Hi Guys I have just taken delivery of a UMA VSI unit and noticed something that needs attension. The needle does not sit on zero. If I place my finger over the rear port and apply slight pressure it will zero or even show a descent depending on the amount of pressure applied. This is understandable and proves that it is working I suppose. It has an adjustment screw in the bottom left mounting screw position. Would this be the zero adjustment for the unit or something else? The literature that came with the unit is of no help in this regard at all. For interest sake, does anybody know exactly how these things work. I know it measures the rate of change in static pressure but then the needle should return to zero or at least move in that direction if I keep a constant pressure on the rear port with my finger. Thanks Regards Dene Collett KR2SRT builder South africa Whisper assembler See: www.whisperaircraft.com mailto: av...@telkomsa.net
