Tex, we hold the plane on the brakes at a standstill until the engines are stable at about 30% thrust - we check the rpms, temps, and pressures to make sure they're all behaving - then let the brakes go and push the power up the rest of the way. We're normally up around 145kph before the power is settled on take-off power.
I guess we could go to max power on the brakes, but it's not a good idea as the engines will, for example, suck a man standing in front of the plane nearly 25 metres away, let along crud on the runway and grass on the sides.
For other reasons it's also dangerous to do. For example, if one engine stalls (yes, it can happen) and loses power when the other three are up near maximum then the plane WILL turn very sharply and most likely will go right off the side of the runway, you just can't stop it in time. Being a rather expensive toy, we don't do that.
However ....
one day in Liverpool in the UK we were empty and did a full power take-off and I would it up a fair bit on the brakes before letting it go. The thrust was so much that the nosewheel nearly jumped right off the ground! We hardly used any runway at all, and blasted up at a really steep angle into the cloudy English sky.
The really run bit was that the tower called us up and said that we'd dug a hole in the runway from all that thrust! (Yeesssss, my work is done ....)
The stall speed varies with a few things, but the simple answer is from about as low as only 165kph up to as high as 430kph.
I guess we could go to max power on the brakes, but it's not a good idea as the engines will, for example, suck a man standing in front of the plane nearly 25 metres away, let along crud on the runway and grass on the sides.
For other reasons it's also dangerous to do. For example, if one engine stalls (yes, it can happen) and loses power when the other three are up near maximum then the plane WILL turn very sharply and most likely will go right off the side of the runway, you just can't stop it in time. Being a rather expensive toy, we don't do that.
However ....
one day in Liverpool in the UK we were empty and did a full power take-off and I would it up a fair bit on the brakes before letting it go. The thrust was so much that the nosewheel nearly jumped right off the ground! We hardly used any runway at all, and blasted up at a really steep angle into the cloudy English sky.The really run bit was that the tower called us up and said that we'd dug a hole in the runway from all that thrust! (Yeesssss, my work is done ....
)The stall speed varies with a few things, but the simple answer is from about as low as only 165kph up to as high as 430kph.
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