<story><title>How SR-71 Blackbird Designers Overcame Canonical Jet Engine Limitations</title><url>http://www.reddit.com/r/aviation/comments/vouxj/this_sr71_holds_the_flight_airspeed_record_at/c56rwsn</url><text></text></story><parent_chain></parent_chain><comment><author>D_Alex</author><text>Unfortunately, while the reddit post seems authoritative, it contains a multitude of errors and ends up somewhat misleading. The most significant error is:&lt;p&gt;&quot;What the front half of a jet engine (the intake/diffuser, and the compressor blades, i.e. all the stuff that happens before fuel is burned) does is; it heats up the air until it&apos;s hot enough for fuel to ignite&quot;  ...etc.&lt;p&gt;The heating up of air in the gas turbine cycle (Brayton cycle) is an UNDESIRABLE, but difficult to avoid consequence of the ideal gas law. A higher efficiency and power output would be possible if this heating did not occur, hence measures such as water injection or intercooling on large stationary gas turbines.&lt;p&gt;There are a number of other more subtle errors in the post.</text></comment>
<story><title>How SR-71 Blackbird Designers Overcame Canonical Jet Engine Limitations</title><url>http://www.reddit.com/r/aviation/comments/vouxj/this_sr71_holds_the_flight_airspeed_record_at/c56rwsn</url><text></text></story><parent_chain></parent_chain><comment><author>jluxenberg</author><text>Neat anecdote about the SR-71&apos;s speed from a former pilot &lt;a href=&quot;http://www.jumbojoke.com/the_king_of_speed.html&quot; rel=&quot;nofollow&quot;&gt;http://www.jumbojoke.com/the_king_of_speed.html&lt;/a&gt;&lt;p&gt;(couldn&apos;t find a better link; this is an excerpt from &lt;i&gt;Sled Driver: Flying the World&apos;s Fastest Jet&lt;/i&gt; by Brian Schul)</text></comment>