Rolls-Royce Liftjets from RB82 to XJ-99


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6 June 2006
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Thread to discuss this family of lift engines, and aircrafts related. I've gathered some infos on the subject...

Le Fana de l'aviation, october 1997. Article on the Mirage IIIV.
"Circa 1967 RB-162 were to be replaced by RB-189, product of a join program between RR and Allison. Thrust was 2700 kgp"

Skomer (superb website) Thust is given for 3500 kgp (for the AVS, circa 1968)

Le Fana de l'aviation, April 2003. Grumman 200 : 1* F-401 + two XJ-99 lift jets, thrust 4270 kgp.

Was the RB-189 / XJ-99 ever tested or did it remained a paper project ? more projects around this engine ?

Thanks in advance!
Try the Flight archives :)

Rolls-Royce officials would give few details of the lift jet
which will be developed in co-operation with the Allison Division
of General Motors (as reported on page 743 of last week's
Flight) although it was indicated that the design would be
based on the RB.189, Derby's third-generation lift jet of some
9,0001b thrust and a thrust.-weight ratio of 20:1.

Also has a pic of a mockup

XV99-RA-1 Military twin-spool lift jet. Now scheduled to be
on test, the XV99-RA-1 is the subject of a UK/USA governmental
agreement for joint development of an advanced lift jet for V/STOL
applications. Financed on a 50/50 basis, the engine is a collaborative
design by Rolls-Royce and Allison, but reportedly making
extensive use of the former's RB.189 third-generation lift-engine
technology. Objectives include a thrust/weight ratio of at least
20:1 and a thrust/volume ratio in excess of 1,200lb/cu ft, the latter
being considerably in advance of present lift-engine attainments.
Thrust is understood to be in the region of 9,000lb. Four
XV-99-RA-ls are specified for the US/FRG AVS project, involving
a novel installation with a pair of engines swinging-out on arms
either side of the front fuselage. After transition, the units retract
into the fuselage.

Lots more to look at...
Merci! These archives are a goldmine... :-X

Au fait, I've just noticed while posting this that the dedicated engine section of the forum had disapeared ::) Hope I didn't post my thread at the wrong section...
RR work on pure-liftjets derived from 1946-work by Chief Scientist, ex-RAE Dr.A.A.Griffith. His first device to run was RB82 Soar for (not yet RPV) Vickers Special Products T.895 Red Rapier, which was refined into RB108, 5 of them levitating Short S.C.1. The newly-constituted W.German aero-industry was funded by FRG and by US Mutual Weapons Development Program to explore combat V/STOL. MoS funded ever-lighter lift, as RB162. RR/MTU/Allison in Oct.,65 began XJ99:4 were to lift EWR-Süd/Boeing (becoming Fairchild-Hiller/Republic)AVS, MWDP part-funded until Luftwaffe despaired of the practical inoperability of such a thing. AVS died Spring,1968 (and MRCA was conceived in a menage of 6), but MoA funding for XJ99 endured to 1971 (my memory is as composite materials proof-of-concept vehicle).
I remember the RB189 team having offices down the corridor from ours was the first time I saw a door that you had to punch a key code into it in order to gain access..... I never did. There were development team members there so I reckon it ran on the test beds. As I remember the technologies that were around I would guessestimate that the sequence of lightweight engine development would look like this:
RB.82 1st run Jan 1951, a forerunner of the RB. 93 which became known as the Soar, built to test the feasibility of Allen A. Griffith's calculations that more, smaller propulsive devices are lighter than one large one; gradually developed into:
RB.93 Soar - 1st run Jan '53-a lightweight, short life engine for missiles making use of sheet metal wherever possible.
[Westinghouse J-81 was licence-produced version for US missile use.]
RB.108 - 1955- next generation, more conventional design using the latest aero and thermodynamics to achieve the power/weight ratio
RB.145-Apr '61 -RB108 with extra compressor stage and more thrust
RB.162- Jan '62 - next generation with fibre glass in compressor casing vanes and blades
RB.153- early '63- Spey technology scaled down with an afterburner and swivelling single nozzle (a conventional engine with a counter-rotating hp compressor to cancel out inertia effects in hover.
RB189 - 1969 -a push to get thrust/volume and thrust/weight down and max thrust up for VTO application.. there was a lot of cinterest in carbon-fibre at this time so I would guess that this featured.. also I can't imagine the P/W ratio aimed at being generated without going to more than one shaft in order to avoid surge/stall of compressor aerofoils.
I may have more info in the garage filing system (tea chests)... certainly have on Soar.


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I felt there was something wrong with our assumption of the Soar being the RB.82... having now got my hands on my notes (written in the 60s!) I can confirm the Soar was in fact the RB.93!
The RB.82/1 was the first complete test bed engine made to test out how well the design ideas met the following objectives:
a) low specific weight
b) high thrust per unit frontal area
c) minimum use of strategic materials
d) to be suitable for large scale mass-production.

The RB.82/1 engine had a 2-bearing rigid rotor and had a 14'' overall diameter, weighing 267 lbs; for concept testing, the engine did not have its own fuel, oil, air or ignition system, but had a slave system provided at the test bed.

Testing showed that the combustion chamber was too short so a new design, RB.82/1 was put in hand, adding 5'' to length and converting it into a three bearing construction... a distance piece was inserted between the outer casing and exhaust unit to achieve the added length... weight rose to 292 lbs.

RB.82/3 was a new design engine incorporating feedback from testing and was intended to result in a flight suitable unit. A 3-bearing design with overhung turbine disc, it contained its own fuel pump and control, oil and cooling air system. The NGVs were fabricated from sheet and numbers reduced from 36 to 12. Such radical changes meant the design study was estimated to weigh 237 lbs, 55 less than /2 even though it contains its own fuel, oil and air systems. Experience from this resulted in ..

RB.82/4 (design only) modified the design, moving the bearing from the front to rear of the turbine disc to allow room for NGV alterations... the design was then dropped in favour of the RB.93/1.
I'll post a RB82 pic later. [now posted above]
The logic for developing small lightweight engines where engine life is traded for weight etc is laid out here in a Flight article.
The point about the maturity of technology featuring in the mix is well made and is reflected in the evolution of the RB.82>RB.93>RB.108>RB.162 story with the added frisson of moving from short life -1 to 10 hours for unpiloted planes, missiles, etc- to more reliable piloted VTOL applications and eventually as a booster in the Trident airliner.
The first UK RPV project for the Soar was the Vickers Red Rapier project. As I only havean A4 scanner and my line drawings are at least double foolscap I shall have to get my local bureau to scan them in.. they have an A3 plus but fullscap challenged them so I have divided the vehicles: the first is possibly Red Rapier and the second possibly the Northrop XQ-4 drone installation (single engine).


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The RB.93 series are Rolls-Royce's serious attempts to incorporate both the more advanced design thinking that had been going on plus the actual learning from the test bed. The RB.93 was designed in response to the needs of Vickers, etc. as they looked at flying bomb possibilities. The OR that led to Red Rapier was issued in November 1951 with a request for proposals. RR Project Design Department had been working on a possible propulsion unit and had by June 1951 issued a proposal for the RB.93, This had not yet built in test bed feedback from the RB.82 as not many hours had been run. Serious running of the RB.82 commenced in Sept, 1951 and nearly 100 hrs were built up by the end of the year. Another 50 or so hours were added by the time of the first run of the RB.93/1 in December 1952. Total running hours built up to 200 by mid-September 1953, and the RB.93/2 ran at the end of the month. 215 hours had accumulated by the end of 1953. April 1954 saw the Soar RB.93/2 pass its type test... a 2-hour type test reflecting the short life of the application.
The Meteor flying test bed first flew, I think, at the end of February 1954 and by year end had accumulated 10 hours or so ... a few lifetimes of intended use! In December 1954 an RB.93/2 ran a successful endurance test of 15 hours. The end of June 1955 saw the completion of the first production Soar which was shipped to Westinghouse who were supplying them as the XJ-81-WE-3 for the Northrop Radioplane division's XQ-4 . The first air launch of an XQ-4 drone occurred in January 1956.

RB.93/1: The engine diameter settled on went up from the 14 inches on the RB.82 to 15.25 inches.
2 versions of this engine were specified - one for development running on the test bed, and the other for flight installation -
The test bed engine has a detachable exhaust unit and final nozzle and a flanged exhaust disc, whereas the flight model deletes the flanged joints at the rear and has a flash butt-welded turbine disc and an air intake fairing with integral oil tank. The estimated weights are 293 and 295 lbs for test and flight versions, respectively.

RB.93/2: The RB.93/1 compessor aerodynamic design did not deliver the promised performance so an alternative design scaled from the RB.82 was initiated. Also the compressor blades were projection welded to the rotor discs rather than the copper furnace brazed compressor rotor assembly of the 93/1. This saved 11 lbs. The new compressor had increased mass flow so that the Nozzle Guide Vanes and turbine blades had to be lengthened (radially) increasing their overall diameter by around half an inch. A new air intake was built without oil storage as the flight applications would result in the oil freezing. This results in a 3.5 lb saving in weight, with all the other modifications the weight is estimated at 276 lbs.[I believe this is the engine supplied to Westinghouse]
The engine delivers a maximum thrust of 1810 lb at 18,600 rpm. the configuration is 7-stage axial compressor driven by a single axial turbine with an annular combustion chamber. Overall length is 77.08" (including intake) with an overall diameter of 15.8".

RB.93/3 makes an obvious change to the combustion chamber to take advantage of the NGV changes on the 93/2 This improves combustion stability but at the expense of 5.5 lbs in engine weight. Much bench running has proven the design.

Air launching of the Soar at high-altitude will necessitate improved light-up capability and also stability in normal operation could be improved. The simplex burners used at present suffer both in terms of stability and light-up above 15,000 ft altitude. The use of air blast atomisers which are only dependent on air velocity were proposed.
Another need is variable engine speed especially for target drones... Improvements to the fuel system will enable this to be achieved and modifications were proposed. It is known that with compressor bleed the tet rises by 40 deg. so already by improving the cooling flow could enable a thrust rise to 1980 lb; Thrust could be improved by changing the radial traverse to reduce the peak temperature without reducing the average or turbine entry temperature. Combined with more advanced turbine materials such as use of Nimonic 95 for blades could enable thrusts of just over 2100 lbs. Any further increase in thrust would probably be best coming from improved compressor blade aerodynamics to raise the present low efficiency and adopting a two-stage turbine to drive it results in 2,400 lb thrust from the projected engine.
A need to improve engine life necessitated employing more forging stock instead of sheet metal and soon the project morphed into the RB.108.


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Alan Arnold Griffith and the RB.108:
Way back in the mid-1920's 'Soap-bubble' Griffith, as he was then known, turned his attention to the aerodynamics of turbines driven by the insight that most machines of that era were running stalled. He developed a way of applying aerofoil theory to the design of the blading which made his reputation (again!). Fast forward to 1940's when he left RAE Farnboro' and joined RR Derby. He worked on ways of securing high efficiency in gas turbines and early in 1945, while work on Whittle-style engines proceeded, he commenced detailed studies of a simple jet engine with an axial compressor. He realised the need for an engine incorporating the latest ideas on axial compressor blading and that such a design would give reduced fuel consumption and reduced specific weight. The blade design proposed by Griffith permited a small diameter hub at entry, a high tip speed with a large air flow capacity and a low (relative to existing designs) number of stages, driven by a single-stage turbine. All this leads to an engine of high performance, low weight and small diameter. Griffith had a preliminary design scheme prepared to be included in his technical paper of June 1945. He mentions in the paper the possibilty of installation in the rear of an aircraft fuselage and soon this design scheme became the basis of the Avon engine.
The achievement of a light powerful engine of small diameter led Griffith to the idea of a supersonic interceptor which could take off vertically - a design layout was made in Dec 1945. He then came up with the idea of a bypass engine which became the basis for the Conway and then postulated the idea of a VTO aircraft with additional small engines for vertical thrust, supplementing the diverted thrust of the main bypass engine. Furthermore he suggested the wing of a VTOL 'plane could be optimised for high-speed flight without all the shape changing devices for Take-off and landing. The ARC published a paper on the criticality of fast response control of the aircraft in hover mode - ARC 14472 by Ann C. Thorpe so Griffith proposed a rig to investigate the needs... the preliminary design of which was started 27th March 1952. The ARC endorsed the proposal and finance to build the flying test bed were granted and this became the Flying Bedstead...which hovered in a tethered gantry 3rd July 1953. The first free 'flight' was on 3rd Aug 1954, with an altitude of 8 to 10 feet being achieved for a flight of 8.5 minutes!
Having proved the concept RR and Griffith looked to evolving the RB.82/RB.93 into a reliable vertical lift engine starting just after the first free flight of the Flying Bedstead. The RB.93 twin turbine concept was made more robust by eliminating welded rotor blades and sheet metal casings and soon became a new but related design... the RB.108.
The Ministry asked for proposals for an experimental aircraft incorporating the Flying Bedstead control concept and the RB.108 for lift and propulsion... this became the Short SC1.
The RB.108 gave a thrust of 2,200 lb with bleed and 2,400 without for a weight of 285lb. Dimensions are diameter of 20" with length 42".


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Glad you find it interesting... your bottom quote reminds me of a non-aeronautical one:
"Issues are emotional,
are technical
Decisions are political”
Jacques Fontaine
European Recovery& Recycling Association
AeroFranz said:
Tartle, thanks for the interesting history bit.


We can dig in books and archives, but memories of people who were there are a resource that sadly will one day be gone.
(T:) Thank you - I shall distance the name Soar from RB.82. Should you add RB.193 to your 23/10 list?
My memory is of MoA funding for RR/Allison/MTU XJ99 1965-68, when its application, US/FRG AVS, lapsed. Again, memory, is of demonstrator work - light materials pertinent to (to be) RB.199/RB.211 - continuing (?as RB.189? to bring data ownership to UK?) to 1971. There had been no MoA funding for a 3rd. generation liftjet (RB.189) so that mock up, Hanover, 5/66, was conceptual.

After Red Rapier chop, 1954, liftjet funding was confined to RB.108 and its S.C.1, on MoS' modest Aircraft Research budget (where such as suction laminar flow, jet flap, Rotodyne would also sit). That was a kitty for bright ideas that had not yet stimulated a User draft Target (it also funded Bristol/AWA T.188 after it ceased to be the proof vehicle for Avro 730 recce/bomber; and the slender deltas HP.115 and BAC T.221 when France declined to admit them as Concorde project expense; and the first 2 P.1127s after MWDP made a contribution). From 1957 US MWDP money cascaded into FRG to startup R&D in V/STOL, while production was relaunched on conventional US/French types. Some of that found its way to RR's liftjet work and that's why RB.162 technology was made available as "background" to XJ99 without additional project charge. It was US that inspired NATO Basic Military Requirements, inc. the strike type NBMR.3 and its transport NBMR.4, for both of which RB.162 was seen as crucial. Neither RAF nor FAA cared for deadweight liftjets, but did respond to NGTE's revival of Whittle W2/700 plenum chamber burning, to enhance BE.53 as BS.100 to give real V/STOL payload range in (to be) P.1154. PCB killed pure-Griffith all-lift and sent RR down a route of patent-dodging, until RR acquired use of the BSEL/Wibault patents, 10/66. When grotesque complexity killed AVS, Spring 1968, liftjets died.
I thought you might be interested in seeing how the use of materials (based on weight) changes over the period we have been exploring so far.
As I have said, A A Griffith had managed to scheme out an axial engine idea that became the Avon and then moved on to small engines of high specific power that could be used in multiples.
If we look at Forgings, Castings, Bar and Strip we get a feel for how the duty of an engine influences the designer's choice:
Looking at
the Avon Mk.1, a typical conventional turbojet,
the RB.93/1, short-life, minimum weight, and RB108, high thrust/weight requirement but not by sacrificing reliability
we get the table below:


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Alertkin... whilst the AVS airframe was cancelled, bizarrely the XJ-99 was not... I agree with your thought...... it was felt there was merit in continuing to explore light weight high thrust engines as the technology developed may have been of use elsewhere..perhaps we can explore that later.

Yes we can add the RB.193 not the mix, plus 153, 155 and 175 if I remember correctly.
This photo gives a feel of the relative sizes of the Flying Bedstead and SC1:
The SC1 was a VTOL research aircraft powered by five Rolls-Royce RB.108 turbojets (four for lift, one for propulsion). Two aircraft were built The first SC-1 (XG900) was used until 1971 for VTOL research and is now part of the Science Museum’s aircraft collection at South Kensington, London. The second SC-1 (XG905) can be seen at the Flight Experience exhibit at the Ulster Folk and Transport Museum, Cultra, Northern Ireland
Dimensions Span, 23ft 6in; length from face of nose to rudder trailing edge, 24ft 5in; length over nose probe, approximately 29ft 10in; height from belly to fin tip, 8ft 2.5in; height to fin tip from ground, 9ft 10in (main gear forwards) or 10ft 8in (gear aft); wheelbase, 8ft 1.5in (gear forwards) or about 9ft (gear aft); track, 11ft 6in; axial distance between pitch jet nozzles, 22ft 7.8in; distance from centreline to roll nozzles, 8ft 9.14in. Areas Wing, gross (apexed), 211.5 sq ft; wing, net, 141.9; elevators (aft of hinge). 14.76; ailerons (aft of hinge), 8.55; fin and rudder, gross, 28.64; fin and rudder, net, 11.63; rudder (aft of hinge), 4.44. Empty weight: 6,260 pounds Loaded weight (CTOL): 8,050 lb with "comprehensive test equipment and instrumentation" Loaded weight (VTOL): 7,700 lb Performance Maximum speed: 246 mph Range: 150 miles Service ceiling: 8,000 ft Rate of climb: 700 ft/min The thrust of the Rolls-Royce RB.108s installed in the aircraft is given as 2,130lb, suggesting that the maximum lift available from the lift engines is 8,5201b.


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I am doing some research on the Rolls-Royce Merlin at the moment and one thing that has come out of it is the interactions between the forces, Air Ministry, aircraft and engine companies that led to the array of aircraft we had available at the start of WW2. It is also fascinating how the aircraft were used in practice instead of how they were intended to be used. RR in particular responded to the RAF's needs as the actuality of the war unfolded. It reminds me of how we envisaged VTOL being exploited and how it was actually exploited....
these conversations were going on throughout the late 50's and by the start of the 60s the ability to respond and counterattack after a nuclear attack. NATO began to take this threat very seriously and conversations around VTOL strike and transport aircraft began. So RR, Bristol, etc on the engine side began project schemes to 'provoke' radical thinking around their powerpalnt's potential.
RR had realised that the RB.108 in the SC1 was not quite powerful enough to be of use in this new battlefield world and so designed an uprated version that became the RB.145 that first ran in April 1961. Rolls-Royce's project design department produced models to show off the conceptual thinking including swept and delta wing strike aircraft (see below). Just as the 1930s the Ministry had sponsored some unusual aircraft to explore different ways of meeting requirements, so NATO began to explore the practicalities of producing a viable VTOL solution. By the end of 1961 the (NATO Basic Military Requirement) NBMR-4 was issued for a strike fighter to replace the F-104. The Germans had come up with preliminary ideas based on the F-104 using 6 RB.145s.. this became the VJ 101C (3rd picture). This had 4 swivelling 145s and 2 vertical 145s in fuselage.
RR and MAN collaborated to develop a version of the RB.145 tailored to the VJ 101C and also an afterburning version.
The fourth picture shows the forward propulsion version of the RB.145. Note the increased complexity of the control system and accessory drives as the engine is 'dressed' for a more conventional role.
The fifth picture shows an afterburning version; the sixth picture reveals the divergent nozzle petals of the afterburner exhaust nozzle.


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Leaving aside the RB.153 for the moment, the next evolution in lightweight lift engines was the RB.162- the first RR engine to be designed from scratch specifically for lift duties. Developed as a response to the needs of aircraft designed to NMBR-3,4 and 22 (fighters and tactical support transport). Funded by the French,German, US and British governments, it first ran in December 1961 with a total of six development engines available by the middle of 1962. By February 1963 a windtunnel was available to test the engine over a wide range of conditions... see below.
The section shows the material types used in the RB.162/1. The dimensions are length and diameter 51.64 and 25 inches respectively delivering 4,400 lb without bleed at a thrust/weight of 16:1.
Responses to to NMBR-4,-22 included the Fiat G222, Dornier Do31 and Armstrong Whitworth, later Hawker Siddeley HS681. The first two included RB.162s and the 681 had Medway RB.141 and in later concepts lift fans based on the 162 engine.
The sketch below shows a 2-d section of the Dornier lift pod being tested in the wind tunnel.
One of the issues that had arisen from the testing of SC1 etc was the jet induced circulation of gases and air in the hover mode. (think shower curtains and their movement when shower is on).
Another issue was whether there were any issues with fire control in the lift pods at low forward speeds. To investigate this in the winter of 63-64 RR Hucknall set up a lift pod from Do31-E2, the static test build, on a stand to give the height off the ground equivalent the aeroplane on the ground. This was placed on an outdoor test pan consisting of a concrete pan surrounded by earth banks maybe 15 feet high on three sides. Inside the pod were dummy engines and to the leading engine there was a fuel supply that was not kerosene tight at the gimball joint. The idea was to test the pod's firewire detection system by 1) pumping in fuel for 20 second's then hitting a button to an ignitor placed in the pod cavity, watching through an observation port until flames were seen, waiting for firewire detector alarm, and then hitting a second button to fire the fire extinguishers. Repeat several times noting time from ignition to flame detection by firewire and observer. Analyse and present to Dornier and MAN engineers. The engineer in charge of test was leaving the company and my colleague and I (18 year old apprentices were sent to sit in a workman's canvas 'tent' and work the buttons and record times on a stopwatch. We did this over several cold mornings and on one particularly rainy day decided to liven up the proceedings by bringing in a dart nacelle and propeller on a stand to generate a wind over the pod for forward motion tests. We had to stand with an anemometer between Dart and pod to determine airspeed. A wet day!!
The next day the Germans arrived to see what was going on. We were sent to set up the demo and found that the wiring across the pan was a little damp from the day before so we mopped up and then proceeded to run a test... nothing happened on the flame front, we left a two minute gap as specified in test procedure and tried again ... no luck... ten minutes later after our fifth try the German angineers arrived at the top of the embankment and as they looked down we hit the button to pump fuel, then the ignitor. Luck was on our side??! The fuel in the pod caught fire and we waited for the firewire warning and hit the extinguisher button. Instead of going out there was a whoosh and a flame came out of a pod drain pipe and the whole pan caught fire... the airfield fire tender was there within a minute and insisted on jetting foam over the pan even though the fire had gone out. At a welcome teabreak a while later the head of the German group came over and praised our work so far but asked us to be careful with the pod as it was soon going back to Germany and on the 'plane for other tests! So I remember the Do31 very vividly. The picture, from Flickr
below reminds me of the excitement of the project at that time... great fun, whatever the outcome.


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"... prototypes are a way of letting you think out loud. You want the right people to think aloud with you.” - Paul MacCready, aeronautical engineer.
In order to explore ways of exploiting VTOL on the battlefield a great deal of prototyping and thinking went on. This Flight page shows the various concepts using lift jets all drawn to a common scale.

If you research the RB.153 you will find that there is little hard published data to go on. When you have found information it will no doubt confuse as the press seemed to think it was a turbojet, no... turbofan and was of small 25 inches diameter which meant it must have been 'hot' to generate the quoted thrusts,; quite a mystery. In fact, unusually for Rolls-Royce the RB.153 (maybe to do with the MAN connection) is two engines, one a turbojet development building on the experience of the RB.145 and the other a 'scaled Spey' in other words a turbofan.
The RB.153/17 was the first engine to be built in 1959-60 and was a single shaft turbojet with a 9-stage axial compressor driven by a 2-stage turbine. 65 inches long and 25 in diameter the engine delivered 3934 lb thrust dry and 5463 lbs with afterburner. Its construction was more conventional, like an Avon. It was designed for the VJ 101.

As an aside... today I learned that Ann 'Spitfire' McLean was born in Knutsford- our local town- in 1911. She died a few days ago having leant her nickname to the famous Supermarine Spitfire aircraft, that started life as a fixed wing day fighter with night capability but metamorphosed into an an iconic interceptor...
The VJ101 travelled in the other direction... designed as an interceptor to NMBR-3 the military operational requirements changed to a fighter and so the performance requirements dictated longer patrol times at low altitude and a top speed of M2.2 at higher altitudes.... this became the VJ101D. To meet the propulsive requirements an afterburning turbofan was schemed out which also had thrust deflection. The RB.153/61 was a two-shaft engine with 4 fan stages driven by 2 turbine stages and a high-pressure compressor of 12 stages also driven by a 2 stage turbine. The vertical lift deflector diverts the total air flow before the afterburner system.. see below.


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The use of deflectors on Rolls-Royce engines came about because of the expertise they had built up with thrust reversal. The story of the RB.141 illustrates this.
As the advantages of the turbofan or high bypass ratio engine became apparent RR first adopted the approach on the Conway and when the de Havilland 121 was proposed RR early in 1958 started on a new engine design optimised for the duty requirements. The DH121 similar in size to the Boeing 727 was designed to meet the perceived needs of BEA. The RB.141 first ran in November 1959 but by then BEA lost perspective and scaled down their ambitions for the 121; this meant that there was no way RR could derate the engine economically to meet the spec so they started again in July 1959. The same design team schemed an aerodynamically scaled down version, the RB.163, to meet the revised requirement. Using the two-years of accumulated experience the RB.163 was not a direct scale. For instance the bypass ratio was increased from 0.7:1 to 1.0:1. This was achieved aerodynamically by leaving off the last stage of the LP compressor, putting a stage on the front of the HP compressor and rematching the turbines.
The RB.141 had 5 lp compressor stages driven by a 2-stage turbine and the hp compressor had 11 stages also driven by a two stage turbine. The overall Pressure ratio was 16.75: 1. Nine engines were built to accumulate experience relevant to the RB.163 Spey programme but also as a candidate for various aircraft concepts that were at the preliminary stage.
One of these turned out to be the Armstrong Whitworth AW (later HS) 681 VL transport.
I went to Baginton on an apprentice visit and saw the HS 681 mockup; after the Do31 pod it impressed me as a much larger transport and not surprisingly it needed bigger engines than the German offering.
Being 3 times the weight of the Do31 the proposed powerplants were 4 Pegasus or RB.141s for propulsion and vectoring for STOL; also the vectoring was to be used , supplemented by pods of lift engines in the VTOL version.
Rolls-Royce built on its experience with the thrust reversers and came up with a vectoring solution that was aerodynamically more efficient than the Pegasus trousering. Testing showed that an improvement of 4% on cruise sfc could be had. For a longer range aircraft this would be significant... on something like the P1127 it would be marginal.
The three pictures show the original RB.141(intake O/dia about 36"; length about 111"), RB.141 installation with thrust reverser, diagrams of how switch-in thrust deflection would be built into the HS 681.


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Getting back on topic after a Concordian diversion... why should we be concerned of the lessons of 40 years ago? Well....My magazine came in the post yesterday with this pair of pictures within.
Makes you think doesn't it?


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When the area of VTOL was first being explored there were several araes of concern that potentially affected the operation of the lift jets. These included distortion of flow into air intake, lower fuselage exhaust interactions and hot gas recirculation and injestion. These were also influenced by forward speed during transition from flight to hover and vice versa. The first aeroplane of concern to RR was the SC1
Rolls-Royce extensively tested a quartet of RB.108s in their windtunnel but still wanted actual experince in flight where windtunnel effects were eliminated. They decided to modify a Meteor FR.9, V2608, by placing a single RB.108 in the bay behind the pilot. This 'plane still survives at Newark Air Museum

The first illustration is a very small reproduction of a diagram showing the flow into the Meteor bay and the use of a (coal)'scuttle' in order to overcome the negative ram of these aircraft in flight; the scuttle causes a suction over the jet nozzle.
The second is the Meteor at Newark via


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Where to next? Keeping focused on Derby activities - the original RR brfore all the mergers- means the next two places to visit are RB.162 and RB. 193... so on to the logic for the latter engine.
The RR/MAN RB.193 engine design was started in the middle of March 1964 as a vectored lift/propulsion engine for the VFW/Fokker 191B. If we go throught the thermal calculations for the heat engine performance of a jet engine (sketch below) we find that the requirement for low specific weight at take-off suggests a compression ratio of less than 8:1 (at mid-60s aerodynamic technology) whereas cruising at 25,000ft and M0.8ish suggests that for a decent sfc compression ratios of more than 20 are best. The only operational V/Stol aircraft around at this time was the P.1127 and this was powered by the Bristol Pegasus for both lift and forward propulsion. As a consequence the BS53 Pegasus is a compromise between what would be optimal at cruise and take-off resulting in a compression ratio (CR) of 11.7:1.
If we split the two duties then we can optimise the propulsion engine for the cruise duty and take whatever thrust it gives in the take-off condtion. Thus the RB.193 has a CR of 16.55:1. This is still less than the twenty as compromises still need to be made to account for the small elbow losses (technology of nozzles is from Pegasus) versus a straight through duct of a conventional engine and also the amount of air bleed for control nozzles at take off. (RB.193 section below). It is arguable that if much loitering at high subsonic cruise is required of a fighter then splitting duties between engines is better.... however when supersonic duty is required then the cruise engine will be underpowered and a single engine with plenum chamber burning is a better idea... hence the BS100 in the P.1154.
The case for special lift engines is improved as the relative volume of the engine, as wells as lift/weight ratio, is improved and this led to discussions about the likely configuration of a 3rd generation lift engine (generations 1/2/3: RB.108; RB.162/ what became the RB.189)
This led to a smaller volume engine shown below which turned into the joint US/UK development programme for the RB.189/XJ99 engine which was built and run at Derby over the next few years.


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The Fiat (now Aeritalia) G.222 originally started out as a VTOL transport aircraft, powered by two Rolls-Royce Dart turboprop engines and with six to eight RB.162 lift engines to give VTOL capability. A picture of Rolls-Royce model is attached. The aircraft attracted the attention of the Italian Airforce and was built as a STOL aircraft without the RB.162s and with General Electric T64s substituted for the Darts. A further development had Tynes instead of the T64s to get round American trade embargos.


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View of G-222 VTOL model.


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and Erasmo Pinero, a drawing which shows the different engine pods for the V/STOL, ASW and
CTOL versions.


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We have the Dart plus lift, the Dart and T-64 versions... anyone got a Tyne in G.222 drawing?
The 1960s saw growth in civil aviation with package holidays becoming popular. There was great pressure to invest in new airports with their huge costs and disruption. Other ways were examined, such as VTOL. There was a great deal of work done to understand the economic costs and benefits of developing such aircraft. Hawker Siddeley certainly looked at using RB.162/RB.189 technology and Rolls's project office looked at ways of satisfying the lift demand whilst acknowledging the noise levels as a driving factor. The result was the RB.202 engine originating in the late 60s.


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The 119 seat Hawker Siddeley HS141 VTOL airliner was designed to have 16 RB202s along each side of the fuselage. This is a photo of a model.
See also this thread


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Once more into the archives... about a year before the SC1 made its first vertical flight and 3 years before it did the full transition VTO-HorizontalFly-VL the Avon RA.28/49, 10,000lbt, had powered the Ryan X-13 Vertijet into the record books . The first picture shows the aircraft hovering by its 'hook' on 11 April 1957 when the full transition from trailer TO forward flight back on to trailer was made, and the second is a build photo showing the engine being installed.
I have just looked closely at the vertical platform and realised there is a batman on top helping the pilot with his manoeuvres as he hooks onto the landing wire!
I have added a third picture from the batman's perspective.


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Firstly, thank you for all your contributions to this forum so far. Secondly, I have a question, do you happen to know the dimensions of the RB.189 and RB.202 designs? I have also seen a reference to an RB198 in the context of lift engines but I have been unable to find any information about it?

Edit: some digging around tells me that the RB202-36 had a height of 52.8 inches and a diameter of 80.5 inches, however this engine seems to have come in multiple variants so I assume that the diameter would have varied?

Also, a great article about the XJ-99:
Barrington Bond... nice pictures! The VJ101C picture reminded me to look in my collection again and I came up with the first picture below. I remember there was talk of working with MAN Turbo on thrust vectoring for other versions of the VJ101 which took me to the second picture. But this won't work on the 101D which is the next project. I found the third picture here which is the arrangement for the 101D. In fact I believe the second picture shows a development for the 101E.. see material at this webpage including the next pic for the D and for the 101E.


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I think this paper [Practice in Communities: how engineers create solutions ‐ the Bloodhound Guided Missile and the Hawker Harrier “jump jet”. by Jonathan Aylen and Mike Pryce] sums up the ascendancy of the Harrier approach to vtol:
In 1957 the initial design team at Kingston, known as the Project Office, numbered just 25 staff, out of a total in the Design Office of around 400. The Project Office looked after all the aerodynamic work for the company, including both new and existing aircraft and analysis of flight and wind tunnel test results [Williams Interview 26/04/2005]. Indeed, the Project Office was the location of all technical design work outside mainstream structural and mechanical design. This was in addition to their activities in new project design which required the generation of new concepts, writing proposals and liaising with suppliers and customers for such project designs. Staff in the Hawker Project Office tended to be young, with a mix of graduates and former shop‐floor apprentices among their number. . The Chief Designer, Sir Sydney Camm, had a special interest in his ‘Young Gentlemen’ of the Project Office, being both their harshest critic and fiercest defender. The rate of ‘turnover’ in front line combat aircraft and related technology meant that it was clearly seen that the future of the company was directly linked to the work of the Project Office.
The central innovation of the Hawker P.1127 was to use the same single engine to both lift vertically and then drive forward in flight, a system known as ‘vectored thrust’. Other ‘jump jets’ designed in the UK relied on separate lift and propulsion engines for each flight regime, often installed by the half dozen or more. The origins of the vectored thrust engine lay in the work of a French designer, Michel Wibault, who approached NATO in Brussels with the outline idea in 1956. NATO officials saw the idea had merit, and passed the concept on to the Bristol Engine company in England, with whom NATO were already working.
At Bristol the idea of vectored thrust was simplified and made more practical, the work being led by a young engineer called Gordon Lewis. An essential part of this work was finding aircraft designers who could explore the issues raised by the new type of engine. Bristol were linked by cross‐shareholdings to the Shorts aircraft company. But Shorts were more interested in the alternative lift jet system as they had a contract from the UK Government to develop a research aircraft using that approach. Shorts therefore used design work on vectored thrust as an opportunistic way to gain a meeting with NATO, where they put forward their own favoured type of lift jet design ahead of vectored thrust ‐ hardly a way to gain popularity with Bristol. Design collaboration between the two firms ended immediately, a clear illustration that communities of practice which coalesce around a boundary object – such as vectored thrust – can divide off irrevocably from those with a different focus.
Since vertical take‐off and landing jet aircraft were a ‘hot topic’, and as Hawker were desperate to secure their future after cuts in the UK fighter programmes, Camm wrote to the head of Bristol engines, Sir Stanley Hooker, to enquire about their work on the subject. A brochure on vectored thrust was passed back to the Hawker Project Office, but it was not initially seen as an attractive system. The brochure was initially picked up by Ralph Hooper, a project engineer at Hawker, who admitted he did so out of boredom with his main task of designing a flight control system on another project. He produced a few sketches of types of aircraft that could use the new vectored thrust engine, but none looked too promising. After a period of going back to his main work, he returned to the idea of the vectored thrust design and it was then that “the blinding flash of the obvious happened”. The original Bristol brochure proposed that only half the engine’s power would be ‘vectored’, limiting the weight it could support. Hooper realized that all the power could be vectored, allowing a much more useful aircraft design to emerge.
Hooper visited Bristol to discuss the idea with Lewis. It turned out that Bristol had anticipated the development Hooper outlined and put it into their engine’s patent application, although the more detailed scheme Hooper created was also the subject of a Hawker patent. Despite this apparent conflict of interest, with Bristol fiercely defending their patent rights against other engine companies, they waived them with Hawker. This was a direct result of the design community that developed between Bristol and Hawker, with both feeding new ideas into the design of the engine and airframe over a period of several years. Many decades later it was impossible for participants to recall who had created what, and it was never a point of argument between them.. The design of what became the Harrier and its engine evolved over time through an informal process of joint working between Hawker and Bristol engineers (located 120 miles apart) with novel technical problems dealt with in a mutually supportive way – demarcation was neither technically nor organisationally desirable. This was a far cry from the often fractious relationship between other engine and aircraft companies, illustrated by a cartoon from the time:
An informal approach to working was supported by management – Camm and Hooker at director level having known and worked with each other for many years. In addition, within the two firms management trusted their project engineers to make decisions and act on them, and provided resources when needed. At a briefing for NATO it is reported that Lewis brought the wrong costing figures to win NATO funding for the engine. Too late to correct the mistake, and having obtained NATO approval at the lower costs presented, Arnold Hall, Bristol’s director, accepted Lewis’s explanation and approved the significant additional spending the company would incur. A similar relationship operated with government – the Ministry of Defence ultimately funded the Hawker P.1127, but contract cover was only received a few months before the aircraft flew in 1960, with the design and manufacturing costs having been met by the company up to that point, a highly unusual state of affairs in the aircraft industry. However, Camm’s reputation with the MoD meant that Hawker’s directors were willing to place their faith in the innovative project his design team created. Such support ‘greased the bearings’ of the design process, and formed a vital part of the community that developed the Harrier.
The role of the community in obtaining support and sustaining practices within the Harrier design team is highlighted by the difficulty those outside the community faced in understanding the engineering sense of the design. Many analytical studies were produced that ‘proved’ that the vectored thrust system produced the ‘optimum worst’ solution to vertical flight by jet aircraft. It was seen in these studies that the lift jet system provided a ’better’ solution, with a hybrid of vectored thrust and lift jets producing the ‘optimum’ best. On the basis of these studies a number of aircraft were built in France, Germany, the UK and elsewhere. The Germans built an aircraft that used the optimum ‘best’ system, which turned out to be, in Ralph Hooper’s words, “amongst the most expensive and useless of all time”. The French had a similar experience, one of their lift jet equipped designs having the dubious distinction of crashing twice and killing two test pilots.
Central to the Harrier’s success was that it was the simplest, most practical engineering solution to the problem. In large part, this was due to the community nature of the way the engine and aircraft designers worked together. Occam’s razor shaped their way of working and the new fields of design knowledge the community required. This informal approach was not used on the disastrous prototypes produced by others. Instead, rigid contracts, separate design teams (often spread across a continent) and patent disputes were commonplace and complicated engineering and project failure the result.


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