NAR HPR Recovery Systems & Deployment 5

Question 1

What is the significance of 'electronics arming altitude' in a dual-deploy flight computer?

Accepted Answer

The altimeter arms its pyro outputs only after detecting a minimum altitude gain, preventing ground-level misfires

Answer

Requiring a minimum altitude gain before arming pyro outputs prevents accidental deployment if the rocket is bumped or handled after arming on the pad.

Question 2

A rocketeer uses 1.5g of black powder for ejection on a 4-inch diameter rocket. Test results show the sections barely separate. What is the correct response?

Accepted Answer

Increase the charge mass in small increments and retest until reliable separation is achieved

Answer

Incremental increases with repeated ground testing is the correct method to find the minimum reliable charge mass for separation.

Question 3

Which scenario best illustrates a 'ballistic recovery' failure in high-power rocketry?

Accepted Answer

Both the drogue and main chutes fail to deploy and the rocket impacts at near-terminal velocity

Answer

Ballistic recovery describes an uncontrolled descent where no recovery device deploys, resulting in high-speed ground impact — the most dangerous recovery failure mode.

Question 4

When selecting parachute material for high-power rockets, ripstop nylon is preferred over regular nylon primarily because:

Accepted Answer

The ripstop weave prevents small tears from propagating into catastrophic canopy failure

Answer

Ripstop weave contains reinforcing threads at intervals that stop tear propagation, maintaining canopy integrity even if the fabric is nicked or stressed.

Question 5

For a Level 2 HPR rocket weighing 35 lbs, which ejection charge testing approach meets best safety practice?

Accepted Answer

Ground test multiple charge sizes with all shear pins installed and parachutes packed to confirm reliable deployment

Answer

Testing with actual flight configuration (shear pins + packed chutes) is required because real deployment resistance cannot be accurately modeled without physical testing.

(NAR HPR) NAR High-Power Rocketry Certification Practice Test

(NAR HPR) NAR High-Power Rocketry Certification Practice Test

NAR HPR Recovery Systems & Deployment 5