Blackburn Buccaneer developments

[PMN1]

Does anyone have information on the various Buccaneer developments (P.140, P.145, P.150...).

I've seen the descriptions in Project Cancelled and British Secret Projects but I wondered if there was anything else around.

 

[overscan (PaulMM)]

You *really* need a copy of Roy Boot's From Spitfire to Eurofighter.

 

[hesham]

Hi PMN1,

a small info and drawing to P.150 are here;
http://www.thunder-and-lightnings.co.uk/buccaneer/history.html

 

[PMN1]

Does anyone know what AAM were being thought of for the proposed P.140 fighter Buccaneer version and how they would have been carried?

 

[PMN1]

BSP 4 has the B.112 carrying four Red Tops, one on each wing and two on pylons under the forward fuselage while the B.117 would have a larger wing carrying four Red Tops controlled by a multi mode radar (though Roy Boot's book does say there wasn't a suitable UK radar...).

Would the Buccaneer's underside lend itself to semi recessed carriage of AAM or carried in the same way the Phoenix was on the Tomcat?

 

[PMN1]

Interesting video despite the scramaled music in one place

http://www.youtube.com/watch?v=-Btdi8qNutw&feature=related

How low is he at 0.33!!!!!

 

[PMN1]

From Spitfire to Eurofighter by Roy Boot.

'In 1959 serious attempts had been made to sell the NA.39 in its original configuration to the West German Navy'

Does anyone know what the West German Navy thought of the design?

A version of the Buccaneer (the B.113, itself a version of the non wing folding B.112 offered to the RAF)) was offered to the RAAF as a strike and all-weather interceptor (not sure when).

Does anyone know what the RAAF thought of the design?


Later on he also says that there were hopes that the US would adopt the Buccaneer in the same way the USAF adopted the Canberra to make the Martin B-57.

What were the chances of this?

 

[Trident]

Without being able to cite a source offhand, I seem to recall hearing that the Marineflieger quite liked it!

 

[TinWing]

From Spitfire to Eurofighter by Roy Boot.

'In 1959 serious attempts had been made to sell the NA.39 in its original configuration to the West German Navy'

Does anyone know what the West German Navy thought of the design?

It didn't really matter in the end. The F-104G was accepted on the basis of industrial concerns, as well as other possible inducements than became known many years later.

Overall, the F-104G must have had far lower unit costs, and while attrition was a major issue, the type was exemplary in terms of production techniques.

Later on he also says that there were hopes that the US would adopt the Buccaneer in the same way the USAF adopted the Canberra to make the Martin B-57.

What were the chances of this?

The United States largely funded development of the Buccaneer, and made use of the early research, some of which was applied to the Grumman Intruder. Obviously, the Intruder program proceeded more quickly, which meant that the American type entered production long before the application of the "area rule," hence the inferior transonic aerodynamics of the eventual A-6.

I don't think there was ever a realistic chance of a direct collaboration between Grumman and Blackburn.

I also think that the Buccaneer S.1 was a far more problematic type than the A2F-1/A-6A, largely due to the Gyron Junior, which undoubtedly was inferior to the J52. If the Spey engined S.2 had been canceled, I think that the Buccaneer would have had a very short, unsatisfactory service history.

 

[Hammer Birchgrove]

Would it have been possible to have a Buccaneer with RR Speys earlier than 1965?

In another thread, about a DH Sea Vixen with Speys, it was told that the particular aircraft would have flown as "early" as 1960 if RAF had bought it. However, Wikipedia says that the RR Spey wasn't until 1964, but that may be because the Buccaneer Mk 2 first flew then.

Thanks in advance.

 

[zen]

It would certainly have been possible with Avons, Spey is more a unkown quantity and depends on how much is spent to push out a military variant.

 

[TinWing]

It would certainly have been possible with Avons, Spey is more a unkown quantity and depends on how much is spent to push out a military variant.

Engines in the Sapphire/Avon class were specifically rejected early on due to weight and fuel consumption concerns. The entire point of the Buccaneer was to produce an airframe with a balance between range and an acceptable landing weight/approach speed for very marginally sized carriers.

The Gyron Junior was chosen because it best fit the specification, despite marginal thrust. At the time, it was thought that a scaled down version of the Gyron was the low risk solution, although it obviously wasn't.

 

[TinWing]

Would it have been possible to have a Buccaneer with RR Speys earlier than 1965?

In another thread, about a DH Sea Vixen with Speys, it was told that the particular aircraft would have flown as "early" as 1960 if RAF had bought it. However, Wikipedia says that the RR Spey wasn't until 1964, but that may be because the Buccaneer Mk 2 first flew then.

Thanks in advance.

The RR Spey came about when the aircraft that became the DeHavilland Trident was scaled down due to a short sighted request by BEA. Consequently, since the Trident was no longer the size of the later 727, it didn't need an engine as large as the JT8D, so the Medway was scaled down to what we know as the Spey.

Needless to say, Rolls Royce was left without a JT8D competitor, and the Trident was very obviously outsold by the 727.

The Spey indeed entered commercial service in 1964, although, arguably, it could have been available somewhat earlier and it is quite obvious that the Medway itself would have been available earlier still.

 

[Hammer Birchgrove]

Would it have been possible to have a Buccaneer with RR Speys earlier than 1965?

In another thread, about a DH Sea Vixen with Speys, it was told that the particular aircraft would have flown as "early" as 1960 if RAF had bought it. However, Wikipedia says that the RR Spey wasn't first used until 1964, but that may be because the Buccaneer Mk 2 (prototype) first flew then.

Thanks in advance.

The RR Spey came about when the aircraft that became the DeHavilland Trident was scaled down due to a short sighted request by BEA. Consequently, since the Trident was no longer the size of the later 727, it didn't need an engine as large as the JT8D, so the Conway was scaled down to what we know as the Spey.

Needless to say, Rolls Royce was left without a JT8D competitor, and the Trident was very obviously outsold by the 727.

The Spey indeed entered commercial service in 1964, although, arguably, it could have been available somewhat earlier and it is quite obvious that the Conway itself would have been available earlier still.

I read on Wikipedia that British engineers had worked on what would become turbofans as early the 1930's.

Development

[edit] Background

In early jet engines the exhaust was much faster and hotter than it had to be for efficient thrust; capturing some of that energy would improve the fuel economy of the engine. The turboprop is an obvious example, which uses a series of additional turbine stages to capture this energy to power a propeller. However there is a tradeoff in propeller efficiency compared to forward speed, so while the turboprops are efficient engines, they are only efficient at speeds of up to 500 mph (800 km/h; 430 kn). This meant there was a sweet spot between the high efficiencies of the turboprop at low speeds and the jet at high speeds that was not being directly addressed. This spot, between about 450 mph (720 km/h; 390 kn) and 700 mph (1,100 km/h; 610 kn), was precisely where the vast majority of commercial jet aircraft spent most of their time.

The basic concept of bypass had been studied from the earliest days of jet engine design. Alan Arnold Griffith had proposed a number of different bypass engine designs as early as the 1930s while he and Haine Constant were trying to get their axial-flow jet engines working at the Royal Aircraft Establishment. Frank Whittle's Power Jets also studied a number of bypass configurations. However, the need to get jet engines into service during the war meant this work had to be put aside in favor of simpler designs with shorter introduction times. The ending of the war changed priorities dramatically, and by 1946 Rolls-Royce agreed that existing engines like the Rolls-Royce Avon were advanced enough that it was time to start work on new concepts like bypass.

Griffith suggested building a purely experimental design using parts of the Avon and another experimental jet engine, the Tweed. In April 1947 a 5,000 pounds-force (22,000 N) design was proposed, but over the next few months it was modified to evolve into a larger 9,250 pounds-force (41,100 N) design in response to a need for a new engine to power the Mk.2 low-level version of the Vickers Valiant bomber. A go-ahead to start construction of this larger design was given in October, under the RB.80 name.

A pity about the DH/Hawker Siddeley Trident... A typical mistake by British airliners at that time (Bristol Brabazon comes to mind). But if it lead to the creation of the Spey, something good came out of it. (Hopefully, the Spey might have been developed anyway, perhaps as a military jet engine from the start?)

 

[robunos]

the Conway was scaled down to what we know as the Spey

According to Gunston's 'Rolls-Royce Aero Engines', page 148, the Spey was a scaled-down RB.141 Medway, not Conway.

Only five prototype Medways were built, although a lot of parts were used unchanged in the Spey.

cheers,
Robin.

 

[zen]

According to Gunston's 'Rolls-Royce Aero Engines', page 148, the Spey was a scaled-down RB.141 Medway, not Conway.

I think we've read the same book!

Engines in the Sapphire/Avon class were specifically rejected early on due to weight and fuel consumption concerns.

No they where'nt, as Shorts tender to NA.39 shows and was not rejected due to the choice of engine. Rejected perhaps by Blackburn in their design process for the B.103 perhaps.

Blackburn offered several Avon powered variants of the Buccaneer as a fighter later on. Which is pertient for the discussion on developments of said.

And Blackburn did also consider the more advanced engine BE.33 and seemed to favour it I reccal reading.

At the time, it was thought that a scaled down version of the Gyron was the low risk solution, although it obviously wasn't.

Indeed, yet so little was done on the most intriguing scaled down engine of the periode if a little later in the form a 2/3 sized RB.106 for 10,000lb dry thrust.

 

[Abraham Gubler]

No they where'nt, as Shorts tender to NA.39 shows and was not rejected due to the choice of engine. Rejected perhaps by Blackburn in their design process for the B.103 perhaps.

The Shorts PD.13 was able to meet the tender spec with the bigger Avons because its use of 'vectored' thrust and aero-isoclinic wing tip controllers enabled the aircraft sans engines and fuel to be much lighter than the other, mostly, Junior Gyron powered bids. If they had designed a more conventional aircraft with blown wings like Blackburn, Fairey, Armstrong-Whitney, et al they would have needed to use the smaller engine.

The benefit of the Shorts design with Avons was that the PD.13 was faster on the deck than the other bids. Unfortunately the MoS thought the wing tip controllers and the thrust deflection was too risky for. The Buccaneer may have been the 'easy rider' but the Shorts 'Swallow' powering along at 100 feet, Mach 1 and rolling at a rate of 800 degrees a second would have been a sight to behold.

 

[zen]

Well 800 degrees a second is likely a lethal rotation speed for a human being, and they'd have to put in some sort of limiter. But the Shorts design is a very attractive option if more risky.

They thought at the time that the aero-isoclinic wing was more suitable for a mach.14 fighter than a subsonic low level strike aircraft and its a shame they never flew the wing to supersonic speeds to prove its effectiveness, despite a proposal to do so on a modfied Swift.

Now Vectored thrust as the orriginal option Blackburn looked at, but dropped in favour of blow instead, I see nothing as such that would've prevented this for Shorts design. The PD.13's use of Avons was as much for high speeds and accelerations as for vectored thrust.

I do wonder why Shorts never proposed a fighter for the RN based on their wing.

AS it was the RN chose the balanced option between quickness into service (AWA's submission) and risk (Shorts), which was Blackburns tender.

Had the BE.33 come into being, perhaps the fighter version of the Buccaneer could've been developed and fitting into the decision process of the times.

 

[Hammer Birchgrove]

Thanks guys... I've learned something new today.

 

[Abraham Gubler]

I do wonder why Shorts never proposed a fighter for the RN based on their wing.

They were pushing a aero-isoclinic re-winging of the Swift for a while as a fighter demonstrator but the MoS didn't buy. They probably never had the chance for a Naval fighter submission. At the time the Sea Vixen was to be the fighter and by the next opportunity - early 60s - things had moved onto VSTOL and VG.

The P.D.13 would have made for a very impressive fighter with intake ramps, reheat, a narrow body (no need for side by side seating and the bomb bay) and thin wing (4% down from 10%, no wing fuel but lots less drag). The light weight of the design and the power potential of two reheat Avons would probably mean a positive thrust to weight ratio. Combined with the human tolerances limited roll rate and high control at very fast and high through to very slow and low would have made for a very manoeuvrable aircraft in the 1960s.

Getting off topic from Buccaneers, I think there is an aero-isoclinic thread here somewhere we should probably move this too if the Moderators think that’s important.

Even more off topic, a notional low drag P.D.13 would have looked something like the attachment.

 

[TinWing]

Engines in the Sapphire/Avon class were specifically rejected early on due to weight and fuel consumption concerns.

No they where'nt, as Shorts tender to NA.39 shows and was not rejected due to the choice of engine. Rejected perhaps by Blackburn in their design process for the B.103 perhaps.

Blackburn offered several Avon powered variants of the Buccaneer as a fighter later on. Which is pertient for the discussion on developments of said.

Blackburn worked with with a number of double Sapphire concepts during previous naval fighter studies, and the weight issue was quite a serious one. To achieve an acceptable approach speed, they had to resort to a double folding wing at one point.

The choice of the Gyron Junior was hardly unsurprising, and while there were other stillborn competitors, it's clear that the Gyron Junior was intended to occupy the same thrust category as the successful J-52.

There were the various Buccaneer fighter proposals, mostly for export and involving reheated engines, but most were quite improbable. The Buccaneer had a number of characteristics that made it a very poor candidate for a fighter requirement.

I really don't think that any twin Avon Buccaneer could have met the NA.39 requirement, either in terms of range or approach speed. The Shorts proposal that you mention represented a huge developmental risk and most likely wouldn't have met the NA.39 requirement, as the deflected thrust concept wasn't entirely successful in this era.

 

[TinWing]

the Conway was scaled down to what we know as the Spey

According to Gunston's 'Rolls-Royce Aero Engines', page 148, the Spey was a scaled-down RB.141 Medway, not Conway.

Only five prototype Medways were built, although a lot of parts were used unchanged in the Spey.

cheers,
Robin.

Sorry, made a little mistake. I must have confused the various rivers in Britain.

The Medway, a JT8D equivalent, was indeed based on the earlier Conway, which more or less was the equivalent of the contemporary JT3D. Of course, the Spey didn't exactly have a commercial competitor from P&W, at least not one that made it to production.

The resizing of the DH.121 did pretty much kill any immediate commercial prospects of the Medway, but it took the infamous 1957 defence review to put paid to a number of military applications. The Medway was revived in the 60s for the AW.681, but when that program was cancelled, it was pretty much the end for the type.

 

[alertken]

HB's Q was: Would it have been possible to have a Buccaneer with RR Speys earlier than 1965? Spey's conception was March,1958, BEAC's DH.121 order. NA.39 first flight was 30/4/58 and Duncan Sandys order for 50 (became 40) was 10/9/58. MoA funding for RB168 (to be Buccaneer S.2's Spey Mk.101) was released in 1959, when payload/range limitations became apparent in Gyron Jr...and RR had little else to do, military or civil. Sloth prior to deployment of Mk.101/Bucc S.2 was a matter of junior priority everywhere, as RR tried for higher volume business (Twin Spey P.1154, all those weird German V/STOL things) and HSAL digested Blackburn. The weapons for Bucc. S.2 were to be WE.177A(N) and Martel, neither of which would be available before 1966.

So: Yes, a couple of years earlier S.2 would have been technically do-able...but there was no champion to fund it.

 

[zen]

Post 1957 there is little funding and support for any new or variant warplane beyond one, the TSR.2

 

[Hammer Birchgrove]

HB's Q was: Would it have been possible to have a Buccaneer with RR Speys earlier than 1965? Spey's conception was March,1958, BEAC's DH.121 order. NA.39 first flight was 30/4/58 and Duncan Sandys order for 50 (became 40) was 10/9/58. MoA funding for RB168 (to be Buccaneer S.2's Spey Mk.101) was released in 1959, when payload/range limitations became apparent in Gyron Jr...and RR had little else to do, military or civil. Sloth prior to deployment of Mk.101/Bucc S.2 was a matter of junior priority everywhere, as RR tried for higher volume business (Twin Spey P.1154, all those weird German V/STOL things) and HSAL digested Blackburn. The weapons for Bucc. S.2 were to be WE.177A(N) and Martel, neither of which would be available before 1966.

So: Yes, a couple of years earlier S.2 would have been technically do-able...but there was no champion to fund it.

Thanks, that clears up a lot.

 

[starviking]

It would certainly have been possible with Avons, Spey is more a unkown quantity and depends on how much is spent to push out a military variant.

Engines in the Sapphire/Avon class were specifically rejected early on due to weight and fuel consumption concerns. The entire point of the Buccaneer was to produce an airframe with a balance between range and an acceptable landing weight/approach speed for very marginally sized carriers.

The Gyron Junior was chosen because it best fit the specification, despite marginal thrust. At the time, it was thought that a scaled down version of the Gyron was the low risk solution, although it obviously wasn't.

The Gyron Junior's also doomed the Bristol 188 programme, as it hadn't enough time or thrust available to 'soak' at high mach .

 

[starviking]

Well 800 degrees a second is likely a lethal rotation speed for a human being, and they'd have to put in some sort of limiter. But the Shorts design is a very attractive option if more risky.

800 degrees a second is a little over 2 revolutions per second: I think that knife-thrower's assistants have experienced a similar angular velocity without harm. Not sure about the extremities of the plane though, as centrifugal force increases with distance from the axis of rotation.

Now controlling a plane that can roll twice in a second would be hard, if not impossible IMHO.

 

[Hammer Birchgrove]

It would certainly have been possible with Avons, Spey is more a unkown quantity and depends on how much is spent to push out a military variant.

Engines in the Sapphire/Avon class were specifically rejected early on due to weight and fuel consumption concerns. The entire point of the Buccaneer was to produce an airframe with a balance between range and an acceptable landing weight/approach speed for very marginally sized carriers.

The Gyron Junior was chosen because it best fit the specification, despite marginal thrust. At the time, it was thought that a scaled down version of the Gyron was the low risk solution, although it obviously wasn't.

The Gyron Junior's also doomed the Bristol 188 programme, as it hadn't enough time or thrust available to 'soak' at high mach .

That the Gyron Jr was picked for that aircraft is more puzzling for me. Since the engines aren't inside the "body" but on the wings, it must have been relatively easy to give stronger engines more space, may it be RR Avon, Armstrong/Bristol Siddeley Sapphire or even RR Thames or DH Gyron (the full-size version, not sure if the original version had problems like Junior).

 

[zen]

Not so simple. I bet the knife throwers assistant does'nt go from 0 to 2.222rps (about 133.2rpm) in the sort of acceleration you'd get on the Shorts design. But yes the G-force at the wingtips would be quite something.

But that assumes throwing the controls to maximum rotation, and most likely there would be some need to refine the relationship between stick movement and control surface movement to avoid extreme manouvers by accident.

Oh yes, Gyron Junior was'nt even the more interesting engine for the Bristol 188 to fly. They expected it to run a number of different engines IF I reccal my reading correctly.

 

[alertken]

(Drifting fr. Bucc) RAE's 1953 view of >M2 supersonics was the (sort-of)Meteor layout in stainless steel. Bristol was chosen for the proof-of-concept research vehicle, largely because they were idle when every real airframer was loaded with Korean types. AWA was given large chunks of fabrication. One (iron-)steel maiden plus 2 flight vehicles were ordered, increased to 5 after Avro 730, adopting this layout, was selected as the high altitude recce type in June,1954. "Proper" engine firms were overloaded. When Frank Halford had been DH's engine designer in 1946/47 he had schemed H.6, but no application had emerged. Halford was now gone from DH, but Sir Ralph Sorley (former Air Ministry senior) was MD. He presented the firm as available without distraction from Super Priority, Korean War-inspired real types, and caused H.6 to be selected as expendable power for Vickers Red Rapier ASM, as P.S.43 for N.A.39, and as P.S.50 for T.188. The ASM was chopped; the other 2 applications for Gyron Jr. took junior priority as DH tried to sell Gyron. April,1957's axe left Gyron Junior as DH Engine Co's sole business, T.188 as an orphaned, superseded research exercise, N.A.39 as funded only for a development Batch of 20. Too hard, drift, under-resourced as DH Enterprise concentrated on recovering from Comet and on doing Blue Streak.

(Corrected 29/8: Sorley MD of DH Props, and while influential with MoS, Sir Aubrey Burke (ex-MAP) was Engine MD and succeeded Halford as Chairman, 1955).

 

[overscan (PaulMM)]

The Gyron was also the first British engine designed for highly supersonic (Mach 2) flight. Its low pressure ratio was optimised for high speeds. When the Bristol 188 was conceived, Gyron and Gyron Junior were the only engines designed for the high speed flight regime that were likely to be available quickly. It wasn't at all clear then whether existing designs like the Avon, Sapphire etc were suitable for Mach 2+ speeds.

The 188 was seriously overweight due to problems with the steel construction. Progress with it was glacially slow; it was supposed to help research technologies for the F155T fighter but arrived years too late to be of any use. It consumed £20 million (a substantial sum of money at the time) to no great purpose.

 

[zen]

AWA had the better design within the terms of the tender, EE had the most potential for a exportable fighter with the P6 and with the -D a very interesting concept, Saro gave a good effort and again much potential.

Naturaly Bristol won for reasons even now I'm not that clear on....but I have my suspicions.

 

[Hammer Birchgrove]

The Gyron was also the first British engine designed for highly supersonic (Mach 2) flight. Its low pressure ratio was optimised for high speeds. When the Bristol 188 was conceived, Gyron and Gyron Junior were the only engines designed for the high speed flight regime that were likely to be available quickly. It wasn't at all clear then whether existing designs like the Avon, Sapphire etc were suitable for Mach 2+ speeds.

The 188 was seriously overweight due to problems with the steel construction. Progress with it was glacially slow; it was supposed to help research technologies for the F155T fighter but arrived years too late to be of any use. It consumed £20 million (a substantial sum of money at the time) to no great purpose.

At least it convinced BAC that the Concorde should be limited to Mach 2,2 so it could be built with aluminium.

 

[rousseau]

Here is a compitator of developing layout from Hawker P.1108 were supposed to be powered by four Avon engine.
And a photo of Buccaneer took off by rockets booster.

 

[Petrus]

Here is a compitator of developing layout from Hawker P.1108 were supposed to be powered by four Avon engine.

The P.1108 was to have four Rolls-Royce RB.115 engines. Indeed there is rather little information on the engines available, but I doubt they have anything to do with the Avon.

Piotr

 

[PMN1]

AWA had the better design within the terms of the tender, EE had the most potential for a exportable fighter with the P6 and with the -D a very interesting concept, Saro gave a good effort and again much potential.

Naturaly Bristol won for reasons even now I'm not that clear on....but I have my suspicions.

Intrigue and Infamy....

 

[alertken]

zen #31 - Bristol won (T.188) for reasons even now I'm not that clear on. PMN1, #35 - Intrigue and Infamy....

1953. RAE's perception for far/fast was stainless steel in Meteor-esque layout. In those days the job of industry was to perform to the MoS-piper's bidding. A proof-of-concept vehicle must precede award of a V-Bomber replacement, for which, logically, Avro/HP/Vickers would be preferred candidates. Previous such exercises had been placed with idle design teams (e.g: General did the crescent wing Attacker-for-Victor; BPA had done delta BP.111/120; later, Hunting did the jet flap H.126), knowing no assembly-line would come their way, but hoping for some structural sub-contracts. It would be a waste, fraught with conflict, to put Experiments in proper teams. A one-off called for just as much design effort as a job intended to be built en masse: MoS used them to suckle spare resources, just-in-case.

In 1953/54 Bristol was a design orphan, thus available. Zen noted EE and Saro, but both were well-loaded - Canberra enhancements, P1; sketchy IRBM work and the mixed-powerplant interceptor (to be S.R.53). The essence of (to be T.188) was not airframe scheming, ably assisted by RAE day trips down the A4, but was structure fabrication. All those Daniel Doncasters would pace that. HSAL's Avro was emerging as preferred source for (to be) Avro 730, so HSAL's AWA (busy on other HSAL jobs - ASM/Hunters, NF Meteors, Sea Hawk, Javelin) was imposed onto Bristol, to do the wing. RAE Bedford would do the flying; Filton's job would be assembly, plus not a lot.

By April,1957 Avro 730 and other applications for DH Gyron Jr. had been chopped. Logically T.188 should also have expired, but RAE/MoS tucked it away in a vague "Aircraft Research" budget line, beneath Ministers' radar. VG Swallows, Jet Flap, perforated aerofoils, weird SST shapes also lurked there. All drifted, because no-one really cared. Ministers/Treasury might first have become aware of some of them, pirouetting in front of hospitality tents at SBAC Shows.

 

[rousseau]

Here is a compitator of developing layout from Hawker P.1108 were supposed to be powered by four Avon engine.

The P.1108 was to have four Rolls-Royce RB.115 engines. Indeed there is rather little information on the engines available, but I doubt they have anything to do with the Avon.

Piotr

May I invite your source?

 

[Petrus]

The P.1108 was to have four Rolls-Royce RB.115 engines. Indeed there is rather little information on the engines available, but I doubt they have anything to do with the Avon.

Piotr

May I invite your source?

'British Secret Projects. Jet Bombers Since 1949' by Tony Buttler p. 67:

As Rolls-Royce had no suitable engine for a twin-powerplant configuration (...), the choice settled on a unit still on the drawing board, the small 20in (51cm) diameter RB.115. Four were placed in pairs under the inner wing.

'Buccaneer. The Story of the Last All-British Strike Aicraft' by Tim Laming p. 12:

The design [of the P.1108] featured no less than four RB.115 engines positioned under the inner wing (a preliminary design even featured six engines), and Rolls-Royce's John Fozard had great difficulty convincing Hawker taht the additional safety of four engines would be worth the direct trade-off against additional weight and complexity.

Also the RB.115 designation appears in some drawings of the P.1108 - take a look at what's been attached.

Piotr

 

[BlackBat242]

The Medway, a JT8D equivalent, was indeed based on the earlier Conway, which more or less was the equivalent of the contemporary JT3D. Of course, the Spey didn't exactly have a commercial competitor from P&W, at least not one that made it to production.

The TF30 was virtually equal to the non-afterburning Spey in power, fuel consumption, & weight - but was slightly larger in diameter (42" vs 38") and length (125" vs 115"-118"). As it was originally designed as a subsonic engine* (like the Spey was), it would have been suitable for similar commercial use.

However, P&W had already created a turbofan version of the J52 (the JTD-8, first run in 1960), which (at 42.5"/123.5") was right at the TF30's diameter and length, and was also a little more powerful at the start (12,250lbf) and a lot more powerful in later versions (21,000lbf with a diameter of 49") than either.

This engine saw a lot of commercial success, as well as powering the SAAB Viggen (with inclusion of an afterburner), and powering ships and land power stations as the FT12.


* For the Douglas FD6 Missileer. It also powered the Vought A-7 Corsair II in the A/B/C variants, before a modified Spey was selected for the A-7D/E versions (TF41, jointly developed and produced by Allison and RR).