its late and my brain is mush.... but for some reason i cant get this formula to evaluate properly

HP=(5280/3600)^2*(3500/32.17)/(87.7)^2*(curr rpm - prev rpm)/(curr time - prev time)*(curr rpm + prev rpm)/2/550

prev time=85.14
curr time=85.17
prev rpm=2763
curr time=2777

obviously i am missing a cpl brackets as Excel evaluates it properly but if i do it by hand i get a completely wrong answer.

can someone please help me with the order of the formula? the result should be 65..or 71 but i get 1.14159E-08 or even 101.... which is very very wrong.

 

I get 71 when I do it manually.

 

Yep....71.52 when i do it. Based on the low RPM this seems to be correct.

Shouldn't the first value be 5250 rather than 5280 ? ?

 

would u mind explaing the order, its been a long time since i did these currently i calculate

HP=(5280/3600)^2*(3500/32.17)/(87.7)^2*(curr rpm - prev rpm)/(curr time - prev time)*(curr rpm + prev rpm)/2/550

hp=2.1511 * 108.797 / (7691.29 * 14) / (0.03 * 5540) / 2 / 550
or
hp=234.033 / 107678.06 / 166.2 / 2 /550
or
hp=1.14159E-08

so i am obviousily doing something wrong... and I even tried to do it in VB and the wrong answer there to... hence the request to put the above in brackets or if u dont mind telling me the order. i also get 99.33, if i order them like:

234.033*166.2*550/107678.06*2=99.33

 

P=Paranthesis
E=Exponent
M=Multiplications
D=Division
A=Add
S=Sub

 

HP=[((5280/3600)^2)]*[(3500/32.17)/(87.7)^2]*[(curr rpm - prev rpm)/(curr time - prev time)]*[(curr rpm + prev rpm)/2/550]

That is how I did it. Basically break the equation into pieces. Once you solve each piece...then solve for the multiplication.

 

ahh ha thanks mate

now i can relax for the rest of the day

 

I bolded your error.

It should be:

/7691.29 * 14 and /0.03 * 5540

There are no parentheses there

 

Fun stuff huh?lol My brain is still mush from throwing VDR together.