Dynamic Propeller Balancing and Fairings

Lee Apaka flew down this morning to balance the propellers for Greg and I.  Since I’m running at 2500 RPM with wide open throttle, we tied the plane back to the car and chocked the wheels.  Greg and I both have really smooth engines (a testament to how well Aerosport Power builds then), but they can always be better.  Greg started out at 0.35 IPS (inches per second), so Lee added 17g of weight (a bolt and some area washers) to the spinner backplate.  Amazingly, he nailed it on the first time and hit 0.02 IPS.  Anything under 0.1 IPS is pretty good, and 0.02 is somewhere between excellent and perfect.

After Greg wrapped up his run, I pulled my plane into position and Lee hooked up his gear.  I was only at 0.12 IPS when we started, so I was already a bit better.  We added 5.9g to my spinner backplate and ran it again. That dropped me to 0.11 IPS.  The formula wanted another 6+g mounted just a few inches away from the first weight.  Lee decided instead to add one more washer and a slightly longer bolt.  I did a third run and hit 0.02 IPS.  I’m super happy with the results.

Here’s where the weight was added to the spinner backplate.  There is a washer and an AN364 nut on the other side.  Our fix was to add one additional washer under the head shown here.

I jacked up the plane and started working on the gear leg fairings.I laid up some additional fiberglass inside and then mixed up some epoxy/flox mixture and gooped it around the line where the fairing will sit against the gear.  I then started working on the wheel pants.  With the fuselage level, I supported the rear of the fairing to get the center 8 5/8″ from the ground while simultaneously adjusting the fore/aft position so that the outer support bracket edge lines up with the step in the fairing.  I then drilled it to the outer fairing.

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