Take-off speed reference

[711Hancer]

I have been trying to make calculations for the takeoff reference table provided, but no matter what, I cannot takeoff at the exact speed(+- 5knts) provided by the table.

 

In this case;

 

Taking the reference of gross weight of 40.000 which I checked before starting the mission including empty weight + fuel weight and payload, I should be rotating on 127knts with flaps 7 and the aircraft should takeoff on 137knts. (I tried this with calm winds, i.e crosswind of 4knts)

 

But generally this is not the case. I start rotating on 137 knts as stated but the plane lifts off generally around 165 knts and it wont be a smooth take off since in order to catch the reference figures I sometimes try to push harder on the stick giving me 12 - 15 degrees of pitch as soon as I takeoff. (t/o trim is enabled btw)

 

Do I have to neglect this table and advance to 160knts and then try to rotate slowly or do you guys achieve the takeoff reference table speeds?

[GGTharos]

No, pull the stick back half-way or more to rotate to +10 pitch at rotation speed. Maintain this pitch (ie. do not let it become higher or lower).

[711Hancer]

Thank you for your answer

 

so in our example at 137 knots my ADI and HUD must show 10 degrees before takeoff?

and the plane eventually lifts off at 147?

 

or I have to pull at 137 and wait for a/c to lift off at whatever speed.

 

sorry for my noobish questions :)

[GGTharos]

Yep, pull at 137 (if that is your rotarion speed) get it to +10 (by the gun cross, or whatever other HUD reference you want to use) and on the ADI, and let it lift off at whatever speed it wants to fly - note that speed :)

 

Your take-off might be smooth though that you might not notice, so keep an eye on the VVI as well.

[711Hancer]

Thanks again

 

and I think that by pressing t/o trim, the indicator light flashes just one second right? It does not illuminate all the time.

[GGTharos]

You should hold TO trim down for a few seconds. You'll still have to pull a lot of stick for rotation.

[Sinky]

I usually press and hold the T/O Trim button until it lights up for a few seconds.

[Chris CDN]

Does pressing the take off trim switch actually adjust the trim from the default position on a cold start? I have yet to notice a difference, so I usually omit this step in the start up procedure.

[b101uk]

Taking the reference of gross weight of 40.000 which I checked before starting the mission including empty weight + fuel weight and payload, I should be rotating on 127knts with flaps 7 and the aircraft should takeoff on 137knts. (I tried this with calm winds, i.e crosswind of 4knts

 

they are 21080kg in normal use fully loaded up though the MTW is 23000kg

21080kg is ~46460lb, ~21.08 tonnes, ~20.748 tons (long), ~23.241 tons (US/short)

 

So I don’t quite know what the “40.0” of something is?

 

Also the ambient temperature of the air will play some small part in real life not just with lift but also more power.

[funkster]

AFAIK - Pressing the T/O Trim resets all trim. You should press and hold till you see the light. If you have previously trimmed a lot then you will notice it takes longer before it lights presumably as it is resetting more.

 

You can also use this in bombing runs to get an untrimmed approach.

[Merlin216]

The trim at cold n dark is usually already in the TO state. If you were to trim the aircraft while on the ground, you would notice the stick moving with the trim. If you press and hold the TO trim button while looking at the stick, you will notice it move back to center.

[Frederf]

The depressable pipper is set to the zero sight line by default so that makes a good reference to put on the 10 degree pitch ladder rung.

 

I've found that I am able to initiate rotation at the prescribed speed but lifting off at +10 knots never seems to happen. Main gear tend to leave the surface significantly later.

[Insanatrix]

Same I always tend to rotate around 130 knots and wheels leave the ground around 150-170 knots depending on loadout. Sometimes it feels like the wheels are almost stuck to the pavement and they are trying to come "unglued".