Tank Size Question for New Airgunner

Bob Sterne (an air gunning living legend) used to throw fits about this over at the GTA website. Calling the tanks 98 cubic feet is supposedly a marketing gimmick. They are actually 88 cubic feet because of the nature of compressed gases after a certain pressure, changes. I never concerned myself with it because it is what it is, but no, you did not get ripped off, you got the big tank. Different retailers are just playing with numbers and discounting physics when it suits the bottom line. Go read the stuff over at GTA, I remember getting a good laugh out of it.

send us a picture of both sides of the tank

shalom

John

I wouldn't be worried. 98cu.ft and 100cu.ft are the same as a 88cu.ft which are all basically a 60 minute tank. There are 3 common sizes for SCBA tanks. 

30 minute cylinder = 45 cu ft.
45 minute cylinder = 66 cu ft.
60 minute cylinder = 88 cu ft

I know it sounds wrong but it is what it is. Here's a good read...

https://www.airgunnation.com/topic/what-size-air-tank-do-most-of-you-buy/

A 60 minute, 9L, 550 cubic inch, 88 cubic feet and 97 scf are all the same tank. It is an on going argument has to why, that re-surfaces constantly. As per your measurement you got the right tank. Acecare makes a huge 12L tank that you can order from aliexpress if you are ok with a Chinese product.

I had the same thing happen and went through the same agony for a few days until I found several threads explaining it... Still a little frustrating.

It's just marketing. They use different equations for capacity estimation to one-up each other. I'm sure that some unscrupulous vendors use safe over-pressure specs when calculating volume instead of normal working pressure. All 9-litre bottles with 4500 psi working pressures have the same internal volume. Your confusion is proof that their dodgy methods are working to bamboozle novices into buying their product. They also use confusing mumbo jumbo to claim that their products are safe and everybody else's are not. Beware of snake oil salespeople.

A 60 minute, 9L, 550 cubic inch, 88 cubic feet and 97 scf are all the same tank. It is an on going argument has to why, that re-surfaces constantly. As per your measurement you got the right tank. Acecare makes a huge 12L tank that you can order from aliexpress if you are ok with a Chinese product.

Click to expand...

Since the 12 litre tank was brought up, I’m curious to know if anyone here has one? I never see much talk about these gargantuan tanks. I’m contemplating picking one up.

What I’d like to see is a 12L next to a 9, for size comparison’s sake

Years ago Airhog was the original company selling carbon fiber tanks to the air gun community and their tanks are still advertised at their actual capacity. Their largest tank is 88 cubic feet compressed air capacity at 4500 psi or 9 liters of internal volume. The next size is 6.8 liters internal volume or 66 cubic feet air capacity. In order to one up noobs, the "airgun scientist" advertises 98 cubic feet capacity for the sized 9 liter tank and 74 cubic feet for 6.8 liter tanks. Basically its a gimmick for unsuspecting buyers thinking it means a larger tank. Not to be outdone, Airguns of Arizona sells identical capacity tanks which are the same 9 liter and 6.8 liters internal volume but advertises them as 100 cf and 75 cf air volume. All vendors selling carbon fiber tanks from third party manufacturers are selling the same internal volume tanks regardless of their advertising hype.

It's the same gimmick that cheap airgun manufacturers use when a noob goes to Walmart and sees an el cheapo pellet rifle rated at 1200 ft. per second. Then in fine print is says muzzle velocity is obtained using ultra lightweight pellets that shed velocity and are impractical to use. 

Bigragu, Here you go. The 9 liter is on the left. A 12 liter tank is the same length but much bigger in diameter as you can see in the side by side picture in the ad. The 9 liter tank is 6.8 inches in diameter, the 12 liter is 8.2 inches. It therefore holds 117.3 cubic feet of actual air capacity at 4500 psi. My favorite tank is a 6.8 liter since I own a compressor. I would think the 12 liter tank is a little on the hefty side to lug around. JMO. 

Acecare Scuba Tank 9L CE/12L GB Pcp Air Tank Diving Cylinder Pcp Tank Air 4500psi Carbon Fiber Cylinders Scuba Diving Air Bottle|Fire Respirators| - AliExpress

Wow that is huge. I can see why not too many folks invest in something of that size. 



Thanks, Steve