What does the negative g rating mean when referring to aircraft catagorisation for certificate of airworthines

Question

Im learning about aircraft and have seen this statement refering to aircraft rating. This one is a normal rating but stunt aircraft carry a higher + / - g rating. How do you have a negative g rating. What is it refering to?

Answer 1

Negative Gs are pushing up on the airframe, positive are pulling down, like gravity normally would pull down on an object. So positive Gs would be pushing you down into the seat, negative G's are trying to pull you up out of the seat.

Answer 2

when u do positive Gs its like accelerating in your car..... when u do negative Gs its like hitting the breaks.... So when an aircraft is rated at 7+G 3-G means that it can go 7 positive Gs and 3 Negative Gs... so pulling up in level flight contributes to Positive Gs...... and pushing over in level flight contributes to Negitive Gs.... the reason planes are rated more for Positive Gs and Less for Negative Gs is because planes are designed to go UP more then go DOWN.... like a cessna that is level with the horizon is actually climbing.... In Most cessnas (every one that i have flown) to keep level altitude you must pitch the nose down....

Answer 3

Hello Paul -

Aircraft maneuver specifications are normally listed in three categories: operating loads, limit loads, and ultimate loads. Operating loads are those loads that can be encountered on a daily basis; the aircraft is designed so that fatigue limits are not exceeded by application of these loads. Limit loads are loads that may be applied once or twice during the lifetime of the aircraft. These loads should not result in permanent deformation, although some sacrificial material may be deformed. Aircraft are designed so that metal parts do not yield when these loads are applied. Ultimate loads should never be encountered. The aircraft is designed not to fail when subjected to ultimate loads.

G loads can be applied in all three axes. They can be thought of in terms of the direction that the aircraft moves when the maneuver is accomplished. Pulling back on the stick results in the aircraft pitching up - a positive G load in the vertical axis. Pushing forward on the stick results in the aircraft pitching down - a negative G load in the vertical axis. You can also apply positive and negative G loads in the lateral (side to side) axis or in the longitudinal (fore and aft) axis, although those are not usually what is referred to as + and - Gs.

The limit loads that you quote are a little on the low side. They may be published limits in the pilot's manual, but I suspect that the design limit loads are higher. The published limits may be the design operating loads, or even less,  for the sake of conservatism.

Answer 4

As pilots we sure do seem to like to complicate issues huh. Right side up = one positive G.

Upside down = one negative G.

Answer 5

Positive G's are rated by an inside loop ( you're pressed DOWN in the seat ), Negative G's are rated as an outside loop ( you are being pushed OUT of your seat, held in only by restraints, like going over the first hump in a roller coaster, only continuous). The plane is normally rated more for positive, as that's the conditions it should normally be flown in, but occasionally, the aircraft gets stressed the other way, and that Negative G rating is designed to tell you how much stress the other way an aircraft can handle.

Answer 6

negative G is much harsher on both pilot and airframe. You can pass out from a relatively small amount of negative G.