Hey, Came across this recently and had to share. It's apparently an Xtrac unit from last years Virgin. If you're *really* geeky check out the hi-res version here; http://a.yfrog.com/img736/2254/yukzy.jpg Almost gives me goosebumps it does! Cheers, Ian Image Unavailable, Please Login
Computer control..... They'd never be able to go that small if a jockey were stirring the cogs! All about *perfect* timing of the shifts. And these suckers last, what, 7 races now? Apparently, they'd go smaller yet but the FIA mandates a minimum gear width of 12mm - They were down to ~7mm a few years back IIRC. Cheers, Ian
That is cool! WAY simpler and more straightforward than I would have dreamt...in concept, at least. The complication is making it small (important)...light (more important)...and reliable (most important).
Indeed. I "grew up" with Hewland 'boxes - Very, very, simple yet elegant design. I could do a ratio change in a few minutes - Pop the back off, stand the gear cluster in my (non-patented ) jig, swap the cogs and pop 'er back together. Easy-peasy. Getting the backlash right on the diff was a different tale though..... Cheers, Ian
What sort of backlash does a gearbox like this run on those things. Larger (.012+) or tiny (less than .004).
The original seemless shift boxes used two clutches and were hopelessly unreliable with many components needing to be replaced regularly (as in several times a weekend!). The switch to twin barrel design has been universally adopted for a few years now.
I'm *way* out of touch, but suspect almost none - They're changing so fast these days that it would just mess things up..... The infamous "it selected two gears at once" problem..... Cheers, Ian
Would be nice if Ferrari adopted this design for production - as Lambo did for Aventador - instead of the dual clutch design which is too big and heavy.
Just think, years ago it would be Farrah Fawcett on the real wall instead Next to the obligatory Countach of course.
VERY cool, but I somehow can't get my head around how that gearbox design is supposed to work. Wouldn't you be engaging two gears at once with the two forks attached to each shaft/barrel? And what are the "gears" at the left side of each barrel doing?
Not if the timing is spot on.... Ensuring the timing is indeed spot on. My take [and I've been wrong once today already, so YMMV ] is those plungers on the left are the feedback controls - They feed the TCU which then disengages one at (pretty much) the same time as the other engages - Hence seamless. I think...... Cheers, Ian
Ahhhh. After staring at the picture for some more minutes, I finally got it. I thought of the forks being fixed to the barrels the whole time, which of course would prevent the latter from rotating... and confused the hell out of me So as in a usual gearbox of that kind, the barrels rotate and the forks follow the shape which can be seen directly above them on the barrels. Your suggestion of the plungers on the left makes sense. Now that I have understood how it works, that seems the most plausible explanation to me, too.
Oh no! - That definitely wouldn't work! As BMW guy noted - It's remarkably simple in concept. Getting it to execute correctly is left as an exercise for the reader....... Cheers, Ian
No sir. [But, again, I've been wrong already today....] - It has no idea which gear I'm going to select next so can't "prime" anything IMO. Cheers, Ian
No, if you notice, on the barrel at the top of the picture the paths for each fork are difference. So when selector fork has moved the dog ring for to the middle and the barrel spins again, then the other fork on the barrel will move. Or a variation on that, depending on the way in which the ratios are ordered. Enjoy thinking about that one
I already got that now, but thanks again for the explanation! As I said, I was under the impression that the forks were fixed to the barrels, which would render the usual operation with rotating barrels impossible, which somewhat made my head explode!
As an addendum to this excellent thread, I am adding a couple of bits which arrived for me this morning direct from GB. This is a gear set from none other than W01 I'd guess either 5th or 6th. Good paper weights Image Unavailable, Please Login Image Unavailable, Please Login
