12,46, A very sorry tale.
It was rather apposite that after the recent success of the spitfire flights to Malta that the Am and the CAS should be having a brief but very frank discussion regarding two reports. The first was a technical report commissioned from the Royal aircraft Establishment and Rolls Royce after the recovery of the discovery of fuel injected Jumo engines on the first German aircraft to brought down in the UK. This Heinkel 111 had crashed near Edinburgh in late the autumn of 1939 and the engine had been recovered , examined and tested to reveal their technical secrets and performance. The report had shown that in many ways especially in the use of fuel injection the German engines were superior in engineering to those being used on RAF air craft. That first report in itself had been a very sobering read and had caused Sir Hugh to commission a second report into why the RAF had no comparable fuel injection system in development let alone service.
Henry Tizard himself had elected to chair this second committee as he had certain expertise in the field of fuel development and also personally knew most of the major personalities who would be appearing before the enquiry committee or supplying it with expert opinions.
The First report released by the Royal Aeronautical Establishment in June 1940 set out the results of a joint examination of the engines recovered from the wrecked He 111 by the RAE and Rolls Royce had starkly laid out the advantages gained by the employment of a fuel injection system for the German engine. The fact that there were three immediate advantages to be gained when using fuel injection over carburettors’ was and now as stated in the report an undeniable fact. These advantages were in simple terms:
One an increase of at least 10% in engine power for engines of equal cubic capacity over a carburettor engine by the same engine with fuel injection.
Two: Fuel consumption at least 10% less for the same power output for engines using fuel injection. Three: Due to the auto regulating mechanisms fitted to fuel injection systems in flight engine management was much easier for the pilot, reducing their workload and increasing their fighting efficiency.
To the RAE and the RAF as a whole this was a stark reminder that Britain was not necessarily the proponent of the most advance aero nautical engineering.
Couple these advantages with that of the advantage given to the aircraft with fuel injection engines during high positive and negative G manoeuvres due to the consistent and reliable running of the engine and the combat benefits become even more stark. Attached to this report was another one from the RAE again dated June 1940 written by Beatrice Shilling a carburettor and fuel system engineer, in this she had set out no less than five design or technical deficiencies in the current SU carburettor being used on the RAF’s Merlin engines. It was Miss Shilling who at the height of the battle of Britain in the summer of 1940 had come up with an extemporised fix to mitigate one of the worst problems being experienced by RAF fighter pilots which was engine cut out caused particularly by negative G manoeuvres. The expedient solution, officially called the RAE Restrictor, was in its simplest form a washer with a hole in it to restrict the flow of fuel. Despite its official name this device became known throughout the RAF as ‘Miss Shillings Orifice’. Miss Shillings report on the design and fitting of the RAE Restrictor had been attended to the final report of the Sir Tizard Committee on Fuel Injection. This report had not become available to the Fuel Injection Committee until mid March when Miss Shilling had finished her tour of RAF fighter bases instructing engine fitters in the correct installation of the ‘regulator’ into the Merlin engine carburettor.
In setting up this investigative committee Sir Hugh had made it clear to Sir Henry Tizard that he should not be seeking someone to blame or convenient scapegoat but to genuinely understand the reasons behind the decisions that had been made. What information had been available to those making the decisions and whether there were any systemic failures that could be identified and lessons learnt to avoid any recurrence within future decision making. Sit Hugh also made it clear that his role as the Air Officer for research and development up until the middle of 1936 when he took over Fighter Command should be as closely examined as any other. The Committees investigation started with looking at the very origins of fuel injection and in building up a time line for the technical developments and research into fuel injection systems worldwide. With several world renowned experts on the committee this time line for the initial development of fuel injection was not difficult to construct. Sir Harry Ricardo the renowned engine designer provided full copies of the research carried out by his company which included documentation pertaining to the results of research in America and elsewhere. Evidence from the Ricardo company files also showed the circulation of their reports within the aeronautical and engineering community as well as the government departments to which it was sent.
One of the first Items addressed by the committee was to construct a simplistic time line to show the development of fuel injection by the air powers.
The starting point was chosen as 1900 when diesel engines with a fuel inject system were in production. Fuel injection for diesel engines was the subject of research and refinement from then on. In 1924 the Americans began a scientific investigation of fuel injection use in aircraft engines with papers being published by NACA. In 1927 Germany restarted development of fuel injection for aircraft engines and in 1928 the German Air Ministry issued an edict that in future all new aircraft engines would have to have fuel injection as standard. It was not until 1932 that the British Government sponsored research into fuel injection aircraft engine performance commenced at the Ricardo engineering laboritys. In 1935 the first German production fuel injected engine is in use. In 1937 all British Government funded research into aircraft Fuel injection is abandoned.
American research had by 1940 evolved into the pressure carburettor in favour of full fuel injection and this was now in production whilst the UK was still using downdraught carburettors with all their known faults.
The time line as shown to the committee showed starkly how Britain had come late to the scientific development of fuel injection for aircraft engine and had abandoned it just after the first German production engines had entered service.
The committees investigation had shown that early research by the British into fuel injection was mainly focused on using fuel injection as a way of circumventing the problem of carburettor icing. By October 1933 the carburettor icing problem had been largely solved by adding a small percentage of alcohol to the petrol. In September 1933 the RAE had issued a report that stated that there was no reason to dispense with the carburettor system when using ‘normal fuels’ i.e. petrol or petrol/alcohol mixtures. Only a couple of weeks later the records showed that documents dated the 3rd of October 1933 had recommend the cessation of experimentation using a multi cylinder engine fitted with fuel injection.
The conclusion drawn by the Committee was that the purpose of the fuel injection test had been too focust on solving one particular known problem rather than being a broader examination of the overall benefits of the system. This Focus on one issue was used as justification for ceasing all work and expenditure on what would have been pure scientific research. This institutional failing was not unique to the Air ministry and the committee from personal experience cited other examples of such narrow sightedness meaning that pure research had been curtailed with adverse effect.
The committee practically noted that the RAE had appeared to consider the report publish at that time by the Ricardo engineering company which clearly demonstrated performance advantages gained by using fuel injection had no relevance to the RAE decision to cease multi cylinder fuel injected engine development.
Further in evidence given to the committees by George Bulman who was currently in charge of engine development at the MAP it came to light that after the then Major G. Bulman had visited the USA he had in his reported of June stated the importance being placed by the Americans on fuel injection at that time, adding that this enthusiasm could be down the fact that fuel injection did not suffer from icing. Despite this the report from the Engine sub-committee had on the second of July recommended that further trials should be carried out by adapting a fairly highly super charged Bristol Pegasus engine to fuel injection for direct comparison to the carburettor version of the same engine. For reasons for which there seemed no logical explanation other than the treasuries’ tight hold on budgets no such project had been undertaken.
The Committee had also been shown copies of reports from the NACA in America from 1932 which contained graphs that clearly showed even to a layman that there were distinct performance advantages to be gained by have fuel injection on aircraft engines. These graphs along with those from Sir Harry Ricardo’s research were from the committee’s viewpoint sufficient evidence have necessitated any competent organisation to take notice.
In his evidence to the committee Sir Hugh Dowding had been able to confirm that during his time as Air Member for Supply and Research the details of the Ricardo and NACA papers had never been discussed with him. Such information would have been available to the Government Scientists employed at the RAE and it would have been their reports and recommendations that would have been shown to Sir Hugh.
The Committee at this juncture had discussed at length a report from a senior scientist at the RAE dated September 1936, just after the change in RAF command structure that separated the tasks of supply and research into two separate entities after Sir Hugh had left that post to form and take control of the Fighter Command. This report had concluded, specific in reference to valve overlap that there was no advantage to be gained from using fuel injection over carburettors and therefore there should be no further research or development carried out on fuel injection. This led to the RAE sending out a letter to the British aircraft industry dated the seventh of April 1937. This stated that, there would be no further development by the RAE of fuel injection systems for aircraft engines as it was seen as unnecessary. The letter also said that the engine manufactures could request such research from the RAE if they felt it was needed but the RAE would not be able to give such research any priority at all.
So as Tizard and his committee wrote their reports conclusion they considered that the decision by one expert engineer at the RAE who had consistently opposed fuel injection development in the face of mounting scientific evidence had resulted the complete failure to reap the benefits of such a development. This scientist had now been removed from all roles of any influence but little else could be done as that horse had well and truly bolted. Sir Phillip and Sir Hugh saw little benefit in simply lopping some heads off at the RAE as Sir Archibald Sinclair as the head of MAP under who’s jurisdiction the RAE fell was wont to do
Amongst many recommendations made by the committee the one that Sir Hugh found was most definitely persuasive from his own experience was that all such expert opinions must be subject to some form of peer review. Finally to wrap up the discussion the man from the Sir Archibald gave a short up date of the progress being made by Beatrice Shilling and her team who were now developing a pressure carburettor and fuel injection system at the RAE.
