Eddy current chainsaw dyno.

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wizzy929

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Which forum would be good to discuss saw performance and results from dyno testing different muffler mods, porting and many other mods. I have put together a highly accurate Eddy current dyno,
will get into more details about the dyno and its capabilities at a later time in the proper forum.
 

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The general chainsaw forum will see the most traffic but also have the highest signal to noise ratio, lol.
Dyno results have always been a hot topic for discussion here and I’m sure you’ll get plenty of that.

I’m more curious about your hardware setup and data collection myself.
 
The general chainsaw forum will see the most traffic but also have the highest signal to noise ratio, lol.
Dyno results have always been a hot topic for discussion here and I’m sure you’ll get plenty of that.

I’m more curious about your hardware setup and data collection myself.
I’m using laboratory grade sensors and filtering signals to eliminate niose .
The software is labview and so on,
I can monitor
Quadrant encoder for rpm
Cylinder pressure sensor
Wide band afr
Egt sensor
Head temp sensor
Fuel flow sensor
Inlet air flow
Inlet pressure
Inlet air temp
and a few others if needed.
Like V,E table if looking for knock.
 
Wow, pretty impressive selection of sensors, the cylinder pressure has my attention in particular.
I'd be happy with just the load cell and rpm with good automated data collection.
Have you gotten to the point of running a saw on it?
What is the alternator/eddy current device that provides the load on the saw? A proprietary item specific to dynos or repurposed from something else?
Will cooling be an issue or maybe it's duty cycle exceeds the application?
What are you using for a software filter on the load cell? Decimation filter?

Just for some background, I've been involved (mostly on the mechanical side) in an ongoing saw dyno build project with some other members here and elsewhere, that's going on 5 years now I think.
Basic brake dyno, pretty much a scratch build, including totally one off custom software. Probably the biggest issue to overcome was the sensitivity of the load cell to mechanical oscillation caused by the braking, various filtering helped but still could make the data a bit... subjective...

The goal was/is to create something relatively affordable/portable that eventually could be more or less duplicated by others with mostly off the shelf components and a handful of simple fabricated parts.
It's had sort of an ebb and flow and has been dormant for awhile, though coincidentally there have been recent signs of life on the software front that look promising.
Not nearly as comprehensive as yours and an order of magnitude more budget sensitive but still has a certain level of sophistication none the less...

Most of the info is on another saw site that fosters a much more vibrant builder/modder community and unfortunately protectionist policy here prohibits me from mentioning it in any way, shape or form.
Easy enough to find with a little digging and you'd certainly garner more interest there, as well as depth, in this type of project.
 
I built dynamometers for a elevator company. We used torque transducers between a motor that provided a load vs the new design motor we were testing. We used big 200,000 in. Lb torque transducers. The load machine had the torque of 27/ 427 Chevy big blocks. I built monster dynamometers. Of course a chainsaw dynamometers would be smaller. Wouldn’t using a torque transducer be more accurate? If you drove it off the clutch drum that’s welded to the clutch with a shaft and coupling? Coupled to the torque transducer then to a load motor. Or a wet disc brake as a load application?
 
If you drove it off the clutch drum that’s welded to the clutch with a shaft and coupling?

If I understand this correctly, you'd need to fabricate specific fixturing for each different saw tested...?
We ran many different saws through the dyno at one event, no time for proprietary interfaces...
 
If I understand this correctly, you'd need to fabricate specific fixturing for each different saw tested...?
We ran many different saws through the dyno at one event, no time for proprietary interfaces...

Make a clutch drum for each saw. Or use a rim spline to couple to coupling. A drive shaft setup. No alignment needed. It has to be a quick disconnect and connect.

Here’s the brand we used,
https://www.himmelstein.com/torque-...tra-precise-digital/200-overload/mcrtr-48800v
Too bad my instrumentation guy passed away recently. I was talking with him about building this for dirtbike engines, saws would be the same.
 
Which forum would be good to discuss saw performance and results from dyno testing different muffler mods, porting and many other mods. I have put together a highly accurate Eddy current dyno,
will get into more details about the dyno and its capabilities at a later time in the proper forum.

Nice looking setup. Testing different transfer port mods and port timing would be awesome to see the changes.
 
Make a clutch drum for each saw. Or use a rim spline to couple to coupling. A drive shaft setup. No alignment needed. It has to be a quick disconnect and connect.

The design issue I always run into is running a given load at 15K rpm, usually some gear reduction is a good idea. So jackshaft and/or fairly large sprocket.
First one I went direct from the saw to a 35 pin rim, the next iteration the saw went 1/1 to a jackshaft, then one stage of standard roller chain/sprocket reduction to the load.
 
Why not use a saw chain with no teeth. We need a 325”, 3/8”, 404” chains? Then it will fit every saw. Maybe use a cutoff bar to guide the chain.
 
Was able to mount a 201 that’s tired to try the dyno
I still have to set up sensors and move the rpm encoder.
Off to a good start I saw numbers today, need to fine tune a few sensors but that’s part of the project.
 

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I’m using laboratory grade sensors and filtering signals to eliminate niose .
The software is labview and so on,
I can monitor
Quadrant encoder for rpm
Cylinder pressure sensor
Wide band afr
Egt sensor
Head temp sensor
Fuel flow sensor
Inlet air flow
Inlet pressure
Inlet air temp
and a few others if needed.
Like V,E table if looking for knock.
Will your sensors be capable of measuring peak cylinder pressures at full load rpm?
Do you have any fundamental knowledge with 2stroke design?
I'd be very interested to see how mean effective pressure varies in saws with some minor modifications like ported mufflers.

Welcome to the site.
 
Yes I have some knowledge with 2 stokes as I am involved with turbocharging 2 strokes running upward of 450 hp at 30lbs Of boost. The Sensor can measure peak pressure at full rpm at full load.
I’ll post the full capabilities of the sensors in the next week.
Here’s my 2 stroke turbo
 

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Yes I have some knowledge with 2 stokes as I am involved with turbocharging 2 strokes running upward of 450 hp at 30lbs Of boost. The Sensor can measure peak pressure at full rpm at full load.
I’ll post the full capabilities of the sensors in the next week.
Here’s my 2 stroke turbo
Very nice. Will you have the ability to plot PV curves?
 

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