the extended position. VAHF Archive