On Mar 3, 10:26*am, Frank Paynter wrote:
I installed a TT21 transponder over the winter, and as per the
installation instructions, tapped into my ship's static line for
altitude reporting. *Yesterday I checked the transponder with Orlando
ATC and they reported a good signal and proper altitude reporting. *So
far, so good.

Then I noticed my airspeed indicator seemed to be reading
significantly higher than normal, and I confirmed this with a stall
series. *My Ventus 2bx, which normally stalls in the 40-45kt range
depending on bank angle, now is apparently stalling in the 50-55kt
range. *The ship actually feels pretty much the same as before,
although I haven't flown for 3 months so that's a bit hard to tell for
sure.

My dry flying weight is probably about 5-10lbs higher this year than
last, as I added the TT21 itself, plus a 5-lb battery to support it.
However, I'm pretty sure that by itself doesn't explain the
significantly higher apparent stall speed.

As a troubleshooting step, I removed and plugged the static line from
the airspeed indicator, so now the ASI takes it's static input from
cabin air, and everything else should be unchanged. *I haven't flown
it yet to try it out, but I will today. *I also have a spare airspeed
indicator that I can swap in if necessary.

Anything else I should be considering?

TIA,

Frank

Too bad I didn't get any takers on yesterday's prediction, because
sometimes the cause of a faulty airspeed reading is just the airspeed
indicator. Replaced the indicator for today's flight, and lo and
behold, the airspeed dropped back to what it should be, matching the
CAI-302 indication almost exactly.

Interestingly enough, this little exercise taught me to trust what the
glider was telling me rather than what the ASI was saying. Before I
figured out the ASI problem, I was having trouble getting the glider
slowed down enough at -1 and -2 flaps - it seemed to want to run hands-
off at the fully ballasted speeds even though I was flying dry. Of
course today with the faulty ASI changed out, the glider wants to fly
hands-off pretty much in the correct (dry) speed range for all cruise
flap settings (-1 through S1)

So now all I have to do is figure out what to do with the 'extra'
posts associated with this topic. Do I still need to replace the
Dittel capacitor? Can I recover from the effects of the PW-5
sacrifice? Will the feds swoop down on me for replacing the ASI in my
experimental glider? Stay tuned for next week's episode ;-).

Regards,

Frank