Helicopter propeller speed up too sudden

Traditional helicopter, px4 v1.8.2
Start at Postion mode, the main propeller keep still, unlike multicopter has idle speed.
When I push the throttle up slowly, when the throttle up to 50%, the main propeller speed up suddenly
this is well in multicopter, but in helicopter this is dangerous, helicopter may crash just on the ground
How to make the main propeller speed up smoothly.

It work well. my helicopter take off safely, what i worry did not happen.

Before flying I set MPC_TKO_RAMP_T 0.8, default is 0.4
Is it a good idea to set the param higher for drone that have large propeller?

Position control smooth takeoff ramp time constant

Comment: Increasing this value will make automatic and manual takeoff slower. If it’s too slow the drone might scratch the ground and tip over. A time constant of 0 disables the ramp