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Testing of the Hybrid Rocket

Table of Contents 1 Testing 1.1 December 9th & 10th of 2006 1.2 February 24th & March 24th & 25th 1.3 May 13th, 2007 - Large Rocket Chamber Test

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Testing

This section will include files regarding the testing accomplished by the Steel Rocket team. They will be in the form of photos, movies, and EXCEL spreadsheets. Descriptions and notes will be given where necassary.

December 9^th & 10^th of 2006

This weekend was at the end of Week #1, the first weekend back to RIT for all students on the team other than the Team Leader - Ray Mulato. Ray spent time in the Fall Quarter working on preparing testing for Project METEOR and the Steel Rocket with David Dale, last year's team leader.

The experimental set-up for this testing was decided upon prior to the start of SDI. Testing on these dates was crucial in introducing the current design of the rocket to all of the students beginning SDI who were not previously acquainted with it. Team members grasped the basic elements to the design and became particularly adept at setting up the system for testing. Testing was successful 8 out of 9 times, with the one failure due to an electrical problem.

Here is a close-up picture of the rocket plume:

Summary of Test 1 Results

The following spreadsheet provides a summary of the results for the weekend. Something to note about this particular weekend was the air temperature. On Saturday it was in the low to mid 20's and on Sunday it was in the mid 30's. This caused a lower pressure in the nitrous oxide tank, resulting in lower thrust values.

Summary of Results

11 Degree Half Angle Video (You may have to download the video to get it to work properly)

The current team will take the data and observations and create an experimental design for the next round of testing. It will need to be decided which portions of the rocket to hold as the control and which need to be tested.

February 24^th & March 24^th & 25^th

The objectives for this round of testing originally started out as determining the effects that the post-combustion chamber had on overall results of the rocket burn. It was decided to test between 1.5 and 2.5 inches, incrementing by 0.5 inches. All other variables were held constant, including the nozzle.

The plan was to conduct these 6 tests on February 24^th. However, only three were completed on that day due to a number of problems that were encountered. The next available weekend for testing was on March 24^th & 25^th. Due to the fact that only 3 more tests were needed for this experiment, the team came up with a few more that were determined to be advantageous. These were to vary the pre-combustion chamber length, the injector plate, and a smaller inner diameter of the fuel grain. The goal for testing the smaller inner diamter of the fuel grain was to see if the system was capable of sustaining a burn with such little surface area available for burn and to determine how this diameter affected the regression rate of the fuel.

• Click Here for a summary of the 9 tests conducted on these days

Short Fuel Grain; 2.0 inch Post-Combustion Chamber

Video

Long Fuel Grain; 2.5 inch Post-Combustion Chamber

Video

Short Fuel Grain; 2.5 inch Post-Combustion Chamber

Video of this Test

May 13^th, 2007 - Large Rocket Chamber Test

A larger rocket chamber was manufactured, assembled, and tested during Senior Design II with the goals of acheiving a thrust of 100 lbf for a total burn time of 50 seconds. The diameter of the HTPB fuel grain needed to be increased to acheive this longer burn time. For more details on the design of the fuel grains, see the team's technical paper.

Here are some sample pictures of the scaling up from the small chamber to the large chamber:

After some experimentation and struggles with a gas regulator for the nitrous oxide feed system, the team was able to sustain a 27 second burn, which is in the video linked below.

long burn

You should note that there is an underexpanded plume in this case, thus resulting in a lower thrust than expected (60 lbs as compared to 110 lbs). This was due to the fact that the appropriate chamber pressure was not met.