The 2-stroke motor is still king Electrics are making slow inroads but, even as of 2019, they’re years away from taking over.
There are significant variables in motors. Even two identical motors, spinning the same prop, with the same model carb, sitting next to each other may differ in thrust by 10%. So it’s not appropriate to pin a thrust on a motor without having broad experience with it. Plus, some makers will sacrifice power for quiet.
Thrust numbers are likely to be estimated but that will be clear in the reviews. I try to correct for extra large props. A machine with 120 pounds of thrust using a 51″ prop, for example, will probably be about 105 pounds with a 48″ prop.
Motors will not be reviewed separately from the frame they come with because each manufacturer has a different implementation — different props, carbs, air intake, priming, exhausts, and sometimes even redrives. Since I’m not one to mount stock engines on a frame, it’s not practical. I’m waaay too lazy for that! The best bet for those looking to buy just a motor is to look for a paramotor maker that uses the engine stock.
One last thing regarding thrust: nothing is free. Extra push probably means more vibration, more torque twist, and/or more noise. Not always, of course, but that’s the general trend. Many times three blade propellers help with vibration but do not necessarily increase thrust. I remember an airplane model by Piper, the Seminole, whose manual clearly showed thrust was less with the 3 blade prop than it was with the 2 blade prop as evidenced by longer takeoff runs and slower climbs. So why pay extra for a 3-blade prop? Ramp appeal. Yup, it just looked cooler sitting there.