Wimbledon over, Midsummer past, no more excuses for avoiding preparing the Summer Newsletter - otherwise it becomes the Autumn one.We have a new committee and suddenly I find I have a multitude of entries in the action column to deal with.
One thing I have to do is to bring to your attention to the personal details that the club holds and publishes to members at regular intervals. Would you please ensure that the details are up to date and correct. Please let John Gale the General Secretary know of any required alterations as soon as possible. That brings me to my second action - to let you know the new committee make up - that I have done in the next item below.
Finally as a result of an experience last weekend when I could not reach the website because the server was down (due to a powerfailure and the backup power also just failed to work for a couple of hours) I aquired a new name for the mirror site so that moving over to it is simplified if the main site cannot be reached. The main site is www.rpec.co.uk the mirror site is on my own supplier so I called it www.rpec.me.uk. When you fail to reach www.rpec.co.uk on your browser ( which should be a very unusual occurence jus change the "co" in the address line of the browser to "me" and press enter and you will be sent to the mirror site.Which I will endeavour to update at the same time as the main site.
The Annual General Meeting was held on 11th May. The meeting was chaired by our President - Michael Clinch in the absence of our Chairman John Coneybeare who had been called to do jury service. Following a short review of the past year and reports by the Events Secretary John Green and the Treasurer Frank Whitehead the Meeting approved by a block vote new members John Gale, Don Vickers and Gyles Harris as Committee members and also a new 2 year term for Marcus Palmén.
The resultant committee structure for 2005/06 is as follows:
John Green and Frank Whitehead both offered to assist Gyles Harris and Don Vickers respectively in their new appointments giving continuity to the work - this was gratefully accepted.
A talk by Peter Copeland - "Sound Recording without Electricity" - followed the business part of the meeting. In his talk he related the research that had been done into the archived diaries of recordings made by the use of audio cones. A reminder that sound amplification can be achieved without an electric amplifier or a transitor radio!
Our new Events Secretary has heeded my call for newsletter items and has provided this contribution (The Pictures are ones I have acquired from the internet of liners used on the same service).
Many years ago I was an Engineer Officer on Cunard ships, and for a time was on the Quebec/Southampton service.
Amongst my various jobs was maintaining refrigerators and one day I had a call to repair a ‘fridge where vaccines were stored. outside the ships hospital.
I was dressed in a white boiler suite and an officers cap, and when I arrived one of the hospital doors close to the fridge. was open.
I had just started to look at the machine when the hospital door was violently slammed, and when a nurse tried to open it found that somehow it had been locked .
The door could not be opened, but it was possible to look through an adjacent pipe hole into the locked room, and the resident had a knife and was threatening to kill himself.
It appears that the man had escaped from one of the Communist countries, and was returning to Europe. He had mistaken me for a prison guard or something similar and thought that I had come to return him to a prison.
We were concerned in case he threw himself out of one of the open portholes, and so the crew lowered a long ladder horizontally over the side of the ship so that a rung was blocking the port-hole - it was of sufficient length to secure the ends to two other port-holes either side of the room. It has to be remembered that this was in the middle of the North Atlantic!
After some debate it was decided to get two of the ships policemen (known as Master at Arms) ready to stand by, holding a mattress with the intention of rushing into the room and overcoming the man with the mattress, as soon as access was obtained.
To gain access two of the ships carpenters tried to open the door, without success, so the Master at Arms broke the door down and overcame the man, who burst into tears.
They put the man into a straight jacket, but international law prevented keeping anyone in this constraint for more than about eight hours, so the man had to be held in the ships isolation hospital which was at the extreme stern of the ship, directly above the propellers and subject to violent vertical movement. Two stewards were given the job of continually keeping watch on the man, until we got to Cherbourg. The stewards were less than pleased.
This was the most peculiar ’fridge job that I ever had to do.
In this issue we include a follow up to the most interesting paper our Member Mr Len Target submitted to The Club in the May 2000 newsletter entitled A Rocket History.
Len continues the story with “A Rocket History.Part ll”. As you may be aware Len was directly involved with the V2 project. As Major Len Target, he was attached to The Special Projectile Operations Group, which was the team formed to investigate all aspects of V2 development, associated equipment and firing techniques. This group was responsible for the compilation of the final report on the task.
Following my previous article on the V2 rocket, I have been asked about the method of the control of flight. It is only possible to give a very brief resume of such a complicated system.
To start with there was no satisfactory radio control, and whilst an area was reserved on the control compartment for housing any future development, the control was a combination of the method used to direct a gun and a gyroscopically controlled apparatus, to determine the line of flight from the velocity at engine cut off.
This is a schematic of the controls, and illustrations of the components actuated by the gyros. These were the function of the electrical circuits concerned with the steering and stability of the rocket in flight, also the operation of the fuel and other valves associated with the propulsion unit. They were housed in a four sectioned control compartment in the nose cone. The nose cone containing two batteries, two motor alternators with their frequency regulators, two gyroscopes, a control amplifier, a sequence switch, an emergency switch box and a number of relays.
The actual steering of the rocket was controlled by four carbon vanes operating in the propelling gas flow. These in turn were controlled by four servo mechanisms. There were also four small vanes fitted to the large fixed fins on the tail.
The electrical power for operating the system and fuel valves, was obtained from a 32 Volt lead acid battery providing a discharge of about 100 amps for five minutes, the battery comprising two sections of eight cells each. A second battery was used to provide signals between the two gyroscopes and the control amplifier, this was a 30 Volt Nickel Cadmium type battery providing 300 Milli-amps for approximately five minutes.
The steering of the rocked was by two gyroscopes operated from a 500 cycle three phase supply, running from a motor alternator drawing power from the lead acid battery. One gyro was used to control the turning of the rocket into its trajectory and the other, roll and yaw. The control amplifier accepted signals from the gyros and passed them to the actual steering mechanism.
The second 500 cycle alternator similar to the one used for driving the gyros and running off the same battery, provided the power to operate the control amplifier. The gyros ran at 30,000 rpm. The motor alternators were small machines which took DC at one end and generated 40 volts 3 phase. A separate frequency regulator was used with each machine to maintain the frequency at 500 cycles against battery variations. The signals from the control amplifier were taken to servo mechanisms mounted in a ring in the tail, these controlled the movement of the carbon vanes. The outer vanes on the fins associated with the roll and yaw were directly coupled to the carbon vales by a series of mechanical levers and chain drives. The outer vanes on the fins on the pitch axis were not connected with the carbon vanes controlling the pitch but were driven by separate trim motors which were brought into operation when the roll and yaw vanes were out of synchronisation.
A sequence switch was fitted to control the operation of certain valves and to actuate the turning of the rocket from it’s vertical path onto its trajectory setting. It was also used to check the settings when the rocket was being set up, including the systems brought into use when the weapon was linked and controlled from the ground to carry out pre firing preparations.
That concludes the general overall picture but for those who would like a little more detail, the following on Gyros may be of interest:-
The two gyros are illustrated here. They were similar in design and the motors were driven from the current supplied from the No. 2 alternator at a speed of 30,000 rpm. When running up to speed, the inner precision axis was maintained vertical by a stabilising motor under the mounting for the rotor housing, controlled by a gravity switch on the side of the mounting. The contact openings on this switch were very small, of the order of 1/10th mm. The contacts of this switch controlled the energisation of the coils of the stabilising motor inside, which was a magnetised disc producing a torque to counteract the tendency of the torque axis to move from the vertical. A similar stabilising motor was fitted to the end of the gyro to stop the torque axis from moving from a position at right angles to the middle axis. This motor was actuated from the contacts of a sensitive polarised relay, the tongue of which was normally centre stable, moving from side to side depending on the direction of the current flowing in the relay winding, which was connected to the wipers of the pick-off potentiometer. These were wire wound and connected in parallel to the signalling battery. The resistance of each winding of each potentiometer was 100 ohms.
The wipers were very thin wire, bent into the shape of a V, moving over the potentiometer windings. The connections between the fixed and moving parts of the gyro were made though point swivel contacts, accurately aligned.
The pitch gyro was fitted with a small motor known as the programme motor to control the turning of the rocket into it’s trajectory and consisted of a ratchet driven wheel which turned a small camshaft through a worm drive. The ratchet was driven by an electric magnet energised by interrupted DC current at 45 ips supplied by a reed interrupter fitted in the base of the sequence switch. Also on this camshaft was a pulley driven by an arm fixed to the shaft. This pulley wound up a brass tape which extended over a circular housing accommodating the front pick-off potentiometer.
When it was desired to tilt the rocket in flight, the programme motor cam shaft revolved and the brass tape wound into it’s pulley causing the circular housing and potentiometer to be slowly rotated, giving a signal to the control amplifier which was transmitted to the pitch vanes.
Contributions from members are essential otherwise there is no material to edit. I am open to suggestions as to items to include. Reports on visits and on talks should provide the bread and butter items. Individual articles on subjects of prospective interest to members will also be most welcome. Between 3 and 1000 words, with or without pictures or photos please!
This is a call for papers and contributions for the next edition of the Newsletter. Do share your interesting experiences past and present with other club members. Your views may not correspond with the views of the Club Committee and we shall say so - but that is not a reason why they can not be published. Contact details are as follows: