Amount of elevator trim required for level flight?

[Bremspropeller]

3 hours ago, Nealius said:

I need F to solve CL if I have an IAS. I don't see a value for F in this thread. Perhaps I'm using the wrong formula?

You might want to have a look at the four forces acting on an aeroplane in flight

 

On 10/15/2021 at 1:52 AM, Nealius said:

I would assume museum aircraft would need excess nose trim on account of them lacking the weight of four guns and all that ammo. 

Replacing the guns with weights would be the easiest way to tackle that.

[Nealius]

52 minutes ago, Bremspropeller said:

You might want to have a look at the four forces acting on an aeroplane in flight

Those aren't F in that formula. F is a value of lift force in neutons, kiloneutons, meganeutons, giganeutons, or pounds-force. See calculator here. To get CL at a known speed (or speed at a known CL) I need to know the lift force. But to calculate the lift force I need to know both CL and speed, making it a Catch-22. Which makes me wonder if there is a different formula I should be using. 

Edited October 16, 2021 by Nealius

[Bremspropeller]

7 minutes ago, Nealius said:

Which makes me wonder if there is a different formula I should be using. 

No.

 

Hint:

 

[Nealius]

Where's the specific foot-pounds of lift force in your hint? All I see is words. No numbers.

 

Edited October 16, 2021 by Nealius

[Bremspropeller]

Are you for real?

[Nealius]

Yes, I'm for real. I'm trying to learn and educate myself and you're being a condescending jerk making fun of me for trying to learn. Do you make fun of babies when they fall over while trying to walk? Take that analogy and replace "baby" with layman and "walking" with aeronautical math. 

Edited October 16, 2021 by Nealius

[Bremspropeller]

Well, for starters:

If you want to learn, a good approach would be not insulting people trying to make you.

Next, you'd want to take a look at what those forces actually imply. I could just tell you that lift equals weight, but what are you going to take from that if you don't even try figuring out the easiest stuff?

Then there's your little formula that won't lead you anywhere, as you're mixing imperial and SI units. Covert everything to one system. Best way is using SI, as it doesn't come with a duckton of unit-conversions.

 

 

[BIGNEWY]

Gentlemen we are getting off topic now. 

Yo-yo has explained the trim on the Mosquito unless you have any more to add this thread is nearly done. 

 

thanks

[Nealius]

Right. I shouldn't insult people. And "teachers" shouldn't make fun of those trying to learn in the first place. 

Second, how is that implication clear? Lift is a force overcoming the weight of the aircraft, but there's nothing stating that the force doesn't exceed the weight of the aircraft, so I don't know if that value is exactly the weight of the aircraft or higher than the weight of the aircraft.

At any rate, I should investigate this in a more learner-focused forum.

Edited October 16, 2021 by Nealius

[GAF_flyer]

"but there's nothing stating that the force doesn't exceed the weight of the aircraft"

Yes there is. Its in the headline. Level Flight always implies an equilibrium of forces, wich in this case means Lift = Weight.

And Yes, I'd definitely laugh at a baby falling over 

Edited October 16, 2021 by GAF_flyer

[razo+r]

45 minutes ago, Nealius said:

. 

but there's nothing stating that the force doesn't exceed the weight of the aircraft, so I don't know if that value is exactly the weight of the aircraft or higher than the weight of the aircraft.

.

 

There is, it's in the title. Level flight. 

 

Even in non-level flight, a simple drawing of forces and angles will get you quickly to the corresponding equation. 

[Nealius]

I'm seeing that a lot of the information I missed is an inference that isn't obvious to those without the requisite background knowledge. Background knowledge that I don't have. At this point I'll just give up on trying to learn this on my own until I can save enough money for an actual class where people don't assume you know/can infer things you don't/can't and then treat you like an idiot for failing to meet their assumed expectation. 

Edited October 16, 2021 by Nealius

[razo+r]

Well, it's a basic equation of forces, pretty much one of the first subjects taught in physics classes. So dont be put down when people react in a weird way when someone doesnt understand this at first glance. 

 

You can always ask though. 

[Holbeach]

1 hour ago, razo+r said:

 

 

You can always ask though. 

Maybe if I ask this question for the third time, do you think I'll get an answer?

 

3. 4 ticks nose down, will overcome the elevator power and send it into an uncontrollable dive, from which you can't recover?

This shouldn't be possible.

 

..

[Art-J]

In both high school and at the uni, there were teachers who were feared yet widely respected (even by, let's say, difficult students), and these who seemed to be more interested in showing off their "ubermensch" ego to dirty peasants on the other side of the lecture hall, with teaching being a second priority. Brems, if you're so fond of puzzles, you can deduce which category you're closer to.

Not everyone on this forum has an aviation or even engineering education/proffesional background.

But I digress... Let's go back on topic.

@HolbeachIf I understand correclty, those 4 ticks down are for aft limit of CoG - wherebaouts of 32% MAC? I guess we could try to figure outt how to simulate such a radical loadout config in DCS (if it's possible at all). We don't have bomb bay tank implemented, but maybe a mix of pair of 500-pounders and empty ammo containers in the nose will do? That should move CoG aft quite a bit.

[Bremspropeller]

5 minutes ago, Art-J said:

In both high school and at the uni, there were teachers who were feared yet widely respected (even by, let's say, difficult students), and these who seemed to be more interested in showing off their "ubermensch" ego to dirty peasants on the other side of the lecture hall, with teaching being a second priority. Brems, if you're so fond of puzzles, you can deduce which category you're closer to.

Not everyone on this forum has an aviation or even engineering education/proffesional background.

Yeah, right, "Übermensch". If you think that nudging a person into the right direction, so they can figure things out by themselves and getting the bigger picture is an ego-thing, be my guest. I'll take that over carrying an entitled person over the doorstep.

[Holbeach]

16 hours ago, Art-J said:

@HolbeachIf I understand correclty, those 4 ticks down are for aft limit of CoG - wherebaouts of 32% MAC? I guess we could try to figure outt how to simulate such a radical loadout config in DCS (if it's possible at all). We don't have bomb bay tank implemented, but maybe a mix of pair of 500-pounders and empty ammo containers in the nose will do? That should move CoG aft quite a bit.

The trim is only supposed to relieve the pressure on the pilot stick to achieve a level of flight.

If you advance the trim to about 3.75 you will have to pull the stick back to its full range. This is not possible IRL.

Adavance the trim to 4 and you will have overcome to elevator authority and will entre a dive. Completely unacceptable.

Advance trim to 4.5, (7.5 deg) and the dive is violent and will cause a red out. For obvious reasons this cannot happen on the real plane, (or any plane).

The trim is more powerful than the elevator.    Not possible and therefore incorrect!

 

..

Edited October 17, 2021 by Holbeach

[SMH]

PLEASE reconsider your position on this. I don't know how you can argue against video evidence. 

[Art-J]

  

20 hours ago, Bremspropeller said:

Yeah, right, "Übermensch". If you think that nudging a person into the right direction, so they can figure things out by themselves and getting the bigger picture is an ego-thing, be my guest. I'll take that over carrying an entitled person over the doorstep.

I get the nudging approach, I agree with it and I see Yo-Yo nudging him allright. Your "are you for real?"' tone on the other hand was nothing more than a condescending response to a valid question, not adding anything to the explanation of the issue. The "there are no stupid questions, only stupid answers" phrase comes to mind. Besides, if he bothered to investigate the graphs, calculate the indicator-to-tab angle ratio and search for the formula for a start, that in itself shows me he wasn't just interested in getting a straight answer on a silver plate, but  at least made some effort to understand something - I don't know where your "carrying entitled person over a doorstep" came from then.

47 minutes ago, SMH said:

PLEASE reconsider your position on this. I don't know how you can argue against video evidence. 

One cannot argue with wartime measurements and charts either, though, especially when they provide more data about the plane configuration than the video. So I kind of understand why Yo-Yo implemented things the way he did, but why the restored KA114 controls seem to be rigged in a different way remains a mystery.

[SMH]

1 hour ago, Art-J said:

  

I get the nudging approach, I agree with it and I see Yo-Yo nudging him allright. Your "are you for real?"' tone on the other hand was nothing more than a condescending response to a valid question, not adding anything to the explanation of the issue. The "there are no stupid questions, only stupid answers" phrase comes to mind. Besides, if he bothered to investigate the graphs, calculate the indicator-to-tab angle ratio and search for the formula for a start, that in itself shows me he wasn't just interested in getting a straight answer on a silver plate, but  at least made some effort to understand something - I don't know where your "carrying entitled person over a doorstep" came from then.

One cannot argue with wartime measurements and charts either, though, especially when they provide more data about the plane configuration than the video. So I kind of understand why Yo-Yo implemented things the way he did, but why the restored KA114 controls seem to be rigged in a different way remains a mystery.

I find it very unlikely that they trim out in cruise to anywhere but very close to the center position. Why would you make the center not the center?

And, again, this strong nose-heavy trim is an indicator that we're tail heavy, which explains the extreme touchiness in the pitch axis that real Mosquito pilots don't report. Why would they make the aircraft like this when it's just a matter of balancing it correctly to make it far more stable?

It's clearly wrong, and so is the Spitfire. (I'd bet you money that they started with the Spitfire model for this one.)

Edited October 17, 2021 by SMH

[Yo-Yo]

36 minutes ago, SMH said:

I find it very unlikely that they trim out in cruise to anywhere but very close to the center position. Why would you make the center not the center?

And, again, this strong nose-heavy trim is an indicator that we're tail heavy, which explains the extreme touchiness in the pitch axis that real Mosquito pilots don't report. Why would they make the aircraft like this when it's just a matter of balancing it correctly to make it far more stable?

It's clearly wrong, and so is the Spitfire. (I'd bet you money that they started with the Spitfire model for this one.)

 

You lost. How much money did you bet?

 

[SMH]

12 minutes ago, Yo-Yo said:

You lost. How much money did you bet?

 

I said I would, not that I did. It concerns me that you have reading comprehension issues. That might explain a lot of this, actually. 

[Yo-Yo]

Either Spit or Mosquito have the same stability characteristics as they had during WWII. If you have proofs that something is wrong in comparison to authentic documents - welcome. Otherwise it's only speculations.

[Yo-Yo]

13 hours ago, Holbeach said:

The trim is only supposed to relieve the pressure on the pilot stick to achieve a level of flight.

If you advance the trim to about 3.75 you will have to pull the stick back to its full range. This is not possible IRL.

Adavance the trim to 4 and you will have overcome to elevator authority and will entre a dive. Completely unacceptable.

Advance trim to 4.5, (7.5 deg) and the dive is violent and will cause a red out. For obvious reasons this cannot happen on the real plane, (or any plane).

The trim is more powerful than the elevator.    Not possible and therefore incorrect!

 

..

 

There is no "4.5" position, just pure 4. 3D parallax...

The parrallax depends on the actual camera position, so the right reading is better to see using inner part of the pointer.

 

[Holbeach]

Here is the view I use to set the trim. (No parallax).

Which one is 7.5 deg on the tab? The tab is still moving between the two.

 

Both of these settings will overcome elevator full aft stick.

 

..