Tripoli level 2 Cert Test (Feb 2026)

These flash cards are from the TRA Advanced Study Guide for the Tripoli Level 2 Cert Test. The flash cards were created in Feb of 2026

Which of Newton’s Laws best describes the behavior of a rocket motor?

Newton’s Third Law: To every action there is always an equal and opposite reaction

How does Newton’s Third Law “To every action there is always an equal and opposite reaction” relate to rocketry?

That a rocket flies because the rocket motor “pushes” the rocket in a direction opposite of the exhaust jet.

What are the three forces acting upon a rocket during flight?

Gravity, thrust and aerodynamic drag

What are the three major factors that determine the maximum altitude of a high-power rocket in vertical flight?

Motor thrust, rocket weight, and aerodynamic drag

For an inherently stable rocket, which statement about the center of gravity (CG) and the center of pressure (CP) is true?

The CG must be forward of the CP relative to the desired direction of flight

A 4" diameter rocket with its motor is determined to have the center of gravity (CG) four inches behind the center of pressure (CP). Is this a rocket likely to be stable?

No, the CP must be behind the CG for the rocket to be stable

The center of pressure (CP) of a rocket is generally defined as:

The point at which aerodynamic lift on a rocket is centered

What is the “rule-of-thumb” for a stable rocket?

That the center of gravity should be at least one body diameter in front of the center of pressure

You are at the launch site and decide to fly your rocket on a heavier motor than you simulated it on. Which statement regarding CG is true?

One can install the motor, recovery system and payload and determine the balance point of the rocket as it is ready for flight

What ordinarily happens to the center of gravity (CG) of a rocket during a solid rocket motor’s thrusting phase?

The CG shifts forward

How can a statically unstable rocket be made stable?

Adding weight to the nose

What are three methods used to shift the center of gravity (CG) of a rocket forward?

Add weight to the nose, make the rocket longer, use a smaller (or lighter) motor

What are three methods used to shift the center of pressure (CP) aft?

Make the rocket shorter, use larger fins, increase the number of fins

The definition of coefficient of drag (Cd) is:

A dimensionless number dependent on the rocket configuration, Mach number and angle of attack

What happens to the coefficient of drag (Cd) as the rocket approaches the speed of sound?

The Cd increases.

For a subsonic rocket, what factors most greatly affect the coefficient of drag (Cd)?

Speed, airframe dimensions, nosecone shape and fin shape

What effect does a boat tail have on a subsonic rocket’s coefficient of drag (Cd)?

It decreases the Cd by reducing the base drag

The flight of a high-power rocket can be separated into three portions; they are:

Powered flight, un-powered ascent and descent

Which describes the thrust curve of a regressive motor burn?

A high initial thrust relative to the ending thrust of the motor

Which describes the thrust curve of a progressive motor?

A general increase in thrust during the burn

A Bates grain has an essentially neutral thrust curve because:

The area of burning propellant remains relatively constant

What is the most common function of a motor liner and the O-ring seals in a solid rocket motor?

To keep the hot gasses of the motor from burning or melting the motor case

What is the most common oxidizer in commercially available high power composite solid rocket motors?

Ammonium Perchlorate

What is NH4ClO4?

Ammonium Perchlorate

A small hole is typically drilled near the top of a high-power rocket’s airframe, below the nosecone or payload section. Why?

The hole vents internal air pressure as the rocket gains altitude to prevent premature separation

How do you convert Newtons of thrust to pounds of thrust?

Divide Newtons by 4.45

What is a Newton?

1 kg*m/s^2

What is the oxidizer most commonly used in a commercial hybrid rocket motor?

N2O

For a rocket with a much less than 10:1 “length to diameter” (L/D) ratio, such as spools and pyramids, what type of drag contributes significantly to stability and makes it possible to fly without much, if any, nose weight?

Base drag

When doing an air-start of an L class motor, which of the following would be considered the safest configuration?

A single computer driving a single initiator

A rocket with a motor cluster consisting of a central composite motor and four black powder motors, using five identical igniters:

Will result in the black powder motors starting first followed by the central composite motor

What typically happens to a marginally stable rocket with a hybrid motor during the thrusting phase?

The rocket may become less stable

In general terms, the specific impulse of a rocket motor is:

The total impulse divided by a unit weight of propellant

In general terms, the total impulse of a rocket motor can be described as:

The product of the average motor thrust and burn time

The average thrust of a rocket motor is 100 Newtons, and the burn time is 4 seconds. What is the total impulse?

400 Newton-seconds

Which of the motors listed below has the highest total impulse?

K200

Which of the motors listed below has the highest average thrust?

J400

What is the difference between a J640 and a J320 high power rocket motor (assume full 1280 Newton-second J motors)?

The J640 burns out twice as fast as the J320

Which of the following has a total impulse (It) in the J motor range?

It = 1000 Newton-seconds

What is a Newton?

The amount of force required to accelerate one kg one meter per second per second

What does the motor designation I220-8 mean?

The motor has between 320-640 N-s of impulse, an average thrust of 220 Newtons, with approximately 8 seconds between motor burn-out and ejection

Rocket A is descending at 10 feet per second, rocket B weighs the same but is descending at 20 feet per second. Which statement is true?

Rocket B has four times the kinetic energy of rocket A

Rocket A weighs twice as much as rocket B. Both are descending at 20 feet per second. Which statement is true?

Rocket A has two times the kinetic energy of rocket B

What is the purpose of a launch rod, rail or tower?

Both a. and b

What is the purpose of a launch lug or rail buttons?

To guide the rocket along the launch rod or rail

For a cluster rocket, which construction technique will minimize the effect of one motor failing to ignite?

Make the holes in the forward centering ring slightly closer to the rocket’s centerline than those of the aft centering ring

What can happen if all the motors of a cluster do not ignite at launch?

The rocket may not fly straight

What is a shred?

A failure of the rocket air frame during boost resulting in destruction of the rocket

What is a Cato?

A failure of the motor causing flight termination

What is the primary requirement for a rocket motor ignitor?

It must transfer sufficient heat to the propellant to assure ignition

Most APCP (ammonium perchlorate composite propellant) rocket motors are centralburning rather than end-burning:

Because most APCP has a burn rate that is too low for useful end-burners

Which of the following is most likely in dual-deployment rockets that use a drogue and a main parachute?

The drogue and the main can tangle if not properly arranged

When using an accelerometer-based altimeter in a rocket that may exceed Mach 1:

Neither a. nor b. need be done

When using a pressure-sensor altimeter in a rocket that will not reach Mach 1:

One or more holes must be drilled in the electronics bay for atmospheric access

What is the major issue with accelerometer-based altimeters?

They may not deploy properly if the flight is significantly off-vertical

What is the purpose of the Tripoli Unified Safety Code?

Establish guidelines for reasonably safe operation of rockets at a Tripoli launch

Although Tripoli launches involve several layers of safety rules intended to increase safety, _____ is ultimately responsible for the rocket and flight?

The flier

The flier shall document the location of the center of ____ and be able to demonstrate the center of _____? (Answer in order of blanks)

Pressure, Gravity

Which of the following motor types are not allowed to be made and flown by a Level 2 flier as a research motor?

Both a. and b

Rockets flown at Tripoli launches may carry:

Neither a. nor b.

What is the Authority Having Jurisdiction (AHJ)?

The organization, office or individual responsible for enforcing requirements of a code or standard, or for approving equipment, materials, an installation or a procedure

What is a complex high-power rocket?

Either a. or b.

What are the minimum criteria that define a high-power rocket?

Either a. or b

What is the maximum weight of a model rocket with motors installed?

53 oz. (1500 g)

When is an active recovery device not necessary in a high-power rocket?

When the rocket employs a passive recovery system (e.g.: tumble recovery, aero-braking)

Range activity shall cease whenever a thunderstorm has been detected within ____ miles (kilometers) of the launch site?

10 (16 kilometers)

At what total impulse and/or average thrust does a motor become high power?

A rocket motor with more than 160 Newton-seconds of total impulse or 80 Newtons average thrust

While a 3:1 average thrust to weight ratio is the absolute minimum established in the Tripoli Unified Safety Code, what is the typical initial minimum thrust to weight ratio for a rocket?

5:1

Who may operate a high-power rocket?

A certified user as defined in the Tripoli Unified Safety Code

What operating clearances must be complied with for flying high power rockets?

The Tripoli Unified Safety Code, Regulations controlling airspace for country of launch and any other applicable federal, state and local regulations

What criteria apply to the construction of a high-power rocket?

Use suitable materials to withstand operating stresses and retain structural integrity in flight

When must the stability of a rocket be determined?

When the rocket is prepared for flight

Who can override an RSO decision pertaining to safety?

RSO decisions pertaining to safety are final and may not be overridden by any other range personnel including the launch director

When is it permissible to catch a high-power rocket?

It is never permissible to catch a high-power rocket

Except for pertaining to safety, who may override a launch directors’ decision?

Except for pertaining to safety, the launch director’s decision is final and cannot be overridden

When must a high power rocket launching device incorporate a blast deflector?

When necessary to prevent damage or reduce risk of fire

What is the maximum launch angle from vertical for a high-power rocket?

20º

What are the elements of an ignition system?

Includes an arming switch with a removable key or interlock, which disables the entire launch control system when removed and uses a momentary switch to command the rocket motor ignition

When shall the motor ignitor(s) be installed in a high-power rocket motor?

At the launcher or a designated prep area

When may the physical disconnects that inhibit energetics be connected to power?

At the pad or other designated range area as indicated by the launch director

What is a class 1 rocket?

A model rocket with 125 g (4.4 oz.) or less of propellant and 1500 g (53 oz.) or less pad weight

What is the launch site criteria?

Both a. and b.

What is the minimum distance from a launch site to any person or property not associated with the operation?

1500 feet (457 m

How close can spectators be to a high-power rocket launch?

At the distance defined by the Safe Distances Table

What is the maximum altitude allowed for flying high power rockets if there is a cloud ceiling of 3,000 feet (914 m) and an FAA waiver to 15,000 feet (4572 m)?

Up to 3,000 feet (914 m)

What is the limit of surface wind for launching a high-power rocket?

20 MPH (32km/h)

When may a high-power rocket be launched?

After announcing the rocket and after giving a 5 second countdown

What is a class 2 rocket?

A rocket other than a model rocket propelled by motors with less than a combined total impulse of 40960 N-s (9208 lb-s)

What is the minimum distance for smoking (or open flames) from high power rocket motors, motor reloading kits and pyrotechnic modules?

25 feet (8m

When are you allowed to install an igniter or head end ignition module into any motor including a multistage, cluster or air start type rocket?

At the pad or other designated area as established by the launch director

An R/C Rocket Boosted Glider (RBG) may be launched in which direction in regard to the flightline?

Parallel to or away from

At what impulse does a class 3 rocket start?

Above 40960 N-s (9208 lb-s)

Test flights or first flights of R/C RBG shall be launched from the distance specified by the total installed impulse in the Safe Distance Table plus _____ Ft?

100

What is the maximum angle (in degrees) from vertical a model rocket can be launched from?

30

The minimum safe distance to any spectator when a model rocket is launched shall be_____Ft?

50

The minimum distance for all involved rockets shall be the complex distance for the total installed impulse of the motors in all rockets when _____ or more rockets are launched simultaneously?

3

When can steel nozzles be used in research motors?

When the nozzle throat is recessed within the case of a sugar motor

What is the age limit Tripoli recognizes for a certified solid propellant high power rocket motor user?

18 years of age

What is the minimum safe distance for a non-complex H, I or J motor?

100 ft (30m)

When may Research Motors that have been sold for a profit be used at a Tripoli Launch?

It is never permitted