Conducted 10/20/2012 -
After the last flight we
conducted a manometer test of the airspeed indicator on the ground. We
found the ASI to be accurate, and after consulting with the cozy builder's list,
concluded our static port was the likely culprit. We discovered that it
was originally intended to be mounted to the inside of the skin, as it had a
small .0625 protrusion in the center that was meant to be flush with the outside
skin of an Aluminum aircraft. We filed the protrusion down and waited for
weather to cooperate for us to once again test. We also took the
opportunity to extend the pitch trim bellcrank in hopes of eliminating the aft
stick pressure that was required to keep the nose up. A new camera mount
from Ram Mounts arrived and we fitted that as well.
Three weeks would pass before we finally got a chance to check our improvements.
John's flight report is below:
"After three weeks of
high winds and low clouds this morning finally gave a chance at testing my
modified static port as well as pitch trim system modifications. The TAF showed
calm winds and favorable sky conditions from 7 to Noon. When we arrived at the
airport at 7:30am the fog was just lifting and the sun revealed a clear sky from
just southwest of the airport extending as for northeast as one could see.
I got the plane preflighted and set out for the runway. Takeoff was normal, and after leveling off gave the pitch trim a try. Sure enough it now had the needed force to trim for hands off flight. It’s so much easier to hold a solid airspeed with a working pitch trim. :)
Because of my concern about canard /wing incidence, I made a elevator travel gauge and siliconed it to the canard. As I climbed out to 5k feet at 120 KIAS I noted the elevator deflection at about 3 deg TE down (CG was 99.0). This seemed to be in line with what it should be, but the next task was to make the airspeed calibration runs. I noticed the clouds that had blanketed the area were now about 7 miles to the SW in a line the followed the interstate.
My intent was to run the exact same airspeeds as the last test (100,120,140,160Kts). As I turned to the final heading of the 120Kt test, I noticed that the clouds had actually moved closer and were now about 3 miles to the SW. I notified my ground crew that as soon as I had the data for this point I was coming down, and after the 30 seconds or so it took to get it, notified the tower I was going to descend quickly from 5500’ to a left downwind for 13. I was cleared to land and immediately pulled the power to idle, put the prop to high, dropped the speedbrake, and hung the rudders out as I made a left turn for a teardrop entry to downwind.
I was able to drop 3500’ to get to pattern altitude just as I entered the downwind leg, but I noticed puffy clouds starting to pass about 500’ underneath me, and the blanket that was 3 miles out when I started my descent now appeared to be maybe ˝ mile away. A little too close for comfort, and I began thinking about what I’d do if I needed to go around on this approach. There are only 4 airports in my test box, and 2 of them were to the south, most certainly socked in my the overcast layer That was about to turn my home field to IFR. I had one airport left to the northeast, so I decided that I would make a bee line for Princeton if I couldn’t get down on the first attempt.
The landing was uneventful, and by the time I got back to the hangar and opened the canopy we were covered in clouds. ASOS reported 300 overcast for the next few hours, and we haven’t gotten above 1000’ since. I got almost another hour in the bird, and as it turned out it would be just enough to determine the static port was better, but still not perfect. My ASI is now reading only 8 Kts high. I spent the rest of the day making a new plans style static port. If the weather will cooperate tomorrow, I will test it again."