Regulation Question--5.2.2

[Reca]

Exactly ? Now you are the one who’s joking, right ?

[Monstrobolaxa]

More or less......to some extent he's right!....unless I'm reading it the wrong way....

[Reca]

In every day terminology, if something weighs 1kg, what is infact meant is 1 kg/s (or N). Weights, measure, scales etc. in kg for most uses, are therefore calibrated to measure mg rather than just m.

What I read in Guest2’s post is that when the reading of the scale is 20 kg it means that the force applied on it is 20 kg/s (or N...)
Am I reading it in the wrong way ?

[guest2]

In such hurry made mistake with units. (Should read 1N = kg m/s^2 )
Anyway what I 'm saying is the scales are actually reading 20kg m/s^2 (20N).

(i.e that It is scientifically incorrect to say something weighs 20kg as kg is a unit of mass).

[joseff]

er...no.

g=9.81m.s^-2, give or take, depending on your location

so 20kg of mass weighs (mg) = 20 x 9.81 kg.m.s^-2 = 19.62 N

[guest2]

You missunderstood me. I am saying the scales is actually reading 20 Kg m/s^2 and not how much 20 kg weighs.
If I had a mass of 20 kg I would weigh 20 x 9.81 = 196.2 kg m/s^2 (196.2N)
On scales, this would probably read 196kg (which scientifically would be wrong).

[Mac Man]

Howdy y'all

So, back to the rule, what does this mean?

Me and some buddies are trying to make sense of it at the pub with notes I've taken from the board, but we're still somewhat perplexed. It seems that it is to ban the use of a flywheel to capture energy during braking in order to use the same energy during acceleration. Is that what it's about?

I've seen that a team can contact the F1 technical commision concerning rule clarification, but I doubt that they're going to give me, a fan, a straight up answer.

On an aside, I see that Monstro is from Portugal, where are the rest of you writing from?

wishing I had me some of the other J's

D-Rock

[seymour]

Yes, I believe you are correct. Rule 5.2.1 specifically bans the use of anything other than the engine to power the car. However, energy is inherently stored in any rotating components and that energy might be converted into forward motion. A flywheel is a specific example of this, and though banned by 5.2.1 a clever engineer might argue that a device that serves as a flywheel is part of the engine and should be allowed. Rule 5.2.2 therefore specifically limits the amount of recoverable stored energy in the engine (300KJ) and the amount that can be recovered (20KJ) at a rate faster than 2kW.

So I imagine the idea behind this rule is to prevent some sort of engine braking that is just conversion of forward motion into rotational motion of a flywheel that is part of the engine that can be later converted back to forward motion. It can't be technically forbidden because the engine must have moving parts but it limits the amount of energy that can be stored in those parts in total, and the amount that can be recovered at a rate faster than 2kW which as Mac Man notes, is about 2.7HP, a pretty insignificant rate given the 900HP engine.

I'm not sure if a team could derive a real benefit from this anyway, but then maybe that's the reason for the rule: nobody wants to worry about other teams trying this out. I also doubt that this rule is considered in engine design. The intent is to prevent flywheel designs, so teams don't.

[Reca]

Off topic (sorry Mac Man, it’s necessary) :

If I had a mass of 20 kg I would weigh 20 x 9.81 = 196.2 kg m/s^2 (196.2N)
On scales, this would probably read 196kg (which scientifically would be wrong).

If you had a mass of 20 kg the scale would read 20 kg. Period.
In every day terminology the scale reading is improperly called “weight” while on the contrary it’s the mass but that’s a problem of the common terminology, the instrument is doing his work correctly according to the calibration.
While calibrating a scale the force applied by 1 kg of mass (*) is assumed to be 1. So, when a body is subjected to an acceleration exactly equal to the one that was present while calibrating the instrument, it will indicate the mass of the body (neglecting the errors inherent in the instrument obviously). If the acceleration is different then the scale reading is the mass the body should have, while subjected only to the acceleration present at the calibration, to apply the force the scale is currently measuring. For most uses the gravity acceleration can be assumed to be constant, the variation is lower than the precision of most of weighing scales.

(*) In France, I don’t remember exactly where, there’s, under a glass bell, The Kilogram, the unit of mass. Theoretically you should use this one to calibrate each scale, obviously that’s unfeasible so there are some “kilograms” compared with the original one, each Country has one of them, periodically used for the calibration of very high precision scales then adopted to verify the new samples used for other scales etc etc...

[Mac Man]

howdy y'all,

please dont' confuse me with a NASCAR redneck, as I tend to be more of a cowboy/hippie

first off: thank you seymore! this makes sense to me. You cannot design a flywheel intended to capture massive amounts energy with the intent of reusing said energy. All of us at the pub say, "Ahhh, yes. That makes perfect sense!"

So, as we see it: (1hp=550ft-lbs)

5.2.2) The total amount of recoverable energy stored on the car must not exceed 401.8363hp, any of which may be recovered at a rate greater than 2.682hp must not exceed 26.7890hp.

Now I can wrap my head around what this rule is saying.

No worries about y'all (Monstro take note: one word, "y'all") getting off the topic as long as you get back to it, and where you're going furthers your understanding of the physical world. As I said, I am no engineer. More of an artist, in fact. Not that engineering isn't an art in itself.

"To drop a plumb line into the depths of life, to find thereby the great emotions common to all mankind and to express them so that all mankind will understand the expression--this, I think is what art is for."
--Gutzon Borglum

This to me captures the essence of art, and I don't think that physics or engineering are exempt. We all understand the results of F1 engineers, be they mechanical, electrical or aerodynamic. In the end the results are the results.

Ride hard and Shoot straight

D-Rock

[seymour]

Mac Man, I feel we'd be doing you a disservice if we let you walk out of here thinking power and energy are the same thing. The post that equated 1 horsepower with 550 ft/lbs is incorrect. The poster meant 550 ft*lbs/sec

Power is energy per unit time.

So as regards the rule, 300kJ worth of energy can be recovered from the engine at a rate not greater than 2.7HP. If the energy recovered in KJ divided by the time in which its recovered in seconds is greater than 2, meaning 2KW, then that energy can not be greater than 20KJ.

So, some examples. The 20KJ recovered in 1 second would be 20kW, or about 27 extra HP, but for only 1 second. If the 20KJ were recovered in .1 seconds, it would be 270 extra horsepower, but for only .1 seconds.

If you are really interested in a better explanation, you might want to consult a website that does it much better than me.

Try this: http://auto.howstuffworks.com/horsepower.htm

[Mac Man]

seymour, no worries.

Most of what everyone here is talking about is above my head, but you have done a great deal to help me understand it. As I see it, the only energy allowed to be captured in the flywheel/moving part of the engine, is a relativly trivial amount. I appreciate the lengths that y'all are examining the issue, but I think that now I can make sense of the general spirit of the rule. My pub crew and I were mostly baffled by the wording of it all. Like I said, I, and my crew, are gearheads, not engineers. If we have arrived at a basic understanding of it, then you've all done us good service.

Keep up with the technical discussion, by all means. I'll keep reading, and do what I can to understand it. I ain't leaving, not at all.

Thanks again y'all!

D-Rock