LOLL Supersonic Model Rockets

Using E-25-7 Aerotech ammonium perchlorate core burning motors, single-use. In a light weight rocket, with plastic wings (ali metal was too heavy) and epoxy joints, the impulse of an E-25 can just break the speed of sound at sea level = 760mph. The rocket makes a slight 'crack' sound, unlike the sound it makes in a heavier machine but it is a subtle difference. We couldn't measure the speed for sure - Estimates were using software (speeds were from 1,000 - 1,500mph). These were built for speed rather than altitude but they still go high. Details in the video. I also made even smaller rocket using these motors using 18mm diameter tubes. These are 24mm. If you do this play safe. Mind you I'm not sure these motors are made in this spec anymore. This video was made a while ago.

Category:

Education

Tags:

• Calvertfilm
• Laurie
• Calvert
• rocketry
• model
• supersonic
• rocket
• Estes
• kit
• HART

[nanchuanwushu1]

Is this rocket capable of taking a G motor instead of the E you have at the time? Or it could take to Es and reach at least 1500 ft more.. Is at least one of those solutions possible? Is your rocket capable of going even faster (in order to reach more height)?

[Calvertfilm]

@nanchuanwushu1 The body tube diameter means it couldn't take a G. But an E is possible.

[Calvertfilm]

@geekmanager2000 Its a good point about the sonic cone but experienced rocketeers all felt it was going supersonic, that we could hear the crack, and the simulation software also bore this out. But we did have no specialist recording equipment, so it remains open for debate. Good point you made there.

[Calvertfilm]

@geekmanager2000 The rocket goes supersonic almost instantly. 

[geekmanager2000]

@Calvertfilm ... is quite large. It is entirely possible that the rocket may be at sufficient altitude, and the cone so wide, that no one on the ground would be in a position to hear the boom/crack.

[geekmanager2000]

@Calvertfilm Actually, you would not be able to hear a sonic boom/crack at the launch site since you would already be within the area of the sonic cone when the rocket goes super sonic. Those away from the launch site would hear it at the edge of the sonic cone passes them on the ground. The required distance from the pad to hear this is dependent on the altitude at which the rocket goes supersonic, and the shape of the cone. at low supersonic speeds the angle of the vertex of the sonic cone ...

[1983bfmv]

@VERB65

That easily surpassed the speed of sound.

[Calvertfilm]

@VERB65 The computer software estimated it would reach over 1,000mph and also we heard a 'crack' noise rather like a whip crack. The crack of a whip is due to the tip of the whip going supersonic. But we had no way of conriming the speed other than the noise it made.

[VERB65]

How do you know it went supersonic. I don't believe it sorry. But it's still cool. But not as cool as supersonic. Even a little vehicle such as that would of created a sonic boom of some sort. Sorry

[CobandPeaz89]

Brilliant!!! 10/10