dynamometer freeware

[kenbene]

i'm interested in building a dyno and found this freeware http://www.bivio.com/jon_bondy/files/HomePage/software.html has any one built one or looked in to it i have a old dyno for bigger engines but not r/c engines

[cozmicray]

Yes I have built one of these!
Worked with Jon developing it and have seen a number
of different sensors, interupter, reflective etc

using the audio input to a laptop PC is easy input
and software does the rest.

you could start with a microphone as input.

You need to know the "rotating mass"
to get the power of your system.

What do you intend to tach/dyno with the system?

My current sensor is a photo-transistor and LED
in interupter configuration, and an old CD with notches
cut in edge. Anything I can mount the CD on I can
Tach and use the software to see how it accelerates/decelerates.


Have Phun

[kenbene]

I was going to use it on rc airplane engines starting with .40 and smaller for testing modifications
I'm going to mount it on a table that can be tilted 90% to help keep them from loading up also I'll use a bar bell weight truing it up on a lath
was wundering what software is floating around and there pros and cons
did not see much in the way of threads her
thanks Ken

[OmegaDot]

Please be careful in how fast you spin a CD after "modifying" it with holes or notches (stress concentrations). I have a nice scar on my wrist where a CD (modified with 24x 4mm holes) disintegrated while attached to a speed 400 motor. I added the guard after the accident (duh!).

[LT]

My current sensor is a photo-transistor and LED
in interupter configuration, and an old CD with notches
cut in edge. Anything I can mount the CD on I can
Tach and use the software to see how it accelerates/decelerates.


In order to avoid what happened to OmegaDot I used to use a CD with black sectors painted on it, then using a lightsource and a photodiode to meassure the reflections to get no load rpm of my electric motors.

[jeffs555]

You need to be extremely careful when spinning anything directly off a high powered hobby motor. A 52x cdrom only spins the CD at 10,500 rpm, and there are many cases of them exploding in the drive. The motors we use are capable of much higher speeds than that. There was a show on the Discovery Channel called the Mythbusters where they did spin CD's to destruction, and what it did to their ballistics test dummy was not pretty. Bottom line is that even an unmodified CD is not safe at extremely high speeds.

Jeff

[kenbene]

I'll use a small timing belt reduction 1/4 to drive the disk and weight

[OmegaDot]

There was a show on the Discovery Channel called the Mythbusters where they did spin CD's to destruction, and what it did to their ballistics test dummy was not pretty.Jeff

And definitely don't put 'em in a microwave oven, right Jeff!