{"id":1889,"date":"2025-08-14T10:35:33","date_gmt":"2025-08-14T08:35:33","guid":{"rendered":"https:\/\/acriv.org\/WP\/?page_id=1889"},"modified":"2025-08-14T10:35:33","modified_gmt":"2025-08-14T08:35:33","slug":"%e2%9a%99%ef%b8%8fvariometre","status":"publish","type":"page","link":"https:\/\/acriv.org\/WP\/%e2%9a%99%ef%b8%8fvariometre\/","title":{"rendered":"\u2699\ufe0fVARIOMETRE"},"content":{"rendered":"<div class=\"wp-block-image\">\n<figure class=\"aligncenter size-full is-resized\"><img loading=\"lazy\" decoding=\"async\" width=\"225\" height=\"225\" src=\"https:\/\/acriv.org\/WP\/wp-content\/uploads\/2025\/08\/image-53.png\" alt=\"\" class=\"wp-image-1890\" style=\"width:203px;height:auto\" srcset=\"https:\/\/acriv.org\/WP\/wp-content\/uploads\/2025\/08\/image-53.png 225w, https:\/\/acriv.org\/WP\/wp-content\/uploads\/2025\/08\/image-53-150x150.png 150w, https:\/\/acriv.org\/WP\/wp-content\/uploads\/2025\/08\/image-53-105x105.png 105w\" sizes=\"auto, (max-width: 225px) 100vw, 225px\" \/><\/figure>\n<\/div>\n\n\n<p>Un <strong>variom\u00e8tre<\/strong> (ou <em>vertical speed indicator<\/em> en anglais) est l\u2019instrument de bord qui indique <strong>la vitesse verticale<\/strong> d\u2019un avion, c\u2019est-\u00e0-dire la vitesse de mont\u00e9e ou de descente exprim\u00e9e en pieds par minute (ft\/min) ou en m\u00e8tres par seconde (m\/s).<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">1. <strong>\u00c0 quoi \u00e7a sert<\/strong><\/h2>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Aide le pilote \u00e0 <strong>stabiliser une altitude<\/strong> ou \u00e0 monter\/descendre \u00e0 un taux pr\u00e9cis.<\/li>\n\n\n\n<li>Permet de d\u00e9tecter de l\u00e9g\u00e8res variations verticales invisibles \u00e0 l\u2019\u0153il (ex. vol sans rep\u00e8res visuels).<\/li>\n\n\n\n<li>En vol \u00e0 voile, sert aussi \u00e0 rep\u00e9rer les ascendances et descendances.<\/li>\n<\/ul>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">2. <strong>Principe de fonctionnement<\/strong><\/h2>\n\n\n\n<p>Le variom\u00e8tre utilise la <strong>pression statique<\/strong> (comme l\u2019altim\u00e8tre), mais il ne mesure pas la pression en valeur absolue :<br>il mesure <strong>le taux de variation<\/strong> de cette pression.<\/p>\n\n\n\n<p><strong>Fonctionnement m\u00e9canique :<\/strong><\/p>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>Capsule an\u00e9ro\u00efde<\/strong>\n<ul class=\"wp-block-list\">\n<li>Reli\u00e9e directement \u00e0 la prise statique ext\u00e9rieure.<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>Chambre \u00e9tanche autour de la capsule<\/strong>\n<ul class=\"wp-block-list\">\n<li>Elle re\u00e7oit aussi la pression statique, mais \u00e0 travers un <strong>petit orifice calibr\u00e9<\/strong> ou un <strong>tube capillaire<\/strong>, ce qui retarde les variations (effet amortisseur).<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>Mesure de la diff\u00e9rence<\/strong>\n<ul class=\"wp-block-list\">\n<li>Si la pression change rapidement (mont\u00e9e ou descente), la capsule et la chambre n\u2019\u00e9voluent pas au m\u00eame rythme \u2192 cette diff\u00e9rence d\u00e9place les aiguilles.<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>Affichage<\/strong>\n<ul class=\"wp-block-list\">\n<li>Z\u00e9ro = vol horizontal<\/li>\n\n\n\n<li>Aiguille vers le haut = mont\u00e9e<\/li>\n\n\n\n<li>Aiguille vers le bas = descente<\/li>\n<\/ul>\n<\/li>\n<\/ol>\n\n\n<div class=\"wp-block-image\">\n<figure class=\"aligncenter size-full is-resized\"><img loading=\"lazy\" decoding=\"async\" width=\"400\" height=\"283\" src=\"https:\/\/acriv.org\/WP\/wp-content\/uploads\/2025\/08\/image-54.png\" alt=\"\" class=\"wp-image-1891\" style=\"width:375px;height:auto\" srcset=\"https:\/\/acriv.org\/WP\/wp-content\/uploads\/2025\/08\/image-54.png 400w, https:\/\/acriv.org\/WP\/wp-content\/uploads\/2025\/08\/image-54-300x212.png 300w, https:\/\/acriv.org\/WP\/wp-content\/uploads\/2025\/08\/image-54-310x219.png 310w, https:\/\/acriv.org\/WP\/wp-content\/uploads\/2025\/08\/image-54-148x105.png 148w\" sizes=\"auto, (max-width: 400px) 100vw, 400px\" \/><\/figure>\n<\/div>\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">3. <strong>Avantages et limites<\/strong><\/h2>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Avantage<\/strong> : simple, fiable, pas besoin d\u2019\u00e9lectricit\u00e9 (s\u2019il est m\u00e9canique).<\/li>\n\n\n\n<li><strong>Limite<\/strong> : a un l\u00e9ger <strong>retard<\/strong> (1 \u00e0 2 secondes) car il d\u00e9pend d\u2019un diff\u00e9rentiel de pression entre deux volumes d\u2019air.<\/li>\n\n\n\n<li>Les variom\u00e8tres modernes peuvent \u00eatre <strong>\u00e9lectroniques<\/strong>, utilisant acc\u00e9l\u00e9rom\u00e8tres ou GPS pour r\u00e9duire ce retard.<\/li>\n<\/ul>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">4. <strong>R\u00e9sum\u00e9 mn\u00e9motechnique<\/strong><\/h2>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Variom\u00e8tre = \u00ab <em>vitesse verticale<\/em> \u00bb<\/li>\n\n\n\n<li>Altim\u00e8tre = \u00ab <em>altitude absolue<\/em> \u00bb<\/li>\n\n\n\n<li>Badin = \u00ab <em>vitesse horizontale<\/em> \u00bb<\/li>\n\n\n\n<li>Les trois ensemble donnent une image compl\u00e8te du d\u00e9placement dans l\u2019air.<\/li>\n<\/ul>\n","protected":false},"excerpt":{"rendered":"<p>Un variom\u00e8tre (ou vertical speed indicator en anglais) est l\u2019instrument de bord qui indique la vitesse verticale d\u2019un avion, c\u2019est-\u00e0-dire la vitesse de mont\u00e9e ou de descente exprim\u00e9e en pieds par minute (ft\/min) ou en m\u00e8tres par seconde (m\/s). 1. \u00c0 quoi \u00e7a sert 2. Principe de fonctionnement Le variom\u00e8tre utilise la pression statique (comme l\u2019altim\u00e8tre), mais il ne mesure<\/p>\n<p><a class=\"more-link\" href=\"https:\/\/acriv.org\/WP\/%e2%9a%99%ef%b8%8fvariometre\/\">Read More<\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"parent":0,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"footnotes":""},"class_list":["post-1889","page","type-page","status-publish","hentry"],"jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/acriv.org\/WP\/wp-json\/wp\/v2\/pages\/1889","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/acriv.org\/WP\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/acriv.org\/WP\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/acriv.org\/WP\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/acriv.org\/WP\/wp-json\/wp\/v2\/comments?post=1889"}],"version-history":[{"count":1,"href":"https:\/\/acriv.org\/WP\/wp-json\/wp\/v2\/pages\/1889\/revisions"}],"predecessor-version":[{"id":1892,"href":"https:\/\/acriv.org\/WP\/wp-json\/wp\/v2\/pages\/1889\/revisions\/1892"}],"wp:attachment":[{"href":"https:\/\/acriv.org\/WP\/wp-json\/wp\/v2\/media?parent=1889"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}