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News

PCB Design

  • June 25, 2019June 5, 2020
  • by ben

Our PCB Design is now in its third and final version. After iterating on both Revision 1.0 and Revision 2.0, Revision 3.0 is the culmination of a year of work to perfect the main hub for all the avionics in our rocket. The board is now laid out in a much easier way to build and test with. More voltage levels have been added, and we can now use more actuators and sensors. This allows us the flexibility of performing any actuation or reading we will come across.

The final board layout in EAGLE

A main focus of this revision was to streamline the rest of the hardware development. If two related components were on opposite sides of the board, it would cause us to flip back and forth during testing since it is double-sided. In this revision, this problem is eliminated by placing all the components that need to be accessible on one side and all the components that we don’t need to access on the other.

Another difference between this revision and previous ones is the elimination of the voltage step-up. A higher-voltage power system was designed utilizing two 14V lithium-polymer batteries, eliminating the need to step down then step up multiple times to other voltages. The traces on the board were also increased in size to reduce unnecessary resistivity losses.

Overall, this new PCB design should help speed up development and handle anything we throw at it, whether that is temperature sensors, pressure sensors, triggering valves, or even lighting an e-match!

The populated Rev 3.0 board, with sensors and debugging equipment attached

The final board revision was produced for us by our awesome sponsor, www.customcircuitboards.com!

News

“Always Open”

  • June 24, 2019June 5, 2020
  • by Dakota

Those of you who follow us on Facebook may have noticed a quirk. Under the “About” section, just under the map of Hoboken, it says “Always Open.” This is no mistake.

Here’s a little peek into what we’ve been up to this weekend — at all hours of the day.

Tank Cleaning

As you may recall from a few weeks back, the vast majority of our propulsion system needs to be “Clean for Oxygen Use.” We have finished pipes, fittings, and adapters and are onto the bigger pieces: our tanks.

The helium and oxygen tanks we use were made special for us by Infinite Composites Technologies. We are rigorously cleaning both with isopropyl alcohol baths to dislodge any remaining construction materials from the inside.

Since the alcohol coming out is dirty, we also needed to clean it for reuse — about 34 liters (9 gallons) worth. Monica and Dakota spent much of Saturday vacuum filtering all 34 liters.

  • The process of vacuum filtration. Dirty isopropyl in the top, clean out the bottom.
  • We changed filters once every 2 liters — about when they started to look like this.

Load Cell Calibration

A by-product of last weekend’s Dry Run Mechanical Test, we are confirming all of our load cells work. In order to accurately measure the thrust of the rocket, we will attach it to the ground with cables. These cables will pull on our load cells, which tell us how much thrust the rocket has.

Ben was hard at work making sure the code was solid while Will used the engine hoist to test a few known loads.

  • Will’s load cell testing apparatus.
  • Ben working on code — as seen through the clean room walls.

Now that it’s Monday, Will, Tom, and Abe are out on Walker Lawn with the load cells and duck bill anchors. The anchors are being used to test the load cells, and vice versa. We want to make sure our duck bill anchors are rated properly. After all, the last thing we would want is for an anchor to come out of the ground during a test.

Fitting Tightening

Last but not least, we have our piping. As mentioned above, all of the propulsion subassemblies have been cleaned for oxygen use. Now, it’s just a matter of preparing them for testing and launch.

Our propulsion system has threaded joints from two rival piping standards: JIC (Joint Industry Council) and NPT (National Pipe Tapered). Each of these two standards comes in multiple sizes — and each size requires a unique tightening force. Larger threads require greater tightening force — as much as 100 foot-pounds.

Nathan and Will using two wrenches and a vise to tighten a JIC-12 fitting to specification.

In order to accurately tighten each joint, we use both a torque wrench and a crescent wrench. (One to twist, one to hold the rest of the subassembly.) For some subassemblies, more advanced methods are needed, though. In the case of particularly wiggly or oddly-shaped pieces, a vise is necessary to get a good grip. Thus the above picture outside the clean room — as long as the interior is not compromised, the outside of the subassembly can always be cleaned again.

A Little Fun

We also manage to have a little fun after a long day’s work. (And usually right before another long night’s work.) Friday night, we all stepped outside to enjoy a barbecue dinner. Because how else would we ring in the first day of summer?

News

Dry Run Testing

  • June 19, 2019June 5, 2020
  • by Dakota

[This is a long article. If you’d like to see just pictures and videos of our tests, check out our YouTube and Facebook pages!]

Last week, Castle Point Rocketry had two full days of testing. We verified our mechanical and avionics systems to ensure full preparation for the next round of testing: propulsion. In propulsion testing, we will light the rocket and measure the thrust it produces. It was necessary, then, that we check to make sure the test apparatus works (and can support the weight of the rocket) beforehand.

At the end of the second day, we had a fake rocket towering into the night sky.

It took all of both days, but the test was a success. We strapped a 500-pound surrogate rocket to the test stand and raised it from horizontal to vertical. In the dark!

Day One: Wednesday

We started the day by needing a U-Haul. Our lab in Griffith isn’t too far from Walker Lawn, where we were testing, but hauling a literal ton of metal up the hill sounded … none too fun. Luckily, we had some lifting help from Stevens Physical Plant and some traffic direction by Stevens Police.

Officer Gamez of the SPD posing with the team after helping us back in.

Avionics

The big focus of Day One was making sure all of our Avionics and Ground Control systems worked. To do so, we needed to take over a classroom, too. Ben found an empty room not too far away, overlooking the mechanical proceedings on Walker Lawn. Our ground control station was set up, and the wires started running!

Ground Control to Major Tom…

All the wires serve three purposes: valve actuation, transducer reading, and real-time image processing. So far, the project has grown to incorporate 27 instruments. Eight of these require active actuation, and six send signals to ground control.

After double-checking that the radios worked (another important electronics test), Ben and Faris actuated each valve in the order that they will be used in testing. Though we didn’t have any temperature and pressure sensors set up, Ben also made sure the sensor code was running. Finally, we set up each of our three cameras — one real-time, one slo-mo, and one thermal — and they each came up on-screen!

Avionics Dry Run Testing: Successful.

Mechanical

Mechanical systems were being assembled throughout the avionics tests. All hands were on deck to set up the gantry hoist, test stand, and aluminum truss.

  • Rodrigo, Will, and Abe working on the test stand.
  • Will climbing the gantry hoist to adjust the winch.

These three metal structures will serve as the backbone for our propulsion testing. To restrict movement under fire, the rocket will be bolted to the 30-foot-long aluminum truss. (And tied down, twice-over.) In turn, the truss is bolted onto a short steel structure called the “test stand.” It sinks into the ground to provide added stability. In order to raise the truss, several cables run to another nearby steel structure: the “gantry hoist.” Equipped with a heavy-duty winch, it pulls the truss and rocket into place atop the test stand.

This process of raising the truss is what we tested. After a few preliminary tests and some iterative construction:

  • Checking calculations with a third of the truss section.
  • Supporting the whole truss before it goes up.
Some small edits to the gantry hoist before another pre-test. (Video has no sound.)

It went all the way up!

(Pardon Dakota’s yelling.)

By the time it came back down, it was nearing dark and threatening to rain. So we packed up and vowed to raise a weighted truss another day!

Day Two: Friday

It rained all day Thursday. Bummer. Luckily, we had the lawn reserved Friday, too. So we got back out there at 9:00am and went to work!

Step One: Check Everything

Even though everything had been set up on Wednesday, we needed to make sure everything was ship-shape. Even the slightest wiggle room on a bolt could send the whole thing crashing down. Not optimal.

  • Deputy Chief DiGenova of the SPD making sure our Test Stand was in peak shape.
  • Making sure the gantry hoist’s support cables were taut before testing.

Once happy, we jumped ahead to where we left off: Adding weight to the rocket. Our first subject? Our very own Abraham Edens.

Step Two: A Small Amount of Weight

It didn’t take much coaxing before Abe was hanging upside down. Who doesn’t want to say they’ve hung like a koala from a truss and elevated eight feet in the air?

Abe being raised to Height #1 for the first time.

To check all of our structural components, the truss first took Abe up to about six feet, then up to eight. Twice. (You can see more in the time lapse video below.) After Abe had had his fill, we gave Tom a go as well.

But all this wasn’t just eight college kids goofing off with a 30-foot truss. There was actual science behind it. Before loading up our testing equipment with 500 pounds of wood and concrete, we wanted to be sure that it could repeatedly lift human-sized cargo. And it’s a good thing we tested it out first. We were successfully able to raise both people, but the winch slowed down to a snails pace. This indicated we would need more powerful equipment for the full rocket.

Time lapse footage of both of Abe’s adventures up the truss. (Video has no sound.)

Step Three: Time to Buy Some Stuff

We took a lunch break. After all that heavy lifting (and being lifted), it was time to eat some food. We also took the chance to buy a heavy-duty winch — then the car battery to operate it.

Will and Nathan got to work installing the new winch atop our gantry hoist. Once it was up, we were all ready to go.

Step Four: Fake Rocket, Real Results

500 pounds of concrete is heavy. Our 2-ton pneumatic engine hoist was busy elevating the aluminum truss, so we lifted and moved the fake rocket by hand. Talk about a workout. Coupling the surrogate rocket to the truss required moving it ten feet to the west, then elevating it while another team member temporarily secured it with ratchet straps. Then, three linear rails permanently mounted the rocket to the truss.

But after all that grunting and sweating? We got to stand back and watch this:

Pardon the abrupt switch from landscape to portrait. (Video has no sound.)

So, there we were. Eight rocket engineers standing out on Walker Lawn at 11:45pm on a Friday night. Covered in mosquito bites, still sore from lifting a fake rocket, and getting kinda hungry again. But in front of us was solid proof that our testing structures would support the weight of our rocket.

Gazing up at the fruits of our labors at 11:45 Friday night.

In fact, the fake rocket we lifted weighs more than the rocket parts we will use in testing. The dummy rocket’s 500 pounds accounts for the weight of the entire rocket — when, in testing, we won’t be adding the fins, nose cone, or fuselage. So, really, we have a built-in Factor of Safety greater than 1.0!

Step Five: Teardown

As much as we all could have stood there for hours just gazing up at it, we took it down in a hurry. After all, it was nearing midnight and all of us were tired from two long days of testing. We packed up the U-Haul with all of our materials, leaving behind only the test stand, rocket, truss, and pneumatic hoist for Saturday morning.

Though it looks like someone landed a plane on Walker Lawn, this is what our testing apparatus looks like all wrapped up!

We found out it took even more work to take the rocket off the truss than it took to get it on. So the remaining construction was wrapped in a tarp, and we finished taking it apart the next day. And just like that? We called it a successful Dry Run Test.

News

Industry Advisor Review

  • June 14, 2019June 5, 2020
  • by Dakota

It was June 10th, 2019. A thick, foggy mist had swallowed up New York City. Hoboken traffic was, unsurprisngly, backed up half an hour. And in the back of a machine shop at Stevens Institute of Technology? Nine rocket enthusiasts were ironing out a testing procedure.

Castle Point Rocketry invited our industry advisors, Rich and Luke, in to review our final testing procedure. Somehow, there were still some introductions to be made, too!

Rich Kelly (left) and Luke Colby (right) introduce themselves before we get to work.

Luke Colby is the President and CEO of Triton Space Technologies, providing engineering design services out of Boston, Massachusetts. Luke has been advising our project by phone since Fall 2018, but we have never met in person. His company also manufactured a handful of valves that will travel aboard our rocket.

Rich Kelly is a Senior Project Engineer with Valcor Engineering, based in Springfield, New Jersey. Due to Valcor’s proximity, he has visited our lab many times over the last few months. And they also manufactured several valves we will be launching into space!

After introductions, we quickly showed Rich and Luke the latest work we had done on the rocket. Then, it was down to business.

Sitting down to hammer out the details of chemicals testing.

We crowded around an imaginary table in our makeshift conference room. (Spoiler: It’s our lab with a portable projector screen.) We had less than six hours to go through the entire 64-page Propulsion Testing Document, so… there was little time for games. (There was, however, time for lunch. Self-care is important and, as Rich reminded us, “The food’s not getting any warmer!”)

The team led Rich and Luke through our testing plan page by page, halting when there were questions or suggestions. After reviewing three tank tests, five full-stack tests, and ten procedural methods, we reached the end of our packet. We called it a day, but Luke and Rich left us with a few pointers. Among other things, the team is revising our waste management plan, redesigning the igniter (again!), and renting more robust pressure regulators.

Just some happy nerds doing space stuff.

It was then time to set our sights on the next big exciting task: Dry Run Testing!

News

Fully Recoverable

  • June 6, 2019June 5, 2020
  • by Dakota

From the onset of our project, we were certain of one thing: We wanted to recover our rocket. By recovering the rocket, we would be able to reuse many pieces of the system and redundantly check our data.

So when our team found Fruity Chutes, Inc., we were ecstatic. Here was a company which could provide us with a drogue chute and main chutes — and to specification! You may recognize the pictures below… They are from our first round of “official” drogue parachute tests in December.

  • Will was happy with the Drogue Parachute Visibility Test.
  • Nathan gave the Drogue Parachute Spin Test his all.

Originally, Castle Point Rocketry planned to utilize one drogue parachute and one main parachute. The drogue parachute would deploy at maximum altitude (or “apogee”) and help the rocket fall in the correct orientation. Once the rocket had fallen most of the way back to Earth, our main parachute would open up. The main chute would provide drag (and added visibility) to allow us to track where it fell. It would also ensure the rocket didn’t impact with a big *splat*.

But, as with much of our project, the parachute system has undergone some iterating. Due to our rocket getting longer and heavier over the last few months, we needed more surface area. (More surface area creates more drag, the resistive force which slows the rocket’s descent.) Rather than buy a bigger chute and scrap our first, we decided to buy a sibling. We now have twin main parachutes!

Will counting all the pieces before Tom and Abe pack it up.

Those of you who follow us on Facebook probably recognize this picture. (Those who don’t should go follow us pronto!) The first half of this week, we’ve been busy making sure all of our recovery system will fit in the rocket.

As you can see, here is one more subsystem ready for testing and launch. Everything’s leaning towards a successful summer!

News

Preventing Meltdown

  • June 4, 2019June 5, 2020
  • by Dakota

One of the concerns with an active rocket engine is what comes out the hot end. Particularly, how hot the flame is that comes out and what we have built to stand in its way. Currently, the team has designed testing and launch stands that minimize the infrastructure that the flame could reach. Just in case, though, we want a backup plan.

That backup plan comes in the form of a metal shroud — hand bent by the team — which fits the form of the stand. And just in case a sheet of aluminum alloy wasn’t good enough, we coated it in a layer of intumescent caulk.

The caulk provides the red, tacky texture seen here.

“Intumescent” refers to a material’s ability to grow when an external force is applied. The caulk that we bought chemically breaks down and grows in volume when a flame is directed at it. The resultant polymer/carbon mass provides additional thermal insulation to the structure beneath it.

Testing Theory

In order to prove that it works — and decide how thick we needed to apply it — we ran some tests. The first round, we tested six different caulk thicknesses for a set period of time. The second round focused on the two best candidate thicknesses at various flame angles.

To judge which test worked best, the temperature on both sides of the test strip were taken every 5 seconds. An infrared thermometer gauged the temperature on the back; a thermal camera estimated the front.

The Outcome

We got a definitive answer from the test: Coat the stand shroud with 1/8″ of caulk. This thickness performed the best at all angles we tried — and leaves us more than enough caulk to coat two more shrouds, if we need to.

The caulk certainly did its job. The photos above show what happened to uncoated versus coated aluminum alloy sheets after a minute of direct flame. The uncoated sheet… melted. The coated sheet remained rigid — and sprouted a dense forest of curly, black char.

The intumescent caulk expanded by a factor of 4.25.

The 0.1″ caulk thickness provided optimal thermal resistance. Directing the blow torch at the center of the sheet raised the back temperature only 6°C — not nearly enough to melt any metal we’re using.

So yeah. We feel pretty comfortable covering our test stand shroud. One step closer to testing…

News

New Lab Space

  • May 30, 2019June 5, 2020
  • by Dakota

For the last year, Castle Point Rocketry has practically worked out of whatever space is available. When we first drafted our Initial Proposal in May 2018, we practically lived out of a design loft for three days straight. As the reports got longer, parts started coming in, and a rocket took shape, though, we needed more sophisticated options.

Until a few weeks ago, our working situation was fairly spread out. Half of our time was spent in a windowless, cubbyhole office on the fourth floor of the Edwin A. Stevens building, barely big enough for the eight of us. The other half was spent on the design floor of the Griffith Building, the closest Stevens had to a fully-functional maker space. (And also home to Physical Plant.) Then, we got news that they were remodeling Griffith — starting with where we did the most of our rocket construction.

A new concrete lab being constructed where our clean room once was.

In a frenzied two days, all hands were on deck to rearrange our materials, our work, and our lives. Our EAS cache was moved down to Griffith, then everything was moved to fit in one of two places: Our parking lot shipping container or our new work space. Moving everything from the Griffith design floor to the smaller room in back was… more time-consuming than you may think.

Our new workspace, in the back of the Griffith Building.

The new space we occupy is just big enough for out needs. It’s also slated for renovation — luckily after we finish, though. In the picture above, you can see our whole layout. We have an 8-person table, access to the outdoors (!), a corridor for electronics, and our clean room. Inside the clean room, you can see the outline of our rocket taking shape.

In addition to our team, Stevens Solar Splash got displaced. Our teams share this new space, so there are times when we have thirteen bodies, a rocket, and a boat all crammed into this room. It’s a tight fit, but we make it work — amicably, too!

Our new lab certainly has its perks.

Out back of our new lab, we have a stunning NYC skyline layered behind more concrete lab material. This breathtaking backdrop has served as motivation and invitation, both. Looking up from a challenging design problem to see the city is certainly refreshing! Additionally, we have had the pleasure of hosting many stakeholders (administration and sponsors alike) in our new space. Most recently, Castle Point Rocketry has welcomed President Nariman Farvardin, Dean Jean Zu, Laura Overdeck, and Chris Daggett for a quick tour.

News

Successful First Igniter Test

  • April 26, 2019June 5, 2020
  • by Dakota

As those of you who follow our Facebook and Instagram (@cprocketry) pages might know, we had an exciting night this past Monday.

After several weeks of deliberation on how to ignite, we settled upon a cocurrent jumpstart from a solid rocket motor. Imagine our large engine housing a smaller engine. The heat of combustion of the small engine ignites the rush of fuel traveling through our bigger engine and — POOF. We have lift-off.

Capturing footage of a solid rocket motor — plain, and without our igniter design.

The Theory

Combustion theory is hard. A good assumption to make, one that doesn’t need a Ph.D., is that our oxidizer and fuel will both need to be vaporized before burning. That is: They need to be a gas. This, at least, is handled by the injector.

The second part is the orientation of the starter flame. To summarize many, many studies and papers in one quick sentence: “The igniter should be oriented the same direction as fluid flow.” (Downwards.) Doing so reduces turbulence inside the engine, reducing the chances of the engine exploding. It also orients the igniter flame away from the shower-head face of the injector, which could cause some orifices to close up.

The big question, then, is how to take a solid, put it inside a liquid shower, turn it all into a gas, and light the whole thing on fire.

The Model

A few ideas came to mind. Do we hang it from a shepherd’s crook? Adhere it to the bottom of a plate? Stick it to the side of a wood pole? The problem with each of these ideas was two-fold. One: With the relatively small size of our engine, how do we ensure that these bulky geometries don’t increase the turbulence? Two: How do we take the straight flame from a solid motor and fan it out in all directions to ignite as much fuel as possible?

Luckily, a little bit of CAD helped solve all of these problems. We settled on a cylindrical igniter plug. This design allows for a variety of motors to be installed and incorporates a diverter to spread flames in all directions. (You can see the outline of our model in the video below.)

The Test

After a watching our first prototype plug print for a few hours, we couldn’t wait to test it out. Even though it was printed from polylactic acid (a plastic which melts at 220°C) and solid motors burn MUCH hotter than that, we figured we could get a few seconds of slow-motion burn time on camera.

And boy, did we get a show.

Proof of concept: The igniter plug design works!

After slowing five seconds of burn time down to several minutes, we had 10 seconds worth of good footage. You can see in the video that each of the radial flame outlets has even distribution and steady flow. Which is just what we want!

You can also tell when the melting plastic starts to disrupt the flame dispersion — about 7 seconds in. The result of that were the smoking, charred remains of our plastic igniter plug. It gave renewed meaning to the word “pungent.”

The Future

Though the test was a success, we began optimizing our design immediately. We inverted the design to allow for ease of access during testing and launch. Loading the motor from the bottom required the flame to shoot upwards, though. This, in turn, required us to reorient the flame outlets.

The team also bought several cylindrical bars of aluminum. After a successful test of our new design, we plan to machine a couple out of aluminum — which hopefully won’t be reduced to a smoky pile of ooze.

Currently, the greatest design hurdle is how to remove the igniter from the engine during testing. Since the rocket is attached to the ground and the current igniter design doesn’t move, we’re back to square one — disrupted Mach flow in the engine. (A result of turbulence.) Luckily, we’ve got a crack team of young rocket scientists working on it.

So that’s where we stand! Proof of concept confirmed, future planned out, and a moveable design in the works. Just in time for our rapidly-approaching testing timeline.

News

Tanks!

  • April 23, 2019June 5, 2020
  • by Nate

One of the difficulties of building a rocket is constantly minimizing mass. Every design choice is evaluated to minimize the mass we have to add to the vehicle. The more mass we need to carry, the more fuel we need to lift it… but fuel also has mass… so you need fuel to lift that fuel… if this keeps going, we’ll be doing some unpleasant calculus.

Our Liquid Oxygen COPV, from Infinite Composites

Out rocket features three composite overwrap pressure vessels (COPVs) in two different flavors. Type 3 COPVs have an aluminum liner for extra strength and corrosion resistance. Type 5 COPVs are made of only carbon composite. The tanks that hold our helium and liquid oxygen are type 5, and the tank that holds our fuel, RP-1, is type 3.

Cutaway view of our rocket tanks, from left to right: Helium, Liquid Oxygen, RP-1

Suffice it to say, it would be awesome if there were some sort of material with the strength of steel but the weight of fiberglass. That’s where composite tanks come in. Specifically, COPVs. These tanks are crazy light and sometimes many times stronger than comparable stainless steel or aluminum tanks.

One of our tanks being wound with carbon fiber!

The team just got our RP-1 tank in the mail from Steelhead Composites, and our He and LOX tanks are in the works at Infinite Composites Technologies.

News

techdrawer interview released!

  • April 20, 2019June 5, 2020
  • by Dakota

You may remember that, a few weeks back, the YouTuber ‘techdrawer‘ paid us a visit. We spent the better part of an afternoon in front of the camera for an interview, followed by a quick tour of the lab. Over the past few weeks, all of the raw footage has been whittled down into a coherent interview.

On the morning of 19 April, techdrawer dropped the finished video!

The finished video — all 16 minutes of it!

Sergio, the face of techdrawer, did a great job of leading the team in an informative discussion about or project. Topics covered include our motivation, what we hope comes of the project, and brief explorations of the science behind it all.

We hope you learn a little something about our team over the course of the video. If you do, don’t forget to give it a like! With your help, two Stevens student groups (techdrawer and Castle Point Rocketry) will benefit!

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