Grob 104 Speed Astir

On May 3, 9:34*pm, Greg Delp wrote:
I finally got the chance to fly the 104. I have a few issues to try and sort out.

First the airspeed indicator seems to read lower than the actual speed. I will test the pitot static system for leaks as well as against a known good ASI.

Second, while checking out the Cambridge MKIV vario and the MKIV Director it was obvious that the Vario was not behaving correctly. I think it may be over compensated and hope the video below may help someone more experienced could determine if this is in fact the case. The Winter mechanical seems to indicate fairly accurately. It is connected to the TE probe and a flask.. The MKIV is connected to the aft fuselage static ports(4) and pitot tube. The director is connected to the pitot tube and the forward fuselage static ports with the other pitot static instruments.

The mechanical vario seems to display correctly while cross checking the altimeter. The MKIV seems to indicate opposite especially while changing speeds, which can be seen in the video while changing flap settings. Then it sometimes stabilizes and almost matches the mechanical.

Any suggestions? I haven't had the chance to fly on a smooth day yet.

http://www.youtube.com/watch?v=d6yhK...e&list=UUvGOQo...

Buy a new vario. Really, this is ancient equipment, and nothing --
nothing -- helps your soaring performance more than a really good
vario

John Cochrane