Held on Saturday, May 6, 1995 at the HALO Rocket Motor Test Facility
The following text was taken, with permission, from an article by Tim Pickens, which was published in the May-June 1995 issue of the Southeastern Space Supporter, newsletter of HAL5.
Three weeks after the second test, on Saturday, May 6, we began the third test. Steve, Gene, Ron Lajoie, Ron Creel, new member Peter Ewing, and myself had worked hard the previous week preparing the electronic equipment, the new valves, and the new motors, including three donated by HAL5 member David Dean of McDonnell Douglas.
Each of the foot-long test grains were cut into four 3-inch long cylinders. This way, after a short burn, the center cylinders could be removed and the grain could be measured to plot the fuel regression. (Unlike a solid rocket motor, hybrid rocket motor fuel does not contain any oxidizer; thus these types of cross-cuts do not promote burning between the cylinders.)
While waiting for Larry Larsen to return from Texas (on a trip to get a large milling machine for making even larger motors), we decided to have lunch. Compared to our last event, this was a feast! Hot dogs, beans, chips, cokes, cake, and ice cream --- brought by HAL5 members, family, friends, and associates, including a McDonnell Douglas colleague of Dr. Dean. Ron Lajoie, designated that days HALO Safety Officer, passed around a safety statement from McDonnell Douglas and a HALO safety form/waiver for each person to sign. This was the largest turnout to date, with over 20 people in attendance.
The first test of the day was our third asphalt motor. When all was ready, Steve started the sequencer. The now familiar snap of the ignitor squib was heard by all, and 1.5 seconds later (as programmed), the valve was opened. In a repeat of the Test Day 2, the N2O poured from the nozzle without burning. This time, however, we were able to shut off the flow and stop the test. (We vented the remaining N2O from the oxidizer for safety reasons.) Steve reprogrammed the sequencer for a 2.5 second delay, while I changed out the ignitor in our asphalt motor.
Too bad we had to vent that N2O. The supply bottle was clearly getting low, and Steve had a difficult time of coaxing N2O into the oxidizer tank. The second attempt, however, was a great success! The motor fired beautifully, fully achieving the desired 200 lbs of thrust we need to get into space. After three seconds, when the tank pressure dropped too low to sustain thrust, we stopped the test and began the nitrogen purge to cool the rocket motor.
Our systems operated perfectly; we got great data, nothing was damaged, and even our new flame deflector (a simple thick steel plate) survived intact. I am very pleased thus far with all areas of our HALO rocket motor development program, put together in only eight months.
After the successful asphalt motor test, we set up the first of McDonnell Douglas test motors. By now the N2O supply bottle was obviously low, and Steve barely managed to get enough N2O into the oxidizer tank. The test itself, however, went very well. The sequencer worked fine, and the motor burned gaseous N2O for three seconds. Despite the lack of sufficient thrust, all agreed that this first test was a good data point.
In an unlikely partnership (which reflects the budget realities of the 1990s), aerospace giant McDonnell Douglas, via Dr. David Dean (a new member of HAL5), has asked little space club HAL5 to test a new hybrid rocket fuel he designed last year, but ran out of budget before he could fully tested it. Dr. Dean has offered his fuel as a possible candidate for our HALO rocket motors.
According to Dr. Dean, the fuel should achieve a sea-level Isp of 250 seconds when N2O is used as the oxidizer, and 290 seconds when GOX (gaseous oxygen) is used. (By comparison, we predict our asphalt motor to have an Isp around 220 seconds using N2O.)
As part of the agreement, HAL5 will supply the motor tubing, which Dr. Dean will fill with his fuel. HAL5 will test the motors as instructed by Dr. Dean and provide him with a copy of all data taken during the tests.
HAL5 is honored to have been given this chance to prove how professional an amateur organization can be. We thank both Dr. Dean and the McDonnell Douglas Corporation for taking this great leap of faith. In this new era calling for faster, better, cheaper solutions, HAL5 is proud to be carrying the lead banner for a change, instead of a picket sign. Ad Astra per HAL5!
For more information on Project HALO, contact HALO Project Manager Yohon Lo at (256) 658-2043 or via E-Mail at: email@example.com.
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This file was last modified on Saturday, 15-Apr-2017 13:19:39 EDT