PLEASE post detailed pictures. That pre-rotator option has been discussed, but I've rarely seen pictures. It seems that only the 'old-timers' (I mean that in a reverent way) know of it. Bensen wrote of a 'Big Bertha' option wherein the rotor was powered by a small (or multiple) motor such as you describe. YES, pictures, please. Brian
I have the belt. I just purchased this gyro and I finally have the time to get into it. I plan to remove the upper unit from this one and install it on my original Bensen. My only concern is with the added weight to one side. am still new to this but if I am correct it does not matter where you add weight because a spinning object wants to stay balanced. A good example is when you hold a bicycle wheel by its axle and spin it it is hard to tilt it. I hope that I am wright about this but I am not sure. It sure would be nice if this was a proven system because this little motor should spin that rotor pretty fast. I will try and find out the hp. I am now going to look at it in detail and try and start the motor. Any help with this from a more experienced Bensen guy would really be appreciated. I will post my results once I start the motorA belt appears to be missing. Is that roundish upward-pointing brown object the muffler?
Is there a separate throttle linkage?
Have you tried to start the little engine?
Does it list a Hp for the pre-rotator engine?
Thank you so much for the info. Now my final question. Would you use it ?That unit was Bensen's "deluxe" offering for many years. The O&R engine is not terribly powerful, but would bring Bensen blades (small and light) up to about 150 RPM. At this RRPM, you still have to begin your takeoff run with partial power, lest you flap your blades.
Most prerotators add more weight to one side of the head than to the other. The effect on the controls is there, but is slight.
IIR, there is no engage-disengage control. Once the O&R engine is started, it engages and the blades begin to spin. For that reason, you don't start it near a hangar or spectators; wait until you are near the point where a clear taxi run to your takeoff point is possible. The reach up, yank the cord and hope for a start. A shutoff switch is optional.
Because you start your main engine first, and then reach up to pull the O&R's start cord, it can be hard to tell when the prespin engine has actually started. The guys in our chapter who had one would touch the engine body to feel for vibration.
The 2-stroke O&R engine found other uses in tiny motorbikes and powered concrete finishers.