Helium

[purplepig]

Has anyone ever put Helium in there camper tires? Commercial airlines use this in there tires and so does some Gov. agences.
This is suppose to reduce one's chances for blowouts and increases fuel mileage.

[old turbo]

I use nitrogen in my dually tires. Are you sure they use helium? I think the nitrogen is a sales ploy . No increase in fuel mileage.

[purplepig]

no, I'm not positive they use Helium. I have a lot to learn about this.

[skypilot]

I had not heard of this myself so I did some quick research on it (google and local physics library); yeap - they are now experimenting (and using in limited production) helium in aircraft tires. Weight savings for the new 757 and airbus aircraft; one of the articles spoke about how helium leaks through rubber so quickly so one of the local professors has / is working with NASA on a grant to develop new tire compound that is less porous so as to keep the helium in the tire longer.

Once again, what we learn on the forum.

[William H. Collier]

How much does air weigh?
Bill

[skypilot]

Quite a bit -- according to one of the articles I read, one aircraft manufacturer estimates they save 180 plus pounds by filling the tires with helium vs. nitrogen or regular air! Now, as a pilot, I really don't remember ever hearing a weight for air; I know that standard atmosphere displaces 29.92 inches of water in an air-pressure vessel; know that wet air is heavier than dry air; but I don't recall ever actually getting a weight. Time for another google session I guess .

OK, per http://www.overflite.com/thermo.html, "At 48 F (508 A) a cubic foot of normal pressure sea level air weighs almost exactly 1 1/4 ounces." Now, knowing that air presses down on us from the top of the atmosphere to where we are I looked again and found http://en.wikipedia.org/wiki/Atmospheric_pressure which states "A column of air 1 square inch in cross section, measured from sea level to the top of the atmosphere, would weigh approximately 14.7 lbf. A 1 m² column of air would weigh about 100 kilonewtons (equivalent to a mass of 10.2 tonnes at the surface)." More than you really wanted to know (and more than I probably needed to know ). I really need to get back to my computer class work!!

[bncinwv]

Googled:



Glad to be of help (Ha Ha!!!), Now off to more important things, Beech Fork State Park here I come!!!!
Bingo

[ols1932]

I wouldn't do it. You would have to carry your own helium with you to keep your tires at the proper psi. Helium is lighter than air and you couldn't use the same psi as you do with air. I don't know why it's not good, but I believe the tire guys can tell us. As for me, I wouldn't even consider it.

Orv

[clutch]

It's probably best to go to the desert and fill your tires with dry air since it weighs less.

[skypilot]

You need to remember that you are filling tires to 'psi' of whatever you put inside; theoritically you could fill them with water (or sand for that matter) and as long as you put enough in the tire to offset the pressure placed on them, they would hold your trailer (TV, car) up but the ride would be horrible; This is one of the reasons we went to inflatable tires vs. hard rubber --- the softer ride.

Now,Clutch, if we really want the best 'bang for the buck' we'd need to get sea-level air -- it is the densest (spelling doesn't look correct) )and then we need to be sure to get it on a 'dry' day since humid (wet) air will give us problems as the water condenses. (The Great Salt Lake or Mohave Desert perhaps, as I recall they are both actually below sea level). This is hurting my brain; I think its time for more 'camping'!!

[Countryfolks]

Salton Sea/Anza Borrego in So Cal.

[dsprik]

Actually, guys, I hate to be picky, but wet (humid) air is lighter than dry air...

Oxygen and Nitrogen molecules in the air are always paired up atoms. O2 and N2. Water is H2O - one oxygen and 2 hydrogen. These two hydrogen atoms are MUCH lighter than a single O atom.

Therefore, the two O atoms (16+16=32 amu) that make up the single oxygen molecule are much heavier than two H molecules (2 amus) and the single O atom (16 amus - total=18 amu) that make up the water molecule.

The more H2O molecules that displace the much heavier O2 (21% of "air") and N2 (78% of our air)in a cubic meter of air, the lighter it gets. Doesn't seem like that should be the way it is - but it is...

~On Edit: Actually "always" is not correct either when talking about the oxygen molecule. the very rare - but VERY necessary - O3 (ozone) also occurs naturally.

There... isn't that WAY more than you ever wanted to know about air???

[skypilot]

Ah yes, I messed up my basic weather training (a cold front brings in dry, cooler air; a warm front brings in warm, moist air normally) - but (dating myself and asking you to do so as well) -- do you remember the old 707 jets that TWA used to fly. The Air Force also used them for air-to-air refueling tankers. In Albuquerque they used to 'inject' water into the exhaust (not really sure at what point in the engine) to increase the thrust they got from the engines during take-off. As I recall my training way back when, the water vapor was heavier (denser) than the air without it, hence more thrust. What I really remember is that, on a hot day, without the water injection, a loaded 707 / tanker had trouble getting airborne even using all 13000 (over 2 miles) of runway; used to smoke black and, as my memory serves me, when the water injection kicked in, it went white for a few seconds and then black/gray again. Jeez, that was a long time ago. I remember going out to the base and my folks and us kids would sit at the end of the runway (parking ramp provided back then) to watch the aircraft come and go. Used to be so close you could see, and wave to, the people in the planes as they waited to take off. (That was another time) But I digress.

In any case, I did some more reading earlier today; seems quite a few airlines and aircraft manufacturers are interested in using Helium in their tires. As I mentioned in an earlier post, one airline looks to save 180 plus pounds per airplane -- that will allow then to carry another passenger or more fuel (or just make the plane lighter and save fuel) depending on economics. Another post commented about an experiment where they are supersealing the aircraft structure and filling the voids with helium to offset total weight; hopefully it will prove effective and efficient and further reduce the need for larger engines to lift extreme weight of upcoming super sized super aircraft (Bigger than 747s). This article sounded a bit dated but no-where on it did I find an earlier date (was posted this time in Feb, 2006). Who knows, with the engineers, and creative minds of all types, working on it, it may be feasible. We'll see. ( now lets see, how much helium can we put in front cap to offset our trailer pin weights???? Hummmmmm ....

(It's late and I'm getting loopy (loopier than usual my wife would say).) Take care all, happy and safe camping.

[dsprik]

I do remember those 707s. Flew in some. I think the difference may be water in it's liquid state vs water in it's gaseous state. Liquid water is indeed much more dense than water vapor. Therefore, the extra thrust with injected water.

I used to do science experiments (8th grade science) with hydrogen - just a little smaller molecule (H2) the He. We made our own hydrogen, then trapped it in a balloon and taped the balloon on the end of a meter stick. Then we would blow it up with a wooden match on the end of another meter stick. Sometimes, depending on the balloon mfr, we had a heck of a time keeping the balloons from shrinking to half their original size as the H2 is so small - as would the single He atom - that it is difficult to keep it from leaking through the balloon material...

[skypilot]

Yeap - that problem was described in several of the articles I scanned. There is are University professors working on grants funded by NASA (along with professors from several other colleges/universities). They are working on ways to line tires, and whatever else, with lightweight, yet impermeable materials to keep Helium (and other gases I believe) from seeping out. The one example they had in one published article described how Helium filled Latex balloons go flat (quit 'flying') very quickly as the Helium atoms escape between the latex materials atomic structure, yet a mylar balloon holds the helium much longer but even its structure is too course to hold the helium. Other, more exotic materials have atomic structures much more dense -- the Helium atoms can't slip thru. (This is actually way over my head, I'm just regurgitating what I've read! I understand it but you start giving me chemistry formuli and the brain is mush!!). (This topic keeps on much longer, next months Trailer Life cartoon will be a tow vehicle pulling a 5er by a string!!).

[dsprik]

[bsmeaton]

Well - I fill my tires with Water! It's easier to find the leaks.

[ole dude]

Tooo much pressure, time for a nap!!

[rames14]

You folks need to get a hobby. Here is the scoop on Nitrogen:
"Most tires are filled with compressed air, which when dry consists of about 78 percent nitrogen, 21 percent oxygen, and 1 percent other gases by volume. Water vapor (humidity) can make up as much as 5 percent of the volume of air under worst-case conditions. Filling your tires with nitrogen mainly does two things: it eliminates moisture, and it replaces skinny oxygen molecules with fat nitrogen molecules, reducing the rate at which compressed gas diffuses through porous tire walls. That means, theoretically at least, that a tire filled with nitrogen retains optimal pressure longer, leading to more uniform tire wear and better gas mileage. The commonly quoted figure is that tires inflated to 32 psi get 3 percent better mileage than at 24 psi." from Straightdope.com. See, now you've got me doing it. Are you happy?

[rogue]

If I fill my rear air bag, and 5th Air Borne air bag with Helium, how much lighter will it make my Pin Weight? :-)