PH 171: It's Not Rocket Science

``It doesn't take a rocket scientist to successfully design, build, launch and recover a model rocket, but doing so makes you a rocket scientist! This course introduces the physical principles involved in the design and flight of rocket propelled vehicles with hands-on experience building and flying model rockets. The course covers Newton's description of motion, aerodynamics, operating principles of rocket motors, the history of space flight, and legal issues surrounding hobby rocketry. Taken with PH 173, this course satisfies the Tier 1 Natural Science core requirement.''

Three credits. Must be taken concurrently with PH 173.

PH 173: It's Not Rocket Science Laboratory

``Laboratory course to accompany PH 171. Students develop a working knowledge of the measurement techniques and design strategies necessary to successfully test, launch, and recover model rockets. Students work in groups to design, build, and test a model rocket to meet the challenge goals specified in the current Team America Rocketry Challenge.''

One credit. Must be taken concurrently with PH 171.

On-line information: Fall 2009.

Summer 2007:

We had six students in three groups for the final project. Because the altimeter got hung in a tree, the contest was reduced to retrieval of the (undamaged) egg and longest duration. All groups were required to use 2 Estes D12-5 motors. On the final launch day, the groups and their rockets:

	Group 1 decided shorter is better.
	The second group had to rebuild the booster after substantial damage during test flights.
	Group 3 went with four small fins and an 18 inch parachute, a gutsy decision with the safety of an egg at stake.

	Group members prep their rockets before the final launch.
	An aerial photo indicating the "recovery" locations of all three flights. Only the rockets from groups 2 and 3 were actually recovered enough to check the egg.
	The sight awaiting group 1 when they located their rocket after the flight.
	Group 2 didn't find their rocket, but I was able to find it after tearing down the range. It had drifted almost all the way back to the physics building, missing the basement entrance by less than 50 feet.

Fall 2006:

This year there were six groups competing in the final project. There were two contests:

1. A slightly modified Team America-style contest. Reach 550 feet altitude and a duration of 30 seconds with an unbroken payload of one large hen's egg.
2. Come the closest to the altitude and duration predictions based on the aerodynamics of rocket flight and test flight experience.

The six groups were given the same supplies from which to design and construct their final rockets. However, they were given a choice of (almost) any currently certified 24 mm rocket motor or combination. Here are the groups and their final designs:

	Group 1 went with a full 34 inch length of tubing and a cluster of three C11-5 motors for a quick lift-off and long coast phase. This group's rocket was the most consistent performer, turning in arrow-straight flights even in the stiff breeze on some of the test flight days.
	Group 2 was a bit handicapped with only two students. However, they overcame this difficulty quite well with another full-length rocket and a cluster of two D12-5's. It's not quite visible in the photo, but one of the fins broke off on all but the last flights. Masking tape is a wonderful thing! This group came in first in both aspects of the competition after the final launch.
	Group 3 used a much shorter rocket in an attempt to keep the weight down. Their initial design was based on a cluster of two C11-5's, but further analysis (after the motors had been obtained) indicated that this would not suffice. They ended up using a cluster of one C11-5 and one D12-5.
	Group 4 worked hard to weather some interesting flight failures during testing. First, the parachute did not deploy on all but the final flight with the egg. Second, during one of the test flights two fins separated from the body taking some of the tubing material with them. They stuck it out and rebuilt, producing the rocket they are holding here that uses a cluster of two D12-5's.
	Group 5 chose to use a single Estes E9-4 motor. Given the low average thrust, they designed four large fins. However, this produced severe weather-cocking. For the final flights they trimmed off the fin tips and rebuilt the payload section after a damp coupler from a test flight securely cemented itself into the booster.
	Group 6 also chose a single E9-4 motor and a set of four long, wide fins. Unfortunately, at least one fin separated from the body on every landing. This rocket also has the distinction of having landed in the corn field the most often. Some quick work with masking tape and super glue, and this rocket survived both contest launches.

	As students arrived at the field, they began final flight preparations. Here three students carefully pack recovery systems under the watchful eye of the physics department chairman, Dr. Anis Maize.
	Two members of Group 1 load the rocket onto the launch pad and connect the ignitor clips.
	Group 1 prepares to launch the rocket. The launch controller is on the ground. "5" ... "4" ... "3" ...
	After a successful launch, Group 1 chases after their rocket to find out whether or not the flight reached the target altitude.
	Group 5 makes the first of their two launches in the final contest. This rocket is carrying the altimeter.
	The "Rocket Stare"... Group 5 watches the recovery of their rocket.
	The rest of the class watching (and timing) the flight. Only three students were needed to measure flight durations which were then averaged over both flights.
	Group 6 doing final prep at the launch pad.
	And preparing to launch. One of the members of Group 6 was also timing flights, hence the concentration while holding a stop watch.

The contests were scored by adding one point for each foot of deviation from the target or predicted altitude to one point for each second of deviation from the target or predicted duration. An undamaged egg garnered no points, a cracked egg 10 points, and a smashed egg 20 points. The lowest score is the winner.

Group 2 finished with a completely undamaged egg and won both parts of the contest. They missed the target altitude by only 25 feet and the target duration by less than 5 seconds for a score of 29.5. They were even closer to their own predictions: 22 feet from their predicted altitude and 1.5 seconds from their predicted duration for a score of 23.5 points.

All groups put in a lot of effort and produced stable, flight-worthy rockets.

Spring 2006:

There were only 4 groups in the spring 2006 class. Due to a lack of accurate altitude measurement devices, the contest was simplified to longest duration with an undamaged large hen's egg.

Weather for the test and contest flights was beautiful! Warm temperatures and almost no wind, a nice change after a semester of breezy and cold launch days (some below freezing).

This class was also given the same sets of parts from which to design and build their rocket, though there was a wider choice of body tube diameters. Most groups used a combination of kevlar cord and elastic in the recovery system harness which caused some problems. The kevlar shock cord of group 2's rocket broke in every flight except the very last. (Yes, the kevlar string broke, not the mounting point.)

In the end, all groups chose clusters of two or three D12-5's, depending on the body tube diameter. Some groups chose to use a second parachute on the second contest flight in an attempt to score additional duration. However, most discovered that the additional weight hurt more than the additional drag helped.

Once all the smoke cleared, group 1 came in with the longest duration with an undamaged egg and almost 2.5 minutes (over both flights). Group 3 was in second place with a duration total of just over 2 minutes and an undamaged egg. The other two groups both had recovery system failures resulting in (a) shorter durations and (b) scrambled eggs.