Author Topic: How many revolutions of an engine  (Read 519 times)

Offline Grant Monkhouse

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How many revolutions of an engine
« on: November 19, 2020, 05:46:45 PM »
Something that Carl asked me the other day..

How many revolutions does an engine do down the drag strip?

Let's see who can work it out.

Use some easy numbers though.

Average rpms down the 1/4 mile = 6000rpms.

Quarter mile time = 10 seconds

What's your answer?

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Offline Grant Monkhouse

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Re: How many revolutions of an engine
« Reply #1 on: November 19, 2020, 05:55:33 PM »
Now if you do an average of 6000 rpm in a 20minute race how many time does the engine rotate?

Now with those 2 figures can you work out in each scenario how many times the rotors do a full rotation in a 13B/20B/26B

The rotors don't do the same amount of rotations of the cranks shaft by the way.. Lol

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Online Mr Spiller

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Re: How many revolutions of an engine
« Reply #2 on: November 19, 2020, 05:56:02 PM »
Now if you do an average of 6000 rpm in a 20minute race how many time does the engine rotate?

Now with those 2 figures can you work out in each scenario how many times the rotors do a full rotation in a 13B/20B/26B

The rotors don't do the same amount of rotations of the cranks shaft by the way.. Lol

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Offline Grant Monkhouse

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Re: How many revolutions of an engine
« Reply #3 on: November 19, 2020, 06:07:46 PM »
Yes

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Online Mr Spiller

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Re: How many revolutions of an engine
« Reply #4 on: November 19, 2020, 06:27:10 PM »
Yes

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stumped
I just 3 per rpm
Clearly not that easy


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Offline Jamie R

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Re: How many revolutions of an engine
« Reply #5 on: November 19, 2020, 06:58:32 PM »
Something that Carl asked me the other day..

How many revolutions does an engine do down the drag strip?

Let's see who can work it out.

Use some easy numbers though.

Average rpms down the 1/4 mile = 6000rpms.

Quarter mile time = 10 seconds

What's your answer?

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1000 revolutions


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Offline Grant Monkhouse

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Re: How many revolutions of an engine
« Reply #6 on: November 19, 2020, 06:59:14 PM »
6000 rpm = 100 rps(revolutions per second)

100 rps x 10 second 1/4mile pass

=1000 revolutions of the engine down the drag strip.

Obviously there's the burnout and drive back to the pits but just making it easy

Now in a 20 minute race.

6000rpm (revolutions per minute) x 20

= 120,000 revolutions per 20 minute race

Now the eshaft/Crank does 3 revolutions for one full rotation of a rotor

So in the drag race you take 1000 revolutions and divide that by 3

1000 / 3 = 333.333 ful rotations of one rotor

So a 2 rotor is 333.333 x 2 =666.666 full rotations

For a 20B x3 for a 26B x4

So in a 20 min race

120,000 / 3 = 40,000 full rotations of one rotor

Then multiply that number by how many rotors etc

IT is very interesting as (like myself) everyone thinks that a drag engine is a good testament to a solid built engine.

As the saying goes drag racing outs the most amount of stress on an engine in the shortest amount of time...

However if you look at a circuit car, Clives car as a perfect example, just how much abuse it has done.

5 years with the same engine.

6 race events per year?

Qualifying sessions

20 minute races

At 500hp

That just shows how good the engine is  and also how well tuned the car is testament to the guy that built the engine and also to guy that mapped it, and also nit forgetting the Driver Clive

Now there's a huge amount if variable to consider etc, traction being a major one especially in drag racing because traction puts huge loads onto a drag engine, acceleration a car from 0-60 in 2 seconds at a guess which is a lot different to a track car.

Just looking at the numbers you have got to appreciate how good an engine has to be for drag racing but also on track.

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Offline Jamie R

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Re: How many revolutions of an engine
« Reply #7 on: November 19, 2020, 07:04:35 PM »
Now if you do an average of 6000 rpm in a 20minute race how many time does the engine rotate?

Now with those 2 figures can you work out in each scenario how many times the rotors do a full rotation in a 13B/20B/26B

The rotors don't do the same amount of rotations of the cranks shaft by the way.. Lol

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120,000 revolutions

Each rotor 40000 times for 13b 20b and 26b

Doesn’t matter how many rotors each rotor does one full orbit for 3 revolutions of the eccentric shaft


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Offline boosted

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Re: How many revolutions of an engine
« Reply #8 on: November 19, 2020, 08:49:18 PM »
How many sparks per second on 1 rotor at 9000rpm

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Offline Jamie R

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Re: How many revolutions of an engine
« Reply #9 on: November 19, 2020, 09:06:24 PM »
If there are 12 faces to a dodecahedron, how my any oranges are required to clean windows ??


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Offline jinx

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Re: How many revolutions of an engine
« Reply #10 on: November 19, 2020, 09:55:06 PM »
If you don't know the answer is always 42...you are just too young.

Offline Grant Monkhouse

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Re: How many revolutions of an engine
« Reply #11 on: November 19, 2020, 10:33:02 PM »
How many sparks per second on 1 rotor at 9000rpm

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300, however there's no gaurentee that the spark plug just fires once

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Offline re japi

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Re: How many revolutions of an engine
« Reply #12 on: November 20, 2020, 06:15:12 AM »
Think about TopFuel drag cars for example, how many revs they do on quartermile? 5 or 6

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