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Old 04-06-2008, 02:28 PM   #1

TKMR's Avatar
Aircraft Rotation Speed

Today while playing the map Battle for Qinling, I entered a J10 in order to provide my squad some air support. I taxied out to the Runway, Lined, up, waited a second, and started to take off. Once I got to about 800Kts (Or Km/H whatever the game uses)I attempted to rotate my plane (Takeoff). I, however, realized that my plane wasn't taking off...

This is horribly unrealistic for several reasons. A: If the speeds are in Kts then I was at about Mach 1.5. If the speeds are in Km/H I was nearly at Mach 2. B: The rotation speed of a 747 is about 180 Kts @ 10-20 Degree flaps. Even fully loaded a J10 will not weigh nearly as much as a 747. Taking into account the fact that the J10 only has one engine, even though that engine produces nearly as much thrust as two 747 engines, the J10 should have a rotation speed of no more than 200 kts.

I understand the need, and want, to keep the "noobs" out of the assets such as the planes, but you are afterall trying to be as realistic as possible, and a rotation speed above the speed of sound is completely unrealistic.


This also brings me to another point, the speed of the A10, and Su25. I was flying at approximately 1400Kts, or Km/H. There is now way EITHER of these planes could go THIS fast. They are very slow planes, and normally fly at approximately 200-400Kts (Cruising).

I just wanted to bring these things to your attention.
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Old 04-06-2008, 03:16 PM   #2

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When taking off be sure you are at the very begin of the runway and then use afterburners to get speed.

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Old 04-06-2008, 03:25 PM   #3

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Quote:
Originally Posted by TKMR View Post
Today while playing the map Battle for Qinling, I entered a J10 in order to provide my squad some air support. I taxied out to the Runway, Lined, up, waited a second, and started to take off. Once I got to about 800Kts (Or Km/H whatever the game uses)I attempted to rotate my plane (Takeoff). I, however, realized that my plane wasn't taking off...

This is horribly unrealistic for several reasons. A: If the speeds are in Kts then I was at about Mach 1.5. If the speeds are in Km/H I was nearly at Mach 2. B: The rotation speed of a 747 is about 180 Kts @ 10-20 Degree flaps. Even fully loaded a J10 will not weigh nearly as much as a 747. Taking into account the fact that the J10 only has one engine, even though that engine produces nearly as much thrust as two 747 engines, the J10 should have a rotation speed of no more than 200 kts.

I understand the need, and want, to keep the "noobs" out of the assets such as the planes, but you are afterall trying to be as realistic as possible, and a rotation speed above the speed of sound is completely unrealistic.


This also brings me to another point, the speed of the A10, and Su25. I was flying at approximately 1400Kts, or Km/H. There is now way EITHER of these planes could go THIS fast. They are very slow planes, and normally fly at approximately 200-400Kts (Cruising).

I just wanted to bring these things to your attention.
800 kmh is not mach 2... more like mach 0.75 and i allmost always take off around 400-500 dont know why you couldnt take off at 800.

im not sure but i've been told that the speedometer is fake in bf2.


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Old 04-06-2008, 03:26 PM   #4

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Mora, what you said is irrelevant to his post. He was pointing out how the jets need a coding tweak since they are extremely unrealistic.

Tip: right-click on the GIVE UP button to send a "Need Medic" call. This was an experiment we added in a test build and we forgot to remove or do something better with it for release. Basically we wanted to give the player more opportunities to call for medic while wounded. THANKS DB !!
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Old 04-06-2008, 03:28 PM   #5

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Mora: Yes I know how to take off in PR. The runways in Qinling are rather short, and my aircraft still wasn't taking off nearing 1000Kts...

Mark: If the speeds are in Km/H then yes, I was at about .85Mach, but if the speeds are in Kts than I was at about Mach 1.8 (ASI was at 900ish)
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Old 04-06-2008, 03:39 PM   #6

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the speed is wrong, for every 1000 bf2 speed things, it is about 200mph, mach 1 in the bf2 engine is around 3500.
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Old 04-06-2008, 03:53 PM   #7
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Quote:
This is horribly unrealistic for several reasons. A: If the speeds are in Kts then I was at about Mach 1.5. If the speeds are in Km/H I was nearly at Mach 2. B: The rotation speed of a 747 is about 180 Kts @ 10-20 Degree flaps. Even fully loaded a J10 will not weigh nearly as much as a 747. Taking into account the fact that the J10 only has one engine, even though that engine produces nearly as much thrust as two 747 engines, the J10 should have a rotation speed of no more than 200 kts.
1. The speeds are in BS. You're actually going 1700 BS units = 247 kts.

2. "Rotate"? Why do you like that word so much? First of all you don't measure rotation speed (velocity about an arc at a given point) in kts.

3. Engines are heavy, having two doesn't make you any lighter. Everything about a plane can be changed except for weight. Once you put it on you can't just give it bigger wings and more fuel, cause then you need a bigger engine(s). Which is how the F-111 became the tragedy that it was.

Quote:
I understand the need, and want, to keep the "noobs" out of the assets such as the planes, but you are afterall trying to be as realistic as possible, and a rotation speed above the speed of sound is completely unrealistic.
4. I'm sorry I just cannot for the life of me understand what you mean by "rotate". The planes rotate in the sense of pitch, roll, and yaw, but you can't "rotate" in a straight line.

5. The planes are retardedly easy to fly. Theres no real gravity (try going into a dive or climb and you'll notice something strange), wind, and no real avionics other than the altimeter and compass (stupid speedometers aside). So I can't really say that flying is particularly difficult in PR atm. I've made a way to intensify the force of gravity and drag but its still the BF2 engine.

*REMEMBER

Pulling up = Drag.

Drag = < speed

< speed = < altitude

< altitude = 20 minutes wasted



One is none. Two is one.
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Old 04-06-2008, 04:03 PM   #8
Leo

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Rotate is a term which means raising the nose of the plane during takeoff (AFAIK)

It's cause you're using the J-10, the J-10 blows for some reason
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Old 04-06-2008, 04:03 PM   #9
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CAS, "rotate" is the term used when pulling back on the stick during takeoff; he's using quite correct terminology. Rotation speed is the speed at which the pilot can begin to rotate the aircraft's nose into the air, and is defined as Vr. Suprised you didn't know that, and suprised you didn't google it too

Original poster - CAS is right in that the speeds in the game are completely and utterly bunk; pay no heed to them at all!

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Old 04-06-2008, 04:10 PM   #10

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The takeoff speed required varies with air density, aircraft gross weight, and aircraft configuration (flap and/or slat position, as applicable). Air density is affected by factors such as field elevation and air temperature. This relationship between temperature, altitude, and air density can be expressed as a density altitude, or the altitude in the International Standard Atmosphere at which the air density would be equal to the actual air density.

Pilots of large multi-engine aircraft calculate a decision speed (V1) for each takeoff that dictates action to be taken in case an engine fails. This speed is determined not only by the above factors affecting takeoff performance, but by the length of the runway and any peculiar conditions, such as obstacles off the end of the runway. Below V1, the takeoff is aborted; above V1 the pilot continues the takeoff and returns for landing. After the co-pilot calls V1, he/she will call Vr or "rotate," marking speed at which to rotate the aircraft. The Vr for transport category aircraft is computed such that three seconds after rotation is initiated the aircraft is in the liftoff attitude and at the liftoff speed. Then, V2 (the safe climb speed) is called. This speed must be maintained to meet performance targets for rate of climb and angle of climb.
In a single-engine or light twin-engine aircraft, the pilot calculates the length of runway required to take off and clear any obstacles, to ensure sufficient runway to use for takeoff. A safety margin can be added to provide the option to stop on the runway in case of a rejected takeoff. In most such aircraft, any engine failure results in a rejected takeoff as a matter of course, since even overrunning the end of the runway is preferable to lifting off with insufficient power to maintain flight.

If an obstacle needs to be cleared, the pilot climbs at the speed for maximum climb angle (Vx), which results in the greatest altitude gain per unit of horizontal distance travelled. If no obstacle needs to be cleared, or after an obstacle is cleared, the pilot can accelerate to the best rate of climb speed (Vy), where the aircraft will gain the most altitude in the least amount of time. Generally speaking, Vx is a lower speed than Vy, and requires a higher pitch attitude to achieve.
Takeoff - Wikipedia, the free encyclopedia
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