Rocket Lab
Impulse Engines

Background

The force exerted by a small Estes model rocket engine is very short, very

intense and very well documented by Estes.

Equipment & Software

· An Estes A-1O-OT rocket engine with igniter

Purpose

1. Your task is to collect force vs time data for the duration of the rocket engine "burn" then compare the collected data to engine data published by Estes.

Data Acquisition

1. Use the Data Studio software. The is the Pasco 500 box that was used to collect data. (you can enlarge the thumb nail picture by clicking on it.  When finished click the back button)

500box.jpg (37473 bytes)

2. Clamp the rocket engine holder and student force probe to ring stand.

    appclose.jpg (37147 bytes)

3. Mass the rocket engine. (approximately 7 grams)

engine.jpg (35873 bytes)

4. Carry the apparatus outside, check all electrical connections.

5. Insert the engine into the engine holder so that the exhaust points away from the force probe.

6. When all other preparations are ready, connect the battery to the igniter and stand back. (to view movie, right mouse click and click on play)  If you can not see movie right mouse click and copy to your hard drive then play.)

7. Reconnect the interface box and download data.

Data Analysis

1. Is the shape of the force vs time graph similar to the Estes graph?

2. Use Data Studio to integrate the force vs time data. Select the part of the curve that shows the impulse and choose area under the math functions list. Is the impulse for the engine close to the published impulse value?

  1. Mass the spent engine and using your answer to #2, determine the average change in velocity of the engine exhaust.

(approximately 4 grams)

4. What would be the momentum of a rocket of 35 grams if this engine were used?

 

5. What would be the maximum height for this rocket?

 

6. Calculate the percent error for the impulse of the rocket engine. Hint: use estes value for an A10-OT engine. See diagram below.