Equating pumping and hanging?

This is about pumping but relates to hanging too so I put it here so all could get a chance to see it. If I am correct 1 inch Hg is equal to 0.49psi (pounds per square inch), so if you had your penis in a tube of area 1 sq” at a pressure of 1”Hg it is experiencing a force equivalent to 0.49lb. The most common tube sizes are 1.75” and 2” which have an areas of 2.4 and 3.14 sq”. So at a common vacuum of 5”Hg in a fully lubed packed 2” tube it is equivalent to a force of 7.7lb (5x0.49x3.14)or 5.9lb in a 1.75” tube. This sounds about right, the highest weight I have heard used in hanging is 45lb which would need 29.2”Hg in a 2” tube which is a huge amount. The highest usual vacuum is 15”Hg which is 23lb in a 2” tube or 17.6lb in a 1.75” tube. Bib and others often say it is best to work on length before girth which makes sense as you will have more tissue to try and stretch with a given weight, the max weight you can handle. When the girth increases so does the circumference giving more area to grip with a hanger but there is always proportionatly more inner tissue so it doesn’t help much. However with pumping if you have a lot of girth you can use a wider tube which gives more pull per sq” for a given vacuum, the max vacuum you can handle. This increase in diameter is proportional to your girth increases (a good thing). So could pumping in a lubed tube be equated to hanging? One downside of hanging is that you place it behind the glans so there is a section that is not being stressed at all. The downside of pumping at high vacuum to replicate large hanging weights is blisters etc. If you can fit into both a 1.75” and 2” tube you will get more pull from the 2” tube.

Do any budding physicists have comments? I have ignored friction effects on the tube and the rounding of the glans (I think these non-inline forces cancel out). Have I made some fundamental omission/error. It also shows the need for a wide base on a cylinder at high pressures as it is a lot of equivalent weight/force exerted on your body. If you could take high vacuums shouldn’t your gains be just as permanent as with hanging? They may even be better at a given equivalent vacuum due to the entire penis being subjected to the force.

If pumping in a narrow tube are you really erect? When hanging the penis gets quite thin so I would think this may have to be replicated, could this be where my theory is wrong? does the lateral expansion interfere with the “pulling force”

Please post links if this has been discussed before. I searched and found nothing.

I’m just going to throw this out, and you can do the calculations. Since air pressure works on surface area, wouldn’t you have to figure the surface area of your cock in order to calculate the force on it? Also the force on your cock is working outwards in all directions, not just a pulling force. So to find the surface area of your cock, you will have to take into account it’s length and girth and since it is growing inside the cylinder, the surface area is not constant, but continues to increase.

Thats what I wonder too! Thats what I meant by “I think these non-inline forces cancel out”, don’t know the proper terminology. I was talking of a packed tube but I dont know if an unpacked tube works the same. In a narrow packed tube you wont get much more surface area than if you say glued a coin to the glans which fit exactly in the tube.
Maybe some pumper could check it out, try to lift a known weight up with a pump and see what pressure it falls at. The weight could be anything with a bit of lube to seal it, say vaseline. Then try lifting a rounded weight and see if it is the same.

I am not sure, but I think pressure forces would act perpendicular to the surface so it is pulling the glans out at the sides but when you “vectorise” all the forces it is always the same sum of forces in the upward direction. If you taped a strip of paper to the top of you glans it would increase its surface area but I could not imagine it making any difference to the pull.

Trigger, your reasoning about the pulling or axial force created by pressure in a tube is correct. The axial force is simply the cross sectional area of the tube times the pressure. This axial force on the penis will be 100% at the glans end of the penis and will reduce towards the base if there are sidewall friction forces. At the base of the tube whatever force is not balanced by sidewall resistance on the penis will be pressed against the pubic bone.

Thinking further about the forces on a penis in a vacuum tube. In the above case I was assuming the penis “packed” the tube. If the penis is in a large tube and does not touch the side walls then the axial force on the penis is the cross sectional area of the penis times the pressure. This force is countered by the reaction force in the penis structure.

The whole axial force on the tube is balanced by the pubic bone reaction force at the base of the tube.

Mbuc , So what would 23 inches Hg in 2 inch tube be like on a penis that isn’t really touching the sides? All these calculations take into account that the body(pressurized) is also pushing blood against the penis?

Trigger,

I concur 100% with the caveat that you are packing to tube. If you’re not packing, some of the tugging force will be exerted against the tissues that surround the base of the penis, which get sucked into the tube.

I think pumping gives somewhat less flexibility than hanging as far as positions are concerned. For example, it’s tough to orient the tube so that you exert downward force, as BTC hanging would do.

Another possible downside of pumping is that it tends to engorge the penis. An engorged penis is a much stronger structure than a flaccid one. Therefore, I question whether the force from pumping would have the same effect as hanging on the tissues, even if that force were the same as that used for hanging.

Those objections aside, I think it’s a sound idea.

In the another thread (“pressure in the penis”) I calculated

For a penis of diameter 1.5” with an internal blood pressure of 2.3psi (120mm Hg mercury) then the axial force on the tunica (assuming it takes all the pressure) is 3.14x0.75x0.75x2.3 which equals roughly 4lb. This force must be great enough to fully extend the penis to its erect length.

From experience of hanging in a flaccid condition I can confirm that 4lb is ample to axially stress the penis to the point where the tough fibres of the tunica resist any further easy elongation!

Which explains why pumpers recommend pumping an erect penis - it puts extra force on the penis tissue for the same pumping pressure.

The 23in Hg vacuum is equivalent to 11.3psi so the axial force on a 1.8”dia penis would be 3.14x0.9x0.9x11.3 which is 28.7lb. If it was erect add on the 4lb for the internal blood pressure. NB 23in Hg is a crazy high vacuum and I think any pumper (I don't pump) would say it is way too high