<story><title>Epic Forum Thread on Concorde (2010)</title><url>http://www.pprune.org/tech-log/423988-concorde-question.html</url><text></text></story><parent_chain></parent_chain><comment><author>creamyhorror</author><text>Enjoyable, nostalgic thread. Later on one member (age 78) of the core Concorde design team even appears. Here&amp;#x27;s an amusing anecdote from early in the thread:&lt;p&gt;========&lt;p&gt;Whilst on the Concorde conversion course at Bristol, occasionally crews would have the privilege of meeting some of the original design engineers and draughtsmen who had worked on the Concorde project.&lt;p&gt;...&lt;p&gt;Suffice to say that the senior fire officer who misread litres-per-minute as gallons-per-minute during an Olympus water ingestion test probably would not want any further publicity, likewise the apprentice who didn’t defrost the chicken before firing it into an engine running at full power in the bird ingestion test. My favourite was the supersonic hailstone story, fired as part of a hailstone ingestion test, but with uncertain results, the final resting place of said hailstone still being slightly obscure to this day. If anyone in the greater Bristol area got hit by a particularly hard snowball in the early sixties, the Filton test engineers are very sorry, and would like to apologise!&lt;p&gt;However, it is often the little insights into the past that amuse one the most and stick in one’s mind. During one such conversation, with a couple of thermodynamicists, I ventured to ask how they had settled on the (rather difficult to memorise) various temperature limits associated with Concorde.&lt;p&gt;For instance, why a nose temperature limit of +127°C, why not +130°C, much easier for a pilot to remember?&lt;p&gt;&lt;i&gt;“Isn’t it obvious?”&lt;/i&gt; one replied politely, genuinely puzzled by my question.&lt;p&gt;&lt;i&gt;“Computer generation,”&lt;/i&gt; replied his colleague to him, pointing his pipe stem at me.&lt;p&gt;&lt;i&gt;“Ah yes,”&lt;/i&gt; said the first, &lt;i&gt;“that would be it.”&lt;/i&gt;&lt;p&gt;They then went on to explain, in ever such a kindly manner, that, in thermodynamics, apparently the square, and the square root, of the absolute temperature of a material are terms used in many equations. Being armed mostly only with slide rules (and as they were in the vicinity of 120°C to 130°C as a limit anyway) it had been decided to make life easy and settle on +127°C as the limit, a temperature for which they could easily calculate the square and square root in their heads.&lt;p&gt;Noticing my bewilderment at the thought that anyone might be able to calculate the square or the square root of 127 in their heads, they proceeded to explain it to me still further, very slowly; in the manner that one would speak to an aged and rather deaf great aunt!&lt;p&gt;&lt;pre&gt;&lt;code&gt;    • Absolute zero = -273°C = Zero Kelvin = 0K
    • Max Nose temp = +127°C equal to 400K
    • √400 = 20
    • 400² = 160,000.
&lt;/code&gt;&lt;/pre&gt;
These are the people with the amusing stories to tell!</text></comment>
<story><title>Epic Forum Thread on Concorde (2010)</title><url>http://www.pprune.org/tech-log/423988-concorde-question.html</url><text></text></story><parent_chain></parent_chain><comment><author>idlewords</author><text>This starts off as a discussion of APUs but turns into a Q&amp;#x2F;A with participation by Concorde pilots, designers, and even a flight attendant who all clearly pine for their favorite plane ever. I couldn&amp;#x27;t pick one of the many anecdotes to highlight, so I posted a link to the entire monster thread.  It rewards digging.</text></comment>