TBO of inner tubes

[carusoam]

20 minutes ago, 47U said:

Fuzzy brain… I’d better edit that, huh.  Thank you…

Nobody will ever know…

All my evidence seems to be missing…

-a-

[Pinecone]

In racing, the main reason that N2 is used is that it is more convenient that running a compressor in the pits.  To truly get a complete fill of N2, you need two valve stems to release the air that was in the tire when it was mounted.

Yes, I also road race.  I see no reason to not quickly move large sums of money out of my hands.   And I used to race sail boats.

 

Edited July 10, 2022 by Pinecone

[aviatoreb]

7 hours ago, carusoam said:

We might actually gain some UL here…

We may need a strong mathematician to calculate the benefit… (inviting @aviatoreb)

Volumetric calculation of a tire tube…

Weight of the volume of air….

Weight of the same volume of dry N2…

Experience of a bicycle racer…

And any other experience that can be brought to the MS table…

Best regards,

-a-

Thanks for the call out.  Technically - I think this is physics, not mathematics, per say.  Not that I can't handle PV=nRT with the best of them.  But there are constants involved to look up, but I am going to go ahead and say with confidence.  Don't bother with the major nuisance of swapping out Helium for standard air in your tubes.  The weight savings will be so small it won't be worth it.

...this said - if one wanted to do that, well why stop there?  How about swap out the rest of the air in your mooney with Hellium - I mean in the cabin.   Just put a whole bunch of helium balloons in your cabin to conveniently displace the air with lighter than air stuff.  I mean who needs heavy passengers anyway.  How much weight would be saved?  Some.  You could save some undoctored space where the pilot sits in case you want to breath.  Probably not worth it.  But it would be fun to explain at the fbo.

[PT20J]

3 hours ago, Pinecone said:

 And I used to race sail boats.

Did you fill the sails with air or nitrogen?

[Ragsf15e]

Only on MS can we have a 4 page thread on using/reusing tubes… this thread is a monument to the CB nature of Mooney owners!

[A64Pilot]

The Blackhawk helicopter’s main spar is filled with Nitrogen under pressure, the pressure is checked during preflight to see if a blade’s main spar has a crack in it, periodically the pressure has to be topped off.

So one day I listened to an enlisted crew chief who was topping off a blade telling some Lt. that in their unit they used helium so that the helicopter could carry more weight, the Lt bought it.

But in racing we used Nitrogen bottles to operate the air tools, so as it was the only compressed gas why not use it to fill the tires?

Military we had strut pumps to fill the struts in the 80’s, it had a big piston running off of shop air that compressed a small piston so you got low volume, but high pressure and we had high pressure air compressors and filled tires, hydraulic accumulators, struts etc with air.

Later we used N2 in bottles because it was easier, not because it was better, just easier to get bottles filled than maintaining air compressors.

[Pinecone]

Exactly.

It  easy and convenient to use N2  Especially if you need higher pressures.

[Fly Boomer]

On 7/9/2022 at 8:17 PM, PT20J said:

I've never noticed a significant change in pressure with ambient temperature in my car tires.

If I set my tire pressure in the summer, my TPMS will show at least one low tire come winter.  Happens every year.  I just reset the pressures, and all is good for another few months.

[Fly Boomer]

On 7/9/2022 at 9:02 PM, carusoam said:

I bet you find the O2 molecules are tinier than the rest…

Yep.  In particular, nitrogen atoms/molecules are larger than O2 atoms/molecules.

Is common atmospheric oxygen (2 oxygen atoms bonded together by subatomic forces) still an atom, or does it become a molecule?

[LANCECASPER]

6 minutes ago, Fly Boomer said:

Yep.  In particular, nitrogen atoms/molecules are larger than O2 atoms/molecules.

Is common atmospheric oxygen (2 oxygen atoms bonded together by subatomic forces) still an atom, or does it become a molecule?

It's a diatomic molecule. Technically a homonuclear diatomic molecule since both atoms are of the same element.

[Fly Boomer]

2 minutes ago, LANCECASPER said:

homonuclear

Careful!  This forum is moderated.

[Hank]

19 minutes ago, Fly Boomer said:

If I set my tire pressure in the summer, my TPMS will show at least one low tire come winter.  Happens every year.  I just reset the pressures, and all is good for another few months.

I see more pressure change from driving 10 miles at 62 mph than from seasonal variation. There have been few times I've taxied my Mooney much over a mile, but not nearly that fast. My car tires are filled with compressed atmospheric gases, not just some of them.

[Shadrach]

9 hours ago, Hank said:

I see more pressure change from driving 10 miles at 62 mph than from seasonal variation. There have been few times I've taxied my Mooney much over a mile, but not nearly that fast. My car tires are filled with compressed atmospheric gases, not just some of them.

Interesting. During the winter in my car, I see tire pressures increase about 1.5-2psi in the first 5-10 miles from start up to. Increase in summer is negligible (<.5psi) unless coming of an unusually cold evening. I see larger swings from season to season. 

[A64Pilot]

I top off car tires whenever I rotate them, every 5,000 miles so about three times a year.

I always have to add a couple of PSI whatever the temp, my Wife’s CTS-V will display real time tire pressure, if you push the car pressures go up by quite a lot, like about 10 PSI or so.

So how many cars come from the factory with an N2 fill? Not many I’d imagine, maybe the types that claim “Corinthian Leather” or similar

Pre-charge on an AH-64’s hydraulic accumulator is 1650 PSI, a whole lot easier to roll a bottle of N2 out to the flight line than it is to get a Hypac compressor out there, and then fight the thing to get it running.

[Shadrach]

7 minutes ago, A64Pilot said:

I top off car tires whenever I rotate them, every 5,000 miles so about three times a year.

I always have to add a couple of PSI whatever the temp, my Wife’s CTS-V will display real time tire pressure, if you push the car pressures go up by quite a lot, like about 10 PSI or so.

So how many cars come from the factory with an N2 fill? Not many I’d imagine, maybe the types that claim “Corinthian Leather” or similar

Pre-charge on an AH-64’s hydraulic accumulator is 1650 PSI, a whole lot easier to roll a bottle of N2 out to the flight line than it is to get a Hypac compressor out there, and then fight the thing to get it running.

What's great about that add is that it ran long enough to be ingrained in the pop culture of multiple generations.  I was born the year "Corinthian Leather" was conceived by a midwestern marketing firm, but remember the Ads running when I was of TV age. It's glorious in its pure 70's faux machismo.

Ricardo actually refers to it as a "this small Chrysler".  Those pathetic cornering shots in the twisties showcase just how far the automobile has come in nearly five decades in terms of road holding if not style...

[MikeOH]

On 7/10/2022 at 6:55 AM, PT20J said:

Did you fill the sails with air or nitrogen?

When it comes to sailing, I’d bet they were filled with money

[A64Pilot]

The Cordoba was actually a smaller car, it was a product I believe of the oil embargo.

Smaller is relative but at 18’ I think it was 2’ shorter than the car it replaced.

Pretty much all US made cars of the 70’s were terrible. It’s funny how people want to think they were something, especially when they think they were powerful, when in truth they were mostly dogs.

1977 Pontiac Trans Am 16.9 sec 1/4 mile https://horsepowermemories.com/2017/08/10/1977-pontiac-firebird-trans-am-special-edition/ I mean come on, 17 sec 1/4 mile?

Toyota Corolla is a half sec faster https://www.carindigo.com/toyota/corolla/0to60

Or the “mighty” 428 Cobra Jet Mustang with 335 HP and a high 13’s 1/4 mile.

I don’t miss those days.

[Shadrach]

36 minutes ago, A64Pilot said:

The Cordoba was actually a smaller car, it was a product I believe of the oil embargo.

Smaller is relative but at 18’ I think it was 2’ shorter than the car it replaced.

Pretty much all US made cars of the 70’s were terrible. It’s funny how people want to think they were something, especially when they think they were powerful, when in truth they were mostly dogs.

1977 Pontiac Trans Am 16.9 sec 1/4 mile https://horsepowermemories.com/2017/08/10/1977-pontiac-firebird-trans-am-special-edition/ I mean come on, 17 sec 1/4 mile?

Toyota Corolla is a half sec faster https://www.carindigo.com/toyota/corolla/0to60

Or the “mighty” 428 Cobra Jet Mustang with 335 HP and a high 13’s 1/4 mile.

I don’t miss those days.

To be sure there were a lot of dogs. But that time also hatched some of the most beautiful road going shapes ever built. E-type roadsters, boattail Corvettes, Lamborghini Muira, Toyota 2000GT and on and on and on.

[Pinecone]

5 hours ago, Shadrach said:

To be sure there were a lot of dogs. But that time also hatched some of the most beautiful road going shapes ever built. E-type roadsters, boattail Corvettes, Lamborghini Muira, Toyota 2000GT and on and on and on.

E-type started early 60s

Miura was late 60s.

[Shadrach]

7 hours ago, Pinecone said:

E-type started early 60s

Miura was late 60s.

Yes I’m familiar. I’ve logged a fair amount of time in E types. Unfortunately, I can’t say the same about the the Miura. 
I was speaking more broadly about the the late postwar era of American “muscle” and diminutive European autos which is not defined by a single decade but spans many.

 

 

[A64Pilot]

US cars became crap in the mid 70’s. In 1978 the quickest US production vehicle was a Dodge little red express truck, why? because it was over the weight limit and was exempted from a lot of the pollution controls.

1976 Vette was 180 HP.

14 sec 1/4 miles were real fast.  Most “fast” cars ran like 16’s.

[Fly Boomer]

On 7/14/2022 at 7:36 PM, A64Pilot said:

1976 Vette was 180 HP.

'67 was 435 HP

[A64Pilot]

1 hour ago, Fly Boomer said:

'67 was 435 HP

That’s my point, from about mid 70’s until the early 90’s, Cars, especially US one’s sucked. 

They came back in 93 though, our 93 Z28 was both the quickest and fastest Camaro ever built, in 93 of course, they got quicker and faster, and more refined, polluted less, got better gas milage and last longer too, and actually handle, in short light years better than mid 70’s.

https://www.drivingline.com/articles/the-93-camaro-z28-why-it-was-the-first-modern-muscle-car/