Red Bull RB9 Renault

[tim|away]

... A bullet obstructs the path of gas through the barrel. and the gas is forced to escape around the bullet through the riffling. The swirl of gas plus whatever frictional effects between the rifling and the bullet causes the bullet to swirl.

I hesitate the disagree (because I really don't know). But I can't help thinking that Joseph Whitworth might have a different (less aero-biased) explanation.

I know this is slightly off-topic, but I have a hard time leaving it stand as is.

Bullets are always made of softer metals than the barrel (lead, copper plating, etc vs hardened steel of the barrel). Rather than the gas passing around the bullet, the projectile actually expands and goes into the groves as the propellant goes off. If you recover a bullet you've shot, you can actually see the rifling marks and how it has bitten into the projectile. That's why shooters experience "fouling" of their guns which is a term to describe metal residue on the inside of the barrel from bullets.

[321apex]

Re-exhaust gas swirl
The collectors of F1 engine exhaust headers/pipes are quite short. If you imagine the individual pulses of exhaust gas leaving each cylinder of an engine bank and coming together in said collector, there are doubtful conditions to now make this "collective exhaust gas" spin around the flow axis.
In my view to make exhaust spin/rotate around the short exhaust collector pipe axis would require significant pipe length to attenuate individual cylinder exhaust pulses and.... internal directional fins/vanes, which would be detrimental to the exhaust back pressure. To offset down this back pressure rise, the collector pipe would have to be of larger diameter than normal. Is that the case based on your observations of photos?

Moreover, can anyone describe the real benefit that such flowing/spinning exhaust exiting the exhaust pipe would make?
I think, since hot gas is quite non-dense, or "thin" if you like, it's rotational momentum would "wash out" the moment it exits the exhaust pipe.

[timbo]

In my view to make exhaust spin/rotate around the short exhaust collector pipe axis would require significant pipe length to attenuate individual cylinder exhaust pulses and.... internal directional fins/vanes, which would be detrimental to the exhaust back pressure.

This is a good point. Vortex carries energy and it has to take it from somewhere.

[321apex]

re-exhaust gas swirl #2
Exhaust manifold/header collectors are carefully designed parts, where many geometry aspects of their design are NOT accidental. Basic design elements:

- diameter and the length of individual cylinder pipes and the collector pipe and it's "cone effect" of diametral increase from throat towards the exit; the dimensional changes are slight enough that they are not always noticeable to an eye

- angle between the individual cyl exh pipe axis to the collector axis

- often used in racing "necked-down" throat like feature slightly downstream from where all individual pipes merge; how far downstream is the throat (if used at all) from the merge plane of individual pipes

-stagger or positional clocking of individual cylinder pipes to maximize exh scavenge effect; F1 V8 uses 4 cyl firing pattern along each bank - 1-3 4-2, with 180 deg. firing separation between 4 pipes; typically located adjacently to each other cylinders firing consecutively to achieve "pulling" effect of exhaust scavenging; I said typically because not always does common logic prevail in dyno verification

Lastly. Exhaust manifolds are somewhat of a "black science". Challenging environment of high temperature and extreme vibration put a premium on the longevity of exhaust manifolds. High grade aerospace materials such as seamless, inconel tubes are used in their manufacture, and their mileage is carefully monitored in order to replace them in time. Welding them is highly skilled task. What is invisible are the geometry features also incorporated inside the exhaust manifold. Very often "sharp edges" created inside are beneficial for the overall exhaust gas scavenging efficiency and ultimately engine power.

Typically, engine people specify to the team what should the exhaust system geometry be and usually provide the added bonus to their top customers of validating the functionality of their vehicle exhaust system on the engine dyno.

[Huntresa]

LOL!

Did you guys see the vortice on Marks car when they did the PoV from the FW facing backwards against the sidepod and Mark ? A more stable vortice have i never seen before, it was like a piece of art!

Check this out, right click to show big img.

[turbof1]

It's...beautiful!

They have a much better control over vortices then I originally thought. The way they are able to change angles and directions of the vortex is astonishing.

[Huntresa]

It's...beautiful!

And in the videoclip its so stable, it doesnt move an inch, its 100% steady in that position as that still frame is in, almost unbelieavable compared to what we saw on the Ferrari from the side last week spewing out its vortice.

[Holm86]

Noticed its straight away too. It looked awesome

[turbof1]

Compare it to this image a page back:



Very accurate. And this is something they can definitely use next year to keep sealing the diffuser.

[Huntresa]

haha tweeted my pic to Scarbs and then my mail box exploded with like 25 retweet mails

[oT v1]

awesome!! i wish we could see more of whats going on like in the pic!! seems only in high humidity the public get to see whats going on in practice.

I really hope Ferrari's vortex in the other gifs were to push air around the rear tire....

Very accurate. And this is something they can definitely use next year to keep sealing the diffuser.

probably what Newey was up to with the air sensors all over the back in FP1, refining THAT!

EDIT: Huntresa, have you got a gif/vid of that as well?

[Shrieker]

Newey, the last air bender...

[turbof1]

Newey, the last air bender...

=D>

[Huntresa]

awesome!! i wish we could see more of whats going on like in the pic!! seems only in high humidity the public get to see whats going on in practice.

I really hope Ferrari's vortex in the other gifs were to push air around the rear tire....

Very accurate. And this is something they can definitely use next year to keep sealing the diffuser.

probably what Newey was up to with the air sensors all over the back in FP1, refining THAT!

EDIT: Huntresa, have you got a gif/vid of that as well?

Video is being uploaded as we speak, got slow upload so in like 20 min.

Edit: And now its gotta be converted, sigh, so later like in an hour ill get the video to you.

[stefan_]

Brazil 2013 - Friday (22.11.2013)