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A winning Formula


by Ian Homer. Posted to category: Education

Trustee Steve Liddle talks on his career

Part 1

A winning Formula

This week, we start the serialisation of several articles that will be running on a regular basis throughout 2018. Many will be on aviation history or like this one, on technology and incredible engineering.

Here, a Trustee of the Vulcan to the Sky Trust, Steve Liddle, explains what first inspired him in his career.

If you’ve ever thought about working in F1, here’s an example of how not to do it.

I decided I wanted to be an aerospace engineer because I loved aeroplanes and everything about them; their technology, history and of course noise. I grew up not far at all from South Yorkshire’s premier V-bomber base, although by that time the RAF’s sole airworthy Vulcan at Finningley’s annual Battle of Britain at home day was the closest one could get, the sky being occupied by their red and white training fleet the rest of the time. I was fascinated by the stories of the ingenuity of how aircraft were developed and how they worked, so for me it was always an engineering rather than pilot role that was the dream. Consequently, I eventually ended up at the University of Manchester engineering department as an undergraduate, happily surrounded by enough people who felt the same way.

Steve Liddle sits in the P1 position of a B1 Lancer parked next to the Vulcan XH558 Trailer at RIAT 2017. (Courtesy of B. Jackson/USAF)

What I wanted was to be involved in engineering some real aeroplanes, so I asked the head of engineering at Manchester, Prof Norman Wood, if I could be a spare pair hands at the aero labs over the summer. Following a couple of months of proper student summer activity exploring Australia and New Zealand, I arrived at the Goldstein Research Laboratory on the edge of Barton aerodrome (now City Airport) and got involved in some of the work going on. The lab had two really significant windtunnels, both of which had been imported. The National Power tunnel had been built by CEGB for modelling the wind effect on buildings, the understanding of which was important to them after three cooling towers at Ferrybridge C power station collapsed in 1965. This was used commercially for testing new buildings, which included in my time there the forty seven storey Beetham Tower planned for the centre of Manchester.

The presence of new large buildings can have an effect on the wind speeds encountered at street level, so as well as verifying the loads on the buildings themselves it is necessary to sign them off as safe for pedestrians to pass by. The relatively large size of the tunnel made it useful for many other types of test, one such being investigations into the flight of live geese, which were of course, very carefully supervised.

Much more interesting from my perspective was the Avro windtunnel. This was a seemingly enormous closed return tunnel (with the air passing through a complete circuit) that had formerly been built for and used by Avro at Woodford, before being sold to the university and transported over in the late 1980s.

Steve’s PhD work, testing in the Avro 9x7 wind tunnel at Barton (Steve Liddle).

 

This was a ‘low speed’ windtunnel, used for investigating aircraft performance in subsonic regimes (which even high performance aircraft have to pass through) and more recently for aerodynamic research. Not only was it vast, but pleasingly solid having been constructed from steel left over (or so I was told) at the end of the war from battleships that were never built. As I’d been an enthusiast before an engineer, the idea that these very pieces of metal were the test facility for the Vulcan and other Woodford designed aircraft was spine tingling. Indeed, in the Manchester Museum of Science and Industry a collection of impressively large windtunnel models hung from the roof of the Air and Space gallery, including a Vulcan equipped with the K2 refuelling HDU fairing; that must have been one of the final wind tunnel test of the aircraft and would have taken place in this very facility.

The control room was vastly out of date even then, with a large fixed console tastefully covered in orange plastic and incorporating a couple of small computer monitors but mainly many analogue instruments; some of the electronics within were allegedly Nimrod AEW left overs. Some years later when I was working as a researcher, I helped to open a box for a Nimrod model that had arrived for a contract test of a new sensor fairing. Again, this was an old model that would have been used at Woodford and from memory had a wingspan of around five feet. The box contained a log book showing when the model had last been used – 1982 – and beautifully machined Sidewinder missiles on pylons as well as a refuelling probe. Touching another bit of history, this must have been used to sign off the mods required for Nimrods in the South Atlantic.

  

The Nimrod model and an original Avro Vulcan windtunnel model in the Manchester Museum of Science and Industry. 

The lab had quite a few other relics that had been used (or reused) in university aerodynamics research. There were several half models of Victors; some time after the Falklands war, a project had been undertaken to shed light on why the Black Buck aircraft had used much more fuel than anticipated. Like birds flying in V shaped formations, two aircraft formatting on each other have a strong aerodynamic interaction caused by the trailing vortices shed from their wings, which alters the drag and subsequently the thrust (or engine setting) required to balance it. The heavy weights, long periods spent refuelling and lack of Vulcan data would have been unhelpful to the planners of the missions. However, we did have some moderately more up to date models from the BAe146/RJ airliner programme that were used in some of the more cutting edge work that you would have hoped would be happening.

A BAe146 coming in to land.

During my initial summer, an interesting few days was spent in the Avro tunnel with a real section of 146 elevator. At the time, BAE Systems was developing its new version of this aircraft - RJX – which it had managed to sell to the Bhutanese airline Druk Air. The 146 did not have powered elevators and it was necessary to demonstrate that the latest version would not suffer flutter or vibration of these surfaces in the event of ice build up. An extremely hi-tech experiment was devised in which gravel was glued onto wooden strips to represent the ice, and the elevator oscillated in the windtunnel. We were able to show there would be no ill effects, but sadly the RJX was cancelled just after the prototypes flew and so never got to operate in the Himalayas and prove us correct. In the process, I had worked on the engineering of the last all British jet airliner (to date).

Will this remain the last all-British built airliner? - The Avro RJX.

Part of the Manchester course was six months at the start of year four in industry – if you could find a placement! I was very lucky and managed to get a role in Rolls-Royce’s manufacturing technology department in Derby, where we looked into new processes to make engine parts for future aircraft. Today 3D printing technology is quite familiar, but at the time it had an element of witchcraft, particularly when it was being done in titanium and stainless steel. From our small office and lab in the original 1906 RR factory, we attempted both to move the process on so that it could be used in production and also to ‘sell’ it to the project teams.

The most productive place to aim then was at the volumous new fighter project, for which the contact would be going to Boeing and its X-32 or Lockheed Martin and the X-35. Thankfully for the aesthetes, it was the LM proposal that was announced as the winner. RR had partnered to design and build the vertical lift system of the aircraft – a combination of a swivelling engine nozzle in three segments that rotated to give a vertical axis and a lifting fan geared onto the engine shaft. A key challenge was how to efficiently manufacture the flanges that ran around the joins between the nozzle segments and contained the tracks and bearings that allowed the rotation. We were able to show that rather than the usual approach of making an oversize nozzle and machining most of it away, we could ‘print’ material back on accurately, allowing the basic nozzle to be thinner. Machining away 90% of the material to generate a complex shape is a major problem in aerospace engineering. It would be painful enough in most materials, but in heat resistance engine parts made of exotic titanium and nickel alloys, even small savings in the size of the blank parts could result in major cost savings. Later, after I had graduated I was briefly involved again with the F-35’s lift system as I worked on the structural analysis of the lift fan and its actuation systems. Aerospace projects have long time scales; some fifteen years after I had started work on the then Joint Strike Fighter, I finally got to see one in action at RIAT 2016. Marvellous!

 

The F-35 demonstrates its vertical landing capabilities at R.I.A.T  2016.

 

Next week, PART II of this story looks at Steve's involvement with active flow control and some early experimental work with scale models. Read that here:

 

 

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