10g without g-suit
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10g without g-suit
Folks, question from a non-flying type. I was watching TV last night and saw a great programme about the Red Bull Flying Race (piston aerobatic aircraft low level around an obstacle course). At one stage one of the pilots was pulling 9.8 g, I presume without a g-suit. I thought 10g without the suit was well within the g-loc envelope (reference the recent Blue Angels thread where the lack of a g-suit was suggested as a contributory factor). But then again the g would be for a short duration. Can you suffer g-loc if the g is for (say) only 4-5 seconds.
I was also wondering what is involved in fitting a g-suit facility to a small aircraft. I presume you need a source of pneumatic pressure. How is this achieved in a modern FJ.
Finally, I assume many of the Red Bull types are ex-military. What is it like to 'step down' from a Red Arrow to a Red Bull. It it like handing over the keys to the company jag only to drive the wife's Fiesta home.
I was also wondering what is involved in fitting a g-suit facility to a small aircraft. I presume you need a source of pneumatic pressure. How is this achieved in a modern FJ.
Finally, I assume many of the Red Bull types are ex-military. What is it like to 'step down' from a Red Arrow to a Red Bull. It it like handing over the keys to the company jag only to drive the wife's Fiesta home.
looking at the manoevreability of the Red Bull racing aircraft, I would think it would be more like handing over the keys to the wife's Fiesta and driving the McLaren of Lewis Hamilton home.
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9 Litre, 6-cylinder horizontally opposed, 344hp Lycomings in 530kg of aircraft means massive power to weight ratios, better than most fighters.
Someone please buy me one
Someone please buy me one
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G-LOC can occur at relatively low Gz. Variables such as pilot fitness, previous G-loadings (eg negative Gz just prior to positive Gz will need less positive force to produce grey/black-out), and most importantly length of time sustaining a particular load, will affect when a person G-LOCs. I'd have thought that the Red Bull pilots sustain the G-load for quite a short time, pre-stain their muscles (to slow the flow of blood away from the brain), and have light-weight flying kit (such as no helmet, goon bag, LSJ etc) which puts less of a strain on the neck and torso.
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The g-force experienced by the 'stunt' pilots are very considerable very high! They dont need to wear a g-suit because they only experience this sensation for a short period of time.
Remember all their aircraft ie the various Extra 300's etc are piston aircraft with a whooping great big engine and prop that produces an immense amount of torque. This is why many of these aircraft have a thrust to weight ratio sometimes exceeding 1:1 ie 2:1 for example. Also remember that the aircraft have near to no weight in them. The only real heavy part of the a/c is its 'scaffolding' which is stressed to high heaven and capable of withstanding the high 'g'. Although the 'g' experienced is high, it is not sustained so the blood loss is very quick, however the manouvre is split second in some cases and so the body is quick to recover.
Unlike fighter pilots in jets they need a g-suit because the magority of the time they are under sustained 'g' ie for a lengthy period of time in some cases for a few minutes or so. Therefore, although they may not be pulling 7,8 or 9g they will pull 3, 4 or 5g for a longer period of time. It is because of this that they need the g-suit to prevent blood loss from the brain (cranium) and torso pooling to the lower limbs such as the feet. So, the g-suit is set to approximately 2 - 3g and inflate like when you have your bloodpressure checked by the doctors, it stops the blood flow from running and in doing so it keeps the blood at where it is, esuring that the vital organs such as the brain and heart have the blood when its needed.
The reason you get black out, is because the blood has been 'drained' from your upper body starting with your brain, making you feel woosy and lightheaded, then it 'drains' from your eyes, now you start to lose your poriferal - spelling? vision, which now encroaches on your forward vision getting smaller and smaller. You are now experiencing 'tunnel vision', however you cant see the light at the end of the tunnel and so it closes in on you and you pass or 'blackout'.
Remember all their aircraft ie the various Extra 300's etc are piston aircraft with a whooping great big engine and prop that produces an immense amount of torque. This is why many of these aircraft have a thrust to weight ratio sometimes exceeding 1:1 ie 2:1 for example. Also remember that the aircraft have near to no weight in them. The only real heavy part of the a/c is its 'scaffolding' which is stressed to high heaven and capable of withstanding the high 'g'. Although the 'g' experienced is high, it is not sustained so the blood loss is very quick, however the manouvre is split second in some cases and so the body is quick to recover.
Unlike fighter pilots in jets they need a g-suit because the magority of the time they are under sustained 'g' ie for a lengthy period of time in some cases for a few minutes or so. Therefore, although they may not be pulling 7,8 or 9g they will pull 3, 4 or 5g for a longer period of time. It is because of this that they need the g-suit to prevent blood loss from the brain (cranium) and torso pooling to the lower limbs such as the feet. So, the g-suit is set to approximately 2 - 3g and inflate like when you have your bloodpressure checked by the doctors, it stops the blood flow from running and in doing so it keeps the blood at where it is, esuring that the vital organs such as the brain and heart have the blood when its needed.
The reason you get black out, is because the blood has been 'drained' from your upper body starting with your brain, making you feel woosy and lightheaded, then it 'drains' from your eyes, now you start to lose your poriferal - spelling? vision, which now encroaches on your forward vision getting smaller and smaller. You are now experiencing 'tunnel vision', however you cant see the light at the end of the tunnel and so it closes in on you and you pass or 'blackout'.
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Thanks for that detailed explanation of the workings of the G-suit 4LX. It has cleared a few things up in my mind that have been niggling away at me for a while now.
I attended a seminar a couple of years back on AEA & SE in Munich; there a GAF pilot (Mig) presented an alternative to the pneumatic G suit, it was filled with water. Has anyone come across this before or since? There was a lot of raised eyebrows about it's capability in high G situations, anyone care to expand?
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Thanks for that detailed explanation of the workings of the G-suit 4LX. It has cleared a few things up in my mind that have been niggling away at me for a while now.
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Yes (Could be the last?), I have come across the ‘hydraulic’ liquid water suit you speak of and have actually been fortunate enough to see and feel how it works. Probably not the exact model you have seen or speak of, but one that I’m sure is very similar, both based on the same concept.
Basically the hydraulic g-suit technology is primitive therefore still in it development, testing and evaluating stages at the moment and unlike the pneumatic g-suit which as you rightly infer uses compressed air, the hydraulic technology uses liquid for the same role. As with all new products they both have their advantages and disadvantages.
I think the whole idea is not just for g-suit capability. I have heard and seen developments in the technology and idea which is to also use the liquid or ‘hydraulic fluid’ as a cooling agent for the pilot’s body.
http://www.demon-tweeks.co.uk/produc...Cooling+System
We all know and have felt the ‘greenhouse’ effect in the cockpit. The idea comes from the underclothing suit that Formula 1 drivers wear directly as a first layer on their skin (like long johns) when driving for lengthy periods of time in a small and cramped space (like fast jet cockpits) to prevent their body from overheating thus keeping the body at a constant temperature. Remember that it is the body’s core temperature that is most important and if you can’t regulate heat to keep you or your internal organs warm or fluid to cool yourself you are in deep trouble. Especially, if your core temperature rises or falls by just a few degrees.
Naturally the human body uses up energy especially with regulating body temperature evident with sweating or ‘perspiring’ when you’re hot, or shivering i.e. generating heat through friction when you are cold. The new suit will do all that for you and the g-suit bit aswell! Impressive or what! This in theory will take a load of work off your body and so your energy is not burnt up keeping you warm or cool, thus increasing the indurance of pilots to essentially fly for longer periods of time although there are obviously limits on how many hours you can fly on the trot, like lorry drivers must sop and rest after every 4 ½ hours for a 15 min minimum break or so, it also means that the pilot can concentrate more with what’s in front of him. In this sense the suit is an asset to aviation and may in fact save lives in the future. ‘We have but just touched the surface’.
Where I think it has its flaws is if you can imagine a shoelace being wrapped very quickly and tightly round your legs and arms getting tighter and tighter as you increase the number of g. Rather painful im sure you would agree. This as near as possible as how to explain its sensation. Its quite uncomfortable and somewhat uncomfortable. It still incorporates Nomex fire retardant proofing etc essential and vital safety feature.
Unlike the current g-suit which inflates, distributing its pressure over a larger surface area thus it is not as painful. However, im sure the hydraulic g-suit is more capable and efficient.
Again as with all products they have their advantages and disadvantages, there is still room for improvement and it is (the technology that is) still in its concept stages at this present time is rather primitive but sure looks very effective, if not somewhat painful. Im sure we haven’t heard the last of it. But all good things come to an end.
Sorry for the long post peeps, alot to talk about lol.
Al
Basically the hydraulic g-suit technology is primitive therefore still in it development, testing and evaluating stages at the moment and unlike the pneumatic g-suit which as you rightly infer uses compressed air, the hydraulic technology uses liquid for the same role. As with all new products they both have their advantages and disadvantages.
I think the whole idea is not just for g-suit capability. I have heard and seen developments in the technology and idea which is to also use the liquid or ‘hydraulic fluid’ as a cooling agent for the pilot’s body.
http://www.demon-tweeks.co.uk/produc...Cooling+System
We all know and have felt the ‘greenhouse’ effect in the cockpit. The idea comes from the underclothing suit that Formula 1 drivers wear directly as a first layer on their skin (like long johns) when driving for lengthy periods of time in a small and cramped space (like fast jet cockpits) to prevent their body from overheating thus keeping the body at a constant temperature. Remember that it is the body’s core temperature that is most important and if you can’t regulate heat to keep you or your internal organs warm or fluid to cool yourself you are in deep trouble. Especially, if your core temperature rises or falls by just a few degrees.
Naturally the human body uses up energy especially with regulating body temperature evident with sweating or ‘perspiring’ when you’re hot, or shivering i.e. generating heat through friction when you are cold. The new suit will do all that for you and the g-suit bit aswell! Impressive or what! This in theory will take a load of work off your body and so your energy is not burnt up keeping you warm or cool, thus increasing the indurance of pilots to essentially fly for longer periods of time although there are obviously limits on how many hours you can fly on the trot, like lorry drivers must sop and rest after every 4 ½ hours for a 15 min minimum break or so, it also means that the pilot can concentrate more with what’s in front of him. In this sense the suit is an asset to aviation and may in fact save lives in the future. ‘We have but just touched the surface’.
Where I think it has its flaws is if you can imagine a shoelace being wrapped very quickly and tightly round your legs and arms getting tighter and tighter as you increase the number of g. Rather painful im sure you would agree. This as near as possible as how to explain its sensation. Its quite uncomfortable and somewhat uncomfortable. It still incorporates Nomex fire retardant proofing etc essential and vital safety feature.
Unlike the current g-suit which inflates, distributing its pressure over a larger surface area thus it is not as painful. However, im sure the hydraulic g-suit is more capable and efficient.
Again as with all products they have their advantages and disadvantages, there is still room for improvement and it is (the technology that is) still in its concept stages at this present time is rather primitive but sure looks very effective, if not somewhat painful. Im sure we haven’t heard the last of it. But all good things come to an end.
Sorry for the long post peeps, alot to talk about lol.
Al
CBTL, IIRc the german typhoon gsuit is a liquid filled (dont think it's water) g-suit. These have the advantages of not needing an aircraft water supply, being instantly reactive and you can drink the fluid in a survival situation! Downside is that they are heavy to wear (although the overall weight for the a/c is similar to the pneumatic system) and are somewhat prone to accidental puncture which leads to embaressing effects!
As for the red bull racers, the summary is correct, they "snap" lots of Gz, but even though blood may drain from your brain, your brain cells are sufficiently oxygenated to allow for 2-3 seconds of useful consciousness prior to the onset of blackout/g-loc, no matter how much G you pull. The sustained cornering is done at a lower g.
And iirc, most of the pilots involved are not ex-military at all. Most have been professional aerobatics pilots for quite some time (hence the age of most of them - compare the red bull lineup to an F1 lineup!)
Fantastic sport, shame about the uk one last year!
As for the red bull racers, the summary is correct, they "snap" lots of Gz, but even though blood may drain from your brain, your brain cells are sufficiently oxygenated to allow for 2-3 seconds of useful consciousness prior to the onset of blackout/g-loc, no matter how much G you pull. The sustained cornering is done at a lower g.
And iirc, most of the pilots involved are not ex-military at all. Most have been professional aerobatics pilots for quite some time (hence the age of most of them - compare the red bull lineup to an F1 lineup!)
Fantastic sport, shame about the uk one last year!
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This Link:
http://www.virtualsciencefair.org/20.../Research.html
Provides an explanation of the initial Franks' water filled anti-G trousers and what has followed.
lm
http://www.virtualsciencefair.org/20.../Research.html
Provides an explanation of the initial Franks' water filled anti-G trousers and what has followed.
lm
Per Ardua ad Astraeus
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There is a tendency to get confused over the function of a g-suit. As I posted on the Blue Angel's thread, unless g-suits and the human body have changed drastically since my military days (ok - I KNOW my body has
) the main function of the suit is to reduce fatigue caused by prolonged and frequent applications of high g, which are commonly experienced in the 'average' day of up to 4 sorties in a fighter. By reducing the effort the body has to generate to combat the g they thus make you less tired. I cannot recall the 'increase' in g-threshold with a suit, but I think it was only of the order of 1-1 1/2g, and I further think that seating the pilot in a prone position has a greater effect on g-threshold, but that is outside my experience.
To further the 'water' line, I seem to recall a Russian experiment with a water filled cockpit in which up to 20 g were sustainable by a suitably 'oxygenated pilot'.
Light a/c aerobatics rarely have sustained high g, whereas in jet combat it was not unusual to sustain 4-5 g for many seconds - and that is exhausting even with a suit. The BAe Lightning could sustain a 6g turn for a long time (until the fuel ran out) - ok, 2 minutes, then
) the main function of the suit is to reduce fatigue caused by prolonged and frequent applications of high g, which are commonly experienced in the 'average' day of up to 4 sorties in a fighter. By reducing the effort the body has to generate to combat the g they thus make you less tired. I cannot recall the 'increase' in g-threshold with a suit, but I think it was only of the order of 1-1 1/2g, and I further think that seating the pilot in a prone position has a greater effect on g-threshold, but that is outside my experience.To further the 'water' line, I seem to recall a Russian experiment with a water filled cockpit in which up to 20 g were sustainable by a suitably 'oxygenated pilot'.
Light a/c aerobatics rarely have sustained high g, whereas in jet combat it was not unusual to sustain 4-5 g for many seconds - and that is exhausting even with a suit. The BAe Lightning could sustain a 6g turn for a long time (until the fuel ran out) - ok, 2 minutes, then
Some years back I had an interesting conversation with my wifes uncle, who had been a Spitfire pilot late in WW2.
I was telling him about an anti-g suit displayed at Duxford, used in the Mustang, and how surprised I was that they had them.
He said that he had trialled one and that it was water filled.
As mentioned by a post above, his mates were not particularly kind to him when he came back from a trip where they encountered 109's and one of the bladders had burst!
Amazing how nothing is new in aviation!
lsh.
I was telling him about an anti-g suit displayed at Duxford, used in the Mustang, and how surprised I was that they had them.
He said that he had trialled one and that it was water filled.
As mentioned by a post above, his mates were not particularly kind to him when he came back from a trip where they encountered 109's and one of the bladders had burst!
Amazing how nothing is new in aviation!
lsh.
Reacher: Essentially it works in the same way as your traditional 5 bladder pneumatic suit. The difference is that the liquid is there the whole time, but more spread out. When you pull g the liquid is forced into parts of the suit that are designed to put pressure on your lower extremities, trapping the blood in your upper body (by preventing venous pooling). The challenge is to design a suit that does this without massive quantities of liquid, thus making it prohibitively heavy. This is where the germans have succeeded by using a liquid designed for the task (we suspect some kind of weak beer...)
BOAC: A standard 5-bladder anti g suit as used by majority of the RAF FJ community does indeed "add" 1 to 1.5 g onto your basic g tolerance. However, it tends to have a slightly better effect than this, as it "reminds" you to strain, even for lower g antics where you might get caught out on a bad day(around the 4 g mark). In addition it gives you something to strain against, rather than having to artificially tense your muscles, which is hard to do effectively. However, as you said, it's primary effect is to reduce fatigue when exposed to high g for long periods. However, more modern equipment (combat EDGE and the typhoon g-suit/vest) add considerably more to ones basic g tolerance. Typhoon in the UK has full coverage anti-g trousers, pressure breathing combined with a pressure vest, which allows a (nearly!) relaxed 9g, so very effective. Had the pleasure of seeing it in action in the centrifuge and it's great to watch. (Although apparently makes your feet hurt like hell!)
BOAC: A standard 5-bladder anti g suit as used by majority of the RAF FJ community does indeed "add" 1 to 1.5 g onto your basic g tolerance. However, it tends to have a slightly better effect than this, as it "reminds" you to strain, even for lower g antics where you might get caught out on a bad day(around the 4 g mark). In addition it gives you something to strain against, rather than having to artificially tense your muscles, which is hard to do effectively. However, as you said, it's primary effect is to reduce fatigue when exposed to high g for long periods. However, more modern equipment (combat EDGE and the typhoon g-suit/vest) add considerably more to ones basic g tolerance. Typhoon in the UK has full coverage anti-g trousers, pressure breathing combined with a pressure vest, which allows a (nearly!) relaxed 9g, so very effective. Had the pleasure of seeing it in action in the centrifuge and it's great to watch. (Although apparently makes your feet hurt like hell!)
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pba_target,
Typhoon pilots can wear an optional pair of foot-bladders to protect the feet from discomfort. Not everyone finds the foot-discomfort a big problem, and then it is usually confined to the +7Gz-+9Gz levels of exposure. That said, I 'popped' a vein at the rear of one of my toes when assessing Combat Edge, which has no foot protection, and it felt, and looked, most unpleasant.
Widening the discussion, the most usually voiced complaint when discussing 'High +Gz Manoeuvring' is arm-discomfort/arm-pain. Same reason as for the feet, high hydro-static pressures in the venous system. Libelle, the garment being assessed by the Luftwaffe, protects the arms. However, as usual, whilst a solution resolves one problem, it introduces other problems of its own.
lm
Typhoon pilots can wear an optional pair of foot-bladders to protect the feet from discomfort. Not everyone finds the foot-discomfort a big problem, and then it is usually confined to the +7Gz-+9Gz levels of exposure. That said, I 'popped' a vein at the rear of one of my toes when assessing Combat Edge, which has no foot protection, and it felt, and looked, most unpleasant.
Widening the discussion, the most usually voiced complaint when discussing 'High +Gz Manoeuvring' is arm-discomfort/arm-pain. Same reason as for the feet, high hydro-static pressures in the venous system. Libelle, the garment being assessed by the Luftwaffe, protects the arms. However, as usual, whilst a solution resolves one problem, it introduces other problems of its own.
lm
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Water G-Suits
My father was an FAA engine fitter, WW2;
He was with Seafires at Lee on Solent ( Daedalus ) when the a/c were 'spotting' for warship fire on D-Day; the pilots were wearing water filled anti-g-suits.
This was the first time they'd been seen, at least by Dad ( who is still with us, I just nipped & asked as I remembered him mentioning it before ! )
The suit basically consisted of trousers & waist, & was filled with hot / warm water before flight.
Pretty sure it was 4th Fighter Wing, anyway 897 Sqn was definitely involved.
He was with Seafires at Lee on Solent ( Daedalus ) when the a/c were 'spotting' for warship fire on D-Day; the pilots were wearing water filled anti-g-suits.
This was the first time they'd been seen, at least by Dad ( who is still with us, I just nipped & asked as I remembered him mentioning it before ! )
The suit basically consisted of trousers & waist, & was filled with hot / warm water before flight.
Pretty sure it was 4th Fighter Wing, anyway 897 Sqn was definitely involved.