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The trick with radiation therapy is they spin the beam source around and blast you from lots of different directions, but always aimed through the tumour. So the tumour gets hit with a lot more radiation than the rest of you. And I wouldn't worry about the phone, that's non-ionising radiation...

That's very cool. Working as a structural biologist I've sent samples to the Australian Synchrontron but never had a chance to visit in person. And those are some monster electron beams you work with! I've done a lot of electron microscopy, but the instruments I've used were 200 or 300 kV. 3MV...

For an aluminium piston I would follow the rough rule of thumb of using about 1 thou clearance per inch of bore. Or about 0.025 mm in a 25 mm bore. But I think Reuben might be asking about the injection pump piston/plunger. If that's the case, the gap needs to be truely miniscule. Maybe 0.001mm...

One other thought: what's the situation with your signal wires? As you probably know they can act as antennas for radio frequency noise, which could be coming from the brushes of your motors I suppose. Makes me glad of brushless motors, no noisy commutator!

Dealing with the noise from the PSU is a good start. I'd suggest also putting filters between your Arduino pins and their respective sensors. An RC low pass filter is what you want, this will help remove high frequency electrical noise from the signals. Also with your motors did you put a...

You can use some RC filters to get rid of the noise.

Nice! Do you have a picture of the setup you used?

Maybe you need a big block of concrete to bolt the engine to haha. I suppose the flywheels will help.

Do you have instrumentation for steam flow rate and temperature? If so we could get a guess at your turbine efficiency. Obviously it's going to be lower than the design expectations when you are throttled right back like this (turbines always have reduced efficiency when at part load), but it's...

I think hot enough to glow cherry red would do. But the cooling has to be slow.

Probably not spin cast, just the cheapest quickest sand casting they can do (gym weights just need to be heavy) If they used chills in the moulds the rims would be cooled quick enough to turn into white iron, which is very hard. Be easy to anneal them if you have a fireplace.

There are basically 3 ways to get a seal around the piston: 1. Metal piston rings 2. Viton rubber O-ring 3. Make the gap between the piston and the cylinder so small that the oil itself will form a seal. If you use metal rings the purpose of honing or lapping is to create a slightly rough...

The same rules do apply to models as well. But the scaling means that a fast running "racing" model engine might run at 20,000 rpm or more, much too fast for our taste.

These numbers are not unusual for a faster running engine. The reason is that the air in the intake takes some time to accelerate and slow down, so by having an intake pipe of the right length one can arrange for air to keep flowing into the cylinder even after the piston has passed BDC. Even 60...

Firstly, I think there may be a typo: I would bore to a diameter of 0.873" if lapping to 0.875", while your plans seem to have 0.783." lapping 90 thou out is possible, but you'll spend a long time doing it! On taper: your piston needs to fit with an appropriate clearance in the cylinder across...

Only problem is you need a press to do it! By the way, this method works very well indeed on oilite bushes because their porous structure is naturally a little compressible.

Hah, you won't get rid of me that easily.

No pump now. Due to moving overseas I can no longer work on the engine, I did make a new cylinder head for running on petrol with a spark but I doubt I'll have time to fit a carb and ignition system before leaving, and I cannot take the project with me. So it will be shelved for 2 years until I...

It doesn't account for boundary layer losses, that's a complex fluid dynamics problem that I think would be hard to handle in a spreadsheet, especially because we are often discussing supersonic flows! Perhaps some CFD could be used once an initial set of parameters was obtained.

Partial admission means that only a portion of the turbine wheel is impinged upon by the gas. Only used for impulse turbines, it allows a 'oversized' wheel to operate at lower mass flow rates than it should. Also popular for controlling power output in early stages of larger machines.