Time to reach 9 G and his importance.

Operating an F-16 on the ground or in the air - from the engine start sequence, over replacing a wing, to aerial refueling procedures
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saberrider

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Unread post16 May 2017, 16:50

Time in seconds to 9 G from 1G ? If reaction time is important I guess this is where F16 with slender airframe gain advance in rad/sec. over another types (break turns).
Last edited by saberrider on 16 May 2017, 19:45, edited 1 time in total.
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sprstdlyscottsmn

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Unread post16 May 2017, 17:39

This has much more to do with instability in pitch than slender airframe. The F-16 was the first plane where this became an issue and as I understand it was part of the reason for the CAT-I limiter. The F-16 could hit 9G faster than previous planes could reach 5 or 6. It was very unstable (CG is at 35% mac) and a short body for a low moment of inertia so it was win win. IIRC the Eurofighter is even quicker to 9G. IIRC the G onset rate of the F-16 is 7G/sec and the Tiffy is 9G/sec. I could very well be getting my numbers wrong and mixed up with the vast quantity of numbers thrown around with aviation so if anyone else has a definitive answer please speak up (Gums, Johnwill, JB, Roscoe?)
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johnwill

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Unread post16 May 2017, 21:38

g onset rate is software controlled, so it can be almost anything up to the max rate possible, within structural limits. Also to be considered is the abruptness of the rate, which can lead to overshoots if overdone. Lags and filters are built into the stick force command before it gets to the control surface to smooth out rough commands. On F-16 structural limits are generally associated with fuselage loads and internal equipment qualification. Design pitch acceleration is +/- 3 rad/sec^2 for structure and equipment. Abrupt maximum pitch maneuvers (up and down) are part of the standard structural flight test program.
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sprstdlyscottsmn

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Unread post16 May 2017, 22:21

Thanks John. I love learning from you guys.
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saberrider

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Unread post17 May 2017, 09:48

Thank you . Read about the available max. 9G at 1.5 seconds after application of full back stick, or at least 25lbs of pressure on a stick .There is no time to be ready for this rapid response of Gs with anti g maneuver in my opinion. Operational pilot may not use fully capability of the a/c to access rapidly 9 G when they're executes trainings but is good to know if needed it is possible to access rapidly to reposition in space. My interest is for a Sim.
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vilters

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Unread post20 May 2017, 20:49

9G.
Well, there is a lot of talk about "G" and "9G".
It does not matter for a Simm, but in real life it is a very different story.

Pilot fatigue.

During a mission, one "can" pull 9G a couple of times when fit and well prepared, but certainly not always.
I have seen pilots grey out during the final overhead break at 4G after a heavy mission.

Being fit is one thing, good rest, good food and hydration, clear head and mentally sound are also very important.

"9G" during a morning mission is OK.
In the afternoon that same "9G" can become problematic, and in the evening you say to yourself : Ach, why???

The "trick" during a good setup is to get the opponent suffer, while suffering less yourself. LOL.
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saberrider

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Unread post20 May 2017, 21:33

Thank you for post this statement , because is I believed for many years and no one speak loud about it. We are human and like in sports there's one number one.Plus engine fatigue and echipament malfunction is a player in fighting arena.

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