Saro P.177 scenario(s)

zen

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Saro F.177 Option to NA.47

Scenario(s) examining AH were Saro's F.177 aircraft is built and enters service.

Ok so it will be an absolute certainty that the negatives will pile on this one.
But in turn, if one is looking for a domestic UK fighter and light attack type then this is it.
Actually slated for 150 RAF and 150 FAA machines.
A substantial set of prototypes and development machines.
And something that briefly lasted beyond the 1957 defence white paper.
Cut back on DA numbers but the RN's FAA was still pushing for it.
Until it all fell away by 1958.

1. Assumption is Saro and RAE calculations are correct. That the aircraft is supersonic to Mach 1.4 with Gyron Junior reheat. See Saro's sortie diagram.
Rate of climb Turbojet Reheat ON is 37,600ft in 4.5 minutes.
Cruise at 37,600ft on Turbojet only at Mach 0.9 is 3 minutes.
Climb to 40,000ft with reheat 0.58min.

20 minutes loiter at near Sea Level for recovery on Turbojet only.

2. As per RAE paper TO&L speeds with 'blow' on wings and tail ensures recovery at 140kts at full load. Which would be between 125kts to 115kts relative to the carrier (speeds between 15kts and 25kts)

Arguably had Saro kept the original arrangement of engine and inlet underneath and rocket above for SR.54, then revised design to F.177 would be a more evolutionary process. Arguably so would prototype production.

By 1960 rocket option would be dropped, but the change of tankage to all jet fuel is neither impossible or prohibitively expensive as it was integral to the design.
Endurance was expected to be 2 hours on jet fuel only.

Admiralty was adamant that no long range surface to air missile would be ready before 1972.

F.177 was expected to be effective to 65,000ft out to 85nm using pursuit course weapons and 180nm with extended early warning. At this V-Bombers were already able to act as fleet shadowers flying above 50,000ft.

Saro seem convinced they can swap out Gyron Junior for RB.133 for Germany. Licencing Heinkel. Along with a revised wing for Attack roles.
See Saro Brochure.
In fact see relevant thread.

So what happens if it goes forward?
 
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zen

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You'd need to find some reason why Germany doesn't buy F-104 instead.

Some political rift between US and FRG in 1956-58 timeframe?
The obvious one is the potential for very short take offs using a variant of the rocket.
The problem is the lack of nuclear weapons carriage unless the RN or RAF are funding it.

Of course it would help if say Lockheed had been exposed prior to any contracts being signed.
 

JohnR

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What does DA mean?

What are the necessary adaptions to allow nuclear weapons carriage?
 

uk 75

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It would be more plausible if the SR177 had been developed some years earlier. Like its US counterpart.
If it had already been flying by 1957 and been able to enter service by 1960 instead of the Lightning replacing Javelins and Hunters.
The RN version would have replaced the ill fated DH110 as the successor to the Scimitar.
This would have given the SR177 a leg up against the F104.
 

zen

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It rather raises the issue of what if Saro hadn't changed the locations of jet and rocket on the SR.53, as had they stuck with the original with the jet under the rocket then the P.177 wouldn't have been such a change on the earlier machine.
This might have speeded the process up.
 
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uk 75

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By getting the SR177 into the slots taken in otl by Lightning and Sea Vixen you make a much more interesting scenario.
NATO countries would have had an inUK service alternative to F104. Even France might have shown interest.
 

zen

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Saro had priority over Avro despite both being ordered to F.124 on 14 Oct 1952.
Had Saro kept the jet under the rocket in the revised design to F.137D, then a further revision to F.177D after 17 May 1956 might be possible.
Arguably it's delayed from December 1953, but I suspect work slowed from the start of that year. By Feb talk was of dropping both Saro and Avro, and Bristol's research prize wasn't forthcoming.

Consider Saro was working flat out for first flight in 1957-58 and service entry by 1960. All this from revised design study work in early '55. But ITP was Sept that year, with a programme for 27 machines on 30th September.
Arguably progress on the earlier SR.53 could have flown by '55 and service by '57.
 

Zoo Tycoon

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It rather raises the issue of what if Saro hadn't changed the locations of jet and rocket on the SR.53, as had they stuck with the original with the jet under the rocket then the P.177 wouldn't have been such a change on the earlier machine.
This might have speeded the process up.

The problem with the SR53 rocket location was the sonic fatigue from the rocket nozzle on the airframe. One report I’ve heard was that flakes of aluminium fell like snow from the elevator when the rocket was fired. Elevator replacements were common in the flight testing but would have been impractical for service. So the solution is to move the rocket nozzle to very back of the aircraft which is why this was done on the 177.
 

zen

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It rather raises the issue of what if Saro hadn't changed the locations of jet and rocket on the SR.53, as had they stuck with the original with the jet under the rocket then the P.177 wouldn't have been such a change on the earlier machine.
This might have speeded the process up.

The problem with the SR53 rocket location was the sonic fatigue from the rocket nozzle on the airframe. One report I’ve heard was that flakes of aluminium fell like snow from the elevator when the rocket was fired. Elevator replacements were common in the flight testing but would have been impractical for service. So the solution is to move the rocket nozzle to very back of the aircraft which is why this was done on the 177.
Yes, but my point is, that the earlier design to F.124 had the rocket at extreme rear and the turbojet underneath.
 

Zoo Tycoon

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Ok didn’t pick that up. I met with Dick Stratton (SR53 Chief Development Engineer ) on a number of occasions and we talked about SR53 & 177 (& Princess);- the histories, the trials and about learning but he never mentioned they got the original proposed architect spot on. Oh the questions I wished I’d asked.

One comment I do remember was that the RAE were very influential (indeed overly so) in the early days and concept architecture. I guess there’s a good chance we’ll never know why it was swapped, maybe it was a cg thing and the sonic fatigue phenomenon was just so new, no one understood what it was capable of.
 
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zen

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The RAF with such numbers, would be looking to get the revised wing able to take a 2,000lb Red Beard. Presumably counterbalanced by a drop tank. With rocket and 'fire hose' catapult, very short take offs should be possible. This would cover the 'interim' MRI Strike mission. With NMBR.3 expected to succeed it.
Germany would be egging this on once they commit.

If Germany falls to the P.177, arguably others would as well, and politically this could rather upset the US. Some blowback might be forthcoming here.

France is a possible here, especially the AN with P.177 taking the place of Crusaders.

This all spells trouble for EE and the Lightning of course as it does for the Starfighter.

The impact on the RN is substantial, as only the FAW mission remains for a Sea Vixen successor. Also these machines will operate with ease from modernised Audacious and Centaur carriers.

A deeper thought, could the entry into service of P.177 effect future planning for the RN?
As it was the death of DLI drove increasing demands on CAP, driving up the next generation fighter, from then current 2 hours CAP to a desired 4 hours.
A machine that also had to be the next generation Strike and Attack machine, with TSR.2 levels of capability. Hence OR.346 and the inevitable 'interim' requirement AW.406, that made a navised P1154 a monstrous headache.
But shorn of piling all Fighter needs on a wonder weapon aircraft, the option is there to fund a more reasonable FAW and leave Strike and the Buccaneer successor free of it's demands.
Arguably the USN Vigilante would be the obvious way forward in strike and the F111 later on.
While FAW could either see a enlarged P.177 type design or the F4 chosen.
This all takes some pressure off next generation carrier design.

The impact on Saro is hard to calculate, as this turns them into something more than a flying boat builder. Giving them cash and success to pursue other things.
Arguably a scaled up version partially resurrecting their supersonic research tender could deliver true FAW and succeed the Sea Vixen and Javelin. A sort of British F2/F3.
 
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uk 75

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Assuming the SR177 gets up and flying by 1957 it also provides a project to rationalise the British Aircraft Industry. Saro would be teamed with English Electric and others to get the plane built for the RAF and RN. British Aircraft Corporation comes into being around a hard contract.
With the fighter requirement met for at least a decade, attention would turn to the strike role.
The Buccaneer would give the future Hawker Siddeley a naval strike aircraft and a cost effective way of replacing some Canberras.
With two hard programmes in place, Sandys kills off the RAF's problematic Avro 730. He gives Hawker Siddeley a contract for an MRBM to be based on a US design. After looking at the Atlas, HS rejects it in favour of a single stage Minuteman. At this point in 1958 Earl Mountbatten intervenes and Polaris in land and sea based versions is adopted.
HS and BAC are impressed by the US new generation of aircraft like the Vigilante and Phantom.. They begin work on a multi role VG fighter/attacker for the RAF and RN to replace SR177/Buccaneer/Canberra/Valiant from 1968.
The Hunter serves as the RAF FGA until 1968 when an HS/BAC trainer/close suppport aircraft replaces them.
The Vulcans and Victors serve in the conventional bombing, recce, tanking roles into the 70s..
No TSR2 No P1154/Harrier No Blue Steel
 

Hood

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All this presupposes a lot.

That Saro was actually competent enough to oversee the development programme and get production rolling. Saro had ability, they did some really fine work on rockets and a wide range of aeronautical and marine projects, they were certainly an innovative brains trust but they were not a mass producer and lacked any real experience of actual service aircraft as opposed to interesting prototypes. The SR.53 seems to have performed ok, although one was lost for reasons never discovered (could have been technical, could have been pilot error) and that may have put some disquiet in some minds at the MoS. Remember even experienced companies like Supermarine dropped some pretty big clangers in this period, the MoS was effectively backing a dark horse.

That mixed jet-rocket power was ever feasible. By the time the rocket mania had borne fruit in suitable engines the mania had died off and afterburning turbojets offered a much more efficient path. HTP was tricky stuff, not really suited for having around busy Fighter Command airfields trying to do scrambles and not ideal aboard warships (think what happened to HMS 'Exploder'). The vibration effects on the airframe might have been serious too - as Zoo Tycon alludes to. Engine location choice might have had more to do with CG and thrust lines, certainly the big F.115T design shared the same layout with the rockets on top. One could argue having the rocket on the bottom would have made dumping/draining HTP easier. One the other hand a ventral intake was simpler for the engine, especially the Gyron that was finicky about intake flow.
Yes you could chuck the rocket out and use the space for fuel, Saro certainly calculated for that. But then you've got a single-engined interceptor with an inferior climb rate when at the time time to height was critical to intercept Soviet bombers with stand-off weapons. You are also left with a fuselage fatter and draggier around the rear end than it needs to be for a purpose-built single-engine design. Also, it means the Lightning wins hands down.

That the Gyron wouldn't have been a dog like it was in everything else that ever used it.

That West German interest was actually serious, as I said in the recent P.1121 thread, I don't think it was.

I think hanging Red Beard off it would have been feasible. Would it have been done? Hard to say, for naval use to replace Scimitar possibly but by then Buccaneer is already underway. The RAF might have, but then they didn't fit Lightnings to carry it, as far as I know Red Beard couldn't be flown supersonic anyway so there is no advantage over using a Canberra until the TSR.2 arrives (which would have next-gen bombs anyway).
 

overscan (PaulMM)

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Agreed. A designer of SR.53 / F.177 said something to the effect of "rocket engines give so much thrust we don't need to worry about drag to go supersonic" and both designs seem to embrace this idea.
 

zen

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Are you saying their calculations are off?
Because they seem to show it would be supersonic with reheat. Time to 40,000ft is roughly 5 minutes with reheat on, no rocket power.

Are you saying their claims of fitting an Avon in place of the Gyron Junior are wrong?

Look I get there are a number of issues with this aircraft.
Start with the lack of length between inlet and engine face.
Or the 18" diameter AI.23 set.
Or the narrow main gear.

But this is what was available at the time, and while it's not perfect. It could have been good enough.
 

zen

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Additional thanks to Alertken
Close contact. Timelines don't gell. Design bosses Brennan (Saro), Bishop (DH) would have met at Committees (MoS/ARC/RAe.S) where novelty/RAE thoughts were disseminated, but were alert to competitive advantage and would not reveal their schemes before tenders were safely in. Saro won F.124T (DH no bid) with SR.177, R&D ITP 4/9/55. They competed on F.155T, tenders in 12/10/55: Saro P.187 instantly rejected, DH.117 in 3/56.

DH bought effective control of Saro with 33% stake, 9/56: SR.177 was then still very live and DH's motives were, in part, to protect their Gyron Jr./Spectre position on it, but also to ensure that Saro/Black Knight supported Blue Streak, no more, no less. However they did muscle onto SR.177, which needed production/industrial heft to be credible, especially for export. It was to have been managed from Cowes, assembled at DH (ex-Airspeed) Christchurch and delivered from Hurn (DH site to be obtained - maybe they anticipated the Airwork FRU moving to Yeovilton).

The Saro Divn. of DH Group was sold to Westland 14/7/59, Brennan having decamped to V-A. It had become a confusion in merger discussions, DH Enterprise (already muddled with overseas/props/engines...) with HS Group and (to be) BAC.
Which rather suggests several things.
1. DH is involved so production isn't quite the impediment suggested.
2. DH Gyron Junior could be further developed, as OR.339 interim from Blackburn showed. Expected with cooled compressor for 10,000lb dry.
Bristol T.188 was partially a failure die to DH lack of interest and support for Gyron Junior after '58.
With interest sustained...
Buccaneer mkII with improved engines.

3. DH Saro tie up would be forthcoming. Backed as industry rationalisation.
This could be the key to refusing more mergers?
4. DH Christchurch likely too busy for OR.339 or Hatfield for OR.346. Office and engineers too involved in F.177 production and variants.
 
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starviking

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And if a Saro tie-up is forthcoming, perhaps the government would be happy for de Havilland to pursue their Airco consortium with Hunting and Fairey, on the understanding that something close to HSA structure would eventually result.
 

zen

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And if a Saro tie-up is forthcoming, perhaps the government would be happy for de Havilland to pursue their Airco consortium with Hunting and Fairey, on the understanding that something close to HSA structure would eventually result.
Very good point!
DH Group?

Another thought.....
If close RN relationship results, could DH Engines throw they oar in on marine GT?
Gyron and Gyron Junior are stainless steel and potentially alternatives to marine Olympus and land Avon....
 

Archibald

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You'd need to find some reason why Germany doesn't buy F-104 instead.

Some political rift between US and FRG in 1956-58 timeframe?

Could be related to missiles, nuclear weapons, and De Gaulle's return. In 1957-58 the moribund 4th Republic had a thing called F-I-G to study ballistic missiles: France, Italy, Germany.
 

alertken

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#18: DH lack of interest and support for Gyron Junior after '58.
Sandys
deleted Gyron's 2 berths 4/57 and Gyron Jr. in SR.177 12/57; he inserted it 7/57 in 2 residual Bristol T.188 (ASM P.176 had been in 5, intended as Avro 730 proof-vehicles). Nothing more would come from T.188, retained only because Chairman, Supersonic Transport A/c Committee, Morien Morgan was keeping the option for stainless steel Mach 3. The only real business was 20 Development Batch NA.39 ordered 7/55 and no confidence could be placed on that. The Big Turbojet had become more burden than benefit.

So my What if here is with Sidney Camm rolling over when RAF declined his Gyron/P.1121 (Sandys did not delete it because RAF had not Required it). Camm is not known to have pressed HS Group to continue to fund P.1121, so to stimulate DH to do so for Gyron.
If they could have flown a demonstrator...seeing is believing. If orders had come in for Gyron, DH would have put their best and finest on Big Turbojets, to the benefit of Buccaneers. SR.177 was an aberration, but P.1121s and better Buccaneers sooner....beware, Lockheed and Dassault.
 

zen

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Yes and no.
Gyron Junior is funded as cheap and cheerful alternative to expensive new two spool 30" turbojets called for. AS, RR and BS had such. From scaled RB.106 and P.151 to BE.33.

Technical answer to why, is Cross Sectional Area impacts total system including weight. Twin engines desired for recovery on one rather than loss.

F.177 carries on then T.188 is proof of engine with reheat. Two birds with one Bristol stone.

A further twin Gyron Junior system would result, either to OR.346 or AW.406. Or similar.

Certainly if flown P1121 could lure orders. Gyron could potentially stomp more sophisticated alternatives.
Arguably P.1103.
Arguably P.1125 is what ought to have emerged '54.
But HS is hidebound, pass the complex curves to subcontractors and never mind the loft drawing (HS "what's a loft drawing for?"). In short a mess.

As an aside....Saro last minute options to F.155. Twin Gyron Junior or single Gyron.......with DH backing......
Though Arguably P.163 ought to have piped Bristol's T.188.
With single Gyron, rocket only expanded altitude and supersonic endurance envelope.
Ideal for alternative big engines.
Olympus
Conway
RB122 or 123 or 128
Or later Medway.
 

zen

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BTW I’ve seen T188 performance documents which suggests it’s positive stability margin was “better than Mach 2.8” and was optimistic that flight tests maybe able to demonstrate Mach 3 (windscreen limit). Of course intake control problems limited the max demonstrated speed to Mach 1.88. Sometime after the project was over it was discovered the intake control pressure transducers had been qualified to the wrong operating conditions. The supersonic thermal soak was only a fairly modest 8- 15 minutes depending on speed, just long enough to achieve thermal stability. Of course they didn’t get there due to high fuel consumption;- DH had lost interest in this engine, most of the technical team had left so the fine tuning of the performance just didn’t happen.
 

Nick Sumner

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Arguably P.1125 is what ought to have emerged '54.

Heartily agree. I think with some development (maybe into a P.1129 analogy) P.1125 could have been a UK Phantom contender.
 

zen

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Arguably P.1125 is what ought to have emerged '54.

Heartily agree. I think with some development (maybe into a P.1129 analogy) P.1125 could have been a UK Phantom contender.
Ought to have emerged concurrent with P.1103, as alternative to single big engine.
Ought to have been alternative to single big engine in proposal to F.155.
Though parallel with straight wing Starfighter-esque study using RB.106.
And a scaled P1103 using same engine.
 

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