Welcome! Discussing Airgun Ballistics

Click For Summary
SUMMARY

This discussion focuses on airgun ballistics, specifically the internal ballistics of airguns using compressed air. The primary conclusion is that a converging-diverging (CD) nozzle is essential for achieving supersonic airflow, as it is the only method that allows air to exit faster than the speed of sound. Additionally, the user clarifies that while the airflow "wants" to exceed the pellet's exit velocity of 900 fps, it is physically constrained by the pellet's presence in the barrel. The discussion emphasizes the importance of understanding airflow dynamics in relation to projectile motion.

PREREQUISITES
  • Understanding of internal ballistics principles
  • Familiarity with airgun mechanics
  • Knowledge of fluid dynamics, particularly compressible flow
  • Experience with converging-diverging nozzle design
NEXT STEPS
  • Research the design and function of converging-diverging nozzles in fluid dynamics
  • Explore the principles of compressible flow and shock waves
  • Study the effects of barrel length and diameter on pellet velocity
  • Investigate methods for achieving supersonic speeds in airgun projectiles
USEFUL FOR

This discussion is beneficial for airgun enthusiasts, ballistics researchers, and engineers interested in the physics of projectile motion and airflow dynamics in airgun systems.

RKT
Messages
18
Reaction score
0
Greetings to all Forumites ! I am new to this forum and this is my first post. If the subject of my post does not concur with this section, pls excuse me and redirect me to the correct section. Thanks.

My interest is in ballistics, particularly internal. Most of my questions and discussions will relate to airguns, although I'll discuss the physics here and not mechanical setups. I hope this subject is not taboo.

I should like to start off with this question : Using ONLY compressed air from a reservior, is it possible to let out a stream of air through an orifice faster than the local speed of sound ? I know that a CD nozzle can do it, any other way ?
 
Engineering news on Phys.org
A CD nozzle is the only way to do it. Anything less will choke.

Well, let me make one caveat...if you were to pull the entire barell system under vacuum, you could pass M1.
 
Re : A CD nozzle is the only way ...

Thanks. That puts me on more conclusive footing. So a CD nozzle is a must.

The next thing I want to know ... Would my following understanding be true ?

' If a pellet exits a barrel at say, 900 fps, then, the airflow must WANT to go way faster than that. The key word here is 'want'. The air actually cannot go any faster than the pellet (as the pellet obstructs the flow) but it WANTS to. Thats pressure. That is to say, if discharged without a pellet, the airflow would be way faster than 900 fps.'
 

Similar threads

How Do You Calculate Miller Stability in Excel?
  • · Replies 1 ·
Replies
1
Views
4K
Undergrad On whether the motion of a Foucault pendulum bob is comparable to ballistics
  • · Replies 10 ·
Replies
10
Views
3K
Calculate the air pressure needed for a projectile to travel X distance
  • · Replies 6 ·
Replies
6
Views
3K
Solving Long Mach Nozzle Shape Problem for MBMS
  • · Replies 6 ·
Replies
6
Views
3K
Graduate Question about straight-line ballistics
  • · Replies 3 ·
Replies
3
Views
3K
Compressible flow problem in heated tube reactor
  • · Replies 2 ·
Replies
2
Views
3K
High School Help understanding the physics of airflow
  • · Replies 3 ·
Replies
3
Views
2K
Undergrad Modeling a Bottle Rocket: Analyzing the Maximum Altitude
  • · Replies 4 ·
Replies
4
Views
6K
Graduate How Does Jet Injection Work in Fluid Dynamics?
  • · Replies 6 ·
Replies
6
Views
2K
Undergrad Conservation of Mass for Compressible Flow
  • · Replies 33 ·
2
Replies
33
Views
4K