Flight Bubble Suit

No, the G force cannot be absorbed by a fluid. The suit has to apply pressure to the lower body to keep blood in the brain.

The blood is pulled "down" by those forces into the "lower" extremities and the brain loses blood and you black out. "Down" is any direction that the plane is accelerating away from. This can even be such that your head is pointed toward the earth if the plane is doing loops.

Wings give the lift to the plane, so even if you want to go down, you turn the plane over and pull the stick back. Don't push it forward, that's less effective.

Pitch forward causes negative Gs and redout, which is the opposite of blackout. Blood vessels actually start bursting.

The body can not handle as much negative G load as positive.

Pitch forward causes vomit, too.

My understanding is that it is not shock loads that cause blackouts. It is sustained high 'G' or centrifugal forces that occur during turns & loops. These can cause the blood to move to the lower extremities of the body & so starve the brain of oxygen hence the blackouts. Current G suits have bladders that compress the legs to force the blood back up the body to offset the effects of high G.

I experienced this once, while flying a two seat aerobatic trainer, without a G-suit.

I pulled 5.5 G's in a turn and a black tunnel appeared in front of my eyes and kept getting smaller. It blocked about half my vision before we came out of it. I doubt it bothered the instructor since he flew F-4's in Viet Nam.

Thanks for the response.

My thoughts came from this: if an explosion happens above ground, a shock wave (air movement) hits an object with a force, you can't see the force,( unless there was debris flying) but you can feel the air movement at a certain distance.

If the same explosion happens underwater, it would seem that the water absorbs some of that same force and the force you would feel might be less.

I don't know if that statement is true or not.

If your on a roller coaster and you make a sharp turn a force ( inertia) another unseen but felt force causes your body to move in a direction ( I don't know if the earth's gravitational forces play a part).

Just like liquid filled shock absorbers dampen force. My thought was that a human suspended in a fluid would feel less of the force because the fluid would dampen the inertia.

No. Shock waves are not the same as inertia. Shock waves try to compress the medium and air is compressible, whereas water is not. Water transfers that energy much better than air.

G-forces can be said to be caused by inertia. A G is the amount of downward force exerted by the earth on a stationary object on the surface.

So, in a tight 5.5 G turn, inertia causes 5.5 times the force of gravity to be exerted on the body, in the direction opposite the turn.

The gravitational pull of the earth has little affect on this, as you see on the coaster.

Underwater explosions are worse than air. The resulting shockwave not only travels faster, but with greater intensity.

Ever see someone fish with dynamite?

"My thoughts came from this: if an explosion happens above ground, a shock wave (air movement) hits an object with a force, you can't see the force,( unless there was debris flying) but you can feel the air movement at a certain distance.

If the same explosion happens underwater, it would seem that the water absorbs some of that same force and the force you would feel might be less.

I don't know if that statement is true or not."

Mythbusters have proven that shockwaves are stronger and deadlier underwater than in air.

Also, a shockwave in the air CAN be seen, if you are standing far enough back. the wavefront compresses the air before it, changing its refractive index. Again, watch Mythbusters, there are explosions where you see the shockwave expanding like a perfect sphere, a beautiful soap bubble that will kill you if you're in its way.

There are experimental suits that use liquid bladders instead of air, but not for the reasons you cite. They are a passive system, I believe.

However, the G-Lock problem is due to blood pooling in the lower extremities, not shock.

G-Suits, or speed jeans, as the pilots call them, squeeze the legs and lower torso with air bladders powered from the aircraft.

The latest USAF system is called Combat Edge. It uses additional bladders to compress the chest and back of the head. I have a complete set of these in my attic.

The chest compression is offset by increasing the air mask pressure so the pilot can still breathe easily.

The neck bladder is used to pull the helmet back so the air mask snugs up on the face to prevent leaks.

Even with these systems G-Loading capacity is still transient. You can't maintain high-G for long and the pilots are trained to contract their abdominal muscles (much like taking a constipated crap) to keep blood from pooling in the lower body.

The F-16 actually reclined the ACES II ejection seat back further (60°) to help the pilot with G-load. The F-22 uses the same seat, but angled it back up closer to 80°.

The JSF uses a Martin-Baker seat that sits at an angle closer to the F-22. I guess seating angle is a compromise between functionality in the aircraft, safe ejection, and G-loading.

"the pilots are trained to contract their abdominal muscles"
You can hear the effort the pilots put into this if you watch in cockpit video from something like the Red Bull air races.

. . . . the "grunt" as it is sometimes called.

In theory, I believe you are correct. Floating in water would have the same effect as a pressure suit. But practically a water suit would likely limit the pilot's mobility more than the inflatable suits the pilots use now. Added weight might also be a consideration.

I don't think that "shock" is the problem but rather the high G forces ( v2 / R ) due to maneuvering the aircraft at high speeds.

After reading the responses, I realize my articulations were not correct. I came to this thought because as aerospace technology increases, planes would be accelerating, turning and decelerating quicker. A pressure suit has limitations. The liquid idea came from thinking how an astronaut moves in a vacuum,.

So would a pilot have better control in a pressure suit while he was encased in a vacuum bubble ?

No. Inertia/acceleration works in a vacuum or in space, just as it does on the surface of earth or the seat of an airplane.

Exactly, in space you just have a separation between 'weight' and 'mass.' In 'zero-Gee' a single astronaut could push on a ton of metal and start it moving, v-e-r-y s-l-o-w-l-y. And if said astronaut gets pinned between that mass of metal and his ship, it will crush him to death, v-e-r-y s-l-o-w-l-y.

Wouldn't said astronaut also launch themselves rapidly in the opposite direction?

If said astronaut were drifting towards the ton of metal, and used only his own limbs to push, then yes, he would 'push himself away' without affecting the ton of metal much⁽¹⁾, but if he had an EVA pack and could control himself with thrusters, than he can 'thrust' against the ton of mass and start it moving.

Notes:

1. Let A = the mass of the astronaut, let M = the mass of one ton of metal, and let F = the force the astronaut can apply. The astronaut gains [ F * (M/(M+A)) ] in momentum, the ton of metal gains [ F * (A/(M+A)) ] in momentum(2).
2. Since M >> A, [ M/M+A ] is close to 1, and [ A/M+A ] is close to zero. So without some external force to aid, (Or the hull of a multi-ton spaceship to push off of, the astronaut will me pushing himself 'away' from the ton of metal.
   

Nope. You need to learn more about the physics of inertia.

The solution the USAF is turning to is autonomous and remote piloted vehicles. G limits are now only limited to the airframe.

Secondly, the aerial dogfight is pretty much a thing of the past. Yes, pilots still train for it, but air-to-air (AA) missile technology is getting so good that most action happens beyond visual range (BVR).

The game has changed so much now that it really isn't maneuverability that counts; it's who sees who first.

The latest crop of AA missiles are so good that they are essentially unescapable if fired within the limits of their range.

Missile evasion isn't so much about high-G maneuvers as it is about spoofing the missile's targeting sensors.

Interesting idea, even if it may not be practical.

If the pilot was totally submerged in a rigid "tank" with scuba gear, then under high G, I believe, it would be equivalent to diving to about 150ft for 5 G. The blood could not pool in the legs because the G force would also increase the H2O pressure on his legs (and body). The pressure differential from head to toe would remain approximately constant.

Drones are the real answer - the remote pilot is immune to the G forces.

Sorry, no. In the unlikely event of a centrifuge being operated 150 feet underwater, the generation of 5G would have the same effect on the human body as on the surface. The blood would still pool in the periphery.

fill the centrifuge with water - the blood vessels will have an external pressure developed equivalent to the "pooling effect" - just like a G suit.

No. The pressure in the water will be homogeneous.

A G-suit does not provide homogeneous pressure over the whole body, just the areas that have the air bladders.

That is the whole point! - ref Libelle g-suit or Dragonfly suit. A fluid "filled" G-suit.

There are also references to fluid filled suits that theoretically could allow up to 20 g's - though I am sceptical they would be practical, since even with a "neck down" suit increasing G's in the suit would require a compensating increase in air pressure to stop the chest from being collapsed. - OK, pressure breathing is part of existing pneumatic suits also.

Blood goes to the feet because the air pressure does not have the same density as water / blood - so the blood vessels expand with the increasing G's - the Libelle is passive and with the fluid in the suit the response is instantaneous. The pressure exerted by the fluid increases proportional to the G force.

Come on folks - do some basic physics here!

I am compelled to correct you.

Your original statement regarding fluid was: "If the pilot was totally submerged in a rigid "tank". #13

Later you say, "fill the centrifuge with water" #22

Not until. #30 do you finally, incorrectly refer to "A fluid "filled" G-suit".

In reality, "Two fluid "muscles" - are routed vertically on the front side of the g-race suit and two are routed vertically on the rear side of the g-race suit."

So, you have taken a very circuitous route to arrive at your admonition to," not be hide bound by preconceived ideas".

For those curious enough to do some research and not be hide bound by preconceived ideas:

http://www.fzt.haw-hamburg.de/pers/Scholz/dglr/hh/text_2010_01_28_Pilot_G-protection.pdf
New Concepts in Pilot G-Protection.
Also look up G-Race Suits.

That looks like the passive liquid system I remember years ago (Libelle).

However, it functions just like any other G-suit by compressing the lower body extremities. It's just how this is done that is different.

Rather than compressed bleed air from the aircraft, a liquid encased "muscle" is used inside the flight suit. The walls of the lined suit are fairly ridged, but will bulge when G loading is applied.

High G simply forces more liquid to the lower extremities of the suit, which compresses the legs and abdomen.

If you ever swung a water balloon around your head you would see the water tends to move and budge the balloon at its bottom as centripetal force increases. That is all that is happening inside the liquid G-suit.

Note, that immersion inside a tank of water does not induce the same effect as Libelle.

The big advantage (at least claimed) is increased comfort at high G, making high G less taxing, but it comes at a price.

Significant training is required to use the suit without reverting to learned or instinctive anti g-straining maneuver (AGSM), which negates the effect of the suit. This has been a setback for the Libelle liquid suit.

As G-loading increases, the body reaches a point where a natural fight-or-flight reaction causes pilots to revert to using AGSM. Under combat conditions this becomes a real problem and can lead to dangerous adverse effects.

From what I have heard the liquid suit is close to performance to the Combat Edge suit used by the USAF. The delta in performance is not great enough to warrant displacing the Combat Edge system.

So, the Libelle suit is not a panacea for G-LOC. Like any system it has its advantages and disadvantages and all systems have limits that are close in performance envelopes to each other.

Note, that immersion inside a tank of water does not induce the same effect as LibelleWhy? Please explain your difference of opinion as it is counter to the references given.
The suit provides a "casing" that the hydrostatic force works against - it is passive and uses the G force to increase the pressure against the legs. Full immersion of the legs in a rigid casing (radially and longitudinal) will achieve the same result. If a suit provided fluid level (bladders or whatever) including the legs and abdomen the same affect will include the abdominal cavity. If you include the chest, then pressure breathing will have to be added to prevent compression of the lungs.
If the fluid medium had a higher specific gravity than blood, then you would actually squeeze the blood out of the legs under high G forces. The whole mechanism is the basis of separating materials of different densities in a centrifuge - the lower density material will "float" above the higher density - if the densities are the same no separation takes place.

Total immersion in a tank would act equally on all body parts at the same time.

That is not what you want. You want to provide greater pressure at the points where the blood pools down to (lower extremities).

The Libelle suite is not a tank, it is a sack. Two completely different structures.

The Libelle suit is not ridged, per se. The exterior of the suit is less flexible than the interior so that it can squeeze the lower extremities.

The whole point of a G-suit is to apply a substantial differential pressure, securing a high pressure in the legs and torso relative to the upper body. Filling the centrifuge with water would not achieve that differential.

I know how to solve this. Unmanned the air craft, armed the drone and get ready for war.

Why not use this technology, that is already tested effective.

You are sick, sick, sick!

And, you are not funny, at all!

You see I'm not smiling at all. Seriously, not sick at all.

If you would examine carefully the biological design, you'll find the best technologies are there.

Your vision does not appear erratic unlike cameras when in touch to mechanical vibration because eventually vibrations are damped from point of contact to the eyes.

Babies in the uterus are carefully damped from harsh vibrations (external forces) in the way they are in cased in the placenta. At least if the mother is in touch with unwanted vibration or say riding a car or walking, it can not effect in the inside that much.

The wonders of design is in nature, how am I being sick pointing out technology that would fit requirements?

Your ignorance is showing!

This thread has NOTHING TO DO WITH VIBRATION DAMPING!

If you want to neutralize g-force, everyone knows it has to be damped unless otherwise you want the pilots head to dumped it all up, you see 'im not smiling at all. I mean serious

I'm done with you!

"Do not answer a fool according to his folly, or you yourself will be just like him."

Proverbs 26:4.

Well, I am surprised

Maybe because the rest of us don't have a loose brain ? Does your heart not go out to the poor creature ?

The "poor creature" is an id10t.

How many 'G's does the average expectant mother experience?

I have no clue of the value - the fact is fetus are pretty sensitive and delicate.

We'll ask the R&D (if we get free access) which should be confidential from public.

I'm not sure which R&D you propose to ask.

It would be wholly unethical to subject pregnant women experimentally to acutely increased G forces, not least because you can't ask permission of the foetus, and I am not surprised to find nothing in the scientific literature.

However, I have found one test on a crash dummy constructed to resemble a pregnant mum. The conclusion was that "Energy transmission can be measured in terms of both abdominal force and acceleration within the fetal head and thorax. This new dummy demonstrates substantial transmission of energy..."

Is the goal to crash? I think its quite a different use. Who say's literally pregnant woman are to be tested?

Common sense dictates- that's the marvel of engineering. IdeaSmith has nothing to do with this, anyway

Ever read the owner's manual regarding placement of lap and shoulder belt for pregnant women?

Lap belt is to be placed at HIPS, shoulder belt ABOVE fetus/baby.

Thanks for the responses from everyone.

When I get responses, I like to reply, that way I feel like I'm part of the conversation.

A. The post had nothing to do with pregnant women, if I was going to post a picture of a placentia, or a child in vitro, I would have chosen something with the technical aspect of JAMA, not a picture that looks like it came from Mosby's textbook for nursing assistant's.

B. The interesting aspect of Proverb 26:4 is that it, is a universal truth and I would bet that it would be a quote able quote and every known philosopher has their own version of the same.

C. I wasn't exactly thinking of the military applications but if manned operation has reached it's zenith and the next course is autonomous, then that doesn't explain why military planes are so large unless constraints are fuel, and operational control systems, especially when a relatively inexpensive device can ground a very expensive one.

I really like this site, when I post a question, I get an answer that " explains " the how and why of the subject, unfortunately the responses lead to more curiosity and research and education and training and I think I need another aspirin.

I am late to the show, but I am surprised that I did not see anyone insert the concept of the relative merits of using of a (slightly) heavier liquid than water to enhance the compression effects of the surrounding pressurizing fluid.

The suggestion for a higher specific gravity fluid was suggested in post 35.

Most posters cannot see past the pneumatic suits.

"Most posters cannot see past the pneumatic suits."

Well, you are not supposed to wear them over your head.