1. Development and Principles of Rocketry
Model Rockets
Lecture Six

2. UKRA Model rockets are not toys but are real rockets.
They are launched from a launch pad.
The pad supports the rocket while it accelerates.
The motors are ignited electrically from a distance.
The rocket deploys a parachute.
Rockets can be flown many times.
The specialist body
for all model rocketry in the UK is
The United Kingdom Rocketry Association (UKRA)

3. UKRA UKRA has established A Safety and Technical Committee.
To publish a Safety Code for the launching of rockets,
to liaise with government departments
on safety and regulatory matters,
and appoint Range Safety Officers (RSO)
from UKRA’s most experienced rocketeers.

4. UKRA The RSO’s role is to supervise every launch and
ensure that it can proceed safely.
This includes the technical assessment
of the planned rocket flight,
monitoring airspace around the launch site,
and ensuring that legal and
insurance requirements are met.

5. Model Rockets Boost: The five phases of a model rocket flight are :
An electrical igniter is used to ignite the propellant
and launch the rocket.
The rocket is guided along a launch rod for the first
one or two meters of flight.
At the end of the rod the rocket is travelling between
30 and 50 mph,
and has enough airflow over the fins
to fly in a straight line.
Boost

6. Model Rockets Coast: The five phases of a model rocket flight are :
When the motor burns out the rocket is travelling very fast,
typically between 200 and 600 mph.
The loss of thrust from the motor means
the drag and weight of the rocket
will cause it to decelerate.
During this phase the rocket coasts
to the highest point of its flight,
emitting tracking smoke to improve its visibility.
Coast
Boost

7. Model Rockets Ejection: The five phases of a model rocket flight are :
At apogee the motor fires
a small charge which ejects
the nosecone and the parachute.
The parachute deploys
and the rocket starts its descent.
Ejection
Coast
Boost

8. Model Rockets Descent: Landing:
The five phases of a model rocket flight are :
Descent:
The rocket descends slowly,
between 5 to 15 feet/sec.
The rate of descent depends
on the weight of the rocket
and the size of the parachute.
Landing:
The rocket drifts while descending
and will land downwind
from the launch site.
Ejection
Descent
Coast
Boost
Landing

9. The five phases of a model rocket :
Model Rockets
The five phases of a model rocket :
Boost: The motor propels the rocket
to its highest speed.
Coast: When the propellant has burned
the rocket continues upwards,
slowing due to weight and drag.
Ejection: A small charge ejects the
parachute at apogee.
Descent: The rocket drifts back to
earth under its parachute.
Landing: The rocket returns to earth,
ready to be used again.
Ejection
Descent
Coast
Boost
Landing

10. Model Rockets Model Rocket Design
The nosecone is the aerodynamic front part of the rocket.
The body tube contains the motor and parachute.
Fins ensure that the rocket flies straight.
The motor hook keeps the motor in place.
The launch lug is used to hold
the rocket to the launch rod.
The shock cord holds the
nosecone, parachute and body
together during descent
Nosecone
Parachute
Shock Cord
Body Tube
Launch Lug
Fins
Motor Tube
Motor Hook

11. Model Rockets Model rocket motors are similar to
real solid rocket motors.
The cardboard motor case
contains the propellant.
A ceramic nozzle
accelerates the exhaust gas.
The motor is ignited
by passing an electrical current
through the igniter.
The current heats the wire
this ignites the pyrogen
which fires the motor.
Propellant
Cardboard Motor Case
Ceramic Nozzle
Pyrogen
Igniter

12. A model rocket motor is specified with a simple code:
Model Rockets
Motors
A model rocket motor is specified with a simple code:
A letter denotes the impulse range.
(Impulse is the amount of thrust (Newtons)
multipled by the time the motor provides
that thrust (seconds))
A number for the average thrust
provided by the motor (in Newtons).
A second number which is the
coasting delay (in seconds)
before the ejection charge is fired.
– Impulse between 2.4 and 5 Newton-seconds.
– 6 Newtons – which is an average thrust.
– Delay of 4 seconds. B B 6 6 - 4 4

13. Model Rockets Motors A delay grain creates tracking smoke
while the rocket coasts to apogee.
Hot exhaust gas propels the rocket
until the propellant is all consumed.
The igniter,
held by a plastic plug,
causes a flash of heat
to ignite the propellant.
The gas from
the burning propellant,
pushes the igniter
and plug out the nozzle.
A small
explosive charge
then fires
to eject
the parachute.

14. Check of Understanding
The specialist body for
model rocketry is called?
NASA
RSO
ACPC
UKRA

15. Check of Understanding
What is the name of the document
which defines safety requirements
for model rocketry?
Handbook of Model Rocketry
UKRA Safety Code
The Rocket Safety Manual
UKRA Safety Procedures

16. Check of Understanding
What is the role of the RSO
in model rocketry?
To design rockets so they'll fly safely
To prepare rockets for launch
To supervise every launch
so that it can proceed safely
To select the correct motor for flight

17. Check of Understanding
The five phases
of model rocket flight are called:
Boost, Climb, Ejection, Descent, Landing
Blast-off, Climb, Ejection, Descent, Landing
Boost, Coast, Ejection, Descent, Landing
Blast-off, Coast, Ejection, Descent, Landing

18. Check of Understanding
Which part of a model rocket
is used to hold it onto the launch rod?
Fins
Shock cord
Motor hook
Launch lug

19. Check of Understanding
What does the delay grain do
in a model rocket motor?
Provides thrust and tracking smoke
Delays ejection and provides tracking smoke
Electrically ignites the propellant
Delays ejection and ejects
the parachute

20. Check of Understanding
A rocket motor designated C6-5
has an average thrust of:
5 Newtons
6 Newtons
5 Newton seconds
6 Newton seconds

21. Development and Principles of Rocketry
End of Presentation