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GR142-Pipper
01-20-2006, 12:30 AM
One issue that hasn't been discussed much is the correct modeling of negative G's. Typically, the maximum amount of negative G's a pilot can withstand is about -3. I can you it is very uncomfortable even at the -2 to -2.5G level (a different kind of feeling and far more unpleasant than +6 or +7). It appears that many of the aircraft and/or pilots modeled in this game can certainly withstand a great deal more than -3. I've witnessed extended push-aways as a defensive tactic that certainly appear to have exceeded this.

What say the forum?

GR142-Pipper

GR142-Pipper
01-20-2006, 12:30 AM
One issue that hasn't been discussed much is the correct modeling of negative G's. Typically, the maximum amount of negative G's a pilot can withstand is about -3. I can you it is very uncomfortable even at the -2 to -2.5G level (a different kind of feeling and far more unpleasant than +6 or +7). It appears that many of the aircraft and/or pilots modeled in this game can certainly withstand a great deal more than -3. I've witnessed extended push-aways as a defensive tactic that certainly appear to have exceeded this.

What say the forum?

GR142-Pipper

FritzGryphon
01-20-2006, 07:38 PM
Since the screen never completely reds out, nor do you lose control from redout, the maximum negative G is unlimited.

darkhorizon11
01-20-2006, 08:00 PM
Not perfectly, but they're pretty good, a full redout is impossible but at least its modeled.

The real G problems are the fact that most aircraft aren't modeled for structural stress!

GR142-Pipper
01-21-2006, 01:19 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by FritzGryphon:
Since the screen never completely reds out, nor do you lose control from redout, the maximum negative G is unlimited. </div></BLOCKQUOTE>Just as I suspected as I couldn't get full redout to occur either. Deliberate high -G push aways just don't occur in real life but I see it every day on the servers. This really is a serious FM modeling flaw.

GR142-Pipper

Ugly_Kid
01-21-2006, 07:15 AM
Disagree wholeheartedly. Firstly negative g-manouvers are used and human tolerance is not that limited. In aerobatic competitions pilots fly programs from -10 to +12 g.

Also the following evasive manouver is hardly usable in the game:
http://koti.mbnet.fi/hausberg/sim_stuff/hartmann.jpg
It was used by not so unknown pilot in RL.

Currently, the game allows actually only very moderate gee levels and the application of the gees takes a very long time, response is like glued.

Here is a short test, Bf-109G-2 and P-51D I started from about 300 km/h and 3km altitude. I did testing with and without full forward trim and with P-51D only with trim.
http://koti.mbnet.fi/hausberg/sim_stuff/negativeg.jpg

As it can be seen allthough having a normally very effective elevator P-51 does not reach more than 4 g with all the means possible. Without use of trim one hardly gets -2 g. So there is hardly a point where you reach a structural limit. This is actually completely opposite of what is indicated here. Do you people test at all or just open topics?

FritzGryphon
01-21-2006, 03:31 PM
Ugly_kid, the fact that negative G is less than positive G is not surprising. These are not aerobatic planes with symmetrical airfoil, nor can the pilot push as hard as he can pull.

I'm sure you could get higher negative loading if you used a higher speed.

Also, for that nose over manuever, anything less than 0G would produce the desired effect of the enemy floating in his seat, and unable to aim properly.

Ugly_Kid
01-21-2006, 04:20 PM
Airfoil has actually less to do with this. The elevator usually provides downforce so the natural tendency of the aircraft is to dip the nose. Therefore, in the first approach, the elevator hardly needs to be less effective in push than pull (unless the control surface movement is different up and down - also pilot is typically not more limited in push than pull) You wrote earlier that negative gees as in the game are "unlimited" - they are not, as we can see. Without using the trim, already maintaining inverted level flight is somewhat laborous - so again, I don't really see the game portraying elevator anywhere as a too effective for negative gees - quite on the contrary.

You would not get higher negative gees if you used higher speed, as is, the speed gets already pretty high (the said 300 km/h is only the starting speed). The elevator effectivity drops with raising speed. You'll notice this also with positive gee manouvers, the blackout occurs easiest around 400-500 km/h. You can try yourself to produce higher gees, devicelink is available to everyone, I don't think you get there.

As for the nose over manouver - it still needs to be sufficiently rapid, otherwise chaser'll simply roll and follow you in a positive g manouver. That was actually one reason where injection engines had the defenitive advantage over the carburators. As it is, there is hardly any advantage that one could use. Also, here in the game, the negative half looping usually leads to you getting too fast, loosing too much alt and that results in a smoking hole.

GR142-Pipper
01-21-2006, 05:59 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Ugly_Kid:
Disagree wholeheartedly. Firstly negative g-manouvers are used and human tolerance is not that limited. In aerobatic competitions pilots fly programs from -10 to +12 g. </div></BLOCKQUOTE> Respectfully, I just don't believe that for a minute. Anything over -3G is extremely (repeat extremely) uncomfortable to the point that the pilot can't function.

GR142-Pipper

Ugly_Kid
01-22-2006, 12:39 AM
It's not a matter of belief. You might find this, for example, interesting:

http://www.petermaass.com/core.cfm?p=1&mag=8&magtype=1

Firstly about Sukhoi:
"A Sukhoi weighs about 1,600 pounds and is equipped with a 360-horsepower engine; its closest rival, the German-made Extra, weighs in at 1,450 pounds, with a 300-horsepower engine. Both the Sukhoi and the Extra are endowed with far more juice and strength than you need for level flight. A typical Cessna, for example, is designed to withstand three and a half positive g's and one negative g; a typical Sukhoi can withstand 23 positive g's and 23 negative g's."

Then about the programs and positive gees:
"Elena warned me about this earlier. In aerobatics, your body experiences bursts of 10 to 12 positive g's; the equivalent would be a boulder weighing 10 to 12 times more than your body pressing on your chest. We are not near that level now, but we are heading into high-g territory.

Before going into a high-positive-g maneuver, it is advisable to clench your abdominal muscles, making it more difficult for blood to flow out of your brain. Some pilots take the additional precaution of screaming. These things help prevent light-headedness and the feeling that your stomach is shooting up into your throat. Fighter pilots wear special g-suits that contract around their thighs and stomach during high-g maneuvers, but these would be too bulky in tight aerobatic cockpits. In Arizona, shorts and T-shirts are the preferred flight suits."

And that's about the negative:
"Because there is no military need for maneuvers that bring on high negative g's, fighter jets are not built to fly them; their fuel and lubrication systems can malfunction if the force of gravity is reversed. "I'm pushing minus six and minus eight in my routines, and it's something you never see in fighters," says Mike Mangold, who spent 11 years cracking the speed of sound in an Air Force F-4 fighter jet before turning to Sukhois."

A google might proove more productive. Internet is, BTW, not where I have it from.

GR142-Pipper
01-22-2006, 02:54 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Ugly_Kid:
It's not a matter of belief. You might find this, for example, interesting: </div></BLOCKQUOTE>Not really. Having an aircraft stressed for high + and - G's is not the same as the pilot's ability to execute. If you re-read my initial post I describe "extended push-aways". That means SUSTAINED high -G flight. What you are describing is instantaneous and highly transitory + and - G flight. BIG DIFFERENCE. So to restate, there is NO WAY that a pilot will be able to sustain and function in -G flight of 3 or more.

As is a common problem here, the posts need to read before replying.

GR142-Pipper

Ugly_Kid
01-22-2006, 03:26 AM
And as you see the game engine does not provide "great deal more than -3" negative gees not instantenous nor continuos. So to me it seems you don't have an issue there...

Aaron_GT
01-22-2006, 03:23 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Not really. Having an aircraft stressed for high + and - G's is not the same as the pilot's ability to execute. </div></BLOCKQUOTE>

The pilot quoted reports pushing up to -8G.

I've been to an airshow in which the pilot of one of these Sukhois gave a running commentary including an estimation of Gs during maneouvers, including some hefty negative Gs. There was no G meter, of course, so I had to take his word for it. Not that he talked continuously through the heaviest negative Gs, but he mentioned after the fact. He seemed to be able to talk pretty much through all the positive Gs.

Texan...
01-22-2006, 03:43 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Aaron_GT:
....estimation of Gs.....There was no G meter......I had to take his word for it. </div></BLOCKQUOTE>

darkhorizon11
01-22-2006, 05:33 PM
TWO REALLY IMPORTANT THINGS before your start arguing about how many G's the human body can take:

1. Every person is different, physical conditioning, particularly weight training, is productive to resisiting negative and positive G manuevers. Today fighter pilots are training to strain muscles in their entire body to keep the blood evenly spread throughout their bodies. I don't know if this was practiced in WWII, I've never heard of it being used then. Then again when I went up in an altitude chamber a few times and a couple of the kids that lasted the longest before experiencing hypoxia were couch potatos, so theres no surefire way of predicting how many negatives or positives you can take without actually try it. I know F16 pilots must go into a centrifuge an stay concious while the fuge accelerates them to 9 times the force of gravity. The only need reach this amount however, not withstand for more than a fraction of a second. The problem is it takes the thing about minute or so to get going that fast. Talk about the longest minute of your life! http://forums.ubi.com/images/smilies/16x16_smiley-wink.gif

2. It doesn't matter how many G's a person can take. The most I've heard is about 400 times the force of gravity or so. How is that possible? Tolerance is not a question of amount, but amount over time. That 400 Gs is what is experienced by an Indy car driver when he slams into the wall at about 220mph. He is unconcious with some broken bones, but alive. So theres no magic number where human beings pass out, its not that simple! In this case for the outside loop (again depending upon the pilot) I'd say after about 4 sustained negative G's or so is when most people start to experience a strong redout sensation. Its sort of like deadly amounts of electricity, its not the voltage, its the amperage that kills you!

I've experienced this stuff myself, I have acrobatic experience in both Cap 10s and Decathalons, I've also taken courses in Human Factors and Flight Physiology, thats where I got those numbers from...

But back to topic, they aren't modeled perfectly, but they're not that far off. Actually a great effect in BoB (though it probably won't be modeled) would be when a strong and sudden onset of negative Gs is experienced the blood vessels in the eyes are known to burst. Its pretty painful causing a red ting in vision for awhile and it turns the eyeballs red temporarily, like a devil-child sorta thing. A CFI at my school was doing the pen trick with his student awhile back and pushed the nose over a little too hard and this happened at probably not more than about 3 or 4 negatives, it wasn't pretty.

Grey_Mouser67
01-22-2006, 09:16 PM
talk to a real pilot...one I know talked about -4 g's...very uncomfortable...I'm not sure what the limits are, but it is different than positive g's for sure and both people and aircraft are less tolerant. Negative g's push blood to the brain which can cause blood vessels to pop etc....really, really bad stuff and aircraft arent made for it...whatever their g load is in positive, it is less in negative.

If the game modelled physical changes with combat, negative g's would be much more draining on the stamina and constitution of the pilot.

Aaron_GT
01-23-2006, 03:03 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">....estimation of Gs.....There was no G meter......I had to take his word for it. </div></BLOCKQUOTE>


I am sure there was one in the plane, we just didn't have a big read out at the airshow showing it in real time. I can't see that the pilot had any particular reason to be dishonest about the Gs, though.

NonWonderDog
01-23-2006, 04:21 PM
I've heard plenty of (supposed) f-16 pilots (online) talk about losing their lunches at -2G the first few times or so. Most say they don't do ever do negative G's of any sort ever because of the pain/discomfort/nausea/fatigue/lack of tactical use.

I've never been in an aerobatic craft of any kind myself, but I've never heard any of their pilots say that negative G's are fun (real life, this time).

I don't know how common or likely the whole "red-out" thing is, though. Extreme nausea and the lower eyelids moving to block one's vision are the most common things I've heard.

Viper2005_
01-23-2006, 04:44 PM
Don't forget the headache! In my experience at least negative g used to make me feel as though my head was going to explode (and that would have been something weedy like -1.5 to -2 g)...

No F-16s here, just Bulldogs and Tutors.

TooCool_12f
01-23-2006, 04:49 PM
caldwell (WWII ace) used to say that if you have an enemy behind you and closing in for a shot, you just throuw your stick hard forwards and to one side, while kicking full rudder... in his words "doesn't matter if it hurts, it's still better than getting killed"


basically, when your life depends on it, you do anything, regardles whether you may break your plane or something on yourself to save your neck.. and human resistance is well beyond what most people may believe, especially when your adrenaline flows by gallons in your veins in the middle of a fight

Grey_Mouser67
01-23-2006, 06:14 PM
Yes, between life and death, you'll do anything once...but you won't sustain it for long and if you are unable to disnegage that will be it for the pilot....the issue with the game is that you can do it endlessly with no ill effects...would be nice if too long in negative G brought about a nice long nap...with red of course! nappy time!

Texan...
01-23-2006, 10:12 PM
Kind of reminds me of the days when 190 folks would simply go into an everlasting roll as an evasion "tactic." Of course in real life it simply could not be sustained.

Some of these moves are clearly unrealistic.

GR142-Pipper
01-24-2006, 12:50 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Ugly_Kid:
And as you see the game engine does not provide "great deal more than -3" negative gees not instantenous nor continuos. So to me it seems you don't have an issue there... </div></BLOCKQUOTE>Where did you read that the game engine was limited to -3 G's? That seems to be contradicted by others here.

GR142-Pipper

GR142-Pipper
01-24-2006, 12:57 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by NonWonderDog:
I've heard plenty of (supposed) f-16 pilots (online) talk about losing their lunches at -2G the first few times or so. Most say they don't do ever do negative G's of any sort ever because of the pain/discomfort/nausea/fatigue/lack of tactical use. </div></BLOCKQUOTE>There's also one very weird side affect of experiencing higher -G's (i.e. more than 2 to 2.5)...red eye...real red eye. This is where the small blood vessels in the whites of your eyes rupture and it turns them red. A friend of mine experienced this kind of extreme condition when he found himself in a very violent spin. They guy looked pretty weird for about 10 days until it eventually went away. Definitely spooky.

GR142-Pipper

mazex
01-25-2006, 04:15 PM
Well, I've done a negative loop in a Pilatus B4-Pc11 and I was at -4,5 in the bottom of it. My eyes showed no signs of whiteness for a week or two and I bet that I wouldn't have even been able to squeeze the trigger if I had one in the bottom http://forums.ubi.com/groupee_common/emoticons/icon_wink.gif I did it once and I will never do it again... I did an outside snap roll in a YAK-52 at another occasion and I guess a barn dorr would have gone unscratched there to if it would have had guns http://forums.ubi.com/groupee_common/emoticons/icon_wink.gif

/Mazex