1. BLAST OFF!
Investigations in Model Rocketry

2. • My name is Natasha Honcharik and I am a Sophomore at
Wachusett Regional High School.
• I started my research in rocketry in September of 2011.
• My experiments were performed at home and in sports fields at
my school.

3. PURPOSE:
• The purpose of this experiment is to find out what factors in a
model rocket engine’s design affect the maximum altitude of the
rocket and the temperature of the engine’s flame.

4. BACKGROUND INFORMATION:
• Engines are designated with a letter and a number. The letter
indicates impulse, or total change in momentum, and the number
indicates average thrust in newtons. “A” engines have a 2.5 newton-
second impulse and “B” engines have a 5.0 newton-second impulse.
• Thrust * burn time = total impulse
• Factors affecting engine performance:
o Type/Amount of propellant
o Nozzle size
o Burn patterns

5. BACKGROUND INFORMATION:
Burn Patterns
Solid fuel only burns on the
surface, called the flame front.
Burn patterns are the way the
flame front changes.
A larger flame front at one
point in time means more fuel
burning at once and more
thrust.
The flame front (shown in
yellow) starts as a cone shape
corresponding with the initial
peak in these example thrust
curves.

6. HYPOTHESIS:
• If a rocket engine with a greater total impulse is used then the
rocket’s apogee (highest point reached) will be higher.
This was justified because impulse is equal to change in momentum. A
greater momentum would mean the rocket would reach a greater velocity
and thus a greater altitude.
• If a rocket engine with the same total impulse but a greater
average thrust is used then the flame will have a higher average
temperature.
This was justified because a higher thrust is caused by a larger flame front
where more fuel is burning at once. Because more fuel was burning at once,
it was hypothesized that the temperature from the flame would be hotter.

7. PROCEDURE (EXPERIMENT # 1):
• Independent variable: type of engine
• Dependent variable: altitude reached
• The rocket was remotely launched and recovered ten times with each of four
engine types (A6, A8, B4, and B6) and altitude data was recorded by an
electronic altimeter inside the rocket.

8. PROCEDURE (EXPERIMENT # 2):
• Independent variable: type of engine used
• Dependent variable: average flame temperature
• The engines were placed upside down in this apparatus and ignited remotely.
The average temperature was measured with a temperature probe.
• Average burn time was measured with a video camera and multiplied by the
average thrust given by the manufacturer to calculate total impulses.
Cylindrical Temperature
hole probe
Ignition
wire
Cement
slabs

9. PROCEDURE (EXTENSION):
• Independent variable: engine type
• Dependent variable: thrust produced
• The same apparatus was used with a force plate replacing the bottom concrete slab.

10. RESULTS (ALTITUDE):
This is a box and whisker graph of the altitude data recorded. Student t -tests
were performed and there was found to be a statistically significant difference
between each group. A8 engines reached the lowest altitude, followed by
A6, B4, and B6.

11. RESULTS (TEMPERATURE):
This is a box and whisker graph of the temperature data recorded.
Student t-tests were performed and there was found to be a statistically
significant difference between each group except between A6 and B6
engines which were also the lowest in temperature overall.
(note: temperature
is relative because
the probe could not
be placed directly
in the flame without
damage, so radiant
heat was
measured.)

12. RESULTS (extension):
This is an example graph of one of
the B4 engine’s thrust curves. Note
the initial spike and then leveling off.
This includes only the propellant
phase of the engine.
This curve was averaged and
multiplied by burn times to calculate
impulses which were found to be
close to but less than the given
impulses. These were then used to
roughly predict altitudes without air
resistance.

13. RESULTS (EXTENSION- PREDICTED ALTITUDE):
In these graphs of impulse and propellant mass vs. altitude, the blue represents the
actual average altitude of each engine type. The red is the predicted altitude without air
resistance using thrust and burn time data from the National Association of Rocketry, and
the green is the same calculated altitude using my measured data. Altitude increases
linearly with impulse and propellant mass, while the altitude without air resistance
increases exponentially because calculations for air resistance involve velocity squared.

14. CONCLUSIONS:
• An engine with a higher impulse does yield a higher altitude.
• However engines with the same impulse ranking do not always reach the same
altitudes because the rankings are maximums, not exact values.
• Temperature was not related to thrust as hypothesized. While both thrust and
temperature are affected by burn patterns and propellant formula, thrust is also
affected by nozzle design, causing it to differ.

15. CONCLUSIONS:
• Quest brand engines (A6 and B6) were more efficient than Estes brand (A8
and B4).
• They reached a higher altitude with approximately the same amount of
propellant.
• Quest engines also had an overall lower temperature. This shows that they
more efficiently converted their fuel’s chemical energy into thrust rather than
thermal energy.
• This may be due to Quest’s greater attention to nozzle design. Quest
engines were found to not only have smaller nozzles, but they also had
different nozzle sizes for different engines whereas Estes brand engines all
had the same size nozzle. Quest is a smaller, lesser known brand, so Estes
mass production might lead to less attention to individual detail and less
efficiency.

16. ACKNOWLEDGEMENTS:
• Thank you to my parents who bought me lots of rocket engines and
supervised my experiments.
• Thanks to Dr. Neil Ault for being my adviser at science seminar.
• Thank you to my physics teacher Mrs. Carol Sullivan for helping me every
step of the way and being the best teacher ever.
• Also thanks to my school, Wachusett, for lending equipment and facilities.
THANK YOU!!