ORIGINAL: adrenalnjunky

don't believe everything you read, especially when it comes to flying a 3d plane like a 3d plane. GP/Tower is going to tell you want the bottom line is to fly around in circles so they don't scare a general buyer away by saying it really needs a Supass 70 or .61FX for 3D action.

A 4stroke .65 would fly it - might hover, but not with a lot of pull out. Your 46la would fly it, and probably do loops and rolls and stuff, but the LA series 40 and 46 is notoriously weak, and don't swing big props that well - which is something that 3D planes need.

Plus as mentioned, the UCD 46 is arounf 6 lbs RTF, I wouldn't put less than a good strong bearing .61 2 stroker in it, or no less than a Saito .72 - the 82 would be a better fit.

to answer your other question "Why waste a $300 engine on this..." if that $300 engine makes my $120 arf fly like a dream, it's worth every penny. I'd rather spend good money on engines and radio gear than on a high-dollar arf - the planes tend to get thrown away a lot more regularly than the running gear. A good OS FX or Surpass series, Saito, or YS will stick with you much longer than the UCD probably will.