Recovery Systems & Deployment Flashcards

When two independent altimeters are used for redundancy, how should their vent holes be configured?

Answer: Each altimeter bay should have its own static vent to prevent cross-contamination

Each altimeter should sense pressure through its own static port to prevent one altimeter's pyro firing event from pressurizing the other's sensor.

A rocket experiences a 'zipper' failure. What does this describe?

Answer: The shock cord rips through the airframe tube on deployment

Zipper failure occurs when a taut shock cord under snatch force tears longitudinally through the airframe tube wall, destroying the rocket.

What is the purpose of a 'nomex chute protector' in a recovery bay?

Answer: To shield the parachute from hot ejection gases during deployment

Nomex (aramid) is heat-resistant and wraps around the parachute to protect it from scorching by the hot gases produced by the ejection charge.

Which condition would cause a barometric altimeter to misread altitude and potentially fire recovery events at the wrong time?

Answer: A cracked or unsealed avionics bay allowing dynamic pressure inside

If the avionics bay is not sealed from ram air or body tube pressure, the altimeter receives incorrect pressure readings, corrupting altitude calculations.

How should a shock cord be attached to prevent zipper failure in high-power rockets?

Answer: Anchor to a bulkhead or rail button with a load-spreading anchor plate

Anchoring the shock cord to a structural bulkhead or anchor plate distributes the load and prevents it from cutting through the airframe tube wall.

NAR HPR certification requires that recovery systems be designed so the rocket lands in a specific area. What is the primary method for estimating landing location before flight?

Answer: Drift calculation using descent rate, altitude, and forecasted wind speed/direction

Pre-flight drift calculation combines descent rate, time under each chute phase, and forecasted wind data to predict where the rocket will land.

What is 'main chute reef' and why might it be used on very large high-power rockets?

Answer: Reefing temporarily restricts canopy opening diameter to reduce snatch force, then releases for full inflation

Reefing limits initial canopy diameter during high-speed opening, reducing peak snatch forces, then a cutter releases the reef line for full inflation at safer speed.