DIY Dyno Arduino based with Data logging. Real Cheap success.

[lohring]

Aircraft and large boat engines develop power in a steady state. Endurance testing requires a steady state dyno. Most race engines never run in a steady state. There are places for each type of dyno.

it's hard to build large inertial dynos for high power engines. Froude makes brake dynos for 100,000 hp engines. Direct measurement from cylinder pressures is coming back into favor with fast, high pressure sensors.

A prony brake is great for small, low speed engines like the models most people build on this forum. As power and rpm go up, heat dissipation becomes an issue. Inertial dynos don't have this problem and are used in power measurement for engines from 3 cc displacement to automobile chassis dynos.

Lohring Miller

 

[Lloyd-ss]

Aircraft and large boat engines develop power in a steady state. Endurance testing requires a steady state dyno. Most race engines never run in a steady state. There are places for each type of dyno.

it's hard to build large inertial dynos for high power engines. Froude makes brake dynos for 100,000 hp engines. Direct measurement from cylinder pressures is coming back into favor with fast, high pressure sensors.

A prony brake is great for small, low speed engines like the models most people build on this forum. As power and rpm go up, heat dissipation becomes an issue. Inertial dynos don't have this problem and are used in power measurement for engines from 3 cc displacement to automobile chassis dynos.

Lohring Miller

Lohring, Thank you, I appreciate the discussion. My dyno set up is more of a curiosity and might only be used a few times just for fun. The prony brake version works well within my expectations of its performance. The wooden brake and the v-pulley that it rides in get too hot to touch very quickly, so its use in this configuration is limited. Your electric brake is nice but I am hoping to come up with something less complex. Possibly a disc brake arrangement.

But I am giving a try on an inertial adaptation of the hardware and software that I have. The hall sensor is about all that is needed. I came up with a 62Kg inertial mass mounted on my lathe. The 62 kg has a moment of inertial of 1.59 Nm which will be enough to test the motor that is already on the lathe and see how much correlation there is between the dyno readings and the motor name plate. Ha Ha. I will have to use a lower speed range on the lathe so as not to spin the mass too fast. It is a bit sketchy with 63 pounds of lead inside it.
Lloyd

edit- P.S. I consider the cheap and easy electronics and real time data collection to be the major-win part of this project.

Here is a pic of the mass.

 

[bluejets]

Researching some proper, but inexpensive Hall sensors, load cell elements, instrument amps, disc brake and caliper assemblies, for the first upgrade. The money spent will still be less than $100 USD.
Also considering trying an inertial version. Anyone know the moment of inertial of one of those compact spare tires, LOL? Only half kidding.

You can calculate quite easily.....https://www.omnicalculator.com/physics/mass-moment-of-inertia

 

[lohring]

You can make a much simpler eddy current brake. Below is one a friend uses on his inertial dyno. However, eddy current brakes work the best at high rpm.

Lohring Miller

 

[Lloyd-ss]

Not really on the topic, but I happened to notice an optical illusion in post #22, above. If I scrolled the frame showing the tire in post #22, up and down, the tire appears to rotate.