LPR Technique: Puff of Breath Test. Not working?

[brockrwood]

So, I am trying to use the “puff of breath” test to see if the nose cone on my modified Goblin is loose enough. I have sanded the inside of the tube and the shoulder of the nose cone quite a bit.

I put my soggy old lips on thw rear of the rocket and blow. The nose cone does not pop out.

The nose cone doesn’t seem all that tight.

Is there a special trick to this time-honored test of nose cone fit?

 

[waltr]

You need a quick, sharp blow into the motor tube. If the nose does not come off doing that then it IS too tight.

Try putting the nose in part way and see if it pops off.
Warning: When this works the nose cone flys off. So be sure it is pointed toward a place that will catch it without it getting banged up.

The other nose cone test is:
with the rocket fully loaded, chute and motor, lift by the nose cone. The nose should stay on. Give it a wiggle and the BT should slide off the nose cone.

 

[mh9162013]

I use the blow test to make sure the parachute isn't packed in too tight. I use the "jiggle" test when holding the rocket upside down to see if the nose cone is too tight in the main body tube.

 

[smstachwick]

You need a quick, sharp blow into the motor tube. If the nose does not come off doing that then it IS too tight.

Try putting the nose in part way and see if it pops off.
Warning: When this works the nose cone flys off. So be sure it is pointed toward a place that will catch it without it getting banged up.

The other nose cone test is:
with the rocket fully loaded, chute and motor, lift by the nose cone. The nose should stay on. Give it a wiggle and the BT should slide off the nose cone.

I sometimes use a variation of this. Lifting it by the body tube in a nose-down attitude and seeing if the nose stays on, then lifting it by the nose and seeing if it comes off. If both conditions are satisfied, it passes and it’s ready.

 

[brockrwood]

I use the blow test to make sure the parachute isn't packed in too tight. I use the "jiggle" test when holding the rocket upside down to see if the nose cone is too tight in the main body tube.

I did get the blow test to work. I was not getting my lips firmly sealed around the end of the motor mount. That does take some mandibular dexterity.

 

[Cape Byron]

I did get the blow test to work. I was not getting my lips firmly sealed around the end of the motor mount. That does take some mandibular dexterity.

That's good. My next suggestion was Ventolin...