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G-FORCES (not the VC!) (Read 1512 times)
Dec 16th, 2003 at 6:50pm

Politically Incorrect   Offline
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Curious about g-forces and the human body.
Using a fighter jet for example (pick your fave) I know on take off from a carrier or anywhere else for that matter that your body takes on some major "G's" and the same when making some extreme manuvers.
But the Question is when at a crusing speed (doesn't matter) take mach 1 for example how does the body react to the g-forces?
Does it "adapt" or are the forces constinly affecting the body in some way?
Your body can adjust to temperature, loud noise, and even atmosphereic pressure, but what about sustained g-forces?
Sorry about a odd and matbe cunfusing question, but i'm curious. And since my chances of ever flying in a F16 are slim to none I'll never be able to experiance it.
 
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Reply #1 - Dec 17th, 2003 at 1:31pm

Hagar   Offline
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I'm not quite sure what you're getting at here. Normal flight does not involve great acceleration or G forces. In fact, Michael Schumacher demontrated this recently by beating the EF 2000 Typhoon advanced jet fighter in a "drag race" with his F1 Ferrari. http://cnews.canoe.ca/CNEWS/WeirdNews/2003/12/11/284161-ap.html

Jet fighter pilots wear G-suits (properly named anti-G suits) to overcome the effects of positive G during typically violent manoeuvres. These are like corsets worn around the thighs & lower stomach. They inflate automatically above a certain positive G which helps to prevent blood draining from the upper body (& thus the brain) to delay blackouts. There are also basic excercises an aerobatic pilot without the luxury of a G-suit can do which have the same effect.
 

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Reply #2 - Dec 17th, 2003 at 1:49pm

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if you fly at a constant speed, your acceleration is zero, so according to Newton: F=m.a (force=mass x acceleration). when your a=0, F=0 so no forces. i just came up with this myself, but do you think it's acceptable? no force, no extra G's... Wink
 

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Reply #3 - Dec 17th, 2003 at 1:59pm

Hagar   Offline
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I'm no great shakes at scientific theory or formulae but it sounds logical to me Bones. Wink
The whole point is the accleration or change in relative speeds. If you're travelling straight & level at a constant speed there will be no G forces. Jet aircraft have a surprisingly low acceleration - compared with racing cars for example. I think the average F1 driver experiences more G during a race than a pilot.

Not having experienced it myself I'm not sure about when you hit the A/B button. Shocked Wink
 

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Reply #4 - Dec 17th, 2003 at 2:04pm

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hagar, schumi lost to the typhoon 2 out of 3 times.
i'd imagine the feeling of acceleration is like what ya feel in a standard comercial plane, when ya start out ya get pushed into your seat, but once your airborne and speed up, you dont really feel it
 
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Reply #5 - Dec 17th, 2003 at 2:14pm

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Quote:
hagar, schumi lost to the typhoon 2 out of 3 times.

I'm well aware of that Craig. Read the article from my link. Roll Eyes

The fact that he beat it over a short distance is what I was getting at. Wink
 

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Reply #6 - Dec 17th, 2003 at 3:07pm

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i see:)
my bad, i really should spend extra time interpreting these things better when tired:)
 
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Reply #7 - Dec 17th, 2003 at 5:44pm

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Quote:
hagar, schumi lost to the typhoon 2 out of 3 times.
i'd imagine the feeling of acceleration is like what ya feel in a standard comercial plane, when ya start out ya get pushed into your seat, but once your airborne and speed up, you dont really feel it


This is sort of what I tought. Once at a constent speed your body and plane are moving at the same rate so no differance would be noticed.
But I was wondering the effects ,lets say you start to do a number of barrel rolls at mach 1 (if possible), I would think your guts would all shift because of centrifical force, or am I wrong because once again palne and man are moving at the same rate?
What Bones said does make sense, and if that is true you would only feel effects when making a turn, dive, climb etc, correct?
I guess the best way to find out would be asking a fighter pilot, I know there has to be one here somewhere!!
 
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Reply #8 - Dec 17th, 2003 at 5:47pm

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Quote:
I'm not quite sure what you're getting at here. Normal flight does not involve great acceleration or G forces. In fact, Michael Schumacher demontrated this recently by beating the EF 2000 Typhoon advanced jet fighter in a "drag race" with his F1 Ferrari. http://cnews.canoe.ca/CNEWS/WeirdNews/2003/12/11/284161-ap.html

Jet fighter pilots wear G-suits (properly named anti-G suits) to overcome the effects of positive G during typically violent manoeuvres. These are like corsets worn around the thighs & lower stomach. They inflate automatically above a certain positive G which helps to prevent blood draining from the upper body (& thus the brain) to delay blackouts. There are also basic excercises an aerobatic pilot without the luxury of a G-suit can do which have the same effect.


But what about the effects on the brain? How is damage prevented there?
If I start sounding like a three year old child let me know and I'll stop! Smiley
 
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Reply #9 - Dec 17th, 2003 at 5:57pm

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if i remember rightly Bman used to fly some jet, i might be wrong though
 
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Reply #10 - Dec 17th, 2003 at 11:49pm

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How about in a 747? How powerful are those in that aircraft?
 
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Reply #11 - Dec 18th, 2003 at 5:23am

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Quote:
But what about the effects on the brain? How is damage prevented there?
If I start sounding like a three year old child let me know and I'll stop! Smiley

The human body is quite remarkable & has its own fail-safe system. Excessive amounts of positive G will drain the blood from the brain causing you to black out & become unconcious. This will prevent brain damage but is obviously dangerous in an aircraft or any other form of transport - hence the anti-G suit to delay the effect & enable the pilot to withstand more G than normal.

All aircraft are stressed to certain positive & negative G factors depending on type. Many high-performance aircraft can far exceed the capabilities of the human body & there are obviously restrictions on that which the pilot should be well aware of. The blackout is gradual & if you see the visual symptoms you immediately ease off the pressure to reduce the G forces.

The amount of G the body can stand will vary with the the person, depending on age, general health, experience & how fit they are. If you do something every day you get used to it. Any professional fighter or aerobatic pilot will know the capabilities of their own body. I believe the latest fly-by-wire systems do this automatically. The aircraft is actually flown by a computer which will not allow the pilot to exceed his/her own body's (or the aircraft's) capabilities.

PS. If you've ever been on a roller-coaster & been pressed down in your seat during the ride you have experienced positive G. In fact this is far more than the average private pilot will ever experience while flying.

The loop & barrel roll are positive G manoeuvres. If performed correctly you could do them quite safely without being strapped in.
 

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Reply #12 - Dec 18th, 2003 at 6:25am

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Quote:
PS. If you've ever been on a roller-coaster & been pressed down in your seat during the ride you have experienced positive G. In fact this is far more than the average private pilot will ever experience while flying.



Really? Even in something like a fighter jet?
 
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Reply #13 - Dec 18th, 2003 at 6:41am

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"if i remember rightly Bman used to fly some jet, i might be wrong though "

He flew F-14s with the USN (lucky &*$£"%^)   8)
 

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Reply #14 - Dec 18th, 2003 at 6:51am

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Quote:
Really? Even in something like a fighter jet?

Although this was a long time ago I had a flight in a RAF Hunter advanced trainer (simply a 2-seat version of the front-line jet fighter) & broke the "sound barrier" twice in an almost vertical dive from 43,000 feet. I wore an anti-G suit which was far more painful than the G effects. Despite doing some reasonably high-G manoeuvres these were done quite smoothly with no violence involved.

Earlier this year I was fortunate enough to have an advanced aerobatic lesson in the Extra I use as my avatar. Although this is a very slow aircraft compared with the Hunter or a modern jet fighter it is far more lively & manoeuvrable. The instructor, himself an ex-member of the RAF Red Arrows, told me it will roll faster than the BAe Hawk (400 degrees per second) & is stressed to something like 26 G, both positive & negative. He assured me that I would break myself long before damaging the aircraft. I could be wrong but seem to recall that aeobatic display pilots regulary cope with + or - 9 G. We had no anti-G suits but I was taught a simple exercise to delay the onset of blackouts due to positive G. I was delighted & even my instructor was impressed when I withstood +5 G (the maximum allowed for my first lesson) with no ill-effects. I have a certificate to prove it. Not bad for an old codger the wrong side of 60. Wink

PS. As for roller-coasters, I read they can often pull up to +6G.

PPS. I checked my facts. http://www.geocities.com/cedarpoint6/forces

PPPS. This is the Hawker Hunter T.7. Very much like the one I had that ride in back in 1959. I can still remember every precious moment as if it were yesterday. 8) Wink
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« Last Edit: Dec 18th, 2003 at 10:46am by Hagar »  

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Reply #15 - Dec 18th, 2003 at 2:53pm

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wow Hagar, you lucky &é'é"'&é"(&('  Wink

with some luck, i'll do a flight with a real Fouga Magister next year...but that still has to be arranged  Wink
 

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Reply #16 - Dec 18th, 2003 at 6:06pm

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That is pretty neat Hagar!!!
Beautiful jet! Must have been one wild ride!!!
This weekend weather permitting I'm going to fly a T34 warbird that is here at my local airport. I cut a deal with the owner, I build him a clock of a T34 and charge him a flight in the T34.
There is a whole fleet of warbirds at my local airport and my goal is to fly in every one!!
I  would show a picture of the T34 but i don't know how.

" aeobatic display pilots regulary cope with + or - 9 G"

I thought that the max a human body can withstand was 9g's.
 
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Reply #17 - Dec 18th, 2003 at 6:16pm

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I will have to check my facts on the G factors. That was off the top of my head. Smiley

Enjoy your trip in that T-34. It's a nice looking aircraft. I'm not sure how many there are about these days.

PS. Good old Google. Smiley
Quote:
Aerobatic pilots were found capable to withstand -10+14g maneuvers without blackening out.
As a result, all recent Russian aerobatic planes are built with calculated maximum g-factor 22.5 and service g-factor 15;
More than 30 Su-26M fly in Russian clubs and 20 are in service all over the World.

http://www.flymig.com/maks_pictures/html/info.Su_26.htm
 

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Reply #18 - Dec 18th, 2003 at 7:08pm

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Well i just tried to put a picture of the T34 here but nothing!
I uploaded it and pushed the button with the" picture"  in the " add YABBC tags"  and got this "img URL /img" I inserted the link the way the "upload success page told me but nothing happens what am I doing wrong?? I removed the brackets so that  what popped up would show.
I must have uploaded 4 pictures and don't have the slightest clue as to where they are or what happened to them!!
 
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Reply #19 - Dec 18th, 2003 at 7:20pm

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Check out Rifleman's sticky topic in the Freeware Screenshots forum. http://www.simviation.com/cgi-bin/yabb/YaBB.cgi?board=screen;action=display;num=...

You must get the path exactly right with no spaces in between those [img] brackets. It's case-sensitive including the file extension. If your image is named fretnstuff01.JPG it's no good using fretnstuff01.jpg or Fretnstuff.JPG
 

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Reply #20 - Dec 18th, 2003 at 7:45pm

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...

Here she is! I don't know why it is so big! The file is 800 and is 67kb.

There modified to JPG.
« Last Edit: Dec 19th, 2003 at 5:16am by Politically Incorrect »  
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Reply #21 - Dec 19th, 2003 at 3:44am

Hagar   Offline
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Now that is nice. I always liked the all-yellow scheme best. Wink

Your image is in the wrong format. BMP instead of JPEG (.jpg). Quote:
Rules for posting images on Simviation's forums

Please keep all screenshots/images in JPG format & less than 100K

I'm not sure how it worked as a BMP wouldn't (& shouldn't) usually display on this forum.
The image size is within the rules unless you or somebody else resized it.

PS. At 1.37 Mb the file size is WAY over the 100K limit. Roll Eyes
 

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Reply #22 - Dec 19th, 2003 at 4:04am

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If you put your mouse pointer on the image and right click-properties, This is the info I get:
width-800
Height-603
size of file-62.93 (64441 bytes)

I used Irfanview to resize it and according to that program it is JPG format. So I don't know what the deal is.
I think you must have "image envy" Smiley:)

I went back and tried to resize the original again and I got the same thing (size and file size) so even if this is the wrong  forum please let me know what it is I might be doing wrong, I don't want to be using to much space on the site!!
 
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Reply #23 - Dec 19th, 2003 at 4:47am

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Not sure what's going on here. The file properties didn't show up for me from the right-click option as they usually would. Note the file extension is not displayed either.
...

I downloaded the image to check it out. It only gives the BMP option to save it in which means it's a BMP. When I checked the file size of the downloaded image in Windows Explorer it's 1.37 Mb.

PS. I figured it out. Try changing the path to include the .JPG file extension like this.
http://www.simviation.com/yabbuploads/t34.JPG
 

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Reply #24 - Dec 19th, 2003 at 5:22am

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There is one of the uploads!
I first uploaded it and it was JPG. Then another somehow became BMP. Which was the one on there.
When I tried the link for the JPG photo nothing would appear. I didn't pay attention to the fact that in the link I was typing "jpg" instead of "JPG".
But I modified the picture so now I should be free from "moderator harrassment" Smiley
Now I have to figure out what I did that changed the one upload into a BMP image.
Thanks Hagar!!
I'll gather some of my favorite pics and post them in the photos forum later!!
 
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Reply #25 - Dec 19th, 2003 at 5:33am

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That's better. Cheesy

Quote:
There is one of the uploads!
I first uploaded it and it was JPG. Then another somehow became BMP. Which was the one on there.
When I tried the link for the JPG photo nothing would appear. I didn't pay attention to the fact that in the link I was typing "jpg" instead of "JPG".
But I modified the picture so now I should be free from "moderator harrassment" Smiley
Now I have to figure out what I did that changed the one upload into a BMP image.
Thanks Hagar!!
I'll gather some of my favorite pics and post them in the photos forum later!!

I did point this out earlier. Wink
Quote:
You must get the path exactly right with no spaces in between those [img] brackets. It's case-sensitive including the file extension. If your image is named fretnstuff01.JPG it's no good using fretnstuff01.jpg or Fretnstuff.JPG

The extension might be .jpg or .JPG depending on the graphics editor used to save the original image. I can only suggest that you or someone else uploaded the BMP. It's a good idea to give your images a unique name before uploading them to avoid conflicts. A file name like t34.JPG would not be too uncommon & someone else might have already uploaded an image with the same name. In this case yours would overwrite it & mess up their topic.
 

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Reply #26 - Dec 19th, 2003 at 5:44am

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I see your point, I must have uploaded the BMP because It is a picture I took.
I think I must have uploaded the same pic in a different format (BMP) over top of the JPG. That is why I was having so much trouble getting it to appear. Like i said I uploaded the photo about four times so anything might have happened.
I also remember when posting the link, when copying/ pasting I didn't remove the ".jpg" where you put in the name of your photo, the start of my problems.
I'll remember next time to give my photo's a little something special when nameing them!
I would hate to know that I might mess up someone else's post because of something like that!!
And by the way thanks for the slap on the hand!!
I read your instructions and those of Rifleman's to a T, and still didn't pay attention!!!!Smiley
 
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Reply #27 - Dec 19th, 2003 at 5:52am

Hagar   Offline
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Quote:
I see your point, I must have uploaded the BMP because It is a picture I took.
I think I must have uploaded the same pic in a different format (BMP) over top of the JPG. That is why I was having so much trouble getting it to appear. Like i said I uploaded the photo about four times so anything might have happened.
I also remember when posting the link, when copying/ pasting I didn't remove the ".jpg" where you put in the name of your photo, the start of my problems.
I'll remember next time to give my photo's a little something special when nameing them!
I would hate to know that I might mess up someone else's post because of something like that!!
And by the way thanks for the slap on the hand!!
I read your instructions and those of Rifleman's to a T, and still didn't pay attention!!!!Smiley

Tsk Tsk. Grumpy rule #1. When in doubt RTFM...............! Wink

A JPG would not overwrite a BMP. I suspect that you left the file extension off the path in your original post. This would explain why the file type showed up as unknown & why I could only download it as a BMP.

As for messing up someone else's post, I once did that myself. Ever since then I've used my own naming system. Of course, someone else could also mess up yours in the same way.

PS. Did you spot my not-so deliberate mistake?
Quote:
If your image is named fretnstuff01.JPG it's no good using fretnstuff01.jpg or Fretnstuff.JPG


I plead insanity. Roll Eyes Tongue Wink

PPS. I am not a moderator, simply can't resist interfering. Shocked 8)
 

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Reply #28 - Dec 19th, 2003 at 8:21pm

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No I didn't notice the mistake!
I might have to hold that against you Smiley!!
Actually it proves a very good point, how easy it is to cause problems with something that should be simple!

" I plead insanity. "

It's ok, I think it has to do with all the abbreviations!!
jpeg,JPG,BMP,LOL,RTFM,ETC,etc!!!!!!!!!!!
I'm going to my rubber room to bounce off the walls for awhile!!Smiley
 
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Reply #29 - Dec 19th, 2003 at 8:21pm

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No I didn't notice the mistake!
I might have to hold that against you Smiley!!
Actually it proves a very good point, how easy it is to cause problems with something that should be simple!

" I plead insanity. "

It's ok, I think it has to do with all the abbreviations!!
jpeg,JPG,BMP,LOL,RTFM,ETC,etc!!!!!!!!!!!
I'm going to my rubber room to bounce off the walls for awhile!!Smiley
 
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