rocket Archives - Page 3 of 4 - Castle Point Rocketry

Changing Plans

February 28, 2019June 5, 2020
by Dakota

If you look at our BOM (Bill of Materials, keep up!) you’ll catch us in the middle of a very important decision. How are we going to test our rocket?

The Purpose:

To be sure our design works, we need to have data on-record from a simulated run. This includes measuring the lifting force generated from combustion, the temperature of the engine chamber, and the fluid pressure at a few key points along the plumbing.

It’s also an excellent chance to test our dump, abort and kill sequences in case of emergency down the line.

Plan A:

From Day One, it’s been clear we would need to test the full stack. Otherwise, how could we be convinced it would work before launch? Since our propulsion system is pressure-fed, the tanks need to be tested vertically. (If the rocket were horizontal, our high-pressure helium would be able to flow right through the tanks when they’re half full, rendering the test futile.)

Proof that a horizontal test is no good. We would lose pressurant before we were halfway done.

This means we have to test vertically. Right-side up. Which, with rockets, is also the direction you point them if you want them to leave the ground. Not as much the plan, with a static fire test.

To get around this pesky bit of physics, the team designed, modeled, and specified the materials in our BOM for a full-height, vertical test stand. Essentially, we designed a cylindrical sheath (for containing the rocket) inside a rectangular frame (to provide structure) weighed down with water, sand, and concrete (so it didn’t fly away).

A full CAD render of our initial vertical test stand, complete with counterweight barrels.

The Problem:

Upon igniting the engine, the nose of the rocket would be forced upwards into the integrated force sensor. This is unrealistic launch behavior, since it puts the entire rocket in compression. Alternatively, the rocket pushing upward into the stand can be viewed as the stand forcing the rocket down

Plan B:

Back to the drawing board. We needed to come up with a test mechanism that would better simulate launch by placing the rocket in tension, rather than compression. As it turns out, the best place to turn for inspiration is still the Internet.

The verdict? “Tie it down.” Plain and simple. All that’s needed is a rocket, something tall to hang it from, and a few (very strong!) wires to secure it to the ground. It may sound silly, but there are plenty of videos detailing the process and showing positive results.

A quick sketch of our new vertical testing plan.

It requires less logistically, too, as it no longer requires us to maneuver an expensive rocket inside a bulky steel cage. Sold.

What Now?

Now we continue the process of finding a place to launch. We have yet to nail down an official location, but we’re zeroing in pretty quickly. (A few amazing spots have jumped out at us this week and we’re following up.)

And after that? We build, we go, we test.

Uncategorized

Impinging Jet Test #1

February 22, 2019June 5, 2020
by Dakota

In order for our preferred combustion theory to happen correctly, we designed the injector to shoot multiple iterations of two miniature jets at one other. When the jets collide a few millimeters into the body of the engine, the liquid spreads out into a “droplet fan,” making it easier for the fuel and oxidizer to mix. (And ultimately, burn.)

The CAD was designed, the part was printed — all that remained was to verify it worked. So, three members of Castle Point Rocketry’s mechanical engineering team stayed up into the wee hours of Thursday morning to test our injector.

A five-gallon water jug, some flexible tubing, and one high-speed camera later, the team had a pretty good idea that our brain child was a go. The test differed from final implementation in five keys ways, but the fact that it didn’t — well, explode — is a good sign.

(1) The test was run on an 85% scale model printed on campus at Stevens’s PROOF Lab. (2) Our final injector will be solid metal but the test part was made of plastic shells. (3) We ran a lower operating pressure and fluid flow rate than the real part will encounter. (4) The part was not meticulously deburred before testing. Little shards of print plastic could have been partially obscuring the outlet orifices. (5) Water was used as our test fluid but the rocket will burn jet fuel in pure oxygen.

A still from a test of the model’s liquid oxygen manifold.

Over the course of the day (and night), six runs were performed over a range of water pressures. The first two, performed in a lab sink, were a public spectacle for the whole team. Monica, our resident injector design chemical engineer, spent most of that time with her head in the sink watching the impingement for defects.

Our next steps: Print a new model and find a test liquid with properties closer to that of jet fuel.

You can find a nice slow-motion video on our Facebook page (http://www.facebook.com/CPRocketry/).

Uncategorized

Snow Day!

February 12, 2019June 5, 2020
by Dakota

When most Stevens students get an e-mail saying the day’s classes have been cancelled, they celebrate because it gives them a free day to relax, play Super Smash Bros., or whip up a nice long meal.

Castle Point Rocketry celebrated because it gave us a full day to meet.

So here we all are, gathered together in Dakota’s apartment, calculating blast radius, zeroing in on a test site, and finalizing a plumbing and instrumentation diagram. (Hopefully, the former won’t ever be needed — and the latter is on its last iteration.)

Stay tuned for more exciting news. Until then, we’re holed up hiding from the cold!

Uncategorized

Full Circle

February 12, 2019June 5, 2020
by Dakota

One of the most competitive facets of our rocket is the engine assembly. Rather than the hundreds (and sometimes thousands!) of parts used to create a traditional rocket engine, our team has streamlined the process into just two: an injector and a nozzle.

Since they’re so integral — and so specialized — we’ve spent hours upon hours designing, modeling, and simulating these parts. And we’ve come full circle.

Phase One: Solidworks

The CAD starter kit for any Stevens engineering student, Solidworks helped us make our first few rounds of injectors. It was pretty cool. Tom spent a lot of time on it.

Injector, Mk. 1. It was bulky, but it got the job done.

Phase Two: COMSOL

Once happy with the geometry, we needed to simulate fluid flow through the manifold. What better software to use than a COMSOL, taught to grad students and marketed as a multi-physics program with a hefty computational fluid dynamics (CFD) engine. Dakota’s self-taught COMSOL regimen came to a standstill when, no matter how finely we meshed the part, physics kept saying, “Nope.”

COMSOL needed the injector flipped inside out. Crazy, right? This part seemed okay…

… But this one obviously had some problems.

They ended up both not working out. One kept growing gnarly spikes, the other had faces that wouldn’t meet up. In the end, no amount of curve smoothing could fix it.

Phase Three: Ansys Fluent

So, what now? Let’s try another CFD! Stevens also offers Ansys to its students, which comes with the handy Fluent plug-in. Abe and Dakota worked on modeling the part in early January, only realizing after returning to campus why it wouldn’t work: Even when simplifying the models by excluding symmetrical pieces, the parts were MUCH, MUCH too big for our Ansys versions to handle. (If years of math has taught me one thing, it’s that 1.1 million “cells” is larger than 512 thousand “cells.”)

Phase Four: Back to Solidworks

The most recent iteration of the injector. We’ve come quite a long way!

We were lost. What do we do? Our school’s CFD programs weren’t working. We had tried simplifying the parts to no avail. Were we just going to hope our applications of what we read in NASA journals would work? Would our rocket engine be held together by dreams and back-of-the-napkin calculations?

Of course not. In the words of Professor Aziz, who teaches courses in Modeling and Simulation at Stevens, “You started
in Solidworks. Why did you leave?”

This simulation tracks individual particles traveling through the injector manifolds. Red means high speed, blue means low speed. Good news: They don’t stop!

So we’ve come full circle. We’re back where we started. We’ve been running fluid flow simulations fairly smoothly, these last couple of weeks. Sure, we keep iterating and optimizing. But at least it’s all built-in, now.

And boy, are the simulations colorful.

Uncategorized

Untitled

January 25, 2019June 5, 2020
by Dakota

Sometimes you just gotta step back from the rocket and just…

Uncategorized

It Go Up, It Come Down… Slower

December 18, 2018June 5, 2020
by Dakota

Imagine it’s June 2019. Castle Point Rocketry is on the launchpad at Spaceport America.

The timer goes *beep*. The valves go *click*. The propulsion system goes *ffffshshshhhh*. The engine goes *bbbbhgggghgggghhh*. The rocket goes up. The engine stops. The rocket hits 100km. (The ground crew cheers.)

The rocket turns over and comes back down… and luckily isn’t traveling at terminal velocity when it hits the ground. Why? Our friends at Fruity Chutes, Inc.

After a rigorous set of tests carried out in our Global HQ on Stevens campus, we were satisfied that Fruity Chutes, Inc. had made us suitable chutes.

For those unfamiliar with our current design, we will be employing a double-chute system. Way up in the uninhabited region of the atmosphere, our handy nosecone will pop off and deploy a drogue chute. This helps make sure the rocket doesn’t tumble and snap in two. Much closer to the ground, our bigger chute (not shown) will snap out of hiding, adding drag to give our rocket enough air resistance to fall at a slow enough pace that we can track it and make sure it lands in one piece.

Thanks, Fruity Chutes. We couldn’t do it without you.

News

“Will It Fly?”

December 18, 2018June 5, 2020
by Dakota

It may be the the question we ask ourselves the most. (Behind, of course, “What’s for lunch” and “How’d your exam go?”) The answer: “Ask NASA.” (To them all, obviously.)

Most recently, it’s fallen to the ChemE team to answer this question. Initial assumptions of the chemical reactions out of the way, it’s time to buckle down and do some hardcore engineering.

And when you need to engineer something, who better to turn to than NASA?

Using a little-known software called CEA (made available online as CEARUN), we’ve been iteratively testing hundreds of fuel combinations and engine conditions over the last few days to comb through and find The One.

It’s not every program that can crank out 23,000-some lines of code in under five seconds. That’s just the NASA difference, I guess.

Official Stevens Article

November 15, 2018June 5, 2020
by Dakota

What do Elon Musk, Gen Z, and Castle Point Rocketry all have in common? We’re name-dropped in an article recently published by Stevens Institute of Technology.

A story regarding Castle Point Rocketry was circulated on the Stevens webpage. (And on all of the bulletin TVs around campus!) Following a meeting the team had with members of the Division of Communications and Marketing and the Schaefer School of Engineering and Science, the team’s enthusiasm about reaching the Karman line has officially been adopted into Stevens canon.

The authors of the article met not only with members of the team, but also spoke with a faculty advisor and a couple of our corporate sponsors. It’s always good for morale to hear yourselves called “ambitious and innovative” and “pioneering!”

You can read the full Stevens News article (and re-watch our initial pitch video) here.

News

Prototyping!

November 15, 2018June 5, 2020
by Nate

The team has been busy developing and testing prototypes of critical sub-systems. Most recently the team completed pressure testing a scale model of our 3D printed engine! This print allowed us to learn about the way our design geometry interacts with the 3D printing process. The team was able to gather a significant amount of data from the print and subsequent tests. We used this data to refine our design and improve our printability.

The avionics team has also been working on prototyping. Pictured below is the first iteration of our flight computer! The flight computer will handle all flight functions of the rocket, including actuators and data acquisition.

News

Health and Safety Meet-Up

November 15, 2018June 5, 2020
by Dakota

Last week was a busy one — and one of Castle Point Rocketry’s myriad meetings was with David Fernandez, Stevens’s Director of Environmental Health and Safety (EHS). Obviously, this was pretty important.

David was instrumental in reminding us which materials could be stored on campus and which couldn’t. We held a great discussion about some of the pivots our team could move to, should the current course of action prove inviable. Finally, and most excitingly, we got to go “shopping” for new clothes.

The end of our meeting found us in the EHS office (with David) trying on lab coats like a gaggle of mad scientists. (See the photo of us smiling like some, too.) David also aided us in refining our fire suppression and protection techniques.