Chainsaw Dyno bring saws to there knees. Build from start to end with video

[blsnelling]

Might be good to start a new thread for your build. I'm sure it'll get a lot of interest.

 

[Walter Glover]

Once parts are gathered will do
Thanks

 

[chadihman]

Ordered a strain gauge and amplifier to mess with as well. Should get enhanced accuracy wrt force measurement that way. Will need to figure out a calibration lol
Will orient the torque arm vertical so no weight error. Cal will be a known weight at a precise distance.

Would you care to share the strain gauge you ordered?

 

[Walter Glover]

Ebay bits

 

[Walter Glover]

Chad, looking at your general arrangement sketch, it hit me that your tach is engine rpms? So do you reduce that in your formula by the 7:24 gearing? Iirc that is your sprocket setup?

 

[chadihman]

Chad, looking at your general arrangement sketch, it hit me that your tach is engine rpms? So do you reduce that in your formula by the 7:24 gearing? Iirc that is your sprocket setup?

That was my first sketch and my final product was changed many ways. I read pump shaft rpms

 

[chadihman]

The main reason my dyno sits is because I have failed to find a data acquisition system and software that fits my budget

 

[Walter Glover]

Pad and pencil works lol

 

[Walter Glover]

Thinking about Arduino daq into Excel...... hmmmm

 

[chadihman]

Pad and pencil works lol

For a while. Pad and pencil take a time. Requires more run times to get the rpms exact and steady for recording the scale and rpms. To much time around a loaded smokey saw gave me headaches. Mostly because I was doing my testing indoors during winter months.
I think a high tech data acquisition system would be a quick pull on the saw through rpms and done.

 

[Walter Glover]

How about video recording?

 

[chadihman]

How about video recording?

Yeah I've done that too and that made it better but the scale and rpms took time to stabilize. Then I'd record all the info from my video and put it in a spreadsheet

 

[LegDeLimber]

I mod more than saws. This is my Kubota. Added a turbo and boosted the HP 76% Wait till the end of the video as I have some pictures of my fabrication work to fit the turbo under the hood. I'm looking into building a pulling tractor. If only I could get a turbo on a saw.

I'm still waiting for someone to hook a backpack blower to a saw.
That ought to make tuning the carburetor "fun".
Off-board Supercharger!!

 

[LegDeLimber]

It appears that friction/stiction is the enemy of my hydraulic load sensor
It is repeatable but it takes extra force to overcome the oring stiction. Will try a different seal to see if that can be corrected

I remember reading that motorcycle manufacturers were battling with stiction of fork seals, back in the late 1970's ~early 80's.
Cant recall what sort of material was deemed best for solving it.
Seemed to be a trade off of seal life vs drag.

Then we added pressurizing the air inside the forks.
..somewhere along here.....
I sorta drifted from worrying about those details and got focused more on the Female passengers, to be invited for a ride, on said motorcycles.

 

[Walter Glover]

Spindle arrived for my dyno
Can get the sprocket made now

 

[Walter Glover]

Sprocket blank mounted in lathe using spindle for the arbor. Made first truing cuts now to figure diameter. Looks like 6.445” diameter for 28 pins for .375” pitch chain.

 

[Walter Glover]

Sprocket turned to diameter ready to drill for pins. Will be 28:7 for a four to one ratio. Tach on saw and torque numbers divided by four.

 

[wcorey]

I went with 5:1 mostly for speed reduction.
Had a hell of a time trying to calculate the diameter/pin spacing, enlisted everyone I knew with any kind of math background including a calculus teacher and a nuclear physicist.
“Sure, no problem... Oh, well that’s turned into a tough one... uh, gee, I dunno...”

Ended up physically/manually laying it out, some trial and error with a chain and center punch the same dia as my pins. It’s just that last pin that’s the issue, lol.

Then after grinding down/neutering a drive chain, it wanted to walk up out of the sprocket, drove me crazy trying to figure why.
Ended up being some weirdness with that particular chain, a different one cured it.

After the all the work involved in making it, you may want to consider some type of heat treating like case hardening, plain hot rolled steel was wearing faster than I liked.

 

[John Lyngdal]

$59 https://www.dataq.com/products/di-1100/ for data collection.

You'll still need an instrumentation amplifier with adjustable gain between your load sensor along with a voltage source to drive the load cell.
Let me see if I have an amplifier and voltage source for your project sitting on a shelf in the shop.

Even better, for $29 there is this option:
http://picom2.com/Phillips_Instruments.html
It runs on +/- 12V but a little DC-DC converter will take the +5V from the USB to +/- 12V
https://www.digikey.com/product-detail/en/xp-power/IHL0205D12/1470-3835-ND/6221040



John

 

[Walter Glover]

Diameter that worked in the end was 6.285” iirc. Had a 28 dl chain madeup so was easy to know when diameter was right.