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Old June 21st 18, 04:28 PM posted to rec.aviation.soaring
jfitch
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Default Vario Comparison

On Thursday, June 21, 2018 at 5:23:46 AM UTC-7, wrote:
Hi-

I've searched the archives of this oft-discussed topic, but am not finding specific answers I'm seeking. If you have good experience or knowledge about the specific issues below, I would much appreciate your insights.

1) Latency with accuracy. What is the quickest vario with accuracy? Are they all limited by a 1 sec. latency with updates, or do some update faster? While several now describe their inputs as including both pressure sensor and inertial inputs from gyros and accelerometers, I can't find clarity on the mixture of these in the protocol. Some seem to link inertial inputs more to wind/track sensing than vario responses.

2) TE Compensation. Most all offer pneumatic or electronic, and at least some a gain loop on a pneumatic source so that compensation can be adjusted.. However, pneumatic comp alone will only be accurate for one condition (g loading, alpha delta, etc.) Whereas electronic gain loops have been around for decades, it seems rather archaic that modification of the input is limited to a single gain function. Does anyone provide modification to several points on a curve whether g loading, v, or another pertinent metric?

I am looking at designing a new set of sensors and instruments that would display fundamentally different parameters for a type of flight strategies/optimization which is inertially based in a rapidly changing frame of reference. However, in the mean time I fly very dynamically and would appreciate experienced and accurate input about current vario offerings. I would also appreciate specific comments from pilots who have experience with both AirGlide (Butterfly), LxNav S8 or 80, and/or ClearNav Varios. Pluses and minuses wrt the above two capabilities in particular and notable general issues would be greatly appreciated.

Thanks, and sorry for posting from my wife's account- I don't post often enough to remember my login commands and am away from home records. You can email me directly if you wish:

Gary Osoba


As far as I can tell, the Air Vario is the only one using inertial sensors for variometry, represented in the Vertical Air Mass movement needle. This has a setting to be derived from any mix ratio of 100% barometric to 100% inertial. If set to 100% inertial I find it too twitchy, but set to 80% inertial it can be flown like a variometer, but leads it by a second or more. It is confused by other things, such as changing flap position. I can thermal with it even with the engine boom out, which totally hoses the tail pneumatics.

Every other vario since the 302 has had inertial sensors and some claimed to use them, but none seem to. Currently flying with both Air Vario and Clear Nav vario installed.