The A40's prop is a high priced replacement. I replaced about 3 of them and then switched to MAS which is tougher than
APC. Be careful and not let the A40 get too far away. If you cannot see the planes orientation then you will lose it.
That is how I crashed mine. The Evolution engine wants the idle to be set progressively leaner as it breaks in. After
setting mixture at high speed you get stumbling when rapidly going from idle to wide open when idle is too rich.
After about 30 flights I had to move the idle limiter as it ran out of adjustment range. After a non repairable crash you
can move everything over to a World Models Sky Raider Mach I or II which for $70 gets you going again inexpensively
and with more aerodynamic capability. A MACS muffler is an inexpensive hop up trick which can give a 5.5 lb plane
vertical acceleration with a .46 size engine. Good Luck with your A40.