<instructions>Your goal is to analyze the following comment and estimate how highly it will be upvoted by the Hacker News community.</instructions><comment><author>agurk</author><text>Looking at the Concorde&amp;#x27;s fuel usage taxing is only part of the picture. All turbine engines are very inefficient at low power outputs due to the need to use energy to create sufficient compression for them to function. On top of this the Olympus engines generated a lot of thrust at idle, so much so that only two were used for taxing and it was still apparently tricky to control.&lt;p&gt;While cruising at supersonic speeds the engines were actually the most efficient machines of their time achieving 43% thermal efficiency [0]. Despite being very efficient they still had high fuel consumption rates as the total amount of energy required to sustain those speeds is a lot higher than subsonic.&lt;p&gt;Modern jet are in the 50%s thermally efficient [1] but despite airframe improvements there has been no way to improve fundamental aerodynamics so that supersonic energy costs aren&amp;#x27;t high.&lt;p&gt;The Concorde did use reheat to take off and break the supersonic barrier which is very fuel inefficient.&lt;p&gt;Using a modern airframes and engines that also don&amp;#x27;t need reheat will reduce fuel consumption but not to a level anywhere similar to a modern jetliner.&lt;p&gt;[0] &lt;a href=&quot;https:&amp;#x2F;&amp;#x2F;en.wikipedia.org&amp;#x2F;wiki&amp;#x2F;Rolls-Royce&amp;#x2F;Snecma_Olympus_593&quot; rel=&quot;nofollow&quot;&gt;https:&amp;#x2F;&amp;#x2F;en.wikipedia.org&amp;#x2F;wiki&amp;#x2F;Rolls-Royce&amp;#x2F;Snecma_Olympus_593&lt;/a&gt;&lt;p&gt;[1] &lt;a href=&quot;https:&amp;#x2F;&amp;#x2F;www.nap.edu&amp;#x2F;read&amp;#x2F;23490&amp;#x2F;chapter&amp;#x2F;6#38&quot; rel=&quot;nofollow&quot;&gt;https:&amp;#x2F;&amp;#x2F;www.nap.edu&amp;#x2F;read&amp;#x2F;23490&amp;#x2F;chapter&amp;#x2F;6#38&lt;/a&gt;</text><parent_chain><item><author>DomenicoMazza</author><text>If I recall correctly the Concorde used about 2 tonnes of fuel rolling on the ground alone.. I wonder how this new aircraft fares for fuel consumption?&lt;p&gt;I believe the Concorde is a marvel. You could travel faster than the rotation of the earth in it! However I don’t think we need more environmentally unsustainable travel.</text></item></parent_chain></comment><story><title>Boom supersonic jet readies for rollout</title><url>https://www.airlineratings.com/news/boom-supersonic-jet-readies-rollout/</url></story>
<instructions>Your goal is to analyze the following comment and estimate how highly it will be upvoted by the Hacker News community.</instructions><comment><author>dreamcompiler</author><text>&amp;gt; You could travel faster than the rotation of the earth in it!&lt;p&gt;You can do that in a conventional jet at latitudes far from the equator. You can &lt;i&gt;walk&lt;/i&gt; faster than the earth rotates if you&amp;#x27;re very close to a pole (very very close).</text><parent_chain><item><author>DomenicoMazza</author><text>If I recall correctly the Concorde used about 2 tonnes of fuel rolling on the ground alone.. I wonder how this new aircraft fares for fuel consumption?&lt;p&gt;I believe the Concorde is a marvel. You could travel faster than the rotation of the earth in it! However I don’t think we need more environmentally unsustainable travel.</text></item></parent_chain></comment><story><title>Boom supersonic jet readies for rollout</title><url>https://www.airlineratings.com/news/boom-supersonic-jet-readies-rollout/</url></story>