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slowmover · 12-04-2010, 11:53 AM

It is essentially a pressurized air source driving several instruments (altimeter, air speed, etc). Here's an old-fashioned one, venturi-type:

http://www.eaa.org/experimenter/images/0906_venturi.jpg

As to accuracy, well, winds are not really ever constant, are subject to shifting, and -- as one travels -- the road itself is not straight, so one is not ever likely to see a constant speed read depending on geography, climate & weather (Texas is windy, Georgia ain't). My understanding is that the instrument is going to change indications fairly regularly (but not a constant wobble, either). This assumes a windy day. On a not so windy day the reading is stable. Thus I don't think the mount is critical beyond stable readings on a day of ordinary breezes.

For RV'ers the eye-opener is the change in wind speed when being passed in the same direction as two semi's flying past (or, worse, the other direction) as the wind speed indicator is all over the place from truck bow waves.

No, I don't have one yet . . but it is high on the list. If I find the readings greatlyincreasing as one approaches the warmest part of the day, maybe it's time for lunch. A long one. Or, a different route if it makes winds more favorable. Or get's me away from heavy truck traffic. Etc.

It's all in trade-offs of time versus distance and the schedule to be kept: How far OOR can I go to offset the wind penalty? I might in fact choose to burn more fuel (distance) in order to avoid fighting the steering all day (one reason I used to like driving flatbed). Watching a 53' dry van lift the tandems in the air on one side -- and the driver not be able to feel it (by radio report) -- was an eye-opener.

Note the trailer (RV park model) "snaking" prior to roll over:

http://www.rvvideos.com/search?q=trailer+flips
.

12-04-2010, 11:53 AM	#28 (permalink)
slowmover Banned Join Date: Oct 2009 Location: Fort Worth, Texas Posts: 2,442 2004 CTD - '04 DODGE RAM 2500 SLT Team Cummins 90 day: 19.36 mpg (US) Thanks: 1,422 Thanked 737 Times in 557 Posts	It is essentially a pressurized air source driving several instruments (altimeter, air speed, etc). Here's an old-fashioned one, venturi-type: http://www.eaa.org/experimenter/images/0906_venturi.jpg As to accuracy, well, winds are not really ever constant, are subject to shifting, and -- as one travels -- the road itself is not straight, so one is not ever likely to see a constant speed read depending on geography, climate & weather (Texas is windy, Georgia ain't). My understanding is that the instrument is going to change indications fairly regularly (but not a constant wobble, either). This assumes a windy day. On a not so windy day the reading is stable. Thus I don't think the mount is critical beyond stable readings on a day of ordinary breezes. For RV'ers the eye-opener is the change in wind speed when being passed in the same direction as two semi's flying past (or, worse, the other direction) as the wind speed indicator is all over the place from truck bow waves. No, I don't have one yet . . but it is high on the list. If I find the readings greatlyincreasing as one approaches the warmest part of the day, maybe it's time for lunch. A long one. Or, a different route if it makes winds more favorable. Or get's me away from heavy truck traffic. Etc. It's all in trade-offs of time versus distance and the schedule to be kept: How far OOR can I go to offset the wind penalty? I might in fact choose to burn more fuel (distance) in order to avoid fighting the steering all day (one reason I used to like driving flatbed). Watching a 53' dry van lift the tandems in the air on one side -- and the driver not be able to feel it (by radio report) -- was an eye-opener. Note the trailer (RV park model) "snaking" prior to roll over: http://www.rvvideos.com/search?q=trailer+flips . Last edited by slowmover; 12-04-2010 at 12:19 PM..