Jr. HPR Level 1 Participation Program—Section D: Technical
D1) The rocket’s Center of Pressure (CP) is defined as:
A) The point where the rocket will fail at Max Q
B) The single point where the average of all aerodynamic forces acts through the rocket
C) The point where the rocket balances with the motor installed
D2) The following will increase the stability of a model rocket:
A) Adding nose weight
B) Reducing fin area aft of the rocket’s Center of Gravity (CG)
C) Adding fin area forward of the rocket’s Center of Gravity (CG)
D3) The following is a good rule-of-thumb to ensure a rocket’s stability:
A) The Center of Gravity is located at least one body diameter forward of the calculated Center of Pressure
B) The Center of Gravity is located at least one body diameter aft of the calculated Center of Pressure
C) The Center of Gravity is located the length of the nose cone forward of the aft end of the body tube
D4) Which of the following is considered to be a complex rocket?
A) One with a cluster of more than one motor
B) A staged rocket with motors in each stage
C) Both “A” and “B”
D5) Your current certification rocket has flown several times, in calm winds, with an 8-second delay deploying the parachute right at apogee. In launch conditions with winds at 15 knots, which is the best choice?
A) Use the same delay
B) Use a longer delay
C) Use a shorter delay
D6) What are methods to increase the stability of a model rocket?
A) Increase fin size aft of the Center of Gravity, add nose weight
B) Add more epoxy to the fins to make them stronger, reduce nose weight
C) Move the fins forward (closer to the Center of Gravity), fly the rocket on a higher-thrust motor
D7) Your simulation program indicates that your rocket will achieve safe velocity, with the planned motor, just as it leaves the top of a 10-foot launch rail. At the current launch, with winds over 5 MPH, only 8-foot rails are available. What should you do?
A) Angle the launch rail into the wind to increase the effective velocity over the fins
B) Re-run your simulation using an appropriate higher-thrust motor to achieve safe velocity with the 8-foot rail
C) Launch on the 8-foot rail without concern if your CG is more than 1.5 body diameters forward of the CP
D8) The Center of Gravity (CG) or Mass of a rocket is the point at which:
A) The rocket is the heaviest
B) Aerodynamic forces acting on the rocket balance
C) There is an equal amount of mass forward and aft of this point
D9) If the shoulder of your rocket’s nosecone is a loose fit in the body tube, what is the most likely problem during the flight?
A) The nose cone could drag separate from the body tube possibly accompanied by a high-speed recovery system deployment at motor burnout
B) The ejection charge gases might leak out around the nosecone shoulder and fail to deploy the recovery device
C) The rocket flight might be characterized by a loud whistling noise
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