NAR HPR Ignition Systems & Launch Controllers 2 — Questions and Answers
Question 1: What is the typical resistance range for a properly installed high-power motor igniter as measured during a continuity check?
- 0.001 to 0.01 ohms
- 0.5 to 2.0 ohms (Correct answer)
- 10 to 100 ohms
- 500 to 1000 ohms
Correct answer: 0.5 to 2.0 ohms
A properly installed igniter typically reads 0.5 to 2.0 ohms; readings significantly outside this range indicate a faulty igniter or poor electrical connection.
Question 2: What should a flyer do if the continuity check shows an open circuit (no continuity reading)?
- Increase the launch controller battery voltage and retry the check
- Immediately press the launch button to attempt to clear the fault
- Do not arm or launch; investigate and correct the problem before proceeding (Correct answer)
- Proceed with launch since most motors will fire without confirmed continuity
Correct answer: Do not arm or launch; investigate and correct the problem before proceeding
An open circuit indicates the igniter is not properly connected; proceeding without continuity would result in a misfire and violates NAR safety rules.
Question 3: Which type of igniter is specifically designed and recommended for use with composite propellant high-power motors?
- Standard Estes solar igniter
- Thermalite safety fuse
- Copperhead or similar composite-compatible pyrotechnic igniter (Correct answer)
- Standard electric match (e-match) used for black powder only
Correct answer: Copperhead or similar composite-compatible pyrotechnic igniter
Composite propellant motors require hotter igniters like copperheads designed to deliver sufficient energy to initiate the harder-to-ignite composite fuel grains.
Question 4: What is the purpose of having the RSO oversee or control the arming step of the launch controller?
- To verify the flyer's certification level matches the motor class
- To ensure proper oversight and prevent premature or unauthorized arming (Correct answer)
- To test the launch controller battery before the flyer uses it
- To comply with FCC radio frequency regulations at the launch site
Correct answer: To ensure proper oversight and prevent premature or unauthorized arming
RSO control of the arming step ensures proper procedural oversight and prevents premature, accidental, or unauthorized activation of the ignition system.
Question 5: What determines the required minimum length of launch lead cables connecting the controller to the igniter?
- Exactly 15 feet per NAR standard for all motor classes
- The length that places all personnel outside the minimum safe distance for the motor class being used (Correct answer)
- The length of the launch rail plus five additional feet
- Exactly 25 feet as specified in the NAR High Power Safety Code
Correct answer: The length that places all personnel outside the minimum safe distance for the motor class being used
Launch lead length must be sufficient to place all operating personnel outside the minimum safe distance specified for the motor power level being used.
Question 6: What is the function of the 'safe' position on a launch controller's arm/safe toggle switch?
- It disconnects the battery completely from the launch controller
- It interrupts the firing circuit so the launch button cannot complete ignition (Correct answer)
- It signals the RSO that the controller is ready for arming
- It engages the internal continuity check mode
Correct answer: It interrupts the firing circuit so the launch button cannot complete ignition
In the 'safe' position, the firing circuit is interrupted so that pressing the launch button cannot send current to the igniter, preventing accidental firing.
Question 7: What does 'all-fire current' mean for a pyrotechnic igniter?
- The current required to complete a successful continuity check
- The minimum current guaranteed to reliably fire the igniter (Correct answer)
- The maximum current the igniter can safely conduct without damage
- The current level that causes the igniter to fail open without firing
Correct answer: The minimum current guaranteed to reliably fire the igniter
All-fire current is the minimum DC current that will reliably ignite the pyrotechnic charge; launch controllers must deliver at least this amount to ensure ignition.
NAR HPR Ignition Systems & Launch Controllers 2
What is the typical resistance range for a properly installed high-power motor igniter as measured during a continuity check?