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Author Topic: Vought (LTV) A-7 Corsair II Projects  (Read 89347 times)

Offline PaulMM (Overscan)

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Vought (LTV) A-7 Corsair II Projects
« on: January 02, 2006, 02:45:09 am »
Thread to discuss A-7 Corsair II projects
« Last Edit: January 02, 2006, 08:28:15 am by overscan »
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Offline PaulMM (Overscan)

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Re: Vought (LTV) A-7 Corsair II Projects
« Reply #1 on: January 02, 2006, 08:25:45 am »
Due to concerns over the survivability of the subsonic A-10 over the modern battlefield, the USAF in 1985 launched a program (CAS/BAI) to procure an A-10 replacement with full 24 hour attack capability. 4 firms responded; General Dynamics proposed a modified F-16C (A-16), McDonnell-Douglas a modified AV-8B "Harrier II", Northrop suggested their F-20 and LTV proposed  deep upgrade of the A-7D initially called A-7D+ (other sources: A-7+).

The General Dynamics and LTV proposals were both favourably regarded. LTV were awarded a contract to build two prototype A-7D+, later redesignated YA-7F. The YA-7F replaced the Allison TF41 engine with the afterburning Pratt & Whitney F100-PW-220 (alternatively, the General Electric F110-GE-100) used on the F-16.  This was expected to increase maximum speed to about Mach 1.2. The fuselage was extended ahead of (0.9m) and behind (0.46m) the wings to increase fuel capacity and provide racking space for upgraded avionics. The vertical fin was made 0.25m taller, and LERX and improved flaps fitted to the wing. A modern cockpit was designed with wide-angle HUD and MFDs, a LANA FLIR was incorporated, and laser ring inertial/GPS navigation equipment. Blisters on the lower rear fuselage housed twin ALQ-165 or 184 ECM systems. The existing Pave Penny laser spot tracker and APQ-126 radar retained.

The first flight of the first YA-7F was made on 29 Nov 1989, the second joining the test program on 3 April 1990. LTV were hoping to modify about 307 ANG A-7D to the new standard, for a unit flyaway cost of $4.93 million (other sources say $6.5 million) per aircraft, extending the life of the aircraft as far as 2018. In 1990 the YA-7F was returned to Vought for re-engining with the F110 engine, but never flew with it. The program was cancelled in late 1990 in favour of modified F-16s, and all A-7s withdrawn from service in the early 1990s.

Length: 14.94m
Wingspan: 11.8m
Height: 5.33m

Empty Weight: 10,460kg (F100) 10825kg (F110)
Max Takeoff Weight: 20,865kg
Internal Fuel: 4700kg
Ferry Range: 4260km with 4 external 1,135l fuel tanks

Sources
« Last Edit: January 02, 2006, 08:27:55 am by overscan »
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Offline TinWing

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Re: Vought (LTV) A-7 Corsair II Projects
« Reply #2 on: January 04, 2006, 11:26:12 am »
1.  Early artwork of the A-7F depicted a F-8 style radome.  I wonder if a radical avionics upgrade was proposed early on and then dropped?

2.  Joe Baugher's site refers to the upgrade of 96 Navy A-7Es to the A-7F configuration.  This reference has always been a mystery to me?  Would the Navy have operated a very small fleet of less than 100 A-7Fs or would the 96 airframes in question have been passed on to the Air National Guard?

Offline PaulMM (Overscan)

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Re: Vought (LTV) A-7 Corsair II Projects
« Reply #3 on: January 04, 2006, 01:06:32 pm »
I've never seen the early A-7F configuration. I assume it would be associated with a radar upgrade. In 1987 Carlo Kopp wrote an article which mentions TFR (terrain following radar) on the A-7 Plus.

The most detailed source #I have on the A-7F is Al Adcock's Squadron-Signal volume, he says the first proposal was called "A-7 Strikefighter", then "A-7 Plus", but doesn't mention any differences between the versions.

Al Adcock mentions a separate LTV proposal to upgrade Navy A-7s to a KA-7F tanker-capable version with larger fuselage and 4  x 450 gallon external fuel tanks and an  under-fuselage hose and drogue system, rejected in favour of KA-6D.

Sources
« Last Edit: January 04, 2006, 02:42:28 pm by overscan »
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Offline PaulMM (Overscan)

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Re: Vought (LTV) A-7 Corsair II Projects
« Reply #4 on: January 04, 2006, 01:29:03 pm »
Some additional unbuilt projects

A-7D(ER)
1972 project, lengthened fuselage and the GAU-8A 30mm cannon from the A-10. Outgrowth of their AX proposal, but the A-10 won a flyoff against the A-7D in 1972 and ended the project.

Vought A-529D
Twin F404 engined version for the Navy

A-7G
Version offered to Switzerland in 1971. Uprated TF41-A-3 engine, radar/Loran removed (to be replaced by Swiss specified equipment), Vulcan cannon replaced by 2 23mm Madsen cannons. Two built, flown against G-91M and A-4M Skyhawk. Refurbished Hunters were purchased instead.

Source

  • Al Adcock A-7 Corsair II in Action Squadron-Signal, 1991
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Offline PaulMM (Overscan)

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Re: Vought (LTV) A-7 Corsair II Projects
« Reply #5 on: January 04, 2006, 01:31:32 pm »
Guy Alcala posted this on rec.aviation.military:

Quote
The A-7F, Corasair III, Strikefighter, etc. all included an airframe stretch
and extra fuel in addition to an F100 or F110.  The airframe stretch was to
allow the a/c to be supersonic (Mach 1.4 level IIRR), and the extra fuel was
to keep the range/endurance in the same ballpark.

For instance, here's the proposed Corsair III changes, which was designed to
use rebuilt A-7A/A-7B airframes from the Boneyard, although A-7D/Es would be
easier to convert: An F110-GE-100, 16,700 lb. mil and 27,600 lb. A/B; A
constant-section plug of 29.5" to extend the fuselage around the wing root
area; another plug of 7.5" to the aft fuselage to tailor the airframe to the
F110 and its remote accessory gearbox.  Rear fuselage canted upwards 5 degrees
to provide ground clearance for the longer tailpipe.  A more sharply-pointed
nose cone (see F-8); the original was made blunter to reduce length on
carriers.  Internal configuration changed to increase fuel capacity.

The "Strikefighter" was an upgraded A-7D with an F100 vice F110, and was the
design entered in a CAS/BAI contest against the F-16, AV-8B and F-20.

All data above from Dorr's Osprey book "Vought A-7 Corsair II." There are also
various issues of Air International from the '80s which describe the various
proposals in slightly more detail, but I'm too lazy to hunt them up.

Guy
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Offline TinWing

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Re: Vought (LTV) A-7 Corsair II Projects
« Reply #6 on: January 05, 2006, 08:10:34 am »
Some additional unbuilt projects

A-7D(ER)
1972 project, lengthened fuselage and the GAU-8A 30mm cannon from the A-10. Outgrowth of their AX proposal, but the A-10 won a flyoff against the A-7D in 1972 and ended the project.

Vought A-529D
Twin F404 engined version for the Navy



Source

  • Al Adcock A-7 Corsair II in Action Squadron-Signal, 1991

I'm familiar with many of the AX proposals.  Jay Miller's "Skunkworks" has drawings of both J52 and TF34 powered Lockheed proposals. 

However, I'm very surprised by this mention of of a GAU-8 armed A-7 derivative.

I'm also left to wonder whether or not the Vought A-529D proposal's F404 engines featured reheat.  An A-7 with a pair of "dry" F404s would make an interesting comparison with the cancelled A-6F.

Offline TinWing

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Re: Vought (LTV) A-7 Corsair II Projects
« Reply #7 on: January 06, 2006, 07:22:00 am »
Would it be possible to post these two proposals ??

Cheers, Deino

Yes, here are the Lockheed drawings.  The top drawing shows the TF-34 powered concept, the bottom depicts the J-52 engined proposal.

Source:  Lockheed Martin's Skunk Works by Jay Miller (Midland Publishing LTD, 1995).


Offline elmayerle

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Re: Vought (LTV) A-7 Corsair II Projects
« Reply #8 on: January 08, 2006, 04:45:55 pm »
Some additional unbuilt projects

A-7D(ER)
1972 project, lengthened fuselage and the GAU-8A 30mm cannon from the A-10. Outgrowth of their AX proposal, but the A-10 won a flyoff against the A-7D in 1972 and ended the project.

Vought A-529D
Twin F404 engined version for the Navy

A-7G
Version offered to Switzerland in 1971. Uprated TF41-A-3 engine, radar/Loran removed (to be replaced by Swiss specified equipment), Vulcan cannon replaced by 2 23mm Madsen cannons. Two built, flown against G-91M and A-4M Skyhawk. Refurbished Hunters were purchased instead.

i've got a scan of an artist's conception of the V-529 with the twin F404s, that was partly a political move since the F404 is/was built in Teddy Kennedy's home state and "Tip" O'Neill's (the Speaker of the US House at that time) district.  I'm thinking of trying to work that one up along with a similar re-engining of an F-8.

Offline PaulMM (Overscan)

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Re: Vought (LTV) A-7 Corsair II Projects
« Reply #9 on: January 13, 2006, 09:56:14 am »
The GAU-8 equipped, stretched, A-7DER is also mentioned by Dennis R. Jenkins in Warbirdtech 20: A-10 Warthog
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Offline elmayerle

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Re: Vought (LTV) A-7 Corsair II Projects
« Reply #10 on: January 25, 2006, 07:13:15 pm »
I believe the V529D proposal with the twin F404s used afterburning ones.  For the time period (late 1970s) it was an astute political move given that the F404 was built in the district of the person who was Speaker of the House at the time and in Ted Kennedy's home state.  Commonality in engines with the F-18 would not have hurt, either.  I wonder how many other systems would've been common?

Offline PaulMM (Overscan)

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Re: Vought (LTV) A-7 Corsair II Projects
« Reply #11 on: February 20, 2006, 12:02:05 pm »
Vought building two seat A-7E derivative (Vought V-519) as advanced trainer; seat advanced attack version, with F100 turbofan and second crew member space given over to 30mm cannon ammo also considered.

Source:
  • Air Enthusiast June 1972, p330
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Offline PaulMM (Overscan)

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Re: Vought (LTV) A-7 Corsair II Projects
« Reply #12 on: September 20, 2006, 02:34:35 pm »
According to Roy Braybrook, the V-529D twin engine Corsair project used 2 x 10,000lb st F404s without afterburner. The company aimed to convert 336 Navy A-7Es for $500m, and to provide a twin seat USAF derivative (V-531) to the FAC-X requirement. Other changes include an improved flap and 26% greater fuel, with a 20in centre fuselage stretch.

Air International, April 1978
« Last Edit: February 16, 2008, 01:44:52 am by overscan »
"They can't see our arses for dust."
 
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Offline Antonio

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Re: Vought (LTV) A-7 Corsair II Projects
« Reply #13 on: September 21, 2006, 01:00:52 pm »
I don't know the precise source but it is an italian mag from 1986.

A-7 CAS/BAI (Close Air Support/Battlefield Air Interdiction)

Interim solution for the USAF consisting in reengining the 337 Air National Air Guard A-7 fleet with a new afterburning engine (no more details :- ???), updated avionics and structural modifications.


Offline TinWing

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Re: Vought (LTV) A-7 Corsair II Projects
« Reply #14 on: September 22, 2006, 08:12:16 am »
Vought building two seat A-7E derivative (Vought V-519) as advanced trainer; seat advanced attack version, with F100 turbofan and second crew member space given over to 30mm cannon ammo also considered.

Source:
  • Air Enthusiast June 1972, p330


The bit about the "F100 turbofan" leads me to believe that the YA-7F had a very long gestation period.