Denny Dart II With 6″ MPC Prop

I took it to the park this morning.  Very slight air drift.  Soccer game and dog walking.  With 1,700 turns it did not want to climb much.  I could hear the knots rattling on the stick.  Same with 2,000 turns.  Knots rubbing on the stick prevent the motor from turning the prop.  It might work better with a shorter motor to pull the knots out.  A smaller prop might spin faster.  My motor sizing formula was calibrated on a 6″ Dandiflyer prop.  I went home to see what I could find.
I found a black MPC 6″ prop.  Shiny steel shaft.  The bearing is farther from the stick, giving more room for knot clearance.  It would also produce more up pitch.  About the same downthrust at 5.91 degrees.  Back at the park I put in 2,000 turns.  Up it went, drifting at a right angle to the normal wind direction, over the tall trees along the street, over the condo complex across the street, lost from sight behind the trees.  I ran between the buildings and spotted it again, still climbing.  It circled over the next row of buildings, coming down over the roofs and just cleared to land in the parking lot.  Lucky!  I was sure I had lost it.  It had drifted almost to Camden Avenue, the length of the park.  If it had continued within the park, it would have gone off the lawn and come down in the fenced dog park.  Probably in the air for two minutes.  Next flight on 1,700 turns circled within the open area and came down in the sand of the baseball field.  It was nosing up, so I moved the wing back 3/16″, bent the bearing a bit left and relaunched on remaining turns.  It made a nice steady circle.  Too windy for more trials.  I need a much bigger place to fly.  I will lose this if I wind the motor all the way.
If you want to use a sheet aluminum prop hanger with a single hole, I recommend rotating the wing and tailplane into the same relative angular positions.  Shim the wing up 6 degrees, use no taper on the stick and put a 1/16″ shim between the back of the stick and the tailplane spar.  Or put the tailplane on with the paper on top.  This will get close.  However you set it up, it will need a little adjustment of wing position and sidethrust.

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