This paper describes a method and setup to quickly and easily measure a model rocket engine's thrust curve using a computer data logger and force probe. Horst1 describes using Vernier's LabPro2 and force probe to measure the rocket engine's thrust curve; however, the method of attaching the rocket to the force probe is not discussed. We show how a simple engine holder can be constructed and used with Vernier's LabPro and force probe to record data that students can use to compare to sample data from the rocket manufacturer or the National Association of Rocketry's3 engine certification sheets, calculate total impulse, and make predictions for model rocket launches. PASCO markets a rocket engine test bracket4 that mounts to its PASPORT force sensor for similar measurements. The engine holder described here is very economical, and all the parts can be obtained from a local hardware store or home center.

Topics
Data logger, Sensors, Rocket engines, Model rocket, Educational assessment, News and events
1.
Ken
Horst
, “
Model rocketry in the 21st‐century physics classroom
”
Phys. Teach.
42
,
394
–
397
(Oct.
2004
), and references therein.
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2.
www.vernier.com.
3.
www.nar.org/SandT/NARenglist.shtml.
4.
www.pasco.com, model #ME‐6617.
5.
A larger bolt could be used to better secure the PVC end cap to the force probe if one is willing to drill and tap a hole in the force probe. Experimenters must use their best judgment in measuring thrust curves for larger, more powerful engines using this setup. An additional safety feature would be enclosing the force probe ‐ PVC engine holder in a 4‐to‐6‐ in diameter clear plastic pipe that is 18 in long and open on both ends to act as a blast shield should an engine explode or eject chunks of hard clay.
6.
www.esteseducator.com/Pdf_files/Estes Model Rocket Engines.pdf.
7.
www.nar.org/; the certified thrust‐versus‐time data are provided by NAR for hobbyists to use in trajectory modeling programs like wRASP (Rocket Altitude Simulation Program for Windows), www.wrasp.com, or that described by
David
Keeports
, “
Numerical calculations of model rocket trajectories
,”
Phys. Teach.
28
,
274
–
280
(May
1990
).
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© 2010 American Association of Physics Teachers.
2010
American Association of Physics Teachers
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