Boeing, its based on the amount of hydraulic pressure output vs RPM of your engine. If the idle power output is low on the scale, you have to open the throttle a little, with brakes on, to get the flaps to extend quickly.
A month ago or so, i posted airfiles for a model -- a Corsair IIRC -- which you reported as being too fast for your taste. Well, that *air file happens to have a high output to RPM and extends flaps at any RPM, even low idle. Open the air file and copy/paste/overwrite the entry 514 to your Jug's 514 entry. That should help.
The first graph shows my Corsair mod. The second is the stock Corsair's output.
