# 1:87 vs. 1:64



## Pete McKay (Dec 20, 2006)

I'm starting to write some EXCEL codes for my heat sheets and I was wondering what you other track owners do for establishing scale. I know that originally the Model Motoring cars were pretty close to 1:87th, or true HO Scale so they could accompany train layouts of the same scale. But now-a-days the cars we race are closer to 1:64th. 

While this doesn't make too much difference in establishing ET track records, it plays the Devil when figuring average scale speeds and distances. The track I'm building averages out to 13.75' per lap, which make it either a 1/5th mile, or a 1/6th mile depending on which yardstick you prefer. I more than likely will go with the 1:64th scale measure mainly because it's more realistic. Take the current track record of 1.382 seconds. If you look at it from 1:87th scale, that's a 520.984 scale MPH average speed, from 1:64th, it's down to 394.73 S.MPH. The EXCEL formula works out like this:

=(((LT*6=MS)5280/MS=FPS.S)FPS.S*3600=FPH.S)FPH.S/5280

Take the lap time (LT) and multiply it by 6, since this is a 1/6th mile track. The answer you get will be the time it takes to travel a mile in seconds (MS). 

Take the number of feet in a mile (5280) and divide it by MS. 
That will give you the speed in feet per second/scale (FPS.S). 

Multiply FPS.S by the number of seconds in an hour, or 3600. That gives you the distance traveled in feet, per hour in real time (FPH.S). 

Are you still with me? 

Take FPH.S, divide it by the number of feet in a mile (5280) and the answer will give you the average MPH, scale to the track. 

...it's so much easier when its all automatically figured with an EXCEL sheet.


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## 1976Cordoba (Sep 20, 2000)

Pete McKay said:


> Are you still with me? . . .


Nope :lol: That stuff right there might as well be written in Arabic 

I just call my short track oval a half-mile because that is the kind of bullring short track it is modeled to be.

'doba


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## Pete McKay (Dec 20, 2006)

ROFL!! Farsi is much easier to learn.

Bascially what you're doing is taking the lap time, multiplying it by whatever it takes to equal a mile on your track, dividing a mile distance in feet by that amount, multiplying that by the number of seconds in an hour, then taking that amount and dividing it again by the number of feet in a mile. It sounds complicated, but break it down. It works regardless of your scale it you get the first part right.

If you have EXCEL enter these formulas into line 2, beginning at:

.......(A2).............(B2)..........(C2)..........(D2)..........(E2)
Input Lap Time =(A2*6.6) =(5280/B2) =(C2*3600) =(D2/5280)

Don't worry if you get an ERR message, once you input a lap time it'll go away.

Address E2 will convert your lap speed. Just make sure the numbers in B2 (mine was 6.6) equals the number of laps on your track to equal a mile.

It looks like this on the sheet:

Lap Time..Sec/Mi/S...FPS/S..................FPH/S................Scale MPH
1.382.....9.1212......578.8712012.......2083936.324.........394.6849099

If you want to know your 1:1 speed, in F2 enter =(E2/64). 394.684 works out to just 6.17 MPH in real life.


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## PULVERlZER (Sep 14, 2005)

I understand this isn't the point of the original post, but, I believe the model motoring cars were scaled to 1:76 to go along side trains in OO scale...not HO. I could be wrong though....

just wanted to say.......


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## Slott V (Feb 3, 2005)




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## Slott V (Feb 3, 2005)

OO Scale is a metric European scale.


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## vaBcHRog (Feb 19, 2003)

Most TJETS are closer to 1/76th than any other scale. However the Indy and Slimline indys are some where between 1/55th and 1/43rd. Also don't forget to scale your time too  Tha will make a big difference in you final out come.

Roger Corrie


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## neorules (Oct 20, 2006)

I figure out the speed by taking fps,say in unlimited racing we go 40 fps average on a lot of tracks. 44 fps is 30 mph so 40 fps is about 27.2 mph x 64 = 1740.8 scale mph. I'd drop the mile reference to figure fps, just divide the foot length of your track by the time it took for your fastest lap. Ex 80 ft length, 2 sec lap == 40 feet per second.


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## Hornet (Dec 1, 2005)

Divide your Ft Per Sec by 1.47 ,this will give you real time MPH
40 fps divided by 1.47 =27.21 real mph.
Not trying to step on your toes Bob,but you left that number (1.47) out of your equation :thumbsup: :wave:


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## neorules (Oct 20, 2006)

Nice shortcut Hornet. Thanks!!!


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## Hornet (Dec 1, 2005)

LOL,shortcuts are my specialty :thumbsup: 
For anybody who wants to figure out their average rpm for a lap go here.

http://www.ho-tips.org/index.php?showtopic=504

The orginal posts are here,for anybody having a hard time reading the above ones.Go back a few pages,and you'll find my orginal posts under amchornet

http://www.canho.ca/modules.php?name=Forums&file=viewforum&f=1


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## PULVERlZER (Sep 14, 2005)

Slott V said:


> OO Scale is a metric European scale.


...yup....correct!..it is a scale measure of 4mm to the foot which comes out to 1:76.2...or 1/76th, whichever you prefer....


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