Theoretical and Practical Considerations: Can a Mach 2 Missile Attain Mach 5 When Launched from an Airborne Aircraft?

Overview

In discussions about missile and aircraft speeds, one intriguing question often arises: can a Mach 2 missile attain Mach 5 when launched from an aircraft traveling at Mach 3? This article explores the theoretical framework and practical considerations involved in such a scenario.

Theoretical Speeds and Definitions

Understanding the definitions and calculations involved is essential to answering this question. Let’s break it down step-by-step:

Mach Numbers

Mach 1 refers to the speed of sound, which varies with altitude and temperature. At sea level, the speed of sound is approximately 343 meters per second or 1,125 feet per second. Mach 2 is twice the speed of sound, and Mach 5 is five times the speed of sound. These speeds serve as the basis for our calculations.

Aircraft Speeds

If the aircraft is traveling at Mach 3, it is moving at approximately 3 times the speed of sound. A Mach 2 missile, when launched, has an initial speed of Mach 2 relative to the surrounding air. This is because the missile does not start at absolute zero velocity relative to the ground but rather the aircraft from which it is launched.

Relative Speeds Calculation

The effective speed of the missile at launch would be the sum of its own speed (Mach 2) and the speed of the aircraft (Mach 3). Therefore:

Mach 2   Mach 3  Hypothetical Mach 5.

However, in reality, achieving and maintaining such speeds involves many other factors.

Practical Considerations

While the theoretical calculation states that an initial combined speed of Mach 5 is possible, the practical challenges of sustaining such speeds and dealing with various factors come into play:

Drag and Thrust

Drag is a significant factor that affects the missile's performance. At Mach 2, the drag of the missile is already approaching the available thrust, and at Mach 3, the aircraft's speed limit is exceeded. The drag increases with speed, which can significantly impact the missile's ability to achieve and maintain Mach 5 speed.

Launch Altitude and Conditions

If the missile is ground-launched, like in the case of an MLRS (Multiple Launch Rocket System), the initial altitude of the launch also plays a crucial role. High-altitude launches can provide the necessary conditions to overcome some of the drag issues at lower altitudes.

Air-Launch Scenarios

Air-launch scenarios can potentially achieve higher Mach numbers because the initial conditions are different:

40,000 ft launch: The burnout Mach is 4.84. 50,000 ft launch: The burnout Mach is 4.97. 60,000 ft launch: The burnout Mach is 5.04.

These examples illustrate that while an air-launch from a high enough altitude can get close to the theoretical Mach 5, it still faces significant challenges in sustaining such speeds.

Conclusion

Yes, a Mach 2 missile can theoretically achieve Mach 5 at launch, but the practical challenges, including drag, thrust, and altitude, make it highly improbable. The launch must be conducted from a position and under conditions that minimize these factors to achieve the desired speed.

Further Reading

To delve deeper into missile and aircraft performance, consider exploring the following topics:

Air resistance and drag coefficients Thrust-to-drag ratios High-altitude missile launches