The Anonymous Widower

The Britons Who Played For The Moon

The title of this post, is the same as that of an article on page 15 of today’s copy of The Times.

This is two paragraphs – – .

The team was organised by John Hodge, who was born in Leigh-on-Sea, Essex and who had previously worked for Vickers Armstrong, which during the Second World War built the Supermarine Spitfire.

Mr. Hodge, now 90, would become a flight director at mission control – the one time that ‘Houston’ spoke with a British accent.

I’ve heard of John before.

Like me, John Hodge went to Minchenden Grammar School and one of our maths’ teachers; George Bullen,when I was doing Further Maths in the Sixth Form, told us the full story of one of his brightest students.

If John had a problem, it was that he couldn’t get a language O-level, which was needed to get to University in the late 1940s.

So he went to Northampton Engineering College, which is now the City University, where the qualification wasn’t needed.

I think George Bullen, with his John Arlott Hampshire accent, probably told us the story of John Hodge for motivation.

This is another paragraph in the article.

Peter Armitage, 90, who grew up in Hable-le-Rice, Hampshire, was also in the Avro group. In 1969 he oversaw the simulator that Neil Armstrong used to learn how to touch down on the moon.

As I remember it, the simulator was a hybrid digital-analogue computer using two PACE 231-R computers as the analogue half.

This picture shows the similar computer, that I worked on at ICI in Welwyn Garden City.

These machines could each solve up to a hundred simultaneous differential equations, in real time, so were ideal for calculating the dynamics of complex systems.

They were some beasts!

From what I read at the time, they were key in bringing the Apollo 13 astronauts home, as they could be quickly reprogrammed, if you were familiar with the dynamic model., as undoubtedly NASA’s engineers were.



July 17, 2019 Posted by | Computing | , , , | Leave a comment

DB Says Innovative Freight Train Project ‘Very Promising’ So Far

The title of this post is the same as that of this article in Global Rail News.

This is the first paragraph.

A project to design innovative freight wagons, which is being financed by Germany’s Federal Ministry of Transport and Digital Infrastructure (BMVI), DB Cargo and VTG, is producing ‘very promising’ results.

The article is worth reading in full and in my mind it could be important in the development of efficient and reliable freight trains.

I remember in the 1960s, British Rail were trying to run faster freight trains and a lot of four-wheel wagons kept derailing.

Research at Derby using computer simulation solved the problem and went on to lead to a greater understanding of the dynamics of steel wheel on steel rail.

I do know that British Rail Research had one of the best tools for this job; a PACE 231-R analogue computer.


This is the one, that I worked on at ICI.

They were a powerful computer, which were capable of solving a hundred simultaneous differential equations.

They were late 1950s technology, based mainly on electronic valves, that responded to tender loving care.

But two of them working together, did the dynamic calculations for the moon landings, when linked to the digital computers of an Apollo capsule and lander.

On Apollo 13, when Jack Swigert said “Houston we have problem”, it was these machines, that were used to find a way to bring everyone home.

And the rest, as they say is history!

In my view, after over fifty years in computing, the rescue of Apollo 13 was the greatest piece of computing ever done with an electronic machine.

I’d love to know, whether the superb dynamics of the Mark 3 coach, are down to the work that was done on British Rail’s PACE 231-R

The second paragraph of the Global Rail News article has this phrase.

feature new digital systems which optimise handling.

Does this mean the Germans are worried about the handling?

I do sometimes wonder, if dynamic systems are best analysed using analogue computers and the demise of the technology means the same problems keep returning in different guises.

There can’t be many of us left, who’ve used an analogue computer seriously.

August 19, 2018 Posted by | Computing, Transport | , , , | 2 Comments

Analogue Computing at the Science Museum

There were reports in the papers this week about James Lovell selling the checklist that he used to correctly setup the lunar module to get them back home.

What is always missed out in these discussions, is that all of the calculations for the Apollo moon landings were done on a simulator, built using two PACE 231R analgue computers linked together.

At the Science Museum, they did have Lord Kelvin’s differential analyser, but although it was impressive, with lots of impressive engineering and brass gears, there was little to indicate, what this type of machine grew into by the 1960s. Without analogue computers to solve the complicated dynamics of the moon landings, the Americans wouldn’t have been able to get there when they did. Digital computing didn’t have the capability to match a PACE 231R to solve the simultaneous differential equations involved until the mid 1970s.

I was lucky enough to work with a PACE 231R and there are pictures of the one I used here.

There doesn’t appear to be a working PACE 231R anywhere in the world.  But to get one to work would be a lot easier than say to get an early digital machine working.  An analogue computer is basically a peg board that links a series of amplifiers together.  Now I know that these amplifiers are thermionic valve and not transistor, but a typical machine would have a hundred or so of them. And as they use something very akin to  1960s audio technology, finding someone to fix them would not be difficult. Our machine at ICI Plastics in Welwyn Garden City, was carefully looked after by one Eddie Kniter, a Pole, who walked his way to Switzerland to escape the Nazis.

I wonder if the Science Museum has one of these machines in its reserve collection. Getting it working, would really show kids how differential equations are useful in real  life.

Returning to Apollo, I remember that the magazine, Simulation, published by Simulation Councils Inc., had a detailed description in one issue of all the simulators and simulations done in connection with the project.

I’d love to get hold of a copy.

November 26, 2011 Posted by | Computing, News, Transport | , | Leave a comment