I am just about ready to fit the nose deck on my Searey and have been checking various instruments to make sure they are all working OK. When blowing intio the pitot tubing quickly the analogue ASI works fine but my Dynon D100 registers up to approx 30kts briefly then goes to 0 while the ASI is still reading whatever value I hold it to. If I blow very slowly the ASI still works OK but the Dynon doesn't register at all. My question is should it? or does it only work properly when in flight conditions?
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Dynon D100 ASI readout
- Thread starter searey429
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- Mar 23, 2005
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With earlier versions of firmware, the IAS came alive at 30 knots, and then stayed alive down to 25 knots. Now, in the last bunch of versions, it comes alive at 20 knots, and then below 15 returns to zero. It sounds like that's probably what you're seeing. If so, that's by design (there's too much "noise" in the sensor readings beneath those thresholds to measure accurately.
Thanks for the quick reply. Are you saying that even though I hold pressure in the pitot at say 60 knots on the analogue ASI the Dynon ASI won't read and hold that airspeed? Reading your post it suggests that if I don't blow over 20 knots it will return to 0 but if I go over 20 shouldn't it hold that airspeed?
Just before testing the ASI I downlaoded software version 5.3.
Just before testing the ASI I downlaoded software version 5.3.
- Joined
- Mar 23, 2005
- Messages
- 13,226
It should hold higher airspeeds just like another ASI. It's only down near 20 that you might see a sudden drop.
- Joined
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If there were an actual leak, anywhere, then both would go to zero, so we're a bit stumped. Give us a call when you get a chance. I'm assuming that you mean that you're applying pressure to a single downstream pitot that feeds both units.
If you have the Dynon pitot probe it might be worth verifying the connections so that pitot is going to pitot and AOA is going to AOA. It sounds pretty basic and I do not mean to imply you have not already checked but there was another builder who had a similar situation and as I recall his pitot line was actually connected to the AOA port.
On the bright side, the check is easy to do and costs nothing. If you are fairly satisfied the connections are correct, perhaps disconnect the pitot input at the Dynon and connect a test tube to see if you can get readings with just the Dynon. If you still have a problem at least you have eliminated the entire pitot static system as a source. Just be careful to ensure you do not blow directly into the pitot line while it is connected to any pressure instruments as it is easy to damage them this way.
On the bright side, the check is easy to do and costs nothing. If you are fairly satisfied the connections are correct, perhaps disconnect the pitot input at the Dynon and connect a test tube to see if you can get readings with just the Dynon. If you still have a problem at least you have eliminated the entire pitot static system as a source. Just be careful to ensure you do not blow directly into the pitot line while it is connected to any pressure instruments as it is easy to damage them this way.