Air vs. Nitrogen vs. Helium

[hardingfv32]

Wheel guns can only run on Air or Nitrogen, not Helium.

Why did the teams want to use helium?

Brian

[NonNewtonic]

Wheel guns can only run on Air or Nitrogen, not Helium.

Why did the teams want to use helium?

Brian

Base on the interview with the engineers MercedesGP which is the first team which use Helium gas to power their wheel gun says that due to the property of Helium gas which is less dense than air it actually helps to rotate the wheel guns faster.

[Carbon]

I'm curious, about rule 12.8.4:

"Wheel guns can only run on Air or Nitrogen, not Helium."

Is this a cost savings measure, to ensure safety, or does it create a level playing field among teams? Any idea what teams ran a gas that wasn't 'air' or nitrogen?

[hollus]

Apparently Mercedes was using Helium for this as it made their guns faster. So it is a performance advantage albeit small.
But one that all teams would have had by this year costing everyone a lot of money in the process. No safety issues with Helium, it is just very expensive for this function.

[zorog]

Must be a cost saving measure, helium is very scarce.

Wikipedia says " helium is a non-renewable resource that cannot be practically manufactured from other materials. When released into the atmosphere, e.g., when a helium-filled balloon leaks or bursts, it eventually escapes into space and is permanently lost. "

cant see any safety reasons why not to allow it.

[Carbon]

Thanks guys, I suspected some sort of performance advantage (however costly it might be).

[riff_raff]

As noted above nitrogen is preferable over helium because it is much cheaper. However, nitrogen is preferable over compressed air because it contains no moisture, and thus would not corrode the guns. And most importantly, nitrogen gas is inert. So it would be less hazardous than compressed air in a fire situation.

riff_raff

[Websta]

I'm not much of a chemistry student - does anyone know why helium is faster? I would assume that the FIA limits the level of pressure in the guns, so does helium expand faster?

[NonNewtonic]

Its actually simple physics basically helium is less dense than air so it will escape faster than other air under similar condition thus rotating the gun faster than other gas but due to the cost the FIA decided to ban it

[tok-tokkie]

Its actually simple physics basically helium is less dense than air so it will escape faster than other air under similar condition thus rotating the gun faster than other gas but due to the cost the FIA decided to ban it

Pneumatic guns work on pressure difference not mass or density difference. I don't understand what the advantage is.

EDIT: I suspect that when compressed the specific volume decreases more with helium than air or nitrogen so, as it expands in the wheel gun the volume increases more making it run faster. Quick Googing does not find me specific volumes at various pressures.

[hollus]

It has to accelerate from zero to whatever speed it is moving though the pipes at while moving the gun, so, yes, probably is just the smaller inertial mass allowing it to reach full speed faster.
Interesting to think that is safety didn't come into it, some teams might try to use Hydrogen!

[Richard]

I'm sure its a simply rationalisation of equipment at the circuit for to reduce costs and simplify logistics. So much easier to have everyone on the same system.

There are also some good threads on this subject from before, see the "similar topics" box at the bottom of this page for links.

[Billzilla]

I'm sure its a simply rationalisation of equipment at the circuit for to reduce costs and simplify logistics. So much easier to have everyone on the same system.

It's also very important that helium use be dramatically cut back overall as it's starting to run out, and can't be replaced. Things like party balloon helium mix gas will hopefully be outlawed ASAP (even though it's a diluted mix) as it's too rare to waste for such things.
Using it for the wheel guns on F1 cars should never have been allowed, nitrogen or plain compresses air would be just fine.

[Mikey_s]

Helium was used because it is a small, light atom. This means that the flow rate through the gun could be higher than with a bigger heavier atom/molecule.

As for the environmental credentials, I don't think F1 ever was a major user of Helium and, although there's not an awful lot around in the atmos, if fusion reactors ever take off there should be a decent supply!!

[Ian P.]

Helium is a low density gas that has a much higher flow rate through chocked high delt-P orifices.
Bottom line, air or N2 will see sonic conditions in the wheel guns at much lower velocities that will helium. Advantage He.

To address the issue of the scarcity of helium .... another small oily coloured fish. Prior to about 2003, the US Government mandated that Helium was a Stratiegic Material. A legacey from the Civil War and the WW-II

http://portal.acs.org/portal/acs/corg/c ... 443bb33e8b

This Stratiegic material designation effectively subsidized the cost of production so it was cheap and readily available. Once the subsidy was removed (Economics 101 for those Greek Scholars amongst us) the price went up, scarcity issues surfaced and panic set in.

Helium is naturally occuring and is produced in measurable quantities in natural gas. Virtually all gas contains some amount. The expensive part is the separation process, not the scarcity of the material itself.

On the issue of moisture in compressed air or in N2, same issue with the deep-water reptiles mentioned earlier.
If you run air at 6 to 10 Bar out of an air compressor, you will condense out moisture. This will wind up in the air guns and cause corrosion. N2 on the other hand comes from compressed gas cylinders that are dry simply because at 2000 psi in the tank you can not tolerate more than a miniscule amount of moisture. The gas is dried (PSA or TSA process) to about a -70 deg C dew point (at atmospheric pres) or if you are lucky enough to get your supplies from Edmonton, dried to -40 deg C at 2000 psi, even dryer.
Bottom line, if you had compressed air from cylinders at the same pressure as the N2, the moisture content would be the same.
The teams use cylinders because they are convenient, dry, easy to get and pretty darn cheap. And they come delivered at 100+ Bar. No need to fuss with powered compressors and likely small annoying gas dryers.