<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>tzs</author><text>A bit of searching failed to turn up anything on how the simulation was done. I&amp;#x27;m curious if it was all digital, like a modern simulator, or if it included analog simulation.&lt;p&gt;It was built by Link, which had been building flight simulators since 1929 [1], so certainly had extensive experience with analog simulators.&lt;p&gt;According to Wikipedia&amp;#x27;s article on analog computers [2],&lt;p&gt;&amp;gt; Analog computers were widely used in scientific and industrial applications even after the advent of digital computers, because at the time they were typically much faster, but they started to become obsolete as early as the 1950s and 1960s, although remained in use in some specific applications, such as aircraft flight simulators, the flight computer in aircraft, and for teaching control systems in universities. More complex applications, such as aircraft flight simulators and synthetic aperture radar, remained the domain of analog computing (and hybrid computing) well into the 1980s, since digital computers were insufficient for the task&lt;p&gt;It sounds like the &amp;#x27;60s, then, were well before digital flight simulators were common.&lt;p&gt;[1] &lt;a href=&quot;https:&amp;#x2F;&amp;#x2F;en.wikipedia.org&amp;#x2F;wiki&amp;#x2F;Link_Trainer&quot; rel=&quot;nofollow&quot;&gt;https:&amp;#x2F;&amp;#x2F;en.wikipedia.org&amp;#x2F;wiki&amp;#x2F;Link_Trainer&lt;/a&gt;&lt;p&gt;[2] &lt;a href=&quot;https:&amp;#x2F;&amp;#x2F;en.wikipedia.org&amp;#x2F;wiki&amp;#x2F;Analog_computer&quot; rel=&quot;nofollow&quot;&gt;https:&amp;#x2F;&amp;#x2F;en.wikipedia.org&amp;#x2F;wiki&amp;#x2F;Analog_computer&lt;/a&gt;</text><parent_chain><item><author>ta1234567890</author><text>&amp;gt; The next day, our flight profile was duplicated on the SR-71 flight simulator at Beale AFB, Calif. The outcome was identical. Steps were immediately taken to prevent a recurrence of our accident.&lt;p&gt;Wow! Super impressive that they could simulate that. Didn&amp;#x27;t know that was possible, especially in 1966.&lt;p&gt;Is there any current simulation software (available to the public &amp;#x2F; off the shelf) in which you could accurately simulate something like the situation from the story?</text></item></parent_chain></comment><story><title>When His SR-71 Blackbird Disintegrated, This Pilot Free Fell from Space</title><url>http://www.chuckyeager.org/news/sr-71-disintegrated-pilot-free-fell-space-lived-tell/</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>zarriak</author><text>I&amp;#x27;m going to have to guess that CFD simulation above mach 1 that is good is probably not something that is publicly available but from reading RUAG&amp;#x27;s website they use open source software[1]. From my experience with CFD in F1 the main issue you have with CFD is correlation but maybe driving a car around a track is harder to simulate than going really fast in &amp;quot;clean&amp;quot; air.&lt;p&gt;This reason is what leads me to think that it is a major issue and is why both China and the United States started going into mach 5+ with autonomous craft to gather data for correlation.&lt;p&gt;[1]: &lt;a href=&quot;https:&amp;#x2F;&amp;#x2F;aerodynamics.ruag.com&amp;#x2F;en&amp;#x2F;aerodynamics&amp;#x2F;simulation-analysis&quot; rel=&quot;nofollow&quot;&gt;https:&amp;#x2F;&amp;#x2F;aerodynamics.ruag.com&amp;#x2F;en&amp;#x2F;aerodynamics&amp;#x2F;simulation-ana...&lt;/a&gt;</text><parent_chain><item><author>ta1234567890</author><text>&amp;gt; The next day, our flight profile was duplicated on the SR-71 flight simulator at Beale AFB, Calif. The outcome was identical. Steps were immediately taken to prevent a recurrence of our accident.&lt;p&gt;Wow! Super impressive that they could simulate that. Didn&amp;#x27;t know that was possible, especially in 1966.&lt;p&gt;Is there any current simulation software (available to the public &amp;#x2F; off the shelf) in which you could accurately simulate something like the situation from the story?</text></item></parent_chain></comment><story><title>When His SR-71 Blackbird Disintegrated, This Pilot Free Fell from Space</title><url>http://www.chuckyeager.org/news/sr-71-disintegrated-pilot-free-fell-space-lived-tell/</url></story>