Experiment & Questions

[photofly]

I know I'm not pushing down every minute because I'm not exerting force forward on the stick.

That's because you're trimmed to keep the four basic forces in flight in equilibrium at your present pressure level.

Not true. You are trimmed to maintain an angle of attack.

It's the same thing. The aerodynamic forces are in balance at the trimmed angle of attack and only at the trimmed angle of attack.

[AuxBatOn]

You trim for an AoA, not to balance forces. The result may be balanced forces but it is not necessary. If I have to orbit for a while, I'll trim the aircraft in the turn, so that I can fly hands off, which is accelerated flight.

[photofly]

You trim for an AoA, not to balance forces. The result may be balanced forces but it is not necessary. If I have to orbit for a while, I'll trim the aircraft in the turn, so that I can fly hands off, which is accelerated flight.

From the point of view of the question being asked, in which turns are not involved, it's the same thing.

[photofly]

Strike that. Time for bed.

[AuxBatOn]

You trim for an AoA, not to balance forces. The result may be balanced forces but it is not necessary. If I have to orbit for a while, I'll trim the aircraft in the turn, so that I can fly hands off, which is accelerated flight.

From the point of view of the question being asked, in which turns are not involved, it's the same thing.

Sure, but just generally saying it's the same thing is incorrect. People should think of trim as one of the means to maintain a certain AoA which is generally used to remove control forces. In a straight and level, unaccelerated flight, your statement is true.

[Chris M]

Are you being intentionally dense? You've never taken a highway ramp?

You call this a circle?




I don't understand why some of you have to be so hostile when I'm asking questions about a subject that I'm not
as experienced with. Excuse me for trying to learn and understand what other high level pilots are questioning
while putting their real names out there.

If I may, I'd like to continue with a couple of other scenarios that are related to this topic, but not necessarily
aviation specific. Most of you seem to have a high level of physics and math education which is perfect.

It's because you seem to want to nit pick at details rather than accept the intent of the statement. No, a 3/4 loop ramp is not a full circle. But it does keep you in a constant radius turn for a set amount of time, which is what that analogy was intended to convey. If you turn 357 degrees and then veer off it really doesn't matter, you drove in a circle for long enough to extrapolate what the whole thing would feel like.

So, for the ramp shown above: Lets just say it's 270 degrees. During the beginning and ending phases you'll be increasing and decreasing steering input to begin and end your turn, but for the constant radius section are you constantly turning the wheel farther in? Or just holding it in the correct angle to maintain the turn?

[Learning2Fly]

for the constant radius section are you constantly turning the wheel farther in? Or just holding it in the correct angle to maintain the turn

If the radius is equal throughout and my speed is constant, then my steering angle would remain constant (excluding outside forces ie: wind).

[AirFrame]

I continue to be amazed that i'm even bothering to follow this thread. It's like a train wreck of density.

[lownslow]

I know I'm not pushing down every minute because I'm not exerting force forward on the stick.

That's because you're trimmed to keep the four basic forces in flight in equilibrium at your present pressure level.

Not true. You are trimmed to maintain an angle of attack.

...which at a constant power setting and constant drag (ie. constand speed) will give a constant amount of lift to counter the weight of the plane.

[digits_]

That's because you're trimmed to keep the four basic forces in flight in equilibrium at your present pressure level.

Not true. You are trimmed to maintain an angle of attack.

...which at a constant power setting and constant drag (ie. constand speed) will give a constant amount of lift to counter the weight of the plane.

Just wait a moment. We are still trying to convince him that a plane doesn't shoot into space if you forget to trim. Let's take baby steps and focus on that first. It's going to take at least another 10 pages before we get to the intricacies of trimming.

On the other hand, we might have finally figured out what happend to MH370: the pilots fell asleep and they ended up in space.

[Learning2Fly]

Just wait a moment. We are still trying to convince him that a plane doesn't shoot into space if you forget to trim.

No, you're fighting amongst yourselves about trimming...which is equally as funny if you consider it a baby step.

I never claimed the Earth was flat, I simply asked questions about the aircraft behaviour in level flight with a curved ground.

[lownslow]

I never claimed the Earth was flat

No, but to this point you're pretty invested in the notion that it's faceted or something.

[Bede]

I never claimed the Earth was flat, I simply asked questions about the aircraft behaviour in level flight with a curved ground.

And your question was satisfactorily answered on the first page. And then your questions and math just kept going downhill.

This thread is a train wreck.

[Learning2Fly]

And your question was satisfactorily answered on the first page.

Well, maybe to you with a more in-depth perspective of function it was.

For me, it was still unclear. Right now, I'm letting go however I'm still confused to how the erection system can
distinguish between tiny changes in precession from gravity and aircraft movement in the same axis? Maybe one
day I'll get it...

[Learning2Fly]

I never claimed the Earth was flat

No, but to this point you're pretty invested in the notion that it's faceted or something.

I've learned to question everything, sorry.

Do you know who these people are?

[hotdog1]

Can you tell everyone here who you really are?
I’m sure everyone wants to know, just so they can give you a good reference for your first job.
That way everyone can benefit from your limitless doubt and need to question everything.
Thanks

[Learning2Fly]

Can you tell everyone here who you really are?

My name is Hugh Jorgan

^ Do you know who those peeps are?

[kevind]

Now we have gone from flat earth to conspiracy theory.

Yes, the Challenger exploded and killed the astronauts. Next you will tell Sandy Hook was crisis actors and that the MH370 is safe in Diego Garcia

[Learning2Fly]

New we have gone to flat earth to conspiracy theory.

Yes, the Challenger exploded and killed the astronauts.

Great coincidence though? Twins, sisters, brothers, double with the same name. Not a bad 5/5?

Seemingly identical dental work too!

[kevind]

Maybe you will be comfortable here https://www.reddit.com/r/conspiracy/

[Learning2Fly]

Maybe you will be comfortable here

Maybe you are more comfortable wearing one of these in your mouth?

[lownslow]

I'm still confused to how the erection system can distinguish between tiny changes in precession from gravity and aircraft movement in the same axis?

That was also covered. More than once. We spend the vast majority of our time in unaccelerated flight and the self-erection (teehee) mechanism works really slowly to minimize errors brought on by acceleration forces.

[Steve Pomroy]

Well, maybe to you with a more in-depth perspective of function it was.

What is a perspective of function?

... I'm still confused to how the erection system can distinguish between tiny changes in precession from gravity and aircraft movement in the same axis?

The erection mechanism in an AI is a low-pass filter: https://en.wikipedia.org/wiki/Low-pass_filter. Nowadays, low-pass (and other) filters are usually electronic, or at least electric. But it's common in older tech to see mechanical filters. This is one. A crude but intuitive explanation is that high-frequency inputs (like turbulence or maneuvering) average out (i.e. - an input in one direction is canceled by an immediate input in the opposite direction) and therefore don't generate a response in the system, but low frequency inputs (like the changing direction of gravity as you travel around the globe) don't cancel, and therefore generate a response.

[Learning2Fly]

Thanks Steve,

Having an electronics background helps me understand that
force inputs outside of the filter cut-off will not be transmitted to
the erection system for correction.

In my mind, using a tunable bandpass filter would be even
better to cancel out sub forces below the operating envelope
of the aircraft type (with respect to precession from gravity vs. speed).

Still, there will be flight forces within the filter range that will
allow subtle corrections.

[PilotDAR]

I'm letting go however I'm still confused to how the erection system can
distinguish between tiny changes in precession from gravity and aircraft movement in the same axis

Again, in simple terms, for vacuum powered artificial horizon instruments; two paired vanes, which hang on pivots so as to react only to gravity, each block one half of the four air exits from the gyro housing. If that gyro housing tilts in any direction so as to be not exactly level to local earth, one vane opens more, closing the paired one on the opposite side of the gyro housing. The now fully open air exit will push the bottom of the gyro housing, until it is level with earth again, at which point the pair vanes will move back by gravity, closing off one half of each air exit, balancing the erecting four of the four air exits so the are equal, and apply an equal force to keep the gyro housing erect - level with local earth. If the plane is flown over the horizon, and local earth has curved away, gravity will have curved away too, and the process will repeat so the horizon display will remain level. Does that explain it L2F? Please extent the courtesy of a read back if it does.

During my years of repairing instruments (with Vic leBlanc, if anyone remembers him), if a horizon was reported as not remaining erect, these two paired vanes were the firt thing I would check for proper function. If one pair were not moving freely, that would most likely be the cause.

As for the electronic systems, what I know about electronics is that the whole system must be powered by smoke, 'cause when you let it out, the system fails. So I don't pretend to speak about how they work, I just appreciate the pleasant display!