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Rolls-Royce RB.178 three-shaft commercial turbofan prototype......


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Nov 30, 2007
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Dear Boys and Girls, here is an article in French about the Rolls-Royce RB.178 turbofan prototype which was originally known as the "Super Conway". This was the first large three-shaft commercial high by-pass ratio turbofan designed by Rolls-Royce and it first underwent ground testing in July 1966; it was intended to power the following:-

Hawker-Siddeley HS-132 & HS-134 "projects".
BAC VC-10 DB265 "project". RB.178-14 4:1 by-pass ratio 27,500lbs thrust version.
Bréguet Br.124 "project".
Shorts SC.5/45 "project".

A 6:1 by-pass ratio 44,000lbs thrust version was rejected in favour of the competitive Pratt & Whitney JT9-D turbofan for the Boeing 747 in 1966.

The RB.178 engine was never flight-tested and never went into production as most of the intended applications remained unbuilt "projects". It did lead, however, to the RB.211 engine first used on the Lockheed L-1011 TriStar and the RB.207 engine "project" intended for the abortive original Airbus A-300 "project" of 1967/68......

The article comes from the 1st August 1966 issue of Aviation Magazine International......

Terry (Caravellarella)


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Oct 12, 2009
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this brings back memories... as an engineering apprentice I was assigned to the RB.178 design office for a three month stint... the RB.178-14 demonstrator was on test to allow us to learn the 'art' of big fan engines and I worked on the RB.178-51, designed to the Boeing 747 RFP (Request for Proposal); when that went to Pratt's attention focused on the European Airbus and the Lockheed L. 1011 and Douglas DC-10 RFPs. This meant rescaling the engine down from the -51... one linear scale for the twin-engined EAB.... 0.957 rings a bell and 0.832 for the trijets... this meant an awful lot of photographing of existing drawings..scaling to the new and then scratching out and redrawing the bits that don't scale.. likenuts and bolts.. I remember on one scaling that a .25 in diameter bolt became a No. 10... which was used on older engines but had been banned for all new ones... so we got scratching! Eventually Airbus went CF-6 plus SNECMA and so we were left to get the 211-06 as the .832 scale had become onto the test bed replacing the RB.207-03 (EAB) in priority.


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Jan 20, 2007
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t: thank you for that, all new to me. Maybe this will be to you, explaining how you came to be employed on big fans.

Nothing especially difficult preventing wide body airframe. Problem was power, and operator aversion to >4 engines. 1962/63: basic metals/metallurgy industry came up with means of machining big fanblades, big shafts, big bearings. USAF wrote CX/HLS Spec; GE adapted superb J79 as core for this new hardware, Pratt ditto JT8D. Boeing and Lockheed schemed (to be 747 and C-5A). 10/65 winner was Lockheed/GE TF39; PanAm hoisted Boeing/Pratt out of their mire by offering $5Mn. per for 13/4/66 order of 20, so (to be) CF-6 and JT9D were then onway.

In 1962/63 MoA's engine man in Br.Defence Research & Supply Staff, in the DC Embassy, was Ray Holl. He had been Whittle's Project Engineer on PCB on W.2/700, moving into NGTE. His Reports on Big caused MoA to fund a UK Rig/Demonstrator. So: who should MoA choose: BSEL or RR? In 1963 RR was on the brink of extinction. BSEL chose not to make an offer to take them over, because such assets as they might care to acquire would shortly fall, ripe for the plucking. Ray Holl came back from BDRSS as MoA Project Officer for Big Pegasus: RAF had discovered V/STOL (P.1127/BS.53 Pegasus had been meagre-funded as a Research exercise - no payload/range, but W.Germany was enamoured of runway-less operations, so NBMR.3 sought supersonic V/STOL: Pegasus+PCB). Feebly RR muttered about deflected thrust Twin Spey, but (to be) BS.100 was preferable. UK's (then)biggest-ever engine. Taken together with Olympus 22R/TSR.2 and 593/Concorde, Holl suggested inadequate capacity in BSEL to do his engine and a Big demonstrator. Whereas Conway-folk were idle and able. Shoe-in. 25/3/63: BS.100 funded; same timeframe: MoA component rig contract, then late-63, RB178 demonstrator contract (bench test, 7/66)

Feb/April,1965: B.Ol.22R and BS.100 were chopped; UK tried to chop Concorde. Spey sold to every man and his dog. BSEL suddenly...brink of extinction. They and 593 partner SNECMA wriggled onto JT9D, peddled by Pratt to HSAL and BAC for 11/65 MoA-funded studies of Big Twins for Air France/BEAC. RR bought Bristol Aeroplane's 50% of BSEL, 7/10/66 and terminated UK/JT9D. UK/FRG/France instantly funded Project Definition of Super Galion {HSAL/Sud/(the Consortium to be Deutsche Airbus)}, with RB207.

(On 28/7/67 MoA provided 70% Launch Aid for RB207/A300 and for RB211/L1011. By early 1969 it was evident that RR could not do both and preferred L1011. So, 16/4/69, UK ceased funding Airbus Industrie. On 25/5/69 FRG+France funded A300B+GE/SNECMA CF-6. RR not only could not do both, on 4/2/71 they became unable to do either. Bailed out by market-orientated, spend-averse Tories, spending our taxes, only because RR's ex-BSEL Military business at Patchway had MRCA's RB199).

The Law of Unintended Consequences.

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