Talk:Variometer

Is a variometer the same thing as a Vertical Speed Indiciator (VSI)? If so, this should be noted. If not, the difference should be noted.


 * Same thing. Well spotted.  Power pilots, eh?  They never use a proper English word when they can use an inpenetrable abbreviation.  It helps maintains their mystique, don't you know.  I've combined some information from the "VSI" article into this one and turned "VSI" into a re-direct.  GrahamN 10:01, 9 Mar 2004 (UTC)
 * Well no actually. Varios are far more sensitive and can give air-mass rates and other variations which would be impossible with a powered aircraft instrument. I think that the merge was aRETROGRADE step and should be reverted!! Any discussion?Petebutt (talk) 04:39, 23 July 2012 (UTC)

varios in foot launched aviation
vario is a must have for any paraglider/hang glider pilot and this is the most popular utilization of varios nowadays. there should by more about this usage in the article.


 * I expect you are right. Please feel free to add to the article accordingly.  We don't stand on ceremony here. GrahamN 24 October 2004 [not logged in as have forgotten password]

Question
Just a question from a "power pilot's" viewpoint. The glider instrument is calibrated in knots? Dan D. Ric 11:38, 21 October 2006 (UTC)


 * Definitely. The conversion to feet per minute is trivial (although only really meaningful with an averager, given the variability of lift even in the same thermal!) and glide angles can be computed reasonably quickly. In most European countries, the values are given in metres per second. This is perhaps because altimeters are similarly metric and measure metres (or kilometres); One could draw more parallel to the power world there. --BWDuncan 17:11, 21 October 2006 (UTC)


 * Do European gliders measure altitude in metres, unlike powered aircraft? In powered aviation almost all Free World aircraft use feet... --GCarty 19:55, 5 July 2007 (UTC)


 * Yes, except in the UK. There may be other European countries using feet and knots, but I've only flown in Norway, France and Spain, all of which used metres and metres per second. I'd be interested to know why this is the case!--BWDuncan 12:29, 6 July 2007 (UTC)


 * 'Perhaps it was because gliders aren't subject to Air Traffic Control, which forced the whole of the non-communist world to standardize on a single set of units (nautical miles, knots and feet). --GCarty 08:24, 7 July 2007 (UTC)

Glider pilots are subject to Air Traffic Control when they are in "controlled airspace" as is any aircraft. However glider pilots can demand priority over powered aircraft (for example in landing procedures) but with the good performance of modern gliders they seldom need to. The considerate glider pilot will ensure that ATC knows that he is a glider and depending upon the speeds and positions of surrounding aircraft will simply slot into the landing pattern as a light aircraft after discussion with ATC so that they are aware of the rare need to change "the pattern" and can do so without calling a Pan or Mayday. Because large aircraft flying costs (even per minute) are so high, this courtesy is appreciated by "heavy" operators (and ATC when things are busy.) Gliders can have very high rates of descent when required (by using spoilers, brakes and undercarriage position and also crabbing) and are well suited for landing behind "heavy and slow" aircraft and avoiding their turbulence with an approach that keeps the glider's path above the preceding aircraft's. Also most glider pilots will end their landing in the grass next to the runway so that the runway is clear. With permission from ATC, gliders will land on taxi-ways or the grass so that the tow to stowage is shorter and following aircraft are not delayed unnecessarily. Balloon pilots have priority over all other aircraft except perhaps parachutists. Glider pilots do it for fun, other pilots do it for money. You can draw parallel "moral" conclusions comparing this to other "professions." (lol)Ecstatist (talk) 13:30, 2 December 2016 (UTC)

A "nautical mile" is exactly the distance of "1/60 of the distance between adjacent "degrees of longitude" (= 1 minute of longitude) and this feature aids "mental navigation calculations." The meter was originally defined as 1/64000 (or 1/60000?) of the distance between the equator and North pole, however due to historical errors in the actual geographical measurements, the distance of that convenient fraction does not applies exactly. The modern definition of the meter (based on the wavelength emitted by an electron as it falls between defined orbits) is very useful if you are flying around and about a cesium atom. Ecstatist (talk) 13:30, 2 December 2016 (UTC)

Inertia lead?
From the article:


 * An "Inertia lead" VSI or ILVSI compensates for relative "g" forces experienced in a turn (powered aircraft) and provides appropriate mechanical compensation to remove otherwise erroneous indications of climb or descent.

I am unfamiliar with this type. This does not seem sensible to me unless the rate of turn is a factor in determining if the "g" force is from turn or a stick-induced climb or descent.

The type I am familiar with would be described in the following proposed additional text:


 * In a sailplane the rate of ascent can be modified by small elevator inputs, giving true but misleading rate of climb information, as this does not reflect accurately the contribution of the rising air mass. This indication is removed by also factoring in the rate of change of airspeed, which in older instruments was done by additional connections and air bleeds from the pitot system.

Comments please?

-Leonard G. (talk) 18:04, 12 December 2007 (UTC)

Purpose.
Purpose

Human beings, unlike birds and other flying animals, are not able directly to sense climb and sink rates. Before the invention of the variometer, sailplane pilots found it very hard to soar. Although they could readily detect abrupt changes in vertical speed ("in the seat of the pants"), their senses did not allow them to distinguish lift from sink, or strong lift from weak lift. The actual climb/sink rate could not even be guessed at, unless there was some clear fixed visual reference nearby.

Comment: Powered and un-powered aircraft may be flown very well without a variometer. Using an altimeter to note increases or decreases in altitude and a clock to determine time differences allows the pilot to quickly calculate rates of climb or descent. Alamogordo88 (talk) 18:55, 25 August 2008 (UTC)

RCDI / Rate of Climb and Descent Indicator?
After a recent edit, Rcdi and Rate of Climb and Descent Indicator now redirect here. The later was effectively a short description of a variometer or VSI, before being converted to a redirect. Does anyone have a reference for these terms actually being used? I've never heard them, and Googling does not appear to show any usage other than in Wikipedia. Unless there's some evidence that the terms are real, I'll remove the alternate name, and delete the two redirect pages. Rwessel (talk) 05:17, 26 November 2010 (UTC)
 * Take a look. For what it's worth, I generally avoid a general google search when I'm trying to source stuff here, there are so many wikipedia mirrors. Books and Scholar generally work better. --Nuujinn (talk) 13:21, 26 November 2010 (UTC)

more please.....
Perhaps you should provide information of the history of variometers like the three types  Cosim, Vane Type and Schueman types as well as the use of a insulated bottle to increase the size of the stored volume. Arydberg (talk) 16:44, 9 October 2015 (UTC)


 * It's a wiki, add it...? LjL (talk) 16:48, 9 October 2015 (UTC)

Incorrect statement under Purpose paragraph
The statement "their senses did not allow them to distinguish lift from sink, or strong lift from weak lift" doesn't seem right to me. You can indeed tell quite easily if you're being accelerated up or down, as anyone who's been in a lift will tell you. — Preceding unsigned comment added by RichardKre (talk • contribs) 07:00, 30 April 2020 (UTC)