Crabby. Hows the maiden going - been up yep?. I have exactly the same plane - CMP Yak 54 140 fitted with an SPE40 as well. Its a really heavy plane for the wing loading so keep the speed up - other wise she will tumble out of the sky with no recovery prospects. The SPE pulls this plane with authority - a great combo. At the moment I dont know wether I hate the Yak or love it. It's bitten me twice with no notice. Make sure you keep the elevator movement really tight or she will snap and die. Good luck. lets us know how it goes.