Earthstar Forums

Mark,

Do you have a recommended location for static port location on the Thunder Gull JT2? I'm thinking about putting a port on the right side of the nose a couple inches below the windshield and about four inches forward of the instrument panel location.

When I finally got my plane back in the air, I found that my airspeed indicator was reading about 10-12% high. (I could easily hit 120 mph indicated in level flight at about 6400 rpm.) My GPS confirmed the discrepancy.

I suspect that the old way of leaving the static port open to cockpit air at the instrument panel is the culprit. There is now more air movement inside the cabin, primarily because of a smaller wing root fairing I built, which leaves a gap of about an inch forward of the wing to avoid touching/damaging the D-cell like the old, apparently home-made, fairing did.

I do think the Rotax 503 has a little more power now that I've removed the old HAC system and installed standard jetting and needles. But not enough to produce the airspeed readings I'm seeing.

Dick O'Reilly

Hi Dick, I see you've verified that the static port open to the cabin, and even the Titan guys deal with this. I mounted two static ports, one on each side and tee'd. Sad to say, I still have an error. When I did a large circuit, and averaged groud speed to null out the wind, I saw about 10mph slower ground speed than airspeed. I even put another larger airspeed indicator in, and all it showed was the same error with bigger numbers. My hangar partner loves his 120mph+ indicated with his cabin ported airspeed, and thinks it's real. Hee hee!!

kb

Hi Dick
I recommend plugging the hole in front of the wing. yes the spot you ask
about is a good one but put one on each side and T them together so that when
in turbulence you don't get erratic readings.
Happy Flying
Mark


In a message dated 12/13/2011 9:44:09 A.M. Pacific Standard Time,
dickoreilly@yahoo.com writes:




Mark,

Do you have a recommended location for static port location on the Thunder
Gull JT2? I'm thinking about putting a port on the right side of the nose
a couple inches below the windshield and about four inches forward of the
instrument panel location.

When I finally got my plane back in the air, I found that my airspeed
indicator was reading about 10-12% high. (I could easily hit 120 mph indicated
in level flight at about 6400 rpm.) My GPS confirmed the discrepancy.

I suspect that the old way of leaving the static port open to cockpit air
at the instrument panel is the culprit. There is now more air movement
inside the cabin, primarily because of a smaller wing root fairing I built,
which leaves a gap of about an inch forward of the wing to avoid
touching/damaging the D-cell like the old, apparently home-made, fairing did.

I do think the Rotax 503 has a little more power now that I've removed the
old HAC system and installed standard jetting and needles. But not enough
to produce the airspeed readings I'm seeing.

Dick O'Reilly