I have a 302, a CN vario, and a V9 installed here and there so can compare these. I'm also very fussy about varios, as the CN people will attest.

The 302 is a very very good vario. But it's not in production and it's not as robust as the new ones. It has to be set up right and properly compensated.

Like all these varios it does not like leaks, it does not like flow varios on the same circuit, and it wants the pressures all coming from the same place, not the probe. If you have leaks, flow varios connected together, or you're not using pitot, static, and TE from the probe all these varios will disappoint.

The CN vario is also very very good. The first generation of the filtering software was, in my opinion, a bit better than 302. The second generation (last summer) removed a lot of bugs, but was a step backward in filtering, especially in strong weather and full of water. Now that the navigation stuff is behind them, I gather CN is working again on filtering. Frequent software updates and active development is a plus.

The V9 is a great vario out of the box. The filtering is excellent. It too needs to be set up right and correctly compensated.

It has one big downside for me so far. Where the CN and 302 vario are set up that "2 knots up" means "2 knots up" in both speed command and climb mode, the V9 tones in speed command are set to correspond to horizontal speed differences not vertical ones. It uses somehting like the same tone for "10 knots fast" that it does for "2 knots up." But in a modern glider, the speed to fly is much more sensitive to the lift value. So, bottom line, the tones swing around in speed command mode much more than they do in climb mode. Where this is a problem is when you slow down and sniff around but haven't decided to climb. In speed mode, you'll hear garbage, much too optimistic in lift. So, you have to set it up to switch to climb mode at about 70 knots.

All of these varios have hardware in them that could allow for amazing things, not yet implemented in software.

John Cochrane