Explanation please

[humble]

The "zoom climb" is a very real thing. If you have two planes traveling at the same speed the heavier plane has more stored energy. Thats simple physics. So if a heavier plane is doing 355 and a lighter one is doing 360. The pilot of the lighter plane pulls up thinking he's got seperation and can rope....then watches as the heavier slower plane climbs up his tail pipe. The reason is that energy is not entirely dependant on relative speeds. It is possible for the slower plane to have equal or greater energy available.

[Vad]

Originally posted by humble
The "zoom climb" is a very real thing. If you have two planes traveling at the same speed the heavier plane has more stored energy. Thats simple physics. So if a heavier plane is doing 355 and a lighter one is doing 360. The pilot of the lighter plane pulls up thinking he's got seperation and can rope....then watches as the heavier slower plane climbs up his tail pipe. The reason is that energy is not entirely dependant on relative speeds. It is possible for the slower plane to have equal or greater energy available.

Unfortunately,Humble, it's not basic physics.
Energy is the sum of potential and kinetic energies, and both of them depends on mass.
KE = mv^2/2 - kinetic
PE=mgh - potential.
So, when you zoom kinetic energy transforms to potential, and height of thge zoom will be
 mv^2/2 = mgh, =>
h = v^2/(2g).

As you can see there is no mass in this formula. Alt of zoom depends only on initial speed.


Of course, you are right with you final conclusion, massive fighter tends to zoom higher, but not because of simple physics. In real life you have to add drag into equation which doesn't depend on mass. But it's very complcated, and there is no way to model thsi process correctly in sims.

I don't know how accurate HTC modelled this in AH but I know for sure that they couldn't do that absolutely correct, it's just impossible. Too many different factors are involved.

edit due typo

[humble]

your wrong........{based on my understanding of basic physics}

You have 2 planes not one. So mass effects total energy. The slower heavier plane might have more total energy then the lighter faster one. If you have only a single incident then mass is constant (excluding fuel burn). If you have two planes then you need to compute total energy for both to calculate "zoom"....and as you show mass is an integral part of the calculation to determine total energy. So you would need to calculate "total energy" seperately for both planes..."zoom" is not constant across all planes its a combination of speed and mass....lighter planes have less "zoom" at any given speed then heavier ones....

[Vad]

Originally posted by humble
your wrong........{based on my understanding of basic physics}

You have 2 planes not one. So mass effects total energy. The slower heavier plane might have more total energy then the lighter faster one. If you have only a single incident then mass is constant (excluding fuel burn). If you have two planes then you need to compute total energy for both to calculate "zoom"....and as you show mass is an integral part of the calculation to determine total energy. So you would need to calculate "total energy" seperately for both planes..."zoom" is not constant across all planes its a combination of speed and mass....lighter planes have less "zoom" at any given speed then heavier ones....

I'm right but it's obviously stalemate situation.

You lack knowledge of elementary physics, I don't have enough knowledge of English language  to prove that.

[RASTER]

Is it the "zoom climb" being referred to?

The complication is not only in the mass but in many forces such as in the pull down of gravity which Galileo and Newton demonstrated acts the same regardless of mass and the lighter aircraft has the action of the prop to help maintain its climb inertia and then there is prop pitch, the effect of rapid change in air density and all sort of little scientific snots that always tend to be more important than earlier thought. The centrifugal force on a small mass as compared to a large mass as it changes its attitude into a vertical climb also must greatly enlarge the radius where much of the energy is lost in the transition to vertical.

AH is a fun simulation but there are flight manuevers which do not translate well from RL. I would suggest the orginal poster study AH physics and forget trying to rationalize how these diverge from RL. There would be something to complain about if these attributes that he noticed weren't omni present.

RASTER

[humble]

Originally posted by Vad
I'm right but it's obviously stalemate situation.

You lack knowledge of elementary physics, I don't have enough knowledge of English language  to prove that.

Not a stalemate at all, if your right your right. But an a20 going 400 mph has roughly 4 times the energy of a zeke. Now if your saying both would zoom to exactly the same height just plug the numbers in for me. My understanding is the difference between a sustained climb and a "zoom" climb is based on the retention of inertia due to this stored energy. Basically why heavier planes like the P-47 have such good "zoom climb" even though they have poor sustained climb rates. The plane expends more energy per foot of climb and like a battery this energy is "stored". A planes "zoom climb" has always been a part of its combat capabilities....if all planes "zoomed" the same it would be a constant and not a variable so my natural tendency is to disagree with you on this.

[humble]

Originally posted by RASTER
Is it the "zoom climb" being referred to?

The complication is not only in the mass but in many forces such as in the pull down of gravity which Galileo and Newton demonstrated acts the same regardless of mass and the lighter aircraft has the action of the prop to help maintain its climb inertia and then there is prop pitch, the effect of rapid change in air density and all sort of little scientific snots that always tend to be more important than earlier thought. The centrifugal force on a small mass as compared to a large mass as it changes its attitude into a vertical climb also must greatly enlarge the radius where much of the energy is lost in the transition to vertical.

AH is a fun simulation but there are flight manuevers which do not translate well from RL. I would suggest the orginal poster study AH physics and forget trying to rationalize how these diverge from RL. There would be something to complain about if these attributes that he noticed weren't omni present.

RASTER

Both planes have props....sustained and zoom climb are different. As a general rule heavier planes "zoom" better.

[RASTER]

Yes, both planes have props. However, explained another way,  it is my belief that the lighter plane might benefit more from the constant thrust applied during the climb than the A20 which takes such a long time to gain inertia.

Also the amount of inertia lost in translating a small plane from the horizantal to the vertical would be less than a larger plane in the same radius.

RASTER

[Badboy]

Originally posted by Vad
Of course, you are right with you final conclusion, massive fighter tends to zoom higher, but not because of simple physics. In real life you have to add drag into equation which doesn't depend on mass. But it's very complcated, and there is no way to model thsi process correctly in sims.

One way to think of this, just using simple physics, is to consider which of the two zooming aircraft will lose speed more quickly, that is, which will have the greatest deceleration. To do that you can use Newton's second law, which is the starting point for the equations of motion for aircraft flight models. This is just written as f = ma  and we read that as force equals mass times acceleration. So if you want to figure out which aircraft will slow down more quickly if they both start at the same speed then Newton's law applied to the aircraft's body axis could be written like this:

T - d - m x g x Sin(theta)   = m a

where T = prop thrust, d = total drag, and theta = angle of climb.

If you divide both sides by the mass you get:

T/m - d/m - g Sin(theta) = a

Now assume you zoom climb two similar aircraft at the same angle, but one has full internal fuel and the other is almost empty so that the only difference is their mass. Then for comparison purposes the equation can be reduced to:

T/m - d/m = a

From this it is easy to see that the aircraft with greater mass will decelerate more slowly. So, the amount of deceleration will always depend on the mass of the aircraft.  

I don't know how accurate HTC modelled this in AH but I know for sure that they couldn't do that absolutely correct, it's just impossible. Too many different factors are involved.

I'm sure they model it very accurately. In any flight model the solution of the equations of motion are being done numerically, and the accuracy depends on which numerical method is being used and the frequency, and you can get an acceptable degree of fidelity at 15hz and most modern flight models run a lot faster with a high degree of precision. The significant factors are all being accounted for, if they weren't it would be fairly easy to detect the issues during flight tests.

Hope that helps.

Badboy

[Masherbrum]

Are you two bored?

[Vad]

Badboy, I have PhD in engineering
Don't tell me that, explain that Humble. I was programming and using  Runge-Kutt methods 20 years ago.

BTW, drag in your formula ( and even T but it's the next level of accuracy)depends on V^2, where V- speed. So, you need to integrate the full system of equtions.

Ok, I've already written that final Humble's conclusion is correct -  more massive plane will zoom climb better. My remark was only about the way how he made that conclusion. It's not simply mc^2, and even not mv^2/2

[Vad]

Originally posted by Masherbrum
Are you two bored?

At work? Of course!

[humble]

Originally posted by Vad
Badboy, I have PhD in engineering
Don't tell me that, explain that Humble. I was programming and using  Runge-Kutt methods 20 years ago.

BTW, drag in your formula ( and even T but it's the next level of accuracy)depends on V^2, where V- speed. So, you need to integrate the full system of equtions.

Ok, I've already written that final Humble's conclusion is correct -  more massive plane will zoom climb better. My remark was only about the way how he made that conclusion. It's not simply mc^2, and even not mv^2/2

Hmmm.....

mass effects total energy

mass is an integral part of the calculation to determine total energy

My understanding is the difference between a sustained climb and a "zoom" climb is based on the retention of inertia due to this stored energy

If you have two planes traveling at the same speed the heavier plane has more stored energy

Cant see where I was/am wrong. I dont recall (beyond E=MC2) using any formula. Obviously the theory of relativity is not the correct formula to actually calculate "zoom"....however its fundemental principle that no system "loses" energy. Accordingly under the theory of relativity a plane is "storing" energy as it climbs....the heavier plane needs to expend more energy to reach the same alt and/or speed and accordingly has more "total energy" then the lighter plane at equal speed/alt.

now this is an observable event and a specific formula could be written to explain/perdict this observed event .... or maybe the plane could fall out of the sky and pop a guy on the head.

This is basic high school physics....no PHD required. Applied mathematics is just that. I dont see the problem in taking a fundemental equation and applying it to explain a readily observable event. I was/am "right" because I understand the fundemental laws of energy.

[Vad]

Ok, humble,


1) We have 2 plains, the first with mass m1=10, the second with mass m2=100. The second is 10 times more heavy than the first.

2) Both of them moving with speed V=10.

3) Energy of the first is m*V^2/2, or 10*10^2/2=500
   Energy of the second is 100*10^2/2=5000.

Yes, you are correct, the energy of the heavy plane is 10 times more than the first.

4) Both of them zoom climb, and their kinetic energy transforms to potential energy. Potential energy equal
m*g*h (mass by gravity acceleration by height)

5) the first plane can use all its energy to climb up to
m1*g*h = m1*v^2/2

let take g=10, it doesn't matter, its the same in both calculations.

10*10*h = 10*10^2/2 = 500

It means that using its energy (inertia) it can climb up to
h = 500/(10*10) = 5
The first plane will zoom climb up to 5.

6) The second plane will climb:
m2*g*h = m2*v^2/2

100*10*h = 100* 10^2/2= 5000
what gives us

h = 5000/(100*10)  =5

The same 5.

Ok, just tell me what is paragraph you agree with, what is not and why.

And don't forget, in real life it doesn't work like I've described above because of drag.  And I told it before.

[dtango]

Snaphook:

Take a look at Badboy's equations.  Decceleration (or acceleration) in a zoom climb is:

T/m - D/m - g*Sin(Theta) = a

4 variables determine the rate of zoom: 1) thrust, 2) drag, 3) angle-of-climb (theta), and 4) mass - not just mass alone.

Assuming the same angle-of-climb, the equation is simplified to:

T/m - D/m = a

If you had two similar planes at the same airspeeds but different weights, it's true the plane with more mass would decelerate slower as Badboy points out.

However thrust and drag can be very different from plane to plane and both also vary with airspeed so between dissimilar aircraft you have to account for theses variables as well to determine which plane would decelerate faster or slower in a zoom.

Tango, XO
412th FS Braunco Mustangs