Cadet Level Practice Test

At Mach numbers greater than 2.5, aluminum is no longer an option. The SR-71 was made largely of titanium, which has good high temperature characteristics, but is still light enough for aircraft structures. To allow for the expansion, slip joints are used in many places on the SR-71. On the ground, the SR-71 fuel tanks leak, and they do not seal until the aircraft heats up during flight.

Mach angle is the angle a shock wave makes with the direction of motion. The faster you fly above the speed of sound, the lower the angle. Read more about it here: https://www.grc.nasa.gov/www/k-12/airplane/machang.html

In a single engine aircraft, best glide provides the best forward distance in an engine failure. Keep in mind, this airspeed, however, does not guarantee the longest time aloft during an engine failure.

To be specific, it’s actually Diethylene Glycol Monomethyl Ether, or DEGMME. And when it’s added to fuel, any water that is in the fuel is prevented from crystalizing down to temps as cold as -85 degrees Celsius. That’s cold.

In steady flight, the sum of thrust, drag, weight, and lift is always zero. There can be no unbalanced forces in steady, straight flight based upon Newton’s Third Law. Note: this does not mean the four forces are equal. It means the opposing forces are equal to and thereby cancel the effects of each other.