RE: Everything Radial Engines
Redball, I fly a Sig Waco SRE with a technopower 7cyl 2cu. 33cc, It turns a Graupner 16x8 6900, this equates to 8.83 lbs thrust on the thrust program. she flys very well after take off at half throttle. 5200 does sound alittle anemic for a 16", I would think/hope 5200 relates to the 20" end, at 5200 the 20" equates to 12.24 lbs. of thrust.. The 16x8 is the largest recommended prop for the TP so I would guess the Seidel has more torque at lower rpms and can turn a larger prop, which is what some modelers are looking for as far as scale appearance and functionallity.