Rest of the World without the UK's 1965 cancellations

[CV12Hornet]

But if the USN already has a bunch of P1154s in service only a few years old, would they even be in the market for the Hornet?

Why would the Navy have a bunch of P.1154s in service? It's not an improvement over the Corsair in carrier strike roles and the Navy is currently in the middle of fighting of all attempts at V/STOL carriers. I don't see the Navy spending a dime on the P.1154 and leaving its operation to the Marines.

Except the Navy, at least most? of it, didn't want the F-18, they wanted F-14B and F-14C. Congress forced it on them. If they can point at P.1154 and say "see, light naval fighter/attack", F-18 could seem to be a duplication of effort and Congress would be much less likely to fund it.

However, if P.1154 is in service, a follow up VSTOL with F-18 performance might be in the cards. One of the non-stealth ASTOVL designs, including P.1216 or related designs. I can see US/UK VSTOL/STOVL collaboration becoming institutionalized in that case.

They're not going to want the P.1154, either.

 

[Rule of cool]

When I asked if the US could build these planes it was from a technical/industrial perspective, not if the US would want them. I was thinking greater US experience with digital data busses, integrated circuits and other peripherals and other stuff would have helped the TSR2 for example.

In any case I only think the TSR2 was viable and Britain should never have painted itself into the P1154-HS681 corner.

 

[Scott Kenny]

In any case I only think the TSR2 was viable and Britain should never have painted itself into the P1154-HS681 corner.

And ironically I think that the P1154 and HS681 would be more likely to get to flying prototypes, if not service. The hard part of the HS681 was the engine. The P1154 also needed some avionics packing, which the US was happy to help with on the P1127.

TSR2 had issues, not least with avionics. The US could have done the avionics, at least to interim state at service entry in the mid 1960s. Even the US struggled getting the full avionics packages before 1970. But the whole thing was in a death spiral of weight gains.

 

[Rule of cool]

But the whole thing was in a death spiral of weight gains.

While I've looked into the avionics, and in particular the computers which seem to be the real limitations I haven't looked into the weight gain. Can you give me the the quick and dirty on it? Surely it doesn't mean that XR220 was heavier than XR219, and XR 221 was heavier again, and so on for the 10 completed, almost completed and started TSR2s up to about XR227.

 

[Rule of cool]

Here's a story highly impactful to the TSR2. From RAF serials.

9 Sep 64 As it (TSR2 #2 XR220) was being backed into a hangar that afternoon, the fuselage fell over on its jack-knifed trailer at A&AEE Boscombe Down, to where it was being transferred from Weybridge as part of the Ministry of Aviation Air Fleet for trials flights, with the wing and ailerons on another trailer. The delivery driver had turned too tightly while avoiding Chief test Pilot Roland Beamont’s parked Lightning T.4

11 Sep 64 Fuselage recovered using air bags. Most damage was to the port taileron spigot. Completion delayed by some spares robbing for use on flying prototype XR219.

24 Feb 65 First ground engine runs of XR220 following repair.

Mar 65 Further engine ground runs and fuel flow trials. Ground trials completed towards the end of the month. The aircraft was then placed in temporary storage prior to its first flight, planned for the beginning of April.

2 Apr 65 Planned first flight date - delayed by minor faults. Intended as the trials aircraft for carriage of external stores, initially to be flown at up to Mach 1 low altitude, then gradually extending the envelope.

The 2nd TSR2 spent 4 months being repaired following this mishhap, Without it it would likely have flown months earlier and sped up the entire programme.

 

[Yellow Palace]

While I've looked into the avionics, and in particular the computers which seem to be the real limitations I haven't looked into the weight gain. Can you give me the the quick and dirty on it? Surely it doesn't mean that XR220 was heavier than XR219, and XR 221 was heavier again, and so on for the 10 completed, almost completed and started TSR2s up to about XR227.

No.

The weight issue was that the original performance estimates were based on optimistic assumptions of aerodynamics, engine performance, etc. Nothing too unusual. But because it was so far out on the bleeding edge, solving one problem inevitably added weight, which meant the performance dropped somewhere else, requiring more weight gain to fix....

That cycle was only broken by drawing a line under the design as it was, and accepting that it was the best that could be done. Which didn't meet the original specification. Radius would have been 800 nautical miles rather than the original 1,000 nautical miles, I can't remember the rest - Damian Burke's book has a good comparison table and all the details.

 

[Rule of cool]

Thanks, I suspected that was the case.

 

[red admiral]

Radius would have been 800 nautical miles rather than the original 1,000 nautical miles, I can't remember the rest - Damian Burke's book has a good comparison table and all the details.

Yes, this is the "real" TSR2 that was being built which didn't meet the spec in some significant areas. PP109 gives the guarantee points points being offered by BAC in 1965 when trying to get to a fixed price contract (which never got offered given low confidence in the costs). e.g.

• 750nm radius vs 1,000nm
• 1,100yd take off vs 600yd
• Max Mach 1.75 vs 2.0 (BAC pushing for 1.5)
• No automatic terrain following

The 2nd TSR2 spent 4 months being repaired following this mishhap, Without it it would likely have flown months earlier and sped up the entire programme.

Not that many months earlier. XR219 only started proper flight test in Jan. The September first flight was very much a one off. I think we're talking about maybe another 5-10 test flights if XR220 isn't damaged, on topmof the 25 total for XR219. It's not a significant impact. And in reality, the engines for XR220 didn't turn up until March anyway...

 

[Halcyon66]

TSR2 absolute daddy, F-111 was a total disaster of an airframe. It was the beginning of one after another of Australia's failed military procurement programs that has gone on for decades.



Regards,

 

[Rule of cool]

Not that many months earlier. XR219 only started proper flight test in Jan. The September first flight was very much a one off. I think we're talking about maybe another 5-10 test flights if XR220 isn't damaged, on topmof the 25 total for XR219. It's not a significant impact. And in reality, the engines for XR220 didn't turn up until March anyway...

Probably not a huge impact technically, but I think it would have an impact politically as having a 2nd aircraft flying would indicate progress and momentum for the project.

Yes, this is the "real" TSR2 that was being built which didn't meet the spec in some significant areas. PP109 gives the guarantee points points being offered by BAC in 1965 when trying to get to a fixed price contract (which never got offered given low confidence in the costs). e.g.

• 750nm radius vs 1,000nm
• 1,100yd take off vs 600yd
• Max Mach 1.75 vs 2.0 (BAC pushing for 1.5)
• No automatic terrain following

Presumably this was for the 'Mk 1' based on what was being expected and achieved from the development batch aircraft and the initial flights. Further I expect this was driven by the pressure of looming cancellation, just like that September first flight stunt was driven by political pressure. If these negotiations took place 6 months later, with XR220 and 221 flying and gathering experience maybe the guarantee points might be closer to the original specs.

 

[red admiral]

Presumably this was for the 'Mk 1' based on what was being expected and achieved from the development batch aircraft and the initial flights. Further I expect this was driven by the pressure of looming cancellation, just like that September first flight stunt was driven by political pressure. If these negotiations took place 6 months later, with XR220 and 221 flying and gathering experience maybe the guarantee points might be closer to the original specs.

I'd expect that the change to automatic terrain following (maybe late 70s per Tornado) might be the sole item on that list that would change in a "Mk2".

The range and take off are driven by mass, and they already know this from having built the aircraft. Redesign to remove multiple tons from the aircraft to improve performance vs these points isn't really feasible. The Max Mach point seems partly driven by cost of flight test (for >1.5) but higher than ~1.75 seemed to be into significant rear fuselage redesign and rebuild.

Guarantee points seemed more driven by confidence in the costs rather than the performance as such - and BAC didn't have enough confidence on their costs to offer a firm (or capped) price. And this was really the key issue because there isn't unlimited money.

 

[NOMISYRRUC]

Part of Post 59.

HS681 is very similar to the YC15 which failed to win orders in the 70s as a Hercules replacement. More likely is that C130s are ordered after the 681 fails to attract overseas orders and prove expensive to operate. France did the same with Transall.

To which @Scott Kenny replied in Post 60.

That's probably the real downside.

However, if the US had VTOL HS681s in the late 1970s, all of a sudden Op Eagle Claw and Desert One is a success. Seeking reductions in operating costs and making it easier to work under an HS681 in the hover may still lead to tilt-rotor aircraft instead of turbine VSTOLs.

I watched a YT video about one of the AMST aircraft recently but can't remember whether it was the YC-14 or YC-15. According to said video the C-130 Hercules didn't have the STOL performance necessary to use many of the airstrips in South Vietnam and the purpose of the AMST programme was to give the USAF an aircraft that could use those airstrips. The video also said that both prototypes met the specification but neither was put into production because the end of the Vietnam War meant there was no longer a requirement for them.

Therefore, the USAF may have bought some HS.681s for service in Vietnam ITTL, possibly as a stop-gap for the AMST.

However, at March 1964 the IOC (of 8 aircraft in one squadron) with the RAF wouldn't be until March 1971 and FOC (of 52 aircraft in 7 squadrons) wouldn't be until March 1975. At the same date a total of 62 HS.681s were planned (including 6 for an O.C.U.) and the first 57 were to have been delivered between March 1971 and March 1975.

So my guess is that the HS.681s bought for the USAF would have been built in the USA under licence. Furthermore, the USA completed its military withdrawal from South Vietnam in March 1973 so the USAF's HS.681s would only have served in Vietnam for a year or two because it wouldn't have entered service until 1971 or 1972.

 

[uk 75]

I am enjoying this thread and understand the wish to preserve the three planes as close to their original spec as possible.

I remain loyal to my original UK 75 specs for them.

TSR2 enters service as a Valiant/Vulcan replacement with gradual avionics fit, less demanding specs. Its main role is nuclear delivery with WE177 so ASGW etc is not fitted initially.

1154 does not get air to air radar fit and is much closer to Jaguar as a CAS aircraft It is able to land vertically but usually operates in STOL mode.

681 emerges as a CTOL transport similar to Kawasaki C1 or Il76. Its speed makes it more useful than the C130 or Belfast.

Replacing Lightning and Sea Vixen calls for a new VG aircraft like AFVG unless the carriers are still cancelled when a TSR2 ADV becomes an easier solution.

Drawback with my variant over real world planned and actual solutions is that the three planes are not obvious export hits.

TSR2 (Vindicator rather than Eagle) is very much a nuclear delivery system. Australia is the only possible customer (India and S Africa would be if their governments were more aligned to us).

1154 would interest Belgium, Denmark, and Netherlands as well as India, Jordan, and S Africa.

681 without VSTOL is a harder sell. But if it offers faster airlift times it might take orders away from C130 and Transall.

I think my simplified specs which have to be imposed by Peter Thorneycroft before prototypes fly are the only way to get all three done.

 

[Rule of cool]

I'd expect that the change to automatic terrain following (maybe late 70s per Tornado) might be the sole item on that list that would change in a "Mk2".

The range and take off are driven by mass, and they already know this from having built the aircraft. Redesign to remove multiple tons from the aircraft to improve performance vs these points isn't really feasible. The Max Mach point seems partly driven by cost of flight test (for >1.5) but higher than ~1.75 seemed to be into significant rear fuselage redesign and rebuild.

Guarantee points seemed more driven by confidence in the costs rather than the performance as such - and BAC didn't have enough confidence on their costs to offer a firm (or capped) price. And this was really the key issue because there isn't unlimited money.

I wouldn't expect redesign to save tons of weight, rather not installing things that were found by testing to be unnecessary. I've read elsewhere that testing of XR219 found that variable flap blowing and the extended nosewheel weren't necessary and could be not installed to save cost and weight. The most intriguing thing is what 'variable' flap blowing is, was the TSR2 flap blowing able to be varied?

I think it's important to bear in mind that with computers in particular things were moving at breakneck speed in the 60s. The first digital data bus, of which the TSR2 had Britain's first example, was first invented in 1958 but went to the second generation min by 1969. Similarly the world first integrated circuit only became available in 1960 and the TSR2 had Britain's first example but by the late 60s these had advanced by leaps and bounds. The point being that if the TSR2 had passed through this 1965 bottleneck of nailing down costs where the rubber met the road then electronic components will be available for installation that were not even dreamed of a few years earlier which should make the advanced avionics work in practice. At least that's the vibe I get from that particular rabbit hole.

 

[Scott Kenny]

Part of Post 59.

To which @Scott Kenny replied in Post 60.

I watched a YT video about one of the AMST aircraft recently but can't remember whether it was the YC-14 or YC-15. According to said video the C-130 Hercules didn't have the STOL performance necessary to use many of the airstrips in South Vietnam and the purpose of the AMST programme was to give the USAF an aircraft that could use those airstrips. The video also said that both prototypes met the specification but neither was put into production because the end of the Vietnam War meant there was no longer a requirement for them.

Therefore, the USAF may have bought some HS.681s for service in Vietnam ITTL, possibly as a stop-gap for the AMST.

However, at March 1964 the IOC (of 8 aircraft in one squadron) with the RAF wouldn't be until March 1971 and FOC (of 52 aircraft in 7 squadrons) wouldn't be until March 1975. At the same date a total of 62 HS.681s were planned (including 6 for an O.C.U.) and the first 57 were to have been delivered between March 1971 and March 1975.

So my guess is that the HS.681s bought for the USAF would have been built in the USA under licence. Furthermore, the USA completed its military withdrawal from South Vietnam in March 1973 so the USAF's HS.681s would only have served in Vietnam for a year or two because it wouldn't have entered service until 1971 or 1972.

But continuing that thought, assuming that the US kept the HS681s in service post Vietnam (or sent them to the Boneyard for storage instead of scrapping or sending them to the UK), they'd make Operation Eagle Claw a lot more viable in 1979-80.