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#1
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Airspeed Indicator problems
The original Schweizer airspeed indicator in my glider sticks.
Once on the ground I blew into the pitot and the indicator shows an airspeed but then it takes 10 seconds to slowly go back down to 0. On the back of the instrument there are 2 vertical ports. I disconnected and blew through the top tube which runs to the static ports. Blew just fine, no blockage. The pitot line runs to the bottom port on the back of the instrument but not direclty. It has a tee that routes it off to another instrument also. I would have thought that the pitot should have an uniterupted tube going directly to the airspeed indicator. The diagram in the opertors manual shows a dedicated line going from the pitot to the top port on the back of the instrument and the static line going the the bottom port. Just opposite of my particular installation. Any advice would be appreciated. Stan |
#2
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Airspeed Indicator problems
Stan: First advice: STOP BLOWING IN THE ASI! That's the best way there is to destroy it, which you might already have done. I've seen people walk up to a pitot tube and put their mouth to it, and I cringe at the thought of what they're doing to the internal workings. If you disconnect the plumbing from the instruments you can check it's continuity by drawing a slight vacuum on it and seeing if it holds. I've seen plastic tubing chewed through by mice, and worse yet, I've seen instruments incorrectly plumbed by someone who was "testing the system." If neither of these is the problem you probably need to send the instrument to a qualified shop. Fred |
#3
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Airspeed Indicator problems
On Jun 18, 10:42 am, wrote:
Stan: First advice: STOP BLOWING IN THE ASI! That's the best way there is to destroy it, which you might already have done. I've seen people walk up to a pitot tube and put their mouth to it, and I cringe at the thought of what they're doing to the internal workings. If you disconnect the plumbing from the instruments you can check it's continuity by drawing a slight vacuum on it and seeing if it holds. I've seen plastic tubing chewed through by mice, and worse yet, I've seen instruments incorrectly plumbed by someone who was "testing the system." If neither of these is the problem you probably need to send the instrument to a qualified shop. Fred If it is an old instrument, it could be an accumulation of dirt, especially if flown from turf or a dusty area. Repair or replace the instrurment and check out the plumbing as Fred suggests. Also, plastic tubing degrades over time and can become a problem with leaks. Chip F. |
#4
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Airspeed Indicator problems
If you are interested, I have an old Schweizer airspeed without markings
that has been on a shelf since about 1965. Make me an offer. Bill Daniels "chipsoars" wrote in message ups.com... On Jun 18, 10:42 am, wrote: Stan: First advice: STOP BLOWING IN THE ASI! That's the best way there is to destroy it, which you might already have done. I've seen people walk up to a pitot tube and put their mouth to it, and I cringe at the thought of what they're doing to the internal workings. If you disconnect the plumbing from the instruments you can check it's continuity by drawing a slight vacuum on it and seeing if it holds. I've seen plastic tubing chewed through by mice, and worse yet, I've seen instruments incorrectly plumbed by someone who was "testing the system." If neither of these is the problem you probably need to send the instrument to a qualified shop. Fred If it is an old instrument, it could be an accumulation of dirt, especially if flown from turf or a dusty area. Repair or replace the instrurment and check out the plumbing as Fred suggests. Also, plastic tubing degrades over time and can become a problem with leaks. Chip F. |
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Airspeed Indicator problems
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#6
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Airspeed Indicator problems
wrote in message ups.com... The original Schweizer airspeed indicator in my glider sticks. The pitot line runs to the bottom port on the back of the instrument but not direclty. It has a tee that routes it off to another instrument also. I would have thought that the pitot should have an uniterupted tube going directly to the airspeed indicator. Any advice would be appreciated. Stan -- I agree with the other posters---send it in for cleaning, and calibration. The tee is probably to a netto cappilliary, or possibly to a hidden diaphragm TE compensator. A 10 cc medical syringe is a good "air pump" for testing systems. Hartley Falbaum |
#7
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Airspeed Indicator problems
And then, there can be problems with sending instruments
in for a rebuild. First, it was my altimeter. Off it went to a repair shop in Kansas and came back with the glass cracked. The crack went right to one of the screws. Damn. Turn right around and send it back for 'warranty' service. It has worked just fine since and that was maybe three years ago. Second, my airspeed indicator had a leak. I sent it in to another shop in Kansas and authorized a check-up. Turns out they tore it down and found it pretty much all worn out and were in the process of starting to totally rebuild it. Without my authorization. It was going to cost around US$450. I told them to stop and just send the instrument back to me. So, I bought a new Winter airspeed indicator from Tim Mara at Wings and Wheels for less than the rebuilt one would have cost me. I was hoping the old airspeed would just need a new O-ring and a face cleaning. Oh well. Ray Lovinggood Carrboro, North Carolina, USA PS: The fairly new instruments didn't keep me from landing out on Sunday At 01:06 19 June 2007, Hl Falbaum wrote: wrote in message oups.com... The original Schweizer airspeed indicator in my glider sticks. The pitot line runs to the bottom port on the back of the instrument but not direclty. It has a tee that routes it off to another instrument also. I would have thought that the pitot should have an uniterupted tube going directly to the airspeed indicator. Any advice would be appreciated. Stan -- I agree with the other posters---send it in for cleaning, and calibration. The tee is probably to a netto cappilliary, or possibly to a hidden diaphragm TE compensator. A 10 cc medical syringe is a good 'air pump' for testing systems. Hartley Falbaum |
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