Kent Paser in his book "Speed With Economy" outlines the
various mods he did to substantially increase the speed of his Mustang,
including exhaust nozzles from which he saw some thrust. Unfortunately, he makes
the same mistake so many make when quoting their performance changes; he
only tells how many mph increase he saw. This is only meaningful if you give the
before and after speeds. Speed changes are not additive!
Percentage increases multiply together to give you the increase that mods,
on a certain airframe, can give. So if you get 2%, 1.02 from one mod and 3%,
1.03 from another and 5% from a third, 1.05, then someone with an
identical plane should be able to see 1.02 X 1.03 X 1.05 = 10.3%, 1.103,
more speed when performing the same mods!
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