Too many g's?

saracelica

saracelica

Pattern Altitude
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saracelica
Was reading an article online:
http://life.salon.com/2012/01/16/you_wouldnt_believe_how_long_my_flight_was/singleton/

Some of it is sort of weird: but then he wrote: "I’d show you what a 45-degree climb would actually look like, turning you green in the face. In a 60-degree turn, the G forces would be so strong that you’d hardly be able to lift your legs off the floor"

Is that true? I've done 45 degree turns for steep turns but never tried pulling up to climb (at least not more then the 60-80 ft I may have lost in the maneuver)

Discuss?
 
G forces depend on how hard you are pulling and have nothing to do with bank angles.

If you pull hard enough to maintain constant altitude in a 60 degree banked, coordinated turn, then, yea, your legs will feel heavy. But I've been at 90 degrees of bank and near zero G going over the top of a wingover.

For a climb, well, it depends on how hard you pull during the transition. Last time I rode through a hammerhead my brother probably pulled about 3 Gs. But once you are going straight up, you really don't notice the G forces (you get less than 1 G straight back - depends on how much power you have).

Combine the two, and it depends on how hard you pull.

But I've never seen anything exciting happen while riding in seat 32F...
 
The G force chart used in PPL training assumes a level turn. 60 degress will ALWAYS be 2G for LEVEL TURN.
 
60 degree banked turn, holding altitude, should be a 2 g turn. Nothing fancy about that at all.
 
Jaybird180 said:
The G force chart used in PPL training assumes a level turn. 60 degress will ALWAYS be 2G for LEVEL TURN.
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we've been through this a million times but the 60 deg bank will be 2G as long as you're not accelerating and that does not require a level turn.
 
A 60 degree bank means that the vertical component of the force due to the seat pushing on your butt is one half the force itself (cos 60 = 1/2). If that vertical component exactly balances your weight, then according to Newton's second law your vertical acceleration is zero. You could be in a level turn, or climbing or descending at a constant rate. In all three cases, your vertical acceleration is zero.

That total force pushing on your butt is the g-force, i.e. if you were sitting on a scale it is what the scale would read.

Hope this is intelligible, it is off the cuff and I'm tired from arguing with too many students about quiz questions and about why Pluto is no longer a planet...
 
tonycondon said:
we've been through this a million times but the 60 deg bank will be 2G as long as you're not accelerating and that does not require a level turn.
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If you're not accelerating, you're at 1g (by definition).
If you're at 2g, you're accelerating in some direction (by definition).
 
PilotAlan said:
If you're not accelerating, you're at 1g (by definition).
If you're at 2g, you're accelerating in some direction (by definition).
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Perhaps what Tony meant to say is that as long as any climbs or descents are at constant rate, the 60 degree turn will produce 2 g. Obviously there is acceleration in the horizontal(ish) plane.
 
azure said:
why Pluto is no longer a planet...
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Well, that's just wrong. Either it was a planet and still is, or never was a planet and still isn't. It is true that our our current definition of planet no longer encompasses what we now believe we know about Pluto, but it is our knowledge and/or definition that has changed, not Pluto itself! :wink2:
 
In any event, if you can't lift your feet under the 2g load of a 60-degree bank level turn, you need more exercise. And if the 1.4 g's of a 45-degree bank level turn turns you green, you should have chosen more wisely for your preflight breakfast.
 
And then there's the competition turn where you are turning at almost 90° and maintaining altitude. I can't remember how many G's I pull when I do that, so I'll go back up when it's nice and do it again and report back. :)
 
Ron Levy said:
In any event, if you can't lift your feet under the 2g load of a 60-degree bank level turn, you need more exercise. And if the 1.4 g's of a 45-degree bank level turn turns you green, you should have chosen more wisely for your preflight breakfast.
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I’d show you what a 45-degree climb would actually look like, turning you green in the face.
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I think the 45-degree was the climb angle, not the bank angle, but the bank comment still holds!
 
gprellwitz said:
I think the 45-degree was the climb angle, not the bank angle, but the bank comment still holds!
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In most of the airplanes we (non military) pilots are likely to be flying, it takes quite a pullup to achieve a 45 degree climb and during the pitch up, the g force will be high but once established on a constant 45° climb the g force will be one.
 
gismo said:
In most of the airplanes we (non military) pilots are likely to be flying, it takes quite a pullup to achieve a 45 degree climb and during the pitch up, the g force will be high but once established on a constant 45° climb the g force will be one.
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We did a weapons delivery maneuver involving a 4g pull to 45 nose up and then holding that angle until the bomb came off, and yes, after the initial pull-up, the g-force wasn't very exciting. However, the real fun was after the bomb came off -- roll inverted, pull to 30 nose down, roll upright, re-engage the Terrain Following, and hang on.

BTW, that's a "Low Altitude Drogue Delivery," or LADD, used to get an airburst out of a nuke from a low level run-in. The weapon was delivered with a parachute in the tail to give us more time to escape. More accurate weapons systems than the one in the pre-AMP F-111A/E used a "slick" toss delivery that was basically a half-Cuban-8 with the bomb coming off during the pull-up, but our system wasn't smart enough to toss with sufficient accuracy (and no, despite the phrase, "close" doesn't always count in nuclear weapons).
 
Ron Levy said:
We did a weapons delivery maneuver involving a 4g pull to 45 nose up and then holding that angle until the bomb came off, and yes, after the initial pull-up, the g-force wasn't very exciting. However, the real fun was after the bomb came off -- roll inverted, pull to 30 nose down, roll upright, re-engage the Terrain Following, and hang on.

BTW, that's a "Low Altitude Drogue Delivery," or LADD, used to get an airburst out of a nuke from a low level run-in. The weapon was delivered with a parachute in the tail to give us more time to escape. More accurate weapons systems than the one in the pre-AMP F-111A/E used a "slick" toss delivery that was basically a half-Cuban-8 with the bomb coming off during the pull-up, but our system wasn't smart enough to toss with sufficient accuracy (and no, despite the phrase, "close" doesn't always count in nuclear weapons).
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Save my time in Falcon 4.0, I wouldn't have a clue what you're talking about. Must've been neat to do it in real life...save the blood and guts.
 
Diana said:
And then there's the competition turn where you are turning at almost 90° and maintaining altitude. I can't remember how many G's I pull when I do that, so I'll go back up when it's nice and do it again and report back. :)
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The answer potenially is : infinity
or
Whenever you run out of energy
or
Whenever you black out

Whichever comes first.
 
djpacro said:
If there is a G meter in the aeroplane it will read about 0.7.
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Some will some won't (some electronics G meters sense all three axes) but the more important issue is that all the people on board will experience 1g.
 
Diana said:
And then there's the competition turn where you are turning at almost 90° and maintaining altitude. I can't remember how many G's I pull when I do that, so I'll go back up when it's nice and do it again and report back. :)
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Diana, you only need 60 degrees (2G) in competition...any more just unnecessarily scrubs energy...and I don't think the Citabria has energy to burn. :)
 
bbchien said:
Do RV guys still claim to be able to be conscious at 9G's?
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Where did you come up with that one? :confused: Most RV guys...even the ones who do aerobatics refuse to pull more than 3.5-4G.
 
I've experienced +7 / -5 Gs before and it was OK.. It happened pretty fast so I didn't feel bad. However, doing an inverted turn was uncomfortable as it lasted a while.
It is possible to build a tolerance for Gs with practice. It would seem to me that most folks don't have problems with 2Gs
 
bbchien said:
Do RV guys still claim to be able to be conscious at 9G's?
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A buddy of mine who was a Naval Aviator Instructor, said they were limited to 4.5G's for their overhead breaks (in the SE turboprop trainers, the number is escaping me right now, T-6??). Of course the RV drivers would call the Navy guys wusses.
 
Back when I was pulling g's for a living, I could easily pull 4 g's with my g-suit unplugged, but up around 6 g's, the suit became a necessity. IIRC, the Blue Angels and Thunderbirds do some special selection tests and recurrent centrifuge training to ensure the team members can pull 6-9 g's without a g-suit and without blacking out. Of course, even with all that, it doesn't always work -- the evidence suggests g-LOC was most likely the cause of the Blues' fatal crash in SC in 2007 in a plane which goes to 9 g's but not beyond. If someone who isn't going through that level of training and testing says they are pulling 9g's and not blacking out, I'd say...
bs-Flag.gif

If nothing else, stall speed would be about the same as redline in that case (9 g's means it stalls at three times normal Vs), and I doubt an RV has the power to sustain that amount of g-force for more than an instant before it performs an accelerated stall, and maybe not even to get to that g-load due to deceleration as you're pulling.
 
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Instead of saying B.S. can we just be PC and say "highly dubious" or other words to that effect?
 
Ron Levy said:
Back when I was pulling g's for a living, I could easily pull 4 g's with my g-suit unplugged, but up around 6 g's, the suit became a necessity. IIRC, the Blue Angels and Thunderbirds do some special selection tests and recurrent centrifuge training to ensure the team members can pull 6-9 g's without a g-suit and without blacking out. Of course, even with all that, it doesn't always work -- the evidence suggests g-LOC was most likely the cause of the Blues' fatal crash in SC in 2007 in a plane which goes to 9 g's but not beyond. If someone who isn't going through that level of training and testing says they are pulling 9g's and not blacking out, I'd say...
bs-Flag.gif

If nothing else, stall speed would be about the same as redline in that case (9 g's means it stalls at three times normal Vs), and I doubt an RV has the power to sustain that amount of g-force for more than an instant before it performs an accelerated stall, and maybe not even to get to that g-load due to deceleration as you're pulling.
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Our little acro planes can't, of course, sustain high G's like jets can, but they can very well pull 9G, not stall, and not black out the pilot. But we're talking about a quick pull to or from vertical, lasting no more than a couple seconds. Sustained 9G would be tough.
 
It depends how strong you are. If you have a degenerative muscle disease or are somehow else impaired, potentially a level 60* turn producing 2gs could overcome your abilities to move; not for a healthy adult though.
 
whifferdill said:
Our little acro planes can't, of course, sustain high G's like jets can, but they can very well pull 9G, not stall, and not black out the pilot.
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I don't doubt that something like an Extra 300 can snatch a brief 9 g's if it's going fast enough to start with. However, it most definitely can black out the untrained/unprepared pilot.

But we're talking about a quick pull to or from vertical, lasting no more than a couple seconds. Sustained 9G would be tough.
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Tough? I'd say impossible. I'll bet the initial 9-g load drops rapidly during the pitch-up along with the airspeed. I'd be interested to see the data traces on that.

As I said, it would have to maintain over three times Vs with that induced drag load all the way to the vertical in order to maintain 9 g's, and even with 300HP, I don't see that happening.
 
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