Week 6-Keep on Building

We started off this week with another review of the rocket designations bringing each student to the board to fill in the rocket's total impulse, thrust, burn time, and delay time.  This week went a lot faster than last and we could tell their confidence was building! 

After going through this review we gave the students a little taste ofwhat was going on in the  rocket industry.  It was a busy week in terms of launches. On Friday, March 4th a Taurus rocket carrying a NASA payload failed due to the inability of the payload fairing to jettison.  The students were asking a lot of questions about exactly what happened, who was responsible, and how much money was actually lost.  The satellite cost almost $500 million!  The next night an Atlas V launched an Air Force Space Plane successfully and the Friday after class (March 11) there was a Delta IV launch of a secret NRO satellite.  More details can be found at www.spaceflightnow.com

Finally, it was time to continue building the hobby rockets.  The students all picked up from where they left off last week and didn't miss a beat.  All of the rockets were finished up and we actually tried to launch one.  We decided to go with the weakest engine, an A-engine, just to get a feel for how powerful it was going to be.  Unfortunately, the rocket was too heavy for the engine and it only went up about 15 ft. in the air.  It was a good lesson, however, and the students are looking forward to putting in a more appropriate size next week.

Week 5-Start Building!

We started the class with a 10 minute review of the engine name designations, the current US launch vehicles, and the definition of thrust and total impulse.  Given a table with the total impulse ranges for each letter the students could pick a total impulse and subsequently find the average thrust, total burn time and engine delay time.  For example:

Total Impulse Table

A	1.26-2.50 N·s	0.29-0.56 lbf·s
B	2.51-5.00 N·s	0.57-1.12 lbf·s
C	5.01-10.00 N·s	1.13-2.24 lbf·s
D	10.01-20.00 N·s	2.25-4.48 lbf·s
E	20.01-40.00 N·s	4.49-8.96 lbf·s
F	40.01-80.00 N·s	8.97-17.92 lbf·s
G	80.01-160.00 N·s	17.93-35.96 lbf·s

If we were given a rocket with the designation C8-6 this would be its specifications:

Total Impulse: 7 Ns (it could be anywhere from 5.01-10.00 as stated in the table above)

Thrust: 6 N (the second digit)

Burn Time: 7/6 seconds (Total Impulse/Thrust)


Delay Time: 6 seconds (the last digit)

Then it was time to start building the hobby rockets.  The students each got to choose their own designs because the kit gave enough parts to have 64 different combinations.  Each advisor helped out one student and guided them through the building process.  It was interesting to see how the students mind sets had to change a bit to understand the sequence of steps given in the instructions.  They all seemed to be very interested overall, but definitely needed a lot of help.  They are each about half way through the building process and will hopefully finish up next week.

Week 4: Introduction to hobby motors and hobby rocket kit

We started getting the students acquainted with the kits they will be using and the engines that will power their rockets.   We went through the engine designations and touched on what thrust and total impulse are.  Thrust is the measure of the force the rocket provides to lift itself off the ground and total impulse is the measure of the rocket engine's thrust multiplied by the total time it burns.  We lit a small engine on the ground to give the students a little show.  That thing was a site to see!  After that the students got to open their rocket kits and start dry fitting the pieces together.  I am looking forward to building these hobby rockets and flying them.

Week 3: Water Rocket Optimization

We utilized the water rocket for this class to teach about two things we do in industry on a regular basis, trade studies and optimization.  We had three water rockets; one with fins and a nose cone, one with a nose cone and no fins, and one with no fins and no nose cone.  With these three different designs we were going to run each of them at 3 different water levels to see which design was optimal at each water level.   The trade off for the nose cone was aerodynamics vs. weight and for the fins was stability vs. weight.  The students measured the height of the rocket with a protractor gun.  Because they didn't know sine and cosine yet we just used the angle as an indication of the height.  We were able to get through this lesson in an hour and the data showed some interesting results!  Below is the graph we came up with.

It worked out so nicely!  You can see that at every water level the rocket with no nose cone or fins went the highest.  When you add a nose cone and/or fins any benefit they may add is canceled out and actually hindered by their weight.  In addition, you will notice that 1 L seems to be the best option for what we tested.  What do you think the optimal water level is?

Week 2: Solid vs. Liquid Propellants

This week we discussed real rockets, the difference between solid and liquid propellants, and properties of space and orbit.  After the talk the students decked out their water rockets with fins and nose cones.  They were allowed to do any size they felt and had to start thinking about the tradeoffs of using different designs.  We had some really fancy water rockets by the end of the day.

Week 1: Water Rocket Introduction

This is an excellent way to introduce students to rockets.  All you need is a soda bottle, water, a rubber stopper, a bike pump with a pin (the type used for a basketball), straws and some wood to make a stand.   For the first week we had the students all put the same amount of water in to their bottles to just get a feel for how they work.  Check out the video below.  We spent about a half hour in the beginning lecturing about rockets, and got a glimpse of how difficult it is to hold their attention at 6 o'clock at night after a full day of school and homework!

We wanted to students to get a couple of things out of this particular lesson.

1. Understand Newton's Third Law: Ever action has an equal and opposite reaction
2. Why using some water instead of just air will propel the rocket higher
3. The tradeoff due to the added weight of the water

Check out the videos of the students launching their first rockets!

Development of the Class

The NYA rocket class was developed over several weeks from December 2010-February 2011 by Randy Hirt (Neighborhood Youth Association), David Jackson (Aerospace Corporation), Sam Koshy (Graduate Student/JPL), and Yoni Malchi (Aerospace Corporation).  It is a sixteen week introduction to rockets using hands-on projects and demonstrations for a group of six 9th grade student leaders at the Neighborhood Youth Association (NYA) in Venice Beach.  Each class is an hour long and is designed to give the students an understanding of how rockets work, why they are important, and how careers in science, technology, engineering, and math (STEM) can be interesting and fun!  A goal of the class is to prepare these students for the Team America Rocket Challenge (TARC) and enter a team next year.