Sunday, August 10, 2014

Great Ideas From Phoenix Owners

 This one is absolutely the best one.  Jeff Shingleton reported that he saw significant performance gains from the addition of top surface gap seal to the elevator.  As you probably know, air below airfoils in high pressure areas tries to sneak around the ends (vortex) or up through gaps, to get to the lower pressure area.  So I ordered some 35mm x 33m mylar gap seal tape from Wings and Wheels.  To hold it to the surface, transfer tape is used, 16mm x 33m.  And then to make sure it does not come loose, 25mm PVC tape is used along the leading edge of the mylar.  There are also application instructions on the W&W website.
Ok, so what are the performance changes?  To find out, I took my clean and polished plane up for some pre-gap seal numbers.  Minimal stuff in the baggage area, 5 gallons of fuel total and 190lb me flying solo:  At 0 degree flap, stall buffet is 42kts, stall is 40kts.  With 10 degrees of flap, buffet is at 41kts and stall is 38kts.
After the gap seal was applied the next day, I flew again.  0 degrees flap, buffet is 40kts, stall is 39kts.  At 10 degrees flap, buffet is 39kts and stall is 36kts.  So a 2kt improvement after the gap seal!  I was able to thermal at a constant 40kts without buffet, using 10 degrees of flap.  I'm telling you, it was almost like flying a different glider!  Just amazing.  Thanks Jeff!!!
I will also apply the gap seals to the undersurface of the elevator and both sides of the rudder for drag reduction.  I also bought some 60 degree zig-zag turbulator tape and will apply it to the wing undersurface once I figure out where to put it.

Next up, O rings on the pitot tube.  The Boulder Phoenix Syndicate had very low airspeed readings on both Dynon and mechanical ASI's.  They found a missing O ring (the 3mm ring) and the others were cracked.  They have replaced all of the O rings and everything is good now.  Their probe had been stored on the front panel in the sun so maybe the O rings dried out and rotted earlier than usual.  I keep my probe on the back shelf and apply Carmex regularly.  The photo above is my probe and O rings and they all checked out good.  O rings can be obtained from theoringstore.com  They are Buna-N 70 O rings, 1mm x 3mm, 1mm x 6mm, and 1mm x 8mm and cost 14, 16, and 18 cents apiece.  The Boulder boys plan to replace the rings yearly.  
Oh yes, Eric Greenwell came up with the great idea of wrapping the black probe with yellow tape to make it more visible.  We do that to all of the new planes now.


 The O Ring Store also sells this lube specifically for the O rings, so I bought a tube and will use that from now on instead of the Carmex.


 Another pilot who will remain nameless took off one to many times without the probe installed.  I admit I have done this as well.  (If this happens to you, will you immediately think to use the GPS speed to get back on the ground?).  So his idea is to hang the keys from the probe plug.  Great idea, so I am doing this now too.  Also, the bungee loop on my keys is to hang the keys on the prop feather lever when the prop is feathered so I don't try to start the engine with the prop feathered.  (Someone broke their prop doing this!).
Keep those great tips coming, folks!

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