Technical Talk

[Tyler]

the steel parts are not bad and I would like the side car to be usable again one day although the motor bike that it went with is long gone

[Renegadenemo]

One of the first experts (not to be confused by those fools from the HLF) we appointed was a materials specialist called John Renwick. He was all but retired by then but had spent his working life with Marconi on warship radar arrays in a salt spray environment. He loved corrosion of every kind and was extremely excited by some of the more obscure manifestations on K7 to the point of wanting to bring his students for a look. I thought he was bonkers though when he pointed at the steel frame and said,

'With this, what you see is what you get.'

I questioned him but he repeated what he'd said, though in a slightly different way.

'If it looks OK then it is...'

I still thought he was bonkers but after extensive x-raying and crack testing he was proved completely right. Where a part looked to be in poor condition it was, and where it looked good it turned out to be as good as the day it sank. Repairing it then became a simple matter.

[MikeT]

MikeT- it's only your first three postings that have to run through a moderator- after that you're fully 'live'.

A shamelessly pointless post from ones self should take care of it then. On another note I have a techie question (please feel free to edit or move this post if its in the wrong place). The rudder on BB above it is a triangleish housing that I assume houses the gubbins to turn said rudder, now is it gear driven or chain. My first thought was chain but I read someplace that the first set up failed when tested to a factor of 3 when linkage down the boat failed. But the repair tested to 10 x and I can't see a chain holding up that well so my new guess is a worm gear of some type. Also did the fact it was not central give steering bias in one direction.


Again apolagies if it apears anal but details like that intrigue me.

[Renegadenemo]

The rudder is operated by a push-pull rod running in spherical bearings. It's a ground shaft and the motive force is provided by a steering box at the pointy end. In the original design there was two rudders to counteract any offset forces but only one was used despite there being the vestiges of the second rudder housing still in the structure.

[MikeT]

Many thanks for your reply it may sound dull to some folk but details like that appeal to my mechanical mind. I never thought of a push pull arrangement running the length of the boat. Always thought the would rotate. Must be solid bar or as damn near it to stop it folding under load.

[Renegadenemo]

Must be solid bar or as damn near it to stop it folding under load.

I remember being intrigued by one of my university lecturers, who had a passion for motorsport, trying to devise a process for boring out the centre of a forged steel driveshaft.
Imagining he was trading strength for lightness I assumed it would be a fairly linear relationship until he pointed out that the material at the centre of the shaft was more or less only along for the ride and it was the material near the circumference that actually did all the work. On that basis he was able to shed a disproportionate amount of weight without significant detriment to the strength. One of the few lectures that sticks in my mind...

Another I remember involved the lecturer pouring liquid nitrogen down the barrels of a side by side replica shotgun he'd made from a noggin of wood and some cold-drawn, seamless boiler pipe, then stuffing corks into the ends and aiming it randomly at his students as the gas expanded until the corks exploded out with considerable violence.
We spent most of that lecture under the desks until coaxed out by his intriguing assurance that by using liquid nitrogen you could deaden pain.
Having pulled on a rubber glove he then proceeded to stick his thumb into a flask of the stuff, grimaced for a minute or so, then pulled it out, put it on the bench and hit it with a hammer. Needless to say, it shattered into a thousand pieces causing panic amongst the med students who also had to study engineering in case they ever had to knock up a wooden leg or something.
Assuming that the bloke had pulled this stunt before without reducing his quota of thumbs I wasn't taken in, but it looked impressive. It later transpired that the thumb of the glove was stuffed with mince...

I bet he'd not be allowed to do the thumb thing these days (the shotgun trick was bloody dangerous too! But great fun.) because some do-gooder would want counselling in place for those fools who fell for it and so the world loses a little more of its flavour and becomes a little more bland.

[Dominic Owen]

That sounds more like what we got up to behind the teacher's backs.

One chemistry teacher infamously had to take a six month "holiday".
The one we had after him developed a rather nervous disposition and bad case of the shakes - the poor guy left after one year and went to spend his last two before retirement at a college for refined young ladies. Looking back, it probably hadn't been the best idea for one of the physics teachers to show us how to make gas bombs. It was probably also a bad idea for said chemistry teacher to tell us what would happen if we put a bung in the boiling tube of methanol we were heating and downright foolhardy of him to stand near one end of a sneakily concealed human chain when a van de graaf generator was going flat out at the other.
We realised it might have gone bit far when he tried to take a flake of potassium out of the jar of parafin to place it on a sheet of paper in a large dish of water - his hands shook, he missed the flake and flicked a huge chunk straight past the edge of the paper. Two gallons of water then spontaneously evacuated itself from the dish and relocated to the front two rows, taking the safety screens with it.
The next replacement was a poor sod fresh from university who turned white and nearly passed out when I strolled toward him the middle of a lesson with blood pumping from the back of my hand.

If caning had still been legal I don't think any of us would have made it out of that school alive.

Apologies if that was a bit off-topic

[jonwrightk7]

We had a physics teacher who decided one day to do an experiment to demonstrate "latent heat of evaporation." This involved him placing a small beaker of water in a shallow bowl of ether. the method then, he explained to us, was he would blow through a hollow glass rod into the ether causing it to evaporate. As it evaporated it would cool the water in the beaker eventually freezing it. It evaporated the ether all right! The fumes of which he was then inhaling at a rapid rate of knots whilst trying to explain to us all what was happening to the water. The end result was that after a couple of minutes he was rambling incoherently with a far away look in his eyes, he then decided he needed to go out of the classroom which he achieved by going arse over tit through the open doorway. priceless!!

[rob565uk]

During electronics training, we used to receive practical classes from a wild-eyed and slightly crazy guy who revelled in the name of Gibson Teasdale. He used to keep a row of capacitors on his desk, some uncharged but with the odd one charged to 200-300 volts. If he decided you were not paying his demonstrations full attention, he would select one at random and throw it at you with a shout of "here, catch".... the result of which could be very painful depending on whether the capacitor was charged.....which he always found immensely amusing and laughed uproariously.

He was a good sport though. At the training establishment, there was a small sunken rectangular garden area, around 12 feet by 12 feet, bounded on all four sides by a short flight of steps. One day, about ten or twelve of us picked up his car (An Austin A35, small and light) from the adjoining car park and carried it down the steps into the bottom of the garden, where we neatly parked it right in the middle. Come home time, Gibson went searching for his motor and when he found it his face was an absolute picture until he clocked us watching him and then he saw the funny side. Naturally, we helped him lift it out and but subsequently were treated to more than our usual share of highly charged capacitors for the next few weeks.

The best part was that he was an absolutely brilliant Teacher and we all learned a tremendous amount from him. He had a lifetime of serious hands-on experience and knew how to put it across. The standout quote for me was "The secret of good soldering is to to clean everything thoroughly. You can solder a cat's a#se to a brick wall, provided both are clean"

[Mike Bull]

The only thing I can add to all this reminiscing about physics teachers is that one of mine vanished about the same time a sixth former got pregnant!