Rolls Royce take-off thrust augmentation devices

[Rheged]

A chance comment by Kit that he was unaware of a Rolls Royce LYD  aero-engine started me off on some research, and as a result of that study, I bring before you the previously little-known story of Rolls Royce's research and development establishment at Coleford in Gloucestershire.  I think that this thread is probably where it belongs, I'm sure Chris will relocate it if it seems appropriate

Rolls Royce's contribution to take-off thrust augmentation

By 1935, it was becoming  obvious to the directors of Rolls Royce that the German Chancellor was  making statements of an increasingly belligerent nature and that widespread hostilities  would probably ensue within the next five years. As  an aero-engine maker, Rolls Royce were aware that  increasingly heavy aircraft were in the design stage  at many British companies and that long runways were potential targets for attack.  The situation in the Fleet Air Arm was particularly concerning; whilst Ark Royal and her successors would have adequate flight deck length for current aircraft, there was a limit to aircraft size and weight that could not easily be overcome by the use of large, more powerful but thus much heavier engines.   Some form of light weight thrust augmentation device was essential.

Having decided to embark on research into this subject, Rolls Royce  decided to set up a small design group. The possibility of such a research establishment becoming a target for bombing led the company's property management  team to consider locations in the west of Britain, with a rail connection  and a reasonably large town or city fairly close by.  Coleford in the Forest of Dean in Gloucestershire was chosen.  As the railway line had closed to passengers in 1927, the surprisingly commodious station buildings were available for lease at a very favourable rate but an occasional goods train still used the line should the movement of equipment be required. Gloster Aviation were within a reasonable distance, as was Staverton airfield. By mid 1936, Rolls Royce Coleford was established and research had begun.

Within a very short time, two teams had begun work; the liquid fuel group, using kerosene and liquid oxygen  and the solid fuel group working with cordite. The cordite group found considerable weight difficulties had to be overcome as their solid fuel would easily burn through a thin metal casing causing a danger to the aircraft to which it was fitted. Another major problem was ensuring that  in the case of multiple units, all of them fired at exactly the same moment. Asymmetric thrust in this case was potentially lethal .  Finally, cordite thrust augmentation was a "one-shot" system; once ignited there was no control  and the device once used had to be discarded.

The liquid fuel group had initial problems with fuel supply control and burner nozzle shape and size but by June 1938 the team had assembled a prototype that gave controllable thrust for 30 seconds at full throttle whilst burning any distillate fuel from Diesel to high octane aviation petrol. This was offered for production as the RC 101 thrust augmentation device. This was a bit of a mouthful, so the team referred to it as the Rolls Royce Lyd, naming it  after a local river. Subsequent development produced a series of units of increasing size and power. A river name was given to each of these devices.

By April 1941, Rolls Royce had available  five units. It was decided that liquid fuelled engines should have an initial L in their name;   the longer the name the more thrust available. The  Rolls Royce Lyd, Lugg, Leven, Lossie and  Laxford are all still in use in some specialised applications, most in modified form.  The cordite working group produced two sizes of equipment, known informally as the Cam and the Carron but these were not adopted by the armed services.

Swordfish aircraft operating from escort carriers were  using  a pair of RR Lyds to reduce take off run by June 1942 and as late as October 1961, consideration was given to using a RR Laxford as a means of improving the performance of the Buccaneer S 1 , although the introduction of the RR Spey made that unnecessary.

The newly nationalised British Railways trialled a pair of RR Leven units on a flat truck  propelled by an ex LMS "Black Five"  in an attempt to clear deep snowdrifts at Bleath Gill on the Stainmore line in late February 1955.  It was assumed that the heat and blast would melt or blow away the compacted snow, but all that happened was that the locomotive was pushed slowly back along the track and thus  possibly constituting the first rocket propelled train in Britain. See https://en.wikipedia.org/wiki/Snowdrift_at_Bleath_Gill to see how the line was actually cleared

Pratt and Whitney  acquired a licence to build the RR "L" range under their own names, but apart from a few reference to a P&W Yukon unit, I have not been able to find any further information.

As usual, if anyone has further details to add to or amend this research I'd be delighted to see it.

[PR19_Kit]

I'm literally rolling on the couch with laughter here, that's BRILLIANT! 

Just the thought of anything as hi-tech as a Rolls Royce plant at Coleford is enough to blow your mind. The site of the old station building now is a (very) small shopping centre.

As for using RR Levens to clear the snow at Bleath Gill, BT Films made a film about it, but they didn't get there until after the 'Leven Powered' attempt had failed, so we can only see the more archaic steam powered version. 

https://www.youtube.com/watch?v=-ugIoMD495E

[Pellson]

Sterling work!! 

[NARSES2]