rocket Archives - Page 2 of 4 - Castle Point Rocketry

“Clean For Oxygen Use”

June 11, 2019June 5, 2020
by Dakota

We can all probably agree with the relative levels of cleanliness. Around the bottom of the scale, there’s “I Am Comfortable Living In This.” A little more clean, you probably find “Company is Coming,” closely followed by “My Parents Are In Town.” Near the top of your list, you probably find “Apartment On The Market.”

“Clean for Oxygen Use” may top the charts. It’s certainly not a household standard.

Bottom shelf: Unclean. Top shelf: Clean.

This cleaning method is the entire reason we constructed our clean room. Much of our rocket will come into contact with high-purity oxygen, whether in liquid or gas form. Gaseous oxygen loves lighting things on fire, and liquid oxygen freezes most substances solid — so we need to be sure everything is as clean as humanly possible. To do so, we have a six-step cleaning process.

Step One: Alcohol Bath

After we identify a subassembly to clean, we remove each piece from storage. We bathe each individual fitting, pipe, adapter, and valve in isopropyl alcohol. (That’s the same alcohol you put on wounds to clean them.) For 12 minutes, they rattle around inside an ultrasonic chamber. By vibrating them very, very quickly, the machine dislodges defects, dust, and other gunk that is clinging to them.

Our ultrasonic bath is located on the left.

Isopropanol is also a dehydrant. This agitation bath ensures every out-of-the-way nook and cranny is water-free. Any water left in the system would freeze in contact with cryogenic liquids, decreasing functionality and making the rocket explosion-prone.

Step Two: Nitrogen Purge

After they’re removed from the bath, each part is individually inspected for remaining debris.

A tee junction during the nitrogen drying cycle.

Then, every part is dried with a pressurized jet of filtered nitrogen. Not only does this ensure no isopropyl alcohol is left on the part, it blows away any remaining foreign materials.

Step Three: Alcohol Rinse

As if Step One weren’t enough, we then subject each component to yet another round of alcohol. This time, the isopropanol is targeted in a stream. The entire part is washed beneath a squeeze bottle before moving on to Step Four.

A tee junction having an isopropyl alcohol shower.

Step Four: Nitrogen Purge

More drying! Like most alcohols, isopropanol is flammable so we need to make sure each part is bone-dry before assembly. This last round of nitrogen is usually enough to get the last bits of stubborn junk off of our fittings.

Step Five: Critical Inspection

Once the second nitrogen blow-down is complete, we are fairly certain nothing remains. But just to be sure, though, we inspect each piece from every angle for leftovers. Inside and outside, nothing is allowed to escape our prying eyes. And on the off-chance we still find refuse holding on? We restart the whole process from scratch. We bought smaller ultrasonic bath just for that purpose.

Step Six: Assembly

Finally, we are sure that our parts are Clean for Oxygen Use. We bubbled, tossed, dried, washed, and dried most everything (and even brushed some with a high-grade pipe cleaner), and it’s time to put the pieces together. One by one, being sure not to stir the air or drop anything, the rocket starts taking shape. We have 24 subassemblies ranging in size from one component to thirteen.

One of the subassemblies we will be using for tank testing.

Each über-clean subassembly is then given a new home on the high shelf in our clean room. Small subassemblies are bagged and given a unique name so they don’t get confused down the road.

And that’s how you make a rocket Clean for Oxygen Use!

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Igniter Test #2

June 11, 2019June 5, 2020
by Dakota

Late last week, Castle Point Rocketry ran a successful test of our new igniter design. It is a variation on a theme (see our previous blog). This new model allows for better manufacturability and repeated use, but doesn’t sacrifice the engine-within-an-enigne design we wanted.

Many individual design components have changed over the last month. The fire now shoots down instead of up. There is a bored hole at the bottom so that the igniter can be removed from the engine quickly. We filed the top to a point so it fits into the engine more easily. Beyond that, it’s very much the same part.

Before testing.
After testing.

As you can see, we had a small meltdown problem, consistent with the last test. It’s a good thing that 3D-printed plastic parts are as printable as they are disposable!

Tom designed a gravity-driven system to quickly remove the igniter from the engine. By topping a vertical pole with the igniter, we can easily drop the assembly from the engine after ignition.

Now, we begin the process of moving forward. Our current goal is to outsource manufacturing to a local New Jersey company capable of machining it out of aluminum. That way it’s quick, close by, and made in the USA!

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!

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.

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CPR Ties for First Place!

May 15, 2019June 5, 2020
by Dakota

You may recall Technogenesis. Colloquially called “TG,” it’s the entrepreneurship analog course to Senior Design. TG is designed to teach every team the metrics of making a business out of our projects. Most importantly, it teaches everyone the impact of a good pitch.

The culmination of the Stevens Innovation Expo is the elevator pitch competition — recently rebranded as the Ansary Entrepreneurship Competition. Ten teams compete for $17,500 in prize money. And we tied for first!

The team with our comically large check. We tied for first place!

The Ansary Entrepreneurship Competition is the final round in a series of judged pitches. The quarterfinals are a combination of two votes. First, all teams present in class to a panel of TG professors. Then, the public votes on each team’s pitch video on YouTube.

Castle Point Rocketry’s official TG video.

Castle Point Rocketry passed the quarterfinals on the public vote. Two weeks later, we also passed the semifinals, which left us with about a week to prepare for the Ansary Entrepreneurship Competition. Faris, our resident Pitch Master, worked overtime to make sure the pitch was the best it could be.

We were pretty happy with how he sounded — and apparently the judges were, too! The rest of the team joined Faris on stage after his pitch to answer any questions, of which there were only two. After the other nine teams pitched, they announced the co-winners: LifeSkills Software and Castle Point Rocketry! Castle Point Rocketry also won the “Audience Choice” award.

Our teams are are splitting the $15,000 reserved for the first- and second place teams. (They weren’t expecting a tie!) Castle Point Rocketry’s $7,500 will cover our transportation to and from the launch site. Stay tuned for more exciting updates!

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Innovation Expo 2019

May 5, 2019June 5, 2020
by Dakota

This past Friday, May 3, 2019, marked the annual Stevens Institute of Technology Innovation Expo. 189 senior projects were presented by individuals and teams from all four schools at Stevens: the College of Arts and Letters, the School of Business, the School of Systems and Enterprises, and the School of Engineering and Science.

Even Stevens’ mascot, Attila, dropped by!

Castle Point Rocketry occupied a series of tables in the Griffith Building, located beneath campus on the Hudson River. Alongside many other building-intensive teams, we presented our project to students, professors, Hoboken residents, and potential investors alike.

We brought out all of our toys for show and tell.

From 10:30am to 3:00pm, members of our team rotated through presenting at the table. Notable visitors included Attila the Duck (Stevens’s mascot), Dr. Nariman Farvardin (President of Stevens), Graham Boyd (our Regional Manager for SLM Solutions), and Bob Freno (Principal Member of Engineering Staff at L3 Technologies).

Our quarter-length airframe assembly was a crowd favorite.

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

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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The Hunt for the Best Igniter

March 14, 2019June 5, 2020
by Dakota

So, rockets burn fuel. That much makes sense. And that combustion of cold liquid creates a lot of hot, pressurized gas that makes the rocket go upwards. Got it. But how does that begin?

You can’t light a kitchen stove without the internal igniter sparking. In the forest, you can’t start a campfire without flint and steel. (Or lighter fluid and a barbecue lighter.) But inside a rocket engine… things are a little more complicated. Castle Point Rocketry has been upending shelves worth of books (all online, don’t worry) searching for the question on the forefront of our minds: “How do we start our engines?” And we’ve narrowed it down to three major contestants.

“The Cotton Ball”

Soak a cotton ball (or other highly-porous material) in something really flammable.
Stick said drenched cotton ball on the end of a metal stick.
Set rocket over stick, with cotton ball inside combustion chamber.
Light cotton ball on fire.
Release the fuel and LOX.

Proof of concept: It’s been done before.

Potential drawbacks include the sudden onslaught of liquid, though flammable, extinguishing the burning cotton ball.

“The Salt Crystal”

Finish researching oxidizing rock salts. Some salts, when heated, spontaneously burst into flames and release copious amounts of oxygen — which helps fuel more decomposition.
Acquire a small-ish amount of the chosen salt.
Carefully pack the salt into a small container on the end of a large stick.
Gently place the rocket over the stick, with salt container inside the engine.
Warm the container and wait for sparks, then release the fuel and LOX.

A snippet of molten oxidizing salt shooting flames.. (1:55 – 2:10.)

Potential drawbacks include the risk of salt decomposing before the igniter set-up is prepared.

“Engine-ception”

Now imagine, if you will, an engine inside an engine.

Source a suitable solid rocket motor, given its thrust/time curve.
Semi-permanently affix the motor to the bottom face of the injector.
Ignite the solid rocket motor.
Release the fuel and LOX.

Solid rocket motors produce a very well-regulated flame over a set period of time. Additionally, this set-up allows both flames (from the starter and the combustion) to travel in the same direction. By doing so, we can reduce the chance of the starter blowing out!