Related Clues:

• Yeager's speed
• Supersonic reading
• Speed-of-sound ratio
• Flying speed ratio
• Physicist Ernst
• Airspeed measure
• Sound-speed number
• Speed-of-sound word
• __ 1: speed of sound
• ___ 5 (Speed Racer's car)
• Ernst of sound-barrier fame
• Speed of sound
• Name often followed by a number
• Chuck Yeager's breakthrough
• The 30 Down of sound