Update 9/27/2015 – Blood Moons and Tangled Up

Hi all!

Welcome back to the first real week of rocketry! Some of our subteams had some issues finding times when everyone can meet together, but most of that should be ironed out now. We don’t have too many exciting photos of rocketry, but tonight was the supermoon lunar eclipse, and that’s pretty cool. For those of you who missed it, here’s what it looked like from downtown Minneapolis!

IMG_0420

IMG_0444


 

In non-astronomy news: each of the subteams has set a tentative schedule on what they hope to accomplish, and we’re all careening headfirst towards some more flow rate tests with our new control valves on the morning of October 10th. This will let us get a better idea of how our new valves work and how we can use them to finally conduct a full throttle test of our engine! Exciting stuff. Should be even cooler than the ignition tests we did over the summer. We’ll have to get our new power sources ready, the new valves physically integrated into the system, and edit our operating procedures.


Now for a little bit of a fun tidbit from the non-engineering side of our team. One of the things we’re trying out this year is incorporating a design or team building activity at the beginning of each general meeting. We hope to boost the “funness” of our meetings and make these something our members look forward to each week. Last week, we did a spaghetti tower competition which I lacked the foresight to photograph.  This week, we did the human pretzel, and below are the pics to prove it!

Human Prezels

The concept is simple. A group of people form a circle, grab hands with individuals who are not adjacent, then attempt to untangle themselves without releasing hands.

Human pretzel low angle view

Seems simple, but gets complicated quite quickly. I’m glad to say both groups of six managed to untangle themselves at least once in that 8 minute time frame. Engineering minds hard at work!

And last but not least, a new feature! From now on, you can expect that each blog post will feature a subteam spotlight for those of you interested in the technical details of what we’re doing. The spotlights are written by the subteams, so it’s a first hand account of what’s going on. Without any further ado, welcome to our first subteam spotlight: Sensor/Ignition/Controls subteam!


This briefly goes over what we have done in the summer and what we are going to work on for next project.

  • Test board
  • AC power source

Current Test-Board

Control Board Schematic

Control Board Schematic

This is image of current circuit system for the test-board. It gives you a general idea where to position the test-board and arduino for data collecting. The circuit is the current one for our test board.

Control Board

The two images (left front , right back) above show the test-board we built for our system.

Currently there are 3 switches on the square flat-wood test-board. Red switch can open and close the whole circuit.One the right side of the board, First switch ( Top one) controls the valve for kerosene. under the top, Second switch controls the valve for O2. The bottom hole is for the third switch which is for the control valve.
When press the Red bottom and hold it, the red LED lights it up and it tells you that there is current running into the circuit. You can open or close the other switches for the valves based on the testing. when you release the red bottom it will shut down the circuit.

Below are an transformer (white, on the left)  and a power inverter. The transformer lowers 110VAC to 24VAC. The power inverter (black, on the left) converts DC 12V to 110V AC.

Transformer and Inverter

We are planning to build an AC source convertor for our control valve which needs 24 V AC source for our next project. we are going to use one Inverter and one Transformer to convert DC battery source into the AC from one of our 12v lead acid batteries. Then, we will add another switch to our test-board.

-Zicheng Li <09/25/2015>


All in all, a pretty good week.

-David Deng
9/27/2015

Previous Next

Advertisements

Update 9/20/15 – This Girl is on Fire!

Hi all,

Here’s the video we’ve all been waiting for! The two videos, I should say. Below is video of the full firing.

There are two bangs. The first is the igniter going off. We believe this blasted a portion of the igniter into our nozzle which was then blown out during ignition, causing was the second bang. The reason we bring this up is because in this second, high speed video, we’ve isolated the moment of ignition and our engine appears to produce a green flame.

There’s no reason to believe kerosene would produce this color. We believe this is due to the brass cap of the igniter, but we’ll be exploring this in future tests.

You may have noticed we are not using the igniter mentioned in a previous post

In addition, we took temperature and accelerometer data, which can be seen below. We did not see the expected raise in temperature (but this could be due to our poorly placed temperature probe on test 2), but we did see significant vibrations of the test stand during a ~30 second period. We believe this is due to an effect called “chugging” where at low pressures, an engine will cycle between high and low pressure.

2015-09-02 Ignition With OrbitalATK Temperature 2015-09-02 Ignition With OrbitalATK Accelerometer

When paired with the soot in the engine (shown below), we are inclined to declare that we’ve been successful in igniting a liquid propellant rocket engine! Not to brag, but I wouldn’t be surprised if this was the first amateur built liquid propellant rocket engine of this size or larger to be ignited in a controlled manner in Minnesota.  Hard to believe we made it from here to here to here to here! We’re not done moving yet, and we have big plans for this year.

Post-firing engine

Post-firing engine

Below are some images of the sweet setup OrbitalATK was generous enough to let us use (thank you!) during the tests.

Vaughn stoically manning the control station

Vaughn stoically manning the control station

Examining the test stand after a firing

Examining the test stand after a firing

Video above brought to you courtesy of this video camera setup

Video above brought to you courtesy of this video camera setup

In more recent news, we’ve been busy recruiting and integrating new members. We had several people graduate out last year, and we said our sad goodbyes to others who will be pursuing other paths, but we’re back up to a team of 21! Here’s a selfie of some new recruits and some old members. We might have a each one of them write a spot on the page so you can meet them individually. Who knows.

Welcome new members!

Welcome new members!

– David Deng
9/20/15

Previous Next

Update 9/7/2015 – Welcome Back!

Hi all,

We hope you’ve had a fantastic summer! As the days get longer and we brace ourselves for fall weather, the University students head back to school, and that means LPRD Rocketry will be ramping back up to full operations.

We haven’t been idle over the summer, and we’ve accomplished quite a bit. We took our entire test stand through rigorous rounds of structural pressure testing, so we know everything will hold together up to at least 500PSI.

Here is a video of the test stand pushing water (don’t worry, we wouldn’t just dump a liter of kerosene onto the beautiful West Bank Flats) through the spray nozzle at a pressure of 500 pounds per square inch. To allow for better visibility, the combustion chamber and coolant jacket are not installed.

We also ran some static pressure tests, where we installed the full engine, plugged the nozzle, then pressurized the system. We opened everything up afterwards, and you can see the results in our post-test examination.

Sunset testing

Sunset testing

We’ve also been taking a second look at how we operate and attempting to standardize every action we take. We also ran an ignition test (partially successful) at Orbital ATK’s industrial proving grounds, but we’re yet to receive the footage, so anticipate fire and more details in the next update!

Assembling the Test Stand

Assembling the Test Stand

On the administrative/business end, for the new year, we will be standardizing many of our activities like general meetings and meeting minutes. In addition, we are formalizing several key “positions” in the team and writing up job descriptions to try to provide clarity to the boundaries of each individual’s responsibilities. We are also integrating Basecamp (a personal favorite of our parent group Tesla Works) into our activities as our to-do list manager.

Additionally, we have contacted the UMN’s student branch of AIAA (the American Institute of Aeronautics and Astronautics) to see if we can become an official project under their group as well as TeslaWorks, and the results look hopeful. We have also been reaching out to other student groups on campus to try to find collaboration points.

We’re excited to get this new year started, and we hope you are too!

– David Deng

9/7/2015

Previous Next