MadModder

Nice job, and am looking forward to seeing just how much power one of these engines puts out.  Have always wondered, but have never seen any results.
 

I drilled and tapped the brake arm to accept the stylus at a distance of 10 centimeters from the center of the brake drum, then secured it in place with two nuts. The height of the brake arm is therefore adjustable, and should be set level. A 10 cm moment arm means that every gram registered on the digital scale will be approximately ten times the newton-meters of torque absorbed by the brake. So grams divided by 10 is ~ Newton-meters. From that, and RPM, Watts can be easily calculated.

With this work done, the Prony brake was operable, though I'm not finished. But I couldn't resist setting it up temporarily and trying it out! 

I was disappointyed when at first the engine wouldn't start at all with the brake just sitting, applying no pressure to the drum. And for the first 15 minutes the engine ran I could hardly even touch the drum without nearly stopping the motor. But eventually the engine seemed to loosen up and gradually increase speed to the point where I could attach the brake arm...but without the adjustment springs... just letting the parts run together.

This brake definitely needs to be run in -- it needs more of that. But eventually this evening I was able to adjust the thumbscrews (without springs) for very slight pressure, and get the engine to run at reduced speed, registering a torque reading on the digital scale. I was gratified to see it was a reasonable stable digital reading, probably helped by the inertia of the brass stylus, which, unlike the other parts does not weigh on the drum.

Here's a picture of the first run. I do need to do a little more work to get easier and more consistent readings, to work out a measurement procedure, and to finish it off, but I'm very happy that it works quite well already!

  [ You are not allowed to view attachments ]  

And thinking I'd break out my never before used tailstock die holder, ran into problem number two. Despite the fact that it had many different die holder recesses and attachments, it wouldn't accept a plain 1" hex sided die -- which was what I had for cutting a 6-32 thread. Rats! I should have made one myself instead of buying one to... ahem, save time.

Well, the ER collet holder to the rescue again, I started the threads in the lathe by holding a die handle and then transferred the collet holder block to the bench vise and turned the threads the rest of the way.

  [ You are not allowed to view attachments ]  

Thanks for testing that out! I installed Puppy in W7 using Lick bootloader. By using it, few clicks to install Puppy and dual boot loader are needed.

I also downloaded and extracted Blender package, and it runs as expected, although it's bit laggy. I assume it (Blender) requires something like OpenGL driver for acceleration, so I searched from Nvidia's site (I have 1650 GTX), and found this: https://www.nvidia.com/en-us/drivers/details/245669/

The file is NVIDIA-Linux-x86_64-570.153.02.run. How to install it in Puppy? Don't know if it's the right one, as I've read that different distros may have their own versions of display drivers.

Tried 4.4.3 Blender for Linux.
No need for terminal commands to install it. It's a self contained app, you just download it from the website, unpack it and click on the launcher file in the unpacked folder to start it.

But in my case (with this laptop) it says my video card is unsupported. Probably related to the fact that the version of Puppy Linux I'm using is a few years old, and the computer very new.

However I also downloaded Blender LTS (Long Term Service) version 3.6.22 still current, and that one opens fine in my version of Puppy Linux and my laptop:

  [ You are not allowed to view attachments ]