PartyPooper Posted November 15, 2005 Share Posted November 15, 2005 (edited) I'm trying to use an AutoIt script to determine the estimated Rear Wheel Horsepower from a printout giving the variables of time, speed, distance, wheel circumference & mass. An example of the printout is: Wheel = 1.825 m -- Mass = 285 kg Time -- Speed -- Distance -- RPM -- Gear 0.248 -- 26.46 -- 1.8250 -- 3725 -- 1 0.529 -- 23.37 -- 3.6500 -- 3290 -- 1 0.760 -- 28.48 -- 5.4750 -- 4009 -- 1 0.961 -- 32.68 -- 7.3000 -- 4601 -- 1 1.138 -- 37.20 -- 9.1250 -- 5237 -- 1 1.299 -- 40.66 -- 10.950 -- 5724 -- 1 1.448 -- 44.03 -- 12.775 -- 6199 -- 1 1.588 -- 47.19 -- 14.600 -- 6644 -- 1 1.719 -- 50.09 -- 16.425 -- 7052 -- 1 1.843 -- 53.08 -- 18.250 -- 7473 -- 1 1.963 -- 54.67 -- 20.075 -- 7697 -- 1 2.076 -- 57.89 -- 21.900 -- 8150 -- 1 Speed is in kph and distance is in metres. I've checked out a few formulas I've found on the internet, but none of them seem to work (or I'm not using them correctly - take your pick). Maths was never my strong suite, so any help would be appreciated. Thanks P.S. Sorry, can't seem to get tabs to space the list correctly Edit: used Gene's <spc><spc>--<spc><spc> tip on the list so it displays better. Edited November 15, 2005 by PartyPooper Link to comment Share on other sites More sharing options...
Gene Posted November 15, 2005 Share Posted November 15, 2005 I'm trying to use an AutoIt script to determine the estimated Rear Wheel Horsepower from a printout giving the variables of time, speed, distance, wheel circumference & mass. An example of the printout is:Wheel = 1.825 m Mass = 285 kgTime Speed Distance RPM Gear 0.248 26.46 1.825 3725 10.529 23.37 3.65 3290 10.76 28.48 5.475 4009 10.961 32.68 7.3 4601 11.138 37.2 9.125 5237 11.299 40.66 10.95 5724 11.448 44.03 12.775 6199 11.588 47.19 14.6 6644 11.719 50.09 16.425 7052 11.843 53.08 18.25 7473 11.963 54.67 20.075 7697 12.076 -- 57.89 -- 21.9 -- 8150 -- 1Speed is in kph and distance is in metres. I've checked out a few formulas I've found on the internet, but none of them seem to work (or I'm not using them correctly - take your pick). Maths was never my strong suite, so any help would be appreciated.ThanksP.S. Sorry, can't seem to get tabs to space the list correctly I made A s in Physics in college. but that was a long time ago, I'll look in to this, but I won't add anything to the thread unless I'm very confident. When Tabs are unreliable, try SpaceSpaceDashDashSpaceSpace like I did with the last row of your table. [font="Verdana"]Thanks for the response.Gene[/font]Yes, I know the punctuation is not right... Link to comment Share on other sites More sharing options...
PartyPooper Posted November 15, 2005 Author Share Posted November 15, 2005 Thanks Gene, and thanks for the list expansion tip - I'll go back and edit the original post to make it more legible. Link to comment Share on other sites More sharing options...
Gene Posted November 15, 2005 Share Posted November 15, 2005 I'm trying to use an AutoIt script to determine the estimated Rear Wheel Horsepower from a printout giving the variables of time, speed, distance, wheel circumference & mass. An example of the printout is:Wheel = 1.825 m Mass = 285 kgTime Speed Distance RPM Gear 0.248 26.46 1.825 3725 10.529 23.37 3.65 3290 10.76 28.48 5.475 4009 10.961 32.68 7.3 4601 11.138 37.2 9.125 5237 11.299 40.66 10.95 5724 11.448 44.03 12.775 6199 11.588 47.19 14.6 6644 11.719 50.09 16.425 7052 11.843 53.08 18.25 7473 11.963 54.67 20.075 7697 12.076 57.89 21.9 8150 1Speed is in kph and distance is in metres. I've checked out a few formulas I've found on the internet, but none of them seem to work (or I'm not using them correctly - take your pick). Maths was never my strong suite, so any help would be appreciated.ThanksP.S. Sorry, can't seem to get tabs to space the list correctly On thinking about this I am surprised you didn't give a mass for the vehicle/wt beng moved. I looked up the Work & Power formulas in Machinery's Handbook 20th Edition and came to some results in MS Excel. However it seemd impractical to be just considering the Mass of the wheel. I also poked about a bit on the Internet. The following link takes you to an online calculator. It's units are English, but those are simple conversions.http://www.speedworldmotorplex.com/calc.htmHere are the formulas they use (in javascript), you can compare the results the page gives you with what you get from your interpretation of the formulas.expandcollapse popupfunction hp1() { m = document.autocalc.trap.value/234; w = document.autocalc.weight.value; r = Math.pow(m,3)*w; f = r * 1.18; document.autocalc.result1.value = Math.round(r); document.autocalc.result1a.value = Math.round(f); } function hp2() { m = document.autocalc.et.value/5.825; w2 = document.autocalc.weight2.value; r2 = w2/Math.pow(m,3); f2 = r2 * 1.18; document.autocalc.result2.value = Math.round(r2); document.autocalc.result2a.value = Math.round(f2); } function td1() { wi = document.tire_diam.width.value/25.4; s = (document.tire_diam.series.value/100)*2; wd = 100*(document.tire_diam.wheel.value*1 + (wi * s)); r = Math.round(wd); x = r/100; document.tire_diam.result.value = x; } function mph() { g = document.mph_rpm.gear.value*1; td = document.mph_rpm.td.value*1; x = td/(g*336); document.mph_rpm.r10.value = (x * 1000); document.mph_rpm.r15.value = (x * 1500); document.mph_rpm.r20.value = (x * 2000); document.mph_rpm.r25.value = (x * 2500); document.mph_rpm.r30.value = (x * 3000); document.mph_rpm.r35.value = (x * 3500); document.mph_rpm.r40.value = (x * 4000); document.mph_rpm.r45.value = (x * 4500); document.mph_rpm.r50.value = (x * 5000); document.mph_rpm.r55.value = (x * 5500); document.mph_rpm.r60.value = (x * 6000); document.mph_rpm.r65.value = (x * 6500); document.mph_rpm.r70.value = (x * 7000); document.mph_rpm.r75.value = (x * 7500); } function gr() { a = document.gear.td2.value*1; b = document.gear.rpm.value*1; c = document.gear.speed.value*1; ans = 100*((a*b)/(c*336)); ansr = Math.round(ans); answer = ansr/100; document.gear.result.value = answer; } [font="Verdana"]Thanks for the response.Gene[/font]Yes, I know the punctuation is not right... Link to comment Share on other sites More sharing options...
PartyPooper Posted November 16, 2005 Author Share Posted November 16, 2005 I did, Mass = 285 kg I'll check it out. Thanks. Link to comment Share on other sites More sharing options...
Gene Posted November 17, 2005 Share Posted November 17, 2005 I did, Mass = 285 kg I'll check it out. Thanks.I noticed the 285 kg, I was expecting more like a 1000, you must have been thinking motorcycle instead of car or truck. [font="Verdana"]Thanks for the response.Gene[/font]Yes, I know the punctuation is not right... Link to comment Share on other sites More sharing options...
PartyPooper Posted November 17, 2005 Author Share Posted November 17, 2005 Yes, it's a motorcycle. I built a speed sensor for the front wheel and now I'm trying to display the results using AutoIt. Having fun and learning more about AutoIt as I'm doing it Link to comment Share on other sites More sharing options...
Gene Posted November 18, 2005 Share Posted November 18, 2005 Yes, it's a motorcycle. I built a speed sensor for the front wheel and now I'm trying to display the results using AutoIt. Having fun and learning more about AutoIt as I'm doing it That also makes the numbers I was getting make more sense. Because I wasn't thinking motorcycle, they seemed more than a little unreal. [font="Verdana"]Thanks for the response.Gene[/font]Yes, I know the punctuation is not right... Link to comment Share on other sites More sharing options...
DoctorX Posted November 18, 2005 Share Posted November 18, 2005 Power = Work/Time Work = Force*Distance Force = Mass*Acceleration Acceleration = (Change in Velocity / Change in Time) so... Power = (Mass*Velocity*Velocity)/Time (in Watts) and since 1HP = 746Watts... HP = (Mass*Velocity*Velocity)/(746*Time) It's early in the morning and I haven't had any coffee yet, but the above equation should be what your looking for. Not trying to give the forum a physics lesson here, I just wrote it all out incase I made a mistake hopefully someone will catch it. You need to convert your speeds from kph to m/s to use this formula (divide speed in kph by 3.6 to get m/s). So for your first row of data, the HP calculation would be: HP = (285*7.35*7.35)/(746*0.248) = 83.22HP Similarly, for the second row it would be: HP = (285*6.49*6.49)/(746*0.529) = 30.42HP This will give you the instantaneous horsepower at each time interval. The horsepower profile for the data you gave would be as follows: 83.22 30.42 31.45 32.75 35.82 37.51 39.46 41.33 43.00 45.04 44.85 47.58 If these numbers look right to you, the equation is probably correct. I'm off to get me a cup a' joe... -DRX Link to comment Share on other sites More sharing options...
PartyPooper Posted November 18, 2005 Author Share Posted November 18, 2005 Thanks DoctorX, I'll punch it in and let you know. I have tried a few formula's similar to this but they never worked out. Hopefully, this one will. Link to comment Share on other sites More sharing options...
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