Question

last year in mae 159, the optimal design aircraft cruised at m .78. at an altitude of 35,000 ft, this results in a indicated airspeed of 245 kts. what is its cruise velocity in ft/s? hint, look up how to convert from knots to feet/second. you may want to remember this for the final.

Answer 1

To convert an aircraft's indicated airspeed from knots to feet per second, multiply the speed in knots by the conversion factor 1.68781. For a speed of 245 knots, the cruise velocity is approximately 413.51 ft/s.

Step-by-step explanation:

The student is asking how to convert the indicated airspeed of an aircraft, in knots, to its cruise velocity in feet per second (ft/s). To perform this conversion, we need to understand that the airspeed indicated at the altitude of 35,000 ft is 245 knots. One knot is equivalent to one nautical mile per hour, which is approximately 1.15078 miles per hour (mph), or exactly 1.68781 feet per second. Hence, to convert knots to feet per second, we multiply the speed value in knots by the conversion factor 1.68781.

To calculate the cruise velocity in ft/s for a speed of 245 knots, we follow this step:

1. 
   
3. Convert 245 knots to ft/s: 245 knots × 1.68781 (ft/s per knot) = 413.51445 ft/s.

The aircraft's cruise velocity at 35,000 ft is therefore approximately 413.51 ft/s.