The physics of force transmission in air versus water pumping

The WATER PUMPING > Air Pumping thread has been comparing water pumping versus air pumping. The original poster and others in the thread put forth the proposition that water pumping is better than air pumping. The thread has a lot to say about the how, and the practical aspects of applying the knowledge and experience gained.

The last couple of posts, though:

sparkyx - WATER PUMPING > Air Pumping

capernicus1 - WATER PUMPING > Air Pumping

have been getting me to think about the why - why is water pumping different than air pumping, if the same force is being read at the gauge? Why is it that it “expands the tissues far more effectively at lower vacuum levels” (SparkyX)?

I’ve been thinking about this a lot, and those last two posts have led me to make what seems to be some kind of sense out of this.

My current theory about water pumping versus air pumping is this.

Until now, I’ve been going on the theory that 5 inHg is 5 inHg is 5 inHg, regardless of whether it is air or water. I’m not so sure about that now, for this reason. It occurs to me that creating 5 inHg in air, versus 5 inHG in water, is not the same thing. Since water is much less expandable (or compressible) than air, the 5 inHg you are reading on the gauge is measuring the force you are directly applying to the penile tissues; the force is very closely coupled to the force on the penis itself.

In other words 100% (or nearly so) of the force you are applying is being applied to the penis.

With air pumping, by comparison, air IS more compressible or expandable than water. So, when you are applying 5 inHg on the gauge to your penis in air pumping, some of that force is going to reduce the air pressure, which is turn is coupled (but less directly) to force expanding the penis, as the internal penile pressures meet less resistance to expansion.

Thus, 5 inHg in water pumping is applying more force to the penis than the ‘same’ 5 inHg in air pumping. It may be the same on the gauge, but what it is measuring is different - pure penile-expanding force applied to the smaller volume of just the penis, since the force being applied is doing little to nothing to expanding the water. Compare that to air pumping, where what is being measured is force actually being applied to both air and the penis, which is a greater volume being acted upon, and less force being transmitted to just the penis.

Air is not only more expandable than water; it is more expandable than your penis. Pump your pump, and the air volume will change in the cylinder quite quickly as the vacuum increases. The volume of your penis increases much more slowly in response to the increased vacuum. With water, any increase in vacuum goes directly to your penis, as the force being applied cannot expand the water appreciably.

From the posts earlier cited, ‘milking the tube’ in water pumping is applying 100%, or nearly so, of additional force directly to the penile tissues. ‘Milking the pump’ in air pumping is applying some of that additional force to the penis, but some portion of that force is going to changing the vacuum level of the air.

Great explanation and makes perfect sense.

Wicipedia describes Fluid pressure as follows:
Fluid pressure is the pressure at some point within a fluid, such as water or air.

Daniel Bernoulli developed a formula for determining the pressure within a fluid and basically Bernoulli’s Equation can be used in almost any situation to determine the pressure at any point in a fluid.

Based on the above, it seems to me that there should be no difference between the pressure (vacuum) of air and water.

Lampwick

Very well put, essentially it’s the medium in the tube through which the force is applied that makes the difference, i always think of

what happens when you get air in your brake fluid and the pedal goes spongy and the car wont stop .

The other thing I’m still not sure about though is the effect of the water pressing on the skin surface ?

Does this almost act like pumping in a packed tube if we consider water as a fluid solid ?

An interesting stat with the BathMate Hercules is that it’s capable of a maximum 5hg when air pumping, but 12 hg with water pumping.

I hate science and I’m not going to try to relate this to your theory, but it seems like this may have something to do with what you were talking about.

That would be true, except that the compressibility (or expandability) of water varies markedly from the compressibility (or expandability) of air. If you apply force and try to expand a mixture of tissue and air, you will have much more success than if you try to expand a mixture of tissue and water.

You will expand both the tissue and air with one arbitrary unit of force applied, but if you apply that same arbitrary unit of force to tissue and water, the tissue will expand before the water does; the water is more resistant.

If you really don’t much care about expanding air and the tissue is your real target, any given unit of energy is going to go farther when applied to tissue and water (where the tissue will do most of the expansion) versus tissue and air (where both the tissue and air will respond).

Keep in mind, we’re applying a relative vacuum, so there is no pressure, per se, pressing on the skin surface. The whole purpose of pumping is to reduce the pressure against the skin surface.

The comparison between water pumping and pumping ‘packed’ in a cylinder is an interesting one, and the best comparison I can think of is to picture pumping ‘packed’ in a cylinder where the cylinder is deformable and resizable. That’s what water pumping would be.

I am not an expert of fluid mechanics, but as I recall from high school physics any pressure applied to a fluid in a closed container is felt equally in all directions and on all surfaces. To my way of thinking, 5 inhg applied to any fluid will spread equally to all surfaces at 5 inhg without regard to the composition of the fluid.

However, density is definitely a factor in fluid mechanics. I do know that the amount of force to compress air (or uncompress) is far less than the amount of force required to compress water, which has limited compressability. I know I do not have to suck out anywhere near the volume of water from my tube to reach the same level of perceived pressure on my penis as the volume of air required to reach the same perceived level of pressure. I believe this is the same theory Lampwick described only using different terminology.

Any fluid mechanics experts on board?

The argument would be (as I understand it) : since water expands less than air, your penis will expand more in water, to fill the vacuum, than would happen in air; otherwise said, the ‘gap’ in pressure will be easier filled by air than by your penis.

If you would apply the vacuum in a container of sand, than (if the argument is consistent), at any given pressure your penis will expand more than in water and way more than in air.

Just asking if I got it right.

If so, we have the next frontier : sandpumping!

If you use a hose to draw vacuum by mouth, you can “feel” the difference with your mouth. When drawing air vacuum with your mouth, you can keep going quite a ways up in vacuum force. When drawing vacuum in a water medium, you will find you can only draw a much lower vacuum and it becomes extremely difficult to go past it.

My thoughts on this is the limit in water vacuum is being produced by tunica itself. You will have nice steady draw of vacuum until, boom…you hit a point where it becomes very difficult. I believe that that “wall” is due to the tunica coming to full expansion, and any further would require the tunica to expand past its normal volumn, and that will require a lot more vacuum force to instantly achieve. (of course proper pumping is to use this expansive force over time to begin a slow gradual expansion of the tunica, especially when this force is added to erectile pressures.)

Because there is NO compressibility (and little expandability of water at a set temperature) then the vacuum is directly expanding the penis without any “give” in the medium of transmission, water.

With air, its highly compressible and expandable, therefore you get lots of “give” in the transmission medium.

Hence, water pumpers have found and describe it as “more bang for your buck” or more expansion for the vacuum level used.

Do they are more pumped when go out of the tube?

Very good example.

When there is only fluid in your brake system, the energy is transferred very efficiently to the brake pads, and the car is brought to a stop.

When you get air in the lines, the braking power is reduced to a dangerous level. This is indicating the the air isn’t as capable of transmitting the force as fluid. This is exactly what we experience in pumping.

You can petition the lord with prayer. Petition the lord with prayer. YOU CAN NOT PETITION THE LORD WITH PRAYER!

Oh, sorry. Had a Doors moment there…caused by your post.

Good post, by the way.

Not sure I understand what you are saying Marinera.

If you are asking if I am more expanded when done water pumping at 5 in hg than air pumping for same vacuum and time, I would say yes.

But more important, I believe that the force generated in a given direction is proportional to the surface area effected. If that is true, it would explain why girth is more easily achieved pumping than length. The surface area that is effected in width expansion is far greater than for length. Effectively, its just the end of the glans that provides surface area in the vector of length. With air pumping, it takes a higher vacuum force than most guys can tolerate effectively.

With water pumping, because of the nature of water (non compression, non expansion), far less vacuum levels are sufficient to generate effective lengthening forces. I think the average guy has a much better change of water pumping producing length and girth gains, than with air.

Thats my take on it anyway.

When the penis goes out of the pump, it is more pumped, bigger, fuller? What about gains? I’ve not heard much on that.

Very logical view. Much like the way your disc brakes work on your bike or in your car. Brake fluid is not compressable. Air is. So, if you want your brakes to work, you have to bleed out all the air. Perhaps, instead of water, some other, even less compressable fluid, could be used…something more like brake fluid.