ORIGINAL: KitBuilder
You want to put a 52 in a 1/5 scale cub? Are you keeping the wings full lentgth? If you clip, it won't be enough in my opinion. You'll need to be a bit on the floaty side with the .52.
I have a 70 4 stroke in my 1/6 clipped cub and it seems just right....
straight from the 1/5 specs page from sigmfg.com
<font size="2" face="arial" color="#000000">
Recommended
Engines</font> <font size="2" face="arial" color="#000000">.40 - .46 in³ (6.5 - 7.5 cm³
2-Stroke
.45 - .65 in³ (7.5 - 10.7 cm³
4-stroke</font>
Can't get any more smack dab in the middle of the suggested engine size than the 52 imo. If it comes to it that the motor just isnt enough to fly the plane how I like, I can always just sell it later, or buy a larger motor. But I am looking for something pretty slow and easy going, personally I think its extreamly dumb to take something that looks like a 65hp civilian two seater plane and do torque rolls with, so I am guessing the 52 will prob be just fine. Arobatics are cool and all, but Ireally like doing scale fly bys, touch and goes and I love the way a plane sounds idling over my head as I "buz the tower" lol.
*Edit* - Ohh yeah it's not a saito 52 its a OS surpass, I feel dumb about that >.<