Negative G's

Olympic

Well-Known Member
Negative G\'s

G'day all,

Yesterday I took a flight at my local airport,the Flight Instructor and I did some Negative G's. The Negative G's bothered me to the point that my head was about to exploded haha
. Can this be controled or its just something you need to get used to and the feeling eventually goes away? Thanks.
 

iceman21

Well-Known Member
Re: Negative G\'s

Having never really experienced negatives Gs often, take my answer with a grain of salt.

I believe the incredibly in shape human body can normally sustain 3 negative Gs after that you could have some eye problems (blood vessels bursting, etc). As with any sort of sustained G load on the body, your body must be in some sort of physical shape to withstand the Gs. The better shape you are in the better your body will be able to handle them. Negative G physiology is quite different from positive G physiology, since the blood is travelling in the opposite direction.

Hope it helps
 

E_Dawg

Moderator
Re: Negative G\'s

Physically you can withstand them. But why were you guys doing them in the first place??? What kind of plane were you guys in?
 

Olympic

Well-Known Member
Re: Negative G\'s

We were flying a Cherokee, why we did them ?? I guess we gotta ask the Flight Instructor.
 

I_Money

Moderator
Re: Negative G\'s

Was it just doing a bit of weightlessness? That is always fun until you see the fire extinguisher floating too!
 

panampilot

New Member
Re: Negative G\'s

A Cherokee is not approved for any negative g's at all. You might want to mention that to your instructor the next time he wants to do some cuban eights.
 

Olympic

Well-Known Member
Re: Negative G\'s

This was actually my first flight ... Intro flight .. just wanted to see how it was since Im due at Flight Safety in August
 

rausda27

Well-Known Member
Re: Negative G\'s

Since gravity is considered 1 g, then becoming weightless is actually 0 g's, so technically unless stuff starts sticking to the roof, you are not pulling negative g's. PanAmPilot, the cherokee POH does not state that negative g's are not approved, it just states that inverted maneuvers are not approved. Just to clarify.
 

panampilot

New Member
Re: Negative G\'s

[ QUOTE ]
PanAmPilot, the cherokee POH does not state that negative g's are not approved, it just states that inverted maneuvers are not approved. Just to clarify.

[/ QUOTE ]

I stand corrected.
 

EatSleepFly

Well-Known Member
Re: Negative G\'s

Yeah, I do the pencil trick sometimes with obnoxious little kids. Works well in the 152, and its not "negative" just zero G's. You'll know when you experience "negative"...it goes from the cool roller coaster type feeling to "oh •! I think my head's gonna pop."
 

I_Money

Moderator
Re: Negative G\'s

Dude if it was your first flight do not worry, you will get over it. He probably just did a zero g manuver, which to a new guy feels like a great deal, but really is not as bad you imagine.
 

davetheflyer

New Member
Re: Negative G\'s

Although that's one of my pet peeves. How many pospective students have gone up on an intro flight where the CFI tried to make them sick or scare them. That's stupid.

I usually limited my intro flights to straight and level with occasional very shallow banked turns, at least until I could determine how the student was handling the situation.
 

EatSleepFly

Well-Known Member
Re: Negative G\'s

Yeah, I agree Dave. I was referring to one particular obnoxious little kid, and even then only because he asks to do it every time.

Normally I don't do anything more than S&L Flight and Shallow turns with an intro....I'm scared to death of getting puked on...yuck!
 

EatSleepFly

Well-Known Member
Re: Negative G\'s

For Normal Category, correct. Also, the number where structural damage will occur is technically 150% higher (on both the plus, and minus G sides) and is there as a safety margin.
 

jtrain609

I'm a carnal, organic anagram.
Re: Negative G\'s

There are some more problems here. If you are in a high wing and you do it for a little too long, you can cut the fuel supply off to the engine. Remember that gravity is feeding the fuel down to the engine, and if that gravity stops working then so does your engine. If you have a fuel pump it's not a problem because then it's physically sucking the gas into the engine, probably against gravity anyways if it's a low wing.

The next problem is that you need an inverted oil system if you are going to stay upside down, or in this case without gravity. I don't think you could possible do zero to negative g's for long enough for it to be a problem, but everything still works on that gravity principle that your engine will always be pointed down. That's why there are certain engines with an aerobatic designator on it.

Cheers


John Herreshoff
 

E_Dawg

Moderator
Re: Negative G\'s

[ QUOTE ]
For Normal Category, correct. Also, the number where structural damage will occur is technically 150% higher (on both the plus, and minus G sides) and is there as a safety margin.

[/ QUOTE ]

Yeah, but if you exceed the posted limits there is a good chance of permanantly bending something. Structural failure can and probably will happen above 150% of the 'limits', however permanant damage can still occur the second you exceed the limit (i.e. the wings can bend, but not break). And the older the plane, the less room you have.
 

E_Dawg

Moderator
Re: Negative G\'s

[ QUOTE ]
The Negative G's bothered me to the point that my head was about to exploded haha
.

[/ QUOTE ]

That is definately NOT a required part of private pilot training (or any training for any certificate for that matter; outside of aerobatics). If it makes you uncomfortable, especialy to the point that you're head feels like it's going to explode, tell the guy to kock it off. Basically, you shouldn't have to get used to it.

Maybe he thought you'd enjoy it, but if you didn't, give him one more chance and if he does any more 'tricks' just get a new instructor.
 
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