Dumping the pitch in F16

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saberrider

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Unread post16 Mar 2017, 11:39

When we pull the stick back hard at corner speed and gain some rate /G's, then quickly release to 1 G the same rates are for the unloading every time or this depending on speed ?
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sprstdlyscottsmn

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Unread post16 Mar 2017, 13:35

At one G you either have zero rate or you are falling. The equation for rate to sustain altitude is as follows.

Degrees per second = ((√(G^2-1))*32.2*57.3)/V

If you ignore the need to sustain altitude then it becomes

G*32.2*57.3/V

With V being in feet per second.
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Gums

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Unread post17 Mar 2017, 15:14

Salute!

My old tech description stuff indicates that relaxing the back pressure reduces the gee command right away, but the rate is somewhat slower than when you "snatch" the stick. The roll command is basically "instant", and you can see this with the demos and T-bird solo jets. Relax the stick and that sucker goes to zero roll command and you can see the difference with the Blues' solo jets, as sometimes the wings will "wobble" ever so slightly.

Some of our guys would trim to zero gee and when unloading just release the stick. My unnerstaning is some of the 'birds also trim for slightly less than one gee.

Good equations from Spurts, as usual.

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saberrider

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Unread post17 Mar 2017, 22:37

Gums wrote:Salute!

My old tech description stuff indicates that relaxing the back pressure reduces the gee command right away, but the rate is somewhat slower than when you "snatch" the stick. The roll command is basically "instant", and you can see this with the demos and T-bird solo jets. Relax the stick and that sucker goes to zero roll command and you can see the difference with the Blues' solo jets, as sometimes the wings will "wobble" ever so slightly.

Some of our guys would trim to zero gee and when unloading just release the stick. My unnerstaning is some of the 'birds also trim for slightly less than one gee.

Good equations from Spurts, as usual.

Gums sends...

Thank you , the "wobble" may be because the flaperons are going past over the "in line " rest position when relaxing the stick to brake out inertia of the roll or due pilot not stopping the stick at the center due to hand involved the centrifugal force acting on a/c.My question is about if the rate is changing if the a/c is heavier or is speed up.Muscle memory is something that is must have ,or haptic feedback is not involved?
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saberrider

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Unread post17 Mar 2017, 23:33

sprstdlyscottsmn wrote:At one G you either have zero rate or you are falling. The equation for rate to sustain altitude is as follows.

Degrees per second = ((√(G^2-1))*32.2*57.3)/V

If you ignore the need to sustain altitude then it becomes

G*32.2*57.3/V

With V being in feet per second.

At 1 g it is not possible to climb straight up?
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Unread post18 Mar 2017, 01:15

saberrider wrote:At 1 g it is not possible to climb straight up?


Ask a technical question, get a technical answer. My previous answer was very specific to turn rate so now I will go into more detail about 1G.

It means the total lifting ability of the plane is matching the total mass of the plane times the gravitational accel, not that you are perfectly opposed to gravity. In vertical flight the plane is making zero net lift. If you were in true net 1G vertical climbing flight then you would be pulling out of the vertical while SLOWING DOWN at a rate of ~19kt/sec and then only in that one instance.

The steady state of a climb attitude (no accelerations) means the Nz (G force through the "vertical axis" of the aircraft) is equal to the Cosine of the pitch angle, 1G Nz at 0 degrees pitch and 0G Nz at 90 degrees pitch. In a theoretical steady state vertical climb, no change in airspeed, then you have -1G Nx (down the long axis of the aircraft). So, in a non-level condition then having 1G Nz means a pitch change. If you want zero G Nx then it is either level flight, a dive, or a decelerating climb (with Nx deceleration relative to the Sine of the pitch angle). If you don't care about Nx then 1 Nz can result in all kinds of conditions, including inverted where the aircraft will turn with 2G even though only 1Nz is felt as Nz doesn't care about where gravity is.

I have to run right now, let me know if you need more explanation.
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saberrider

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Unread post18 Mar 2017, 15:42

Thank you.

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