When hand launching, Arduplane accelerates to a minimum speed before pitching up. How does ArduPlane calculate this speed? What parameters can be adjusted to change this speed?
Did you learn how to do it ?
Yes. This is an important and often neglected parameter for fixed wing aircraft, whether you are using conventional taxi takeoff or hand launch. I was surprised to see “someone” pick up on this after more than two years.
Let’s welcome “Someone” to our community! LOL 
I heard that “Someone” figured this out but I don’t remember who it was. No wait, Who is on 1st.
The way the speed to pitch up is calculated is part of the Ardupilot source code. If you are interested in understanding how this is calculated, start reading this section of code at line 151: https://github.com/ArduPilot/ardupilot/blob/master/ArduPlane/takeoff.cpp You will see it is related to the cruise speed of your aircraft. There is a default for cruise speed that works well for estimating a good speed to pitch up for most hand launched model planes. For taxi takeoffs with larger aircraft it is best to have a test pilot perform a few flights, and then set parameters to replicate the best set of conditions.