Yup.That's damn fast....raker height & inner top plate angle would need fine tuning. I'd be wearing decent PPE, 'chain shot' could be a micro second you remember for ever.
Double the speed is four times the energy.
Yup.That's damn fast....raker height & inner top plate angle would need fine tuning. I'd be wearing decent PPE, 'chain shot' could be a micro second you remember for ever.
I made a miscalculation recently on a thread calculating speed with a particular saw at power speed rpm.I'm also wondering if the math on this site for figuring chain speed is correct. I'm very familiar with formulas for figuring speed and adjusting variable pulleys for a specific speed all those formulas take the diameter of the driven and driver pulley into consideration . The closer the driver diameter is to the driven the closer the driven rpms is to the motor rpms . A 2 3/8 inch driver diameter sprocket should be close to the bar nose diameter, haven't measured nose but will . Actual Chain speed was measured with a fluke 820-2 stroboscope. Stay tuned and your welcome to join the Facebook group kisin piston chainsaws. Thanks ,Mitch
That's why I think the formula just taking in the number of pins and not diameter is off a little11 pin, 3/8.
15,000 RPM is 10,312.5 FPM
687.5 ft per 1,000 rpm
68.75 ft per 100 rpm
Your saw would be tuned just over
15,500
Over 120 MPH
I just measureed my bar at 2.510 sprocket at 2.32 so it would be less than engine rpm but I need to do the math also by diameter as a belt and see what I get for fpm.109.9525 × 10,000RPM ÷ 1000mm = 1099.525m/min
109.952m per 1000 rpm
1KM, 99.525m
OR
1099.525m ÷3.37FT = 3705.39925 FPM
--------------------------------------------------------
.750 × 7 = 5.250" of chain per revolution
5.250" × 10000 RPM, ÷ 12 =
4375 FPM
670 FPM difference?
About 15% error on a small sprocket.
I tried to do it with getting the Dia of sprockets on line and matching what Husqvarna posted for specs but I couldn't get their numbers that way.
12015 fpm at 13000 engine room usin heg sheeve diameter formulas . I'm sure the chains drag has some loss withers it's 151fpm I don't know but that math seams to fit my mechanical logical ability of comprehension .190 difference in diameter x13000 =10530fpmI just measureed my bar at 2.510 sprocket at 2.32 so it would be less than engine rpm but I need to do the math also by diameter as a belt and see what I get for fpm.
Yup.
Double the speed is four times the energy.
Lmao..OK I'll playThis is why we call our chainsaws kissin piston saws for the kiss method keep it simple stupid
.
Pertaining to a saw ONLY here. You will get a different behavior with increased/decreased sizes within the tip area but you have not mention of this, only stating the obvious and that being: saw drive sprockets run at a different ratio than the tip sprocket. Heeello!As posted before when working with belts and pulley the diameter of the drive pulley size in relationship to the driven pulley effect speed .of the driven The same can be said on a dirt bike with sprockets .
IF the measurement is correct from driver centers then how possibly could it be wrong. I can see error with using diameter to circumference as on paper if you drew 14 proportionate lines representing the base of the chassis around the circle and the circle representing the 7T sprocket then there is possibly 15% error. In a real application the error would likely be mainly arounding the back of the sprocket. Possibly 6% error.The actual strobe fpm is 10640 fpm of the chain and the actual engine rpm is not 15000 it's less so the formula using just sprocket pins is wrong .
I just thought that was common sense?Anyone with simple mechanical ability can figure that the rpm or fpm which is the same when the driven sprocket is same size as driver is going to be equall to engine rpm . The driver is .190 smaller than the driven . By taking .190 x 13000 engine rpm it's closer to the actual measured for than the pin formula .
try the right formula next time.Everytime we try some fancy formulas they typically don't add up to actual test measured with appropriate testing equipment .
the inertia must be incredible? 2" from the axis and all. Must need extra balancing too.I was really surprised how my 660 ran the 11 pin sprocket on a cut down 36 inch bar to 32.5 inches and full comp chain. I really thought it would pull the saw down but the sprockets mass holds rpms well.
That's a lot lot lot of rpm for a 660 not sure if I would ever run one that high. I'm sure it would make a great cookie cutting saw.11 pin, 3/8.
15,000 RPM is 10,312.5 FPM
687.5 ft per 1,000 rpm
68.75 ft per 100 rpm
Your saw would be tuned just over
15,500
Over 120 MPH
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