North American A3J (A-5) Vigilante

[AGRA]

What would have been very interesting is if the RAAF and RAN cooperated on the acquisition of both the Vigilante and the Phantom, the RAAF operating the bulk of them with the RAN FAA flying a smaller number from a pair of 1960s new build carriers.  The Raaf aircraft would still be carrier capable and able to provide a surge capability to support the FAA.

Maybe in a world where the FAA was never formed and the RAAF maintained the carrier air groups (like onboard HMAS Albatross before WWII). Though I can’t see the RAN ever getting a Forrestal class sized carrier needed to fly Vigilantes.

[elmayerle]

I doubt the RAAF would keep the Vigilante (or is it the Retaliator?) in service beyond the mid 80s. Menzies was right they would want another aircraft in the 70s pretty much as soon as the US Navy stopped flying them. Which is not such a bad thing because the Vigilante replacement could then be in sync with the Mirage III replacement.

If you did keep the Vigilante in service after the US Navy then the J79 is not such a bad engine to keep. Plenty of life left in it and changing engine types with the Vigilante’s titanium fuselage ribs sounds real tough.

That's why I suggested the engines I did.  Both were available starting from the late 1970's and both fit within the installation envelope of the J79 without difficulty.  Both also give improved range due to better sfc.

[AGRA]

That's why I suggested the engines I did.  Both were available starting from the late 1970's and both fit within the installation envelope of the J79 without difficulty.  Both also give improved range due to better sfc.

I originally thought that because of the one piece titanium structure in the aft fuselage any engine change, even to one within the dimensions of the J79, wouldn’t work because it would be too hard to fit in changes in piping, accessory gear etc. But looking in detail at the Vigilante engine bay and there is a lot of room around the engine for secondary airflow. Almost the full radius of the engine below the actual engine.



Also about 40% of the surrounding structure is the fold out engine access doors. These could always be replaced with a new bulged door if more volume was needed.



So after a rethink I agree that an engine change would be quite easy. However my upgrade timeframe is 1976-82. Both the F404 and PW1120 would be too late for this schedule and both the YJ101 and RB199 Mk 101 do not have enough power to replace the J79. PW1120 would be ideal so I guess it’s time for some more research on the topic.

[AGRA]

Looking up the PW1120 on Flight Global’s excellent archive shows it was first publically proposed in 1980 as a low risk turbojet version of the F100.

P&W develops new turbojet
FLIGHT International, 12 July 1980
PRATT & WHITNEY is developing a turbojet of around 20,0001b thrust, based on the core of its F100 turbofan. The new PW1120 will compete with growth versions of the General Electric F404 and Rolls-Royce RB.199. The company expects to flight-test the engine in 1983 with qualification in 1985. The PW1120 is regarded as a low-risk programme.
Design thrust-to-weight ratio is 7-25:1 compared with 7-9:1 for the 25,0001b-thrust F100. Operating temperatures will be lower than the F100 throughout the flight envelope, P&W says. More than 60 per cent of parts will be common with the existing engine. New components will include a low-pressure compressor and turbine and a simplified afterburner.
The PW1120 is 170in long (F100: 190in) and 33in diameter (F100: 40in). The company sees a market for 4,000 to 5,000 engines of this size over the next 20 years. Possible applications include Israel's Lavi and Sweden's JAS single-engined multirole fighter projects. By the time the PW1120 enters service, the F100 will have logged some 3 million flight hours.

In my whiff world I have this nation selecting the F-15 in 1973 for customisation and licence production as the new RAAF tactical fighter and RAN naval fighter. Including production of the F100 engine. So it is perhaps feasible in 1975-76 when the ‘Vigilante’ rebuild program was required that someone could have suggested a leaky turbojet version of the F100. The local engine company is similar to CAC with their engine experience but more extensive local programs (R2800 during WWII and had been licence producing J79s rather than Avons and Atars) and had developed with Rolls-Royce a lightweight turbofan (similar to Adour but a few years earlier) for a light fighter/trainer project. So they would have the experience to lead with P&W support a ten years earlier PW1120 project.

The PW1120 would transform the Vigilante like it was proposed to do with the Super Phantom. More thrust, lower SFC, lower engine weight and less need for reheat in flight profiles. Have to look at the numbers to see how much of an improvement in radius it will provide but it is likely to be substantial: maybe even as much as x 1.5.

[elmayerle]

The F404, which has better sfc and the same thrust as the J79-8 used in the first production batch of RA-5C's, would be available in the late 70's since the F-18 flew with it in 1978.  The real driver for re-engining the Vigilante was an engine capable of fitting through the rear spindle frame which was a massive and expensive forging.  NAA-Columbus was loathe to change that frame on cost considerations; an entirely understandable response given the cost and time penalties involved in re-designing it.

[AGRA]

The F404, which has better sfc and the same thrust as the J79-8 used in the first production batch of RA-5C's, would be available in the late 70's since the F-18 flew with it in 1978.  The real driver for re-engining the Vigilante was an engine capable of fitting through the rear spindle frame which was a massive and expensive forging.  NAA-Columbus was loathe to change that frame on cost considerations; an entirely understandable response given the cost and time penalties involved in re-designing it.

The A-5B and RA-5C were designed for the J79-GE-8 with a maximum 11,000 lbs dry and 17,000 lbs reheat thrust, this is the engine my license built A-5s are built with. The reopened line RA-5Cs built for the USN from ’68 were powered by J79-GE-10s (some were delivered with dash 8s but) that could produce 12,000 lbs dry and 18,000 lbs reheat thrust.

The F404-GE-400 as fitted to the initial F/A-18As had a maximum 10,000 lbs dry and 16,000 lbs reheat thrust. It was a much lighter engine than the J79 but that is still a lot less thrust than the Vigilantes were flying with. Its only with the EPE F404, the F404-GE-402, that wasn’t available until 1990ish that this engine was able to produce as much as 17,600 lbs thrust. Which is still less than the dash 10.

In 1975 that GE could say to the Vigilante rebuild team we have this great new F404 that will fly in a few years and be much lighter and better than the J79 but won’t quite produce as much thrust as the dash 8s and 10s. But P&W could say you can take the engine you are currently producing for the F-15 and cut stuff out of it and it will be lighter and have lower SFC, etc but produce 20,000 lbs and importantly fly the aircraft at speeds that you currently use first stage afterburner for in full military thrust. And with the benefit of being an engine that is highly similar to the J79 in footprint and uses the same mass flow to the intake. I can’t see the F404 being able to compete with this despite the better SFC and weight it can offer.

[elmayerle]

I do know that there were serious studies that said putting the F404 in the F-4 would be a good thing but St. Louis didn't want to compete with itself and I understand that the USN wasn't too keen on generating any concept that might hinder procurement of the F-18.

I agree, though, that the PW1120 would be the better choice and would be feasible in that time frame.

[AGRA]

Thank you for bringing it up because it really helps the Vigilante do things I want it to be able to do in the 1980s like fly very long range tanker supported missions and also fly 500 nm lo-lo-lo missions with 24 Mk 82s under the wings (A-5B could fly 400 nm lo-lo-lo with less draggy and weighty four Mk 84s). Because the PW1120 is being developed primarily for the Vigilante it would be a requirement of the project to fit it within the spindle frame.

Also the PW1120 (have to find a new name for it) fits into the strategic situation this Alternate Australia faces in 75-76 which is a real threat of an invasion. They have the F-15 project underway but it won’t deliver fighters until 78 and even building 50 planes a year won’t replace their legacy tactical fighter well into the 80s. So they have a large fleet of J79 powered Grumman Tigers that could find themselves up against lots of MiG-21s. The Tiger has the edge but fitting them with PW1120s makes it unassailable. 100 a year would be needed to re-engine all the Vigilantes within the time frame providing ample numbers to transform the Tigers instead if an air battle was to break out.

They also have good relationships with the Israelis (only country other than the Dominicans to put into place a large scale immigration scheme for German Jews before WWII) so the ‘Australian’ made PW1120 could make their Lavi plans more concrete.

[elmayerle]

Since the Vigilante did demonstrate the ability to tank other aircraft using a drogue and reel set-up in the linear bomb bay, I could see dedicated KA-5's supporting A-5's and others in a strike.  It would also give you the option of getting a tanker out there quickly if needed.  That's one I intend to model, only question is what markings.

[AGRA]

Unlike the A-6 there is no need to build a dedicated KA-5 because the bomb bay provides room for the drogue/hose unit. KA-6s had to remove their DIANE avionics complex to carry a drogue/hose making them unusable as a strike aircraft. Apart from the easily removable unit in the bomb bay the only other thing a tanking A-5 needs is the buddy tanker control panel which space for was designed in from the start.

It’s one of the advantages of the linear bomb bay that you can just roll in a train of fuel cans with the drogue unit at the end and presto a tanker. My thinking was to use this to make a modular fleet of strike aircraft. After the late 70s rebuild the RAAF Vigilante force is a mix of strike (two wings of 48 aircraft each) and recce aircraft (reinforced squadron of 24), which have different navigator cockpits adn the direct view sight on the recce version (plus of course the ventral canoe). The strike aircraft use the bomb bay to be configurable as:

# conventional strike: three fuel cans in the bay and bombs, napalm, rockets, etc on the wing pylons (3,600 gallons internal fuel).
# submunition strike: full length dispenser in the bay for either anti personnel, anti tank or anti runway loads (2,715 gallons internal fuel).
# PAVE TACK strike: vertical packaged AVQ-26 PAVE TACK laser designator in the forward end of the bay and three fuel cans. Up to four PAVEWAY III laser guided bombs under the wings (3,600 gallons internal fuel)
# WILD WEASEL strike: APR-35 radar homing and warning receiver in forward end of bay with anetennas in short ventral canoe (also plugging into other RWR antennas on the aircraft) and three fuel cans. Up to four AGM-78 Standard ARM under the wings (3,600 gallons internal fuel).
# stand off strike: Project Long Arm TV guided glide bomb with auxiliary fuel in bay (3,520 gallons internal fuel).
# nuclear strike: nuclear weapon with two cans and fin assembly in the bay (3,305 gallons internal fuel).
# refuelling tanker: two cans, buddy can and 78 feet hose reel unit. (3,595 gallons internal fuel)

Like the RA-5C the recce aircraft is configurable between imagining recce and electronic recce and has 3,600 gallons of internal fuel. Plus I’m thinking they have to put a few Vigis (6-8) aside during the rebuild project for conversion to NR-349 standard in long range optical photography and signals intelligence.

[elmayerle]

I've also considered a dedicated EA-5C with a full ALQ-99 in the weapons bay and canoe with a "football" on the tip of the vertical (though that might impede folding the vertical).  I was considering a dedicated KA-5C with appropriate signal lights at the back end of the canoe and with all four wing tanks capable of offloading fuel to other aircraft.

Still, I can see where your modular approach would maximize assets.

I can see a recce derivative of the NAR.349 for high and fast recce work.  For that matter, since the Vigilante is one of only two US aircraft capable, and stressed for, going Mach 1+ on the deck, low and fast recce work.

[Daryl J.]

The other aircraft being.......?

Thanks.

[AGRA]

I've also considered a dedicated EA-5C with a full ALQ-99 in the weapons bay and canoe with a "football" on the tip of the vertical (though that might impede folding the vertical).

The RA-5C actually had something similar via the Passive ECM system (PECM). Fitted around every RA-5C aircraft were a series of antennas and for those flying ELINT missions one of three fuel cans would be removed and replaced by an electronics can (minus 285 gallons of fuel). This was the capability in the fleet which the ES-3 Shadow replaced.

There is no reason the folding tail couldn;t have the antenna football mounted on top of it and it didn’t come close to any other part of the aircraft when folded. The folding tail would actually make it easier to upgrade because you could just build a new one with the football and then bolt it onto the aircraft in place of the old tail. Combined with fuel can located electronics and appropriate wiring you could even make it a mission based modular configuration.

  I was considering a dedicated KA-5C with appropriate signal lights at the back end of the canoe and with all four wing tanks capable of offloading fuel to other aircraft.

Surely the wing fuel issue is just a matter of upgrading the internal plumbing? And signal lights wouldn’t need a canoe but just a scabbed on housing? Lights could even be possibly mounted on an extended bar from the bomb bay train.

  I can see a recce derivative of the NAR.349 for high and fast recce work.  For that matter, since the Vigilante is one of only two US aircraft capable, and stressed for, going Mach 1+ on the deck, low and fast recce work.

For the IMGINT role I was thinking something along the lines of PEACE JACK with the HIAC-1 LOROP camera mounted in the nose. It would be like the IDF Phantoms in this role but with much longer range which is important for the ‘Australians’ compared to the Israelis. The ELINT NR-349 would be used as part of a SEAD/DEAD system. Fly up over and around the enemies integrated air defence system while a few ‘Jindivik’ target drones are fired into it and then record all the signal types and locations. Next day the RAAF launches a major strike package to destroy all the emitters.

[Daryl J.]

PEACE JACK with the HIAC-1 LOROP camera mounted in the nose.

:)

[AGRA]

The other aircraft being.......?

The aircraft who's mention was edited out of this thread and transferred to the Sparring Room.  This is where an emoticon for a face making the 'shush' sound would be appropiate!

[Daryl J.]

Got it....my brain is slow tonight.   


Now to think up some scenario where the Swedes could do some development work on it.     

[elmayerle]

  I was considering a dedicated KA-5C with appropriate signal lights at the back end of the canoe and with all four wing tanks capable of offloading fuel to other aircraft.

Surely the wing fuel issue is just a matter of upgrading the internal plumbing? And signal lights wouldn’t need a canoe but just a scabbed on housing? Lights could even be possibly mounted on an extended bar from the bomb bay train.

I imagine most of the changes would be internal modifications to the fuel system, though there are also wiring mods and a separate panel to mount.  I could see a group of aircraft, if not all of them, modified so that they could take on the refueler role with a minimal amount of work.  You'd carry a bit more gear around the rest of the time, but it's the easiest approach.

Yeah, you could probably go with a scabbed on housing rather than using the entire canoe, but I could see it using the same mounting points as the aft portion of the canoe (you've already got them designed and cleared, why re-engineer more than necessary?).

Regarding the EA-5 concept, I was envisioning using a jamming system similar to that used by the "Spark 'Vark", which is an adaptation of that used by the EA-6B, in addition to the usual passive ESM fit.

[ChernayaAkula]

The other aircraft being.......?

The aircraft who's mention was edited out of this thread and transferred to the Sparring Room.  This is where an emoticon for a face making the 'shush' sound would be appropiate!

The F-111 can be mentioned all right. It's just that we would like the discussions to be polite and not degenerate into online fisticuffs, 's all. 

[GTX_Admin]

How about a Vigilante given similar mods as the F-4X Peace Jack with HIAC-1 LOROP camera and updated performance?

[AGRA]

How about a Vigilante given similar mods as the F-4X Peace Jack with HIAC-1 LOROP camera and updated performance?

A couple of posts ahead of you:

For the IMGINT role I was thinking something along the lines of PEACE JACK with the HIAC-1 LOROP camera mounted in the nose. It would be like the IDF Phantoms in this role but with much longer range which is important for the ‘Australians’ compared to the Israelis. The ELINT NR-349 would be used as part of a SEAD/DEAD system. Fly up over and around the enemies integrated air defence system while a few ‘Jindivik’ target drones are fired into it and then record all the signal types and locations. Next day the RAAF launches a major strike package to destroy all the emitters.

There was a real world proposal for an ELINT version of the NR-349. There is a picture in Ginter’s Naval Fighters but no details:



The IMGINT NR-349 would be similar but without the ventral canoe and the PEACE JACK in the nose. Which should look very cool with the faceted cheeks to accommodate the camera vision ports.

[Daryl J.]

Yeah...the Peace Jack Vigi.   It would be particularly handsome.  Maybe the unassembled Trumpeter kit in the basement will need a bottle of Mr. Dissolved Putty, a reduction in the height of its arched back, and a Peace Jack nose.   Originally being from Montana,  perhaps the MT ANG or the USAF Malmstrom, Glasgow, or Minot had a Recce squadron to train in Eastern MT and western N Dak. 

[GTX_Admin]

Doh!  Missed that one.  Like your scenario.

What about following up with a dedicated SEAD version with ARMs such as Standard/Shrike/HARM?

[AGRA]

What about following up with a dedicated SEAD version with ARMs such as Standard/Shrike/HARM?

Missed that one, too.

It’s one of the advantages of the linear bomb bay that you can just roll in a train of fuel cans with the drogue unit at the end and presto a tanker. My thinking was to use this to make a modular fleet of strike aircraft. After the late 70s rebuild the RAAF Vigilante force is a mix of strike (two wings of 48 aircraft each) and recce aircraft (reinforced squadron of 24), which have different navigator cockpits adn the direct view sight on the recce version (plus of course the ventral canoe). The strike aircraft use the bomb bay to be configurable as:

# conventional strike: three fuel cans in the bay and bombs, napalm, rockets, etc on the wing pylons (3,600 gallons internal fuel).
# submunition strike: full length dispenser in the bay for either anti personnel, anti tank or anti runway loads (2,715 gallons internal fuel).
# PAVE TACK strike: vertical packaged AVQ-26 PAVE TACK laser designator in the forward end of the bay and three fuel cans. Up to four PAVEWAY III laser guided bombs under the wings (3,600 gallons internal fuel)
# WILD WEASEL strike: APR-35 radar homing and warning receiver in forward end of bay with anetennas in short ventral canoe (also plugging into other RWR antennas on the aircraft) and three fuel cans. Up to four AGM-78 Standard ARM under the wings (3,600 gallons internal fuel).
# stand off strike: Project Long Arm TV guided glide bomb with auxiliary fuel in bay (3,520 gallons internal fuel).
# nuclear strike: nuclear weapon with two cans and fin assembly in the bay (3,305 gallons internal fuel).
# refuelling tanker: two cans, buddy can and 78 feet hose reel unit. (3,595 gallons internal fuel)

[GTX_Admin]

Double Doh!

[AGRA]

There was a real world proposal for an ELINT version of the NR-349. There is a picture in Ginter’s Naval Fighters but no details:

Looking at this picture a bit closer and notice the ventral canoe. Its much longer, wider and deeper than the one on the RA-5C. It extends all the way to radome. This could be an interesting concept for conventional two engine Vigilantes. Like a conformal fuel tank or a pannier for missiles or something.