allegretto

First, not being hostile, just that

a) your discussion invited confusion between F and p. I assume you know the difference and while both contribute to the net F at any given moment, the effect of the flywheel is small relative to the F of the engine. Your example ignores the source of far more p than the flywheel, that is the running gear of a vehicle in motion. It is the matching of the motor's F with the F of the running gear that causes a shift to be smooth or not. As I noted, in my Cup you could slam 2-3 with no clutch whatsoever and it was glass smooth. Admittedly that is an extreme example where the flywheel is very light with very little p but the point is the same. It's the rest of the driveline that determines smoothness more than a flywheel

and

b) you're being quite pedantic. Others here might understand the Physics as well, and even shifted on a track as much as you.

Next time perhaps you could just use a little less verbiage and not introduce irrelevant examples (like spaceships) and perhaps we could more easily agree or it might be a bit easier to see your point. My questions arose from being unclear as to why you are raising the issue of flywheel and ignoring the rest of the car. My use of what you call "tautology" is to cut to the chase and stop your cherry-picking of factors. Sorry, had to do it...

simsgw

Marshal, I spent over forty years in the space program and I quit arguing language back when I was a sophomore, but I have to say that I cannot begin to understand what you mean by velocity "does not 'build". Velocity increases over time if acceleration is in progress. And incidentally, it's almost impossible to find a situation where mass is not subject to acceleration for one reason or another. In plain English, when acceleration occurs, velocity 'builds'. And momentum increases along with the increase in velocity. It 'builds' also. Give it up.

As for acceleration, it is not a closed system. It isn't a 'system' at all, it is a phenomenon. I think we're putting civility at risk without communication occurring, so I'm dropping it.

Gary

simsgw

Missed your note, so I'll answer this before I drop the thread. I agree that it sounds like confusion is present.

If I throw a medicine ball at your stomach, it will stop and you will feel a force. That's what happens when you 'pop' a clutch on a manual transmission car when the engine speed doesn't match the road speed. It happens because the engine has rotating mass that must suddenly change speed.

When we 'pop' a clutch, as in let it out without allowing time for slip to smooth the delivery of the force required to slow that internal mass, then we create a spike in the forces acting on the car. It jerks. Why is that controversial? We operate a manual transmission to minimize that unless lap time is more important than wear on the drive line. And the PDK is quite well designed to do the same thing.

As to whether the momentum of the flywheel and the other rotating masses is significant, try a simple experiment. The difference between redline in second and the new rpm in third is greater than two thousand rpm. Limit yourself to 2000 to avoid damaging the car, but in a manual transmission car, rev the engine to 2000 rpm and slide your foot sideways off the clutch pedal to 'pop' engage the clutch. Surely your intuition agrees you will feel a jerk? If it doesn't, then go ahead and try that. Just not in my car.

Gary

allegretto

Hey Gary,

nooo problem. and while it may surprise you, we needn't belabor inelastic collisions as examples. it just puzzled me that you wanted to discuss the vehicle's dynamic whist ignoring everything behind the transmission. just didn't think all the "whys" were being addressed.

i know you know...

Betternotbigger

Reminding ourselves that this debate started with a polite question, is this also a good moment to remember that it is exactly 50 years since Arthur C Clarke famously observed:

"any sufficiently advanced technology is indistinguishable from magic"?

Mike in CA

Issues of MT/PDK aside, you get my vote for best reference of the thread. Clarke was truly ahead of his time and I love his books.

Betternotbigger

Completely OT now but the reason I was reminded of Arthur C:

I've "educating" my teenage son with DVDs of the truly great movies of our time. Last month it was Apocalypse Now and The Godfather, next up is 2001 A Space Odyssey. He is stunned to see what they could achieve without CGI back in our day!!

Hang on a moment, that is kinda relevant to another discussion thread but I'm gonna leave it there. A good movie is a good movie whatever the technology.

simsgw

I dunno. Seems pretty apropos to a discussion about computers taking over our spaceships, don't you think?

Gary

Betternotbigger

I suppose it does, Gary. Wasn't looking at it like that. Just a great, great movie. So much craft in every scene. Sorry. OT.

allegretto

No doubt a profound movie. Every scene told so much more than was manifest in the dialogue. The flow of events is virtually unparalleled in modern movies. Kubrick's finest work by far.

So; when he asks, what are you going to tell him the last scene means...?

mdrums

Really...40 posts about how to shift a PDK....WOW! It isn't hard people!

Betternotbigger

He's still trying to decode the last half hour of Apocalypse Now... just like I was 30 years ago (is it really that long?) That film doesn't look a day older though, nor does 2001, nor Lawrence of Arabia... That's the wonder of these all-time greats... remind you of anything else?

Mike in CA

Absolutely. Could not agree more.

Paul Krol

I wanted to ask is it normal that in normal mode I throttle about 50 % and the mecan starts in 1st but doesn't pass 2000 rpm it just seamlessly changes to
Second gear and continues to about 2600 rpm and them proceeds to 3rd? Is this normal behaviour

ADias

In Auto (D) mode yes, but you can drive it as a sequential in M mode and shift at will. I only use PDK Normal in town in M mode.