Theory, wheels, and Darts
Hoping that all my fellow crew room companions had an enjoyable festive Christmas. Have to be two five pence pieces this time, run out of 10p pieces. Still works out to be two bob in real money.
Dave Wilson,
I have also been told that the Trabby's bodywork was non-conventional, a hardboard or paper mâché type material. Is it true I wonder?
Danny,
Impressed with your multilingual skills. I get found out whenever I try my hand at language murder, the recipient knowing I am UK based (the eyes invariably saying 'englaise' or maybe something less repeatable).
Geriaviator,
I look forward to reading these gentlemen's reminiscences with great interest.
Halton (contd)
Following the successful completion of our "hack 'n' bash", we moved on to the serious business of jet engines, the theory. For those of you who may not be conversant with jet engine theory, it is actually very simple. The four 'cycles' are the same as a Diesel engine with "suck, squeeze, bang, blow" and differs from a petrol engines cycles only in that there is no requirement for sparks to continuously ignite the fuel/air mix. In a Diesel engine, and in a jet engine, the fuel is continuously ignited by the heat of the incoming air being heavily compressed. The "suck" and "squeeze" is accomplished by the compressor section. This may be of a centrifugal or axial configuration, or a combination of both. The earliest British Whittle engines were equipped with centrifugal compressors. The earliest German BMW engines in Me 262's were equipped with axial flow compressors. As the air is drawn in and forced through the compressor section, it is accelerated and compressed. This fast, pressurised hot air is then introduced into the combustion chamber or multiple external chambers where the fuel is mixed with the air and combusts. This produces very hot, very fast, high pressure exhaust gasses which are directed through the turbine section, rotating the turbine. This is the "bang". If the engine is a turboprop, then an additional separate turbine will connect to a propeller. If the engine is a turboshaft for a helicopter, then an additional separate turbine will connect to a shaft driving a gearbox for rotors. The hot gases are then exhausted out of a jet pipe. This is the "blow". The main turbine section is solidly connected to the compressor section (imagine a bobbin), this being known as a spool, and the exhaust gas energy rotates the main turbine section, and in turn, the compressor. Add more fuel, spool turns faster. Like a Diesel engine, to turn it off, shut off the fuel supply. To start the engine, first it must be rotated to a speed sufficient to allow continuous combustion of the fuel. This is accomplished with cartridges, external air start, or electric motor. Once that speed is attained, fuel is added and a spark torch ignition (old school) or a high energy ignition spark (modern) is supplied for starting only, similar in principle to heater plugs on Diesel engines. Once the fuel/air mix has ignited, the combustion of the fuel/air mix is a continuous, self-sustaining action until the fuel supply is cut off or runs out.
There. Now we are all RAF jet engine genius's. Well, not quite, but hopefully now, everyone has a basic understanding of the operation of a gas turbine jet engine.
The theory continues into ever increasing depth and detail. The initial part is methods of construction and materials (sorry, having to do everything here through memory as the original training notes are somewhere "safe"???). We are taught about some of the exotic alloys used in these engines, and are awestruck to find out that all modern civil and military engines have their 'hot' sections of turbines and nozzle guide vanes operating within an environment so hostile that the gasses passing through them are hundreds of degrees hotter than the melting points of the metals used. So how come they don't melt, we ask? That will come later we are told. I don't remember being told about some of the less desirable aspects of some light alloys. The main cases of the Viper engine contained radioactive Thorium.
Although I had passed my driving test at the first attempt at the age of 17, I was now almost 20 and still without my own transport. In the late '70's, I have no recollection of the easy finance the youngsters of today access without difficulty. Unless you were fortunate enough to have wealthy parents, or had been a recipient of some favourite Aunt's bequeathed gift, you generally had to wait until you had worked hard enough to earn the money to buy a car or motorbike. And even then, it would be very second hand. I consider myself to have been fortunate as I had built up a reasonable little kitty in my Bank Account over the previous five years. Now seemed a good time to put it to use. Choice was wide and varied from the smallest Mini through very rough MG's, and any other car in my price bracket. I had over 600 Pounds saved, but didn't want to 'blow the lot' on a car only. There was still road tax and insurance, which as a 19 year old was a bit steep. I was offered a number of cars which were excellent candidates, from Austin 1800 Land Crabs and Vauxhall Viva HA's to a very tempting Ford Capri 1600 GT for just under my total savings. In the end, I decided to be sensible, for the sake of my sanity, licence and pocket, and settled on a delightful ten year old, one previous owner (lady teacher) Wolesley Hornet Mk III in two-tone grey. This was the model with 'hidden' door hinges, 1000 cc 'A' series engine, and vertical 'remote' gear change. The interior smelt like a proper car with leather seats and walnut dash. The Hornet was based on the Austin 7, later known worldwide as the Mini, and shared the extended body shell with the Riley Elf. The extension was at the rear, and incorporated longer rear wings, extended boot floor, and a proper boot lid. And, of course, being a Wolesley, it had an illuminated grill badge, "Wolesley, the only car with its name in lights" I think the advert went.
During the 1960's, motor racing was widespread and popular in the UK. There were various classes, covering everything from saloon racing (the fore-runner of today's British Touring Car racing) to formula 1. Mini's were extremely popular in many aspects of Motorsport, from Rallying to saloon racing. As can be imagined, there was very little difference technically between the racing Mini's. However, on the longer straights, the racing Hornets and Elfs always managed to pull away from the Mini's, and no one could understand why. Until the early 1980's. Ford were developing a new hatchback, and after considerable wind tunnel testing, someone 'tried something'. This 'something' made a massive difference in drag reduction. Bear in mind, for many decades, manufacturers have continually looked to reduce drag in order to make their car more economic than any rivals. The differences are usually measured in tenths of a mile per gallon. Well, this 'something' made a difference measured in whole units. Hence, the new front wheel drive ford Escort did not come as a hatch, but as a 'booted hatch'. The boot extension worked by drawing the airflow down smoothly over the rear windscreen, thereby creating a much smaller region of disrupted airflow behind the car. The Hornet and Elf benefited from this design idea, but of course, it was designed that way for looks only.
Following our introduction to basic jet engine theory, we are given an engine type to relate our newfound knowledge to, the Rolls Royce Dart. We would get to know this engine more fully than anything else in our lives up to that point.
And this satisfies one of my lifetime wishes, but I'll explain later.
Camlobe
Suck, squeeze, bang, bang, bang...got a surge, Chiefy.