Short Duration Test Fire

On February 25, 2018, the club conducted a successful test fire of the Hybrid Motor 7 – Heavy propulsion system. The important shift in this test fire is that we have identified and resolved past issues with combustion stability and thrust. Our propulsion team discovered that the regulator between the pressurant tank and the oxidizer tank was not sufficient, and there was not enough flow for our larger heavy variant of Hybrid Motor 7. We placed two of our smaller regulators in parallel for this most recent test fire, and we produced sufficient thrust to clear the launch rail with a safe speed. The thrust curve for the engine is below:HM7H_Feb252018 (1).jpg

This test served as a proof of concept that increasing flow between our tanks will increase our thrust. With a new single regulator with a higher flow coefficient, performance may even increase beyond what we have achieved in this test. The next steps are to do a full duration test fire to verify the engine continues to operate for a full 17 seconds, and a test launch to verify the system as a whole is ready for IREC. The video of our most recent test fire can be found here. Look out for more updates!

2/3 Duration Test Fire (27 May 2017)

On May 27, Cal Poly Space Systems conducted the first successful 2/3 duration test fire of the HM-7 Heavy hybrid motor. Using data from this test, we were able to build a thrust curve:thrust_720.jpg

As expected with a 2/3 duration test fire, thrust drops at around ten seconds as nitrous oxide (our oxidizer) mixes with nitrogen (our pressurant). Stable combustion occurs for about 10 seconds, and is followed by approximately 5 seconds of unstable combustion. Additionally, the video (final phase of test begins at 23:45) provides a qualitative confirmation to our quantitative data. Average thrust over the entire test was about 520 pounds. We are very pleased with the results of this test!

This test fire is a significant step forward in our progress to IREC, and serves as a complement to our previous short duration test fire. The 2/3 duration test also demonstrates that our new HM-7 Heavy design can withstand temperatures and pressures associated with sustained stable combustion. We hope to conduct at least one more test fire before the final trip to IREC.

HM-7 Test Fire 3

Cal Poly Space Systems conducted a successful full duration test fire of Hybrid Motor 7. The oxidizer pressure was too low, leading to decreased thrust at the end of the burn.

The design parameters of this engine are:
Thrust: 400 lbs
Burn time: 12 s
Fuel: Hydroxyl Terminated Polybutadiene (HTPB)
Oxidizer: Nitrous Oxide (N2O)


Check out the burn here.

Separation Test

Cal Poly Space System’s successfully tested the separation device for apogee deployment of the drogue parachute. The mechanism uses a pyrotechnic charge to shear 8 nylon machine screws. The system will be flown on May 7 at the Friends of Amateur Rocketry site in the Mojave Desert.

Check out the video here.

Test Launch and Open House Weekend

This coming weekend is an exciting one! Several of our members will be at the Friends of Amateur Rocketry (FAR) launch site to test the first two rockets: Lexington and Saratoga. Lexington is built for speed to test the avionics system while Saratoga is built to size for the separator test.

Lexington and Saratoga

The members that remain in SLO this weekend will run the CPSS booth at the Open House Club Showcase and the water bottle rocket launch activity. The Club Showcase booth will be as conspicuous as possible; we’re bringing the trailer down so we can set up the launch rail with the large Caution: Flammable rocket.

HM-7 Test Fire Successful

Cal Poly Space Systems conducted a successful short duration test fire of Hybrid Motor 7.

The design parameters of this engine are:
Thrust: 400 lbs
Burn time: 12 s
Fuel: Hydroxyl Terminated Polybutadiene (HTPB)
Oxidizer: Nitrous Oxide (N2O)

still frame

Check out just the burn here.
Check out the full test video here.

First HM-7 Test Fire Scheduled

After a very successful dry run of the motor test fire last Saturday, we are prepared to do it for real this Saturday (2/20)! Set up will begin on Friday (2/19) at about 3:30 p.m. We will be taking the trailer down to the prop lab and laying out some cable. Electronics set up will begin Saturday morning at about 9:00 AM.

The maximum occupancy for the control room is 10, limited to those conducting the test. We will have a livestream that will be viewable in the Aero Conference room (41-112) near the propulsion lab. The livestream will be available on YouTube, and will have views both of the motor and the control room.

An email will be sent out with the livestream link and the YouTube playlist on the Media page will be updated.

Test Rocket & Trailer nearing completion

The first test rocket has been touched up and prepped for paint. Design of the second rocket, to test the parachute deployment system, has already started.

The trailer is nearing the test fire milestone. There is just 4 more tube bends to make and 2 fittings to install. After that, all that needs to be completed is the electrical. We are now waiting on just a few more parts to finally get the trailer fully operational. Over the next week the team will be finishing up the tasks outlined above as well as wiring the interconnects for the sensors. Assuming all goes to plan, next Saturday will be the full systems checkout for the trailer.

Mechanical & Avionics Progress

The mechanical team has been setting up plans and test procedures for the Black powder Initiated Release Device (BIRD). This is the mechanism that splits the rocket so the parachute can be deployed.

The avionics team is working on assembly of the sensor board prototype and has finalized the design of a timer-based parachute backup board. The first test rocket will be testing our avionics at high-speed.