USCRPL

New Projects

2012-01-24T21:53:00.000-08:00

Happy Year of the Dragon, everyone! With a new year comes new projects... and new bloggers. Bill has passed the torch to two freshmen, Andy and Jason, who are looking forward to conveying the adventures of engineering at USCRPL.

Spring 2012 looks to be a very exciting semester for rocket lab. We are building an avionics test vehicle, developing hybrid hardware, flying Tripoli certification rockets, and making a filament winding machine. Before we delve into these fascinating projects, let's review what's happening with the upside-down horse stuck in the concrete.

Literally.

Traveler is stuck in that 99%-complete phase that all projects seem to end up in. (It's practically Occupying lab.) We are finishing the last of the hardware tasks:

-Sprucing up the cork on the nose cone
-Painting the launch tower and integration stand

The launch tower base being primed.

Bill, Alec, and Kurt are working to secure a land use permit from the Nevada Bureau of Land Management. A May or June launch looks most likely, but we're doing our best to move that to the left. We did examine alternative launch sites to Black Rock, but they all have serious downsides. Spaceport America has too many limitations, while Wallops and other sites mandate launches into the water. So Black Rock is really our only option. The worst-case scenario is that we launch at BALLS at the end of September.

There is an upside to this forced semester of inactivity on Traveler, though. The avionics team will get the opportunity to test Traveler's electronics in flight. We are building a dedicated vehicle for this purpose called the Avionics Test Vehicle. We know it isn't like rocket lab to make an acronym for a vehicle, so we seriously intended to come up with a better name, but no one has yet. Readers with name ideas should write to Mr. Macklin, our Naming Chief, at thuglife@uscrpl.com.

Now for an overview of the ATV. It has a 4" carbon fiber motor case and airframe. This will be only the second time USCRPL has flown such a case, though we have conducted many successful static fires. The ATV has three carbon fiber fins, four AP/Al grains, an RF-transparent fiberglass payload bay for the electronics, a carbon fiber nosecone, and an aluminum death spike. It's a small vehicle compared to Traveler, but it will still pack quite a wallop, flying to 20,000 feet at supersonic velocities.

Work on the ATV has been progressing quickly since the beginning of the semester. The payload bay has been laid up, but will need a lot of sanding. The fins have been laid up and baked, as has the nosecone. We are currently laying up the motor case, and will later machine the vehicle's bulkheads and rings. The ATV is on track to fly in March at the RRS.

But the chief goal of this semester is to fly a hybrid rocket in the form of a 4" booster with the ATV's payload bay and electronics. To gain experience with hybrids, we are remaking Bill, Alec, and Sarah's senior design project of a gas-assisted solid into a full hybrid. This necessitates lots of machining and the casting of a concrete block to enable testing in locations without existing infrastructure. The small hybrid should produce 50-60 pounds of thrust, running on NOS and rubber. We acquired a new mixer and are making a stand for it in preparation for casting the rubber in liquid form. We plan to fire the hybrid on February 11 at Lucerne Dry Lake.

One of four firings of the gas-assisted solid in November.

On that same day, two of our members, Jordan and Jason, will fly their own rockets to become certified by Tripoli, the rocketry association that RPL recognizes. Look for more information on "Momo" and the "Falcon 9th" soon.

Finally, we are building a filament winding machine to lay up motor cases easier and stronger. Stay tuned as we cover the construction, testing, and operation of the machine during the semester.

We are looking forward to a new semester with new members. With senior lab leaders moving on to bigger things, they will be passing on their knowledge to eager younger members. But the challenging projects this semester are sure to put both the experience of the veterans and the enthusiasm of the rookies to the test.

Flight on!

Seasonal Update

2011-12-16T17:53:00.000-08:00

Hey everyone,

We have, as usual, been busy in and around lab. Primarily, the main project has been working on a few final touches for Traveler. We have also been busy with paperwork, hoping for a launch this December. We finally got an FAA waiver, but will unfortunately have to wait a bit for a land use permit to launch from Black Rock Desert in Nevada, which we are hoping will come late spring. In the meantime, we are looking for additional launch sites if we can figure out something to work sooner than that.

Traveler sitting in the launch tower, with its newly machined titanium nosetip

One side project that came out of finishing up Traveler was additional work on the tip-to-tip layup that went over the fins. We were not satisfied with how the cure process went before we made the trip up to Black Rock because we did not have enough time to cure them correctly. This time, we constructed a new oven from the same foam we tried to use before to simply extend our old one. This new oven has a large enough cross section to fit the entire aft end of the 8" vehicle, including the fins, yet is small enough such that it takes very little time to heat up, which is useful when it comes to making test layups.

Meaghan Sullivan standing next to the completed oven.

Matt Orr figuring out the new temperature controller

Size comparison of Traveler (sans nosecone) and the oven. A hole was fashioned through one side of the oven for the rocket to fit into.

RPL cookies, cooked in our oven. This proved that the oven could work and hit the precise ramp up and cool down rates necessary to properly cook chocolate chip cookies.

A few of us have also worked on a separate project, an inert gas-injected solid rocket motor, where inert gas was injected into a burning motor in order to increase the operating chamber pressure, thus the thrust of the motor. The motor was static-fired on the ground four time in one day, setting a record for the number of firings RPL has done in one day (previously with the oxamide motor, we had three).

Picture of the inert gas injected solid during one of the four burns.

Next semester will be a busy one. We are hoping for an early season flight of our upcoming avionics system for Traveler, where we will fly the system in a smaller vehicle at the RRS. Along with investigating other launch sites for Traveler, we will also be testing new propulsion systems with the small gas-injected motor assembly that was constructed, and perhaps designing and testing new solid grain configurations. Expect a lot of static fires, and above all, many flights.

Oh, and we also got together for some end-of-the-semester photos, as you can see below:

Flight On!

Lecture Series

2011-11-07T09:54:00.001-08:00

We have been holding a "Lecture Series" where we talk about all things Rocket Lab - composites, metals, aerodynamics, design, propulsion, etc. once a week. I wanted to make sure the invitation spread to everyone.

Anyone, RPL member or not, is welcome! We have 4 more weeks. Meet us in THH 210, every Monday night at 8:00 - 9:00.

See you there

-RPL

Post BALLS XX Report

2011-10-03T15:08:00.001-07:00

Silent times have fallen upon this blog recently, but I am about to fill you in on our progress with a very long status update.

Ever since we started the Traveler project back in April, we have been working on it diligently. We planned on scaling up our 4" Silver Spur 3 rocket that we flew last year at Balls to an 8" minimum diameter carbon motor case rocket to fly by BALLS this year in Black Rock Desert, NV. And it has been quite a journey - designing and fabricating the hardware necessary was no simple task.

In order to be cleared to fly a rocket of this size (an R 16,000), we had to get a Class 3 amateur rocket waiver from the FAA, which required a decent amount of paperwork and a large amount of diligence - we have never had to get a waiver of this kind before, nor conduct the kind of simulations necessary to get it. To start off the process, most of the key design work was finished before the start of the summer so that we could begin work with Air Force Research Lab at Edwards AFB on POST II 6DOF simulations of the rocket. In the simulations, we conducted several 1,000 run Monte Carlo simulations where the rocket would land in every imaginable case - low drag, high drag, low thrust, failed recovery system - you name it - so that we could see what the landing pattern looked like. This process is required for a Class 3 waiver, and took well over 500 e-mails and several phone calls with our friends at Edwards to complete.

Traveler in a section of the launch tower on display at BALLS. The horse is not flight hardware.

Long story short, we ran out of time. We hit all of the TRIPOLI/FAA deadlines, but during the last week were denied the waiver because of an ATC airspace limitation with two days to spare before the launch. We tried modifying our dispersions but were not able to get it done in time to still receive a waiver. These things happen - it's why it normally takes 45 days to complete this process, and why we are not let down by the results. We are ready to blast through the paperwork one last time for a launch on our own in the near future. While it would have been nice to fly at BALLS under the event waiver, insurance, and land use permits, we will simply have to do this on our own when we decide to launch.

But before I move forward, I want to give a HUGE thanks to the people we worked with from RPL to Edwards/AFRL, TRIPOLI, FAA/AST and ATC. All of you provided tremendous help, with Edwards/AFRL helping us at every second of every working day with simulation data, to TRIPOLI providing an immense knowledge of how to build/tailoring the 6DOF simulations to get the kind of results the FAA needed in order for us to get our flight waiver, to FAA/AST/ATC to pushing our paperwork through all government channels as fast as humanly possible. We realize we were not able to get a waiver in time for BALLS XX, but we would not have even gotten remotely close to it if it wasn't for all of your help. As an organization, we have learned and matured immensely in these past few months, and it’s because of all of you who helped us with this vehicle. This rocket will fly, and it'll fly soon!

Instead of hanging our heads low and coming up to the event empty handed, we decided to (mostly) finish the rocket, launch tower, and avionics and bring them up to the event. It was a great time to complete a mock integration of all of the systems and test them out. While everything would have most likely worked had we actually flown, it is nice to stand back and be able to identify problems with some of our processes and refine them for the future. We were also happy to show off all the work we've done and actually stand around and watch other groups fly (which is something we never have enough time to do).

So, moving on to the actual rocket. Like mentioned before, we were planning on entering the Carmack Prize at Balls, which requires a flight to 100,000 ft with altitude confirmation and a safe recovery on the ground. Traveler is definitely capable of achieving this altitude with a 211 lb R 16,000 motor. Average thrust is 3,500 lbs for 13 seconds, which will take us into the Mach ~6 flight regime.

The rocket itself is pretty much made of entirely composite materials. The motor is based on Silver Spur 3's design that has been successfully static tested and flown - a minimum diameter carbon motor case that has been developed and constructed by USCRPL. This year we increased the diameter of the rocket to 8". The composite systems are extensive to say the least. We manufacture everything except we do not lay up our own phenolic parts (yet). We usually buy pre-cured phenolic, as in the fin leading edges, and machine it in lab.

Layup time! This was the nosecone - most likely 2 a.m. on a random weeknight

Composite systems are as follows:

Unidirectional prepreg carbon (motorcase, fins)

Bi-directional prepreg carbon (motorcase, tip-to-tip fin reinforcements)

Linen Phenolic (fin leading edges)

Canvas Phenolic (motorcase)

Silica Phenolic (nozzle) - AAE Aerospace (see below)

Fiberglass Phenolic (nozzle) - AAE Aerospace (see below)

S-Glass Fiberglass (nosecone)

Cork Sheet (nosecone)

End-Grain Balsa (fins, avionics cartridge retainment bulkheads)

Upper air frame layup with unidirectional prepreg carbon

Setting up for the hydrotest - case passed @ 1,000 psi for 120 seconds

Machining the leading edge of the fins after the layup

Fin attachment with fin alignment guide machined from MDF

5-Layer tip-to-tip prepreg layup over the fins for reinforcement

The nozzle phenolic is the one part of the vehicle that was largely constructed outside of lab. For the first time ever, we have moved from a steel/aluminum outer nozzle carrier with phenolic inserts to a fully phenolic nozzle. The outer part of the nozzle is overwrapped in glass phenolic, with the bulk of the ablative material being silica phenolic. AAE Aerospace in Huntington Beach, CA manufactured the nozzle for us on a cheap budget and really quick timetable, and we are extremely thankful that they managed to do this for us. Our experience with AAE was great and they were very friendly/helpful to us throughout the process. The rest of the nozzle assembly - graphite throat, aluminum bulkhead, etc. was made in-house.

Showing off the nozzle at BALLS

This time around we wanted to mitigate the chances of seeing erosive burning in our motor. Usually with motors of this Length/Diameter (L/D) ratio, erosive burning (where gases in the combustion chamber are accelerated down the length of the motor to a point where they drastically increase heat transfer/burning rate of the propellant near the aft end of the motor) becomes an issue. On the bottom two bates grains, the ID of the propellant grain was opened up to allow the core velocity to drop below a rule-of-thumb value to where it should no longer be an issue.

The nosecone is covered in cork that will serve as an ablative protection against the ~Mach 6 flow at max Q. The nosecone tip is titanium as was with Silver Spur 3 (and thankfully helped protect our avionics after impact).

Nosecone - 10 layers of S-glass with outer cork layer. Tip not attached

The primary recovery deployment is controlled by a single Featherweight Raven. The Raven can ignite four e-matches to trigger double CD3's and a backup black powder charge, which then separate the nosecone and deploy a streamer for recovery. The Raven logs accelerometer, barometric, and temperature data internally. Independent of the Raven are three other systems, each with GPS and live telemetry. The first is an Arduino micro-controller which we have programmed to simultaneously transmit and log to an SD card data read from several components. The components attached to the Arduino currently include a Garmin GPS, pressure transducer (for motor pressure), and accelerometer. The Arduino transmits its data at approx. 900 MHz (33cm amateur radio band). The other two standalone systems are both packages comprised of just a GPS unit and transmitter. One is from Byonics and the other is the BeeLine system from BigRedBee. Both of these systems transmit at the APRS frequency 144.39 MHz (2m amateur band). This not only gives our system triple redundant GPS, but also allows us to use the APRS network (aprs.org) as a backup receiver for the GPS data vital to finding the rocket.

The core of our avionics team (minus Dylan who couldn't make it)

The launch tower was a brand new project this semester as well. It's made of up 3 modules that bolt together on site and are individually small enough to fit in the bed of a pickup truck. It has 4 adjustable steel guides that run 20' in length that guide the rocket without the need for extra buttons on the outside of the rocket. This saves us ~30k ft on our altitude. If we can gain altitude on the rocket by simply building GSE, why not? Well, that 30k ft was some of the hardest fought for - it took a monumental amount of work to build this monster of a tower, but it was finished in about a month. It can also be easily reconfigured to fly any of our past vehicles (8" dia and smaller).

20' of pure awesome

We successfully deployed the launch tower at BALLS to test on-site integration. Everything went well, and we have identified a few areas that would benefit from a little bit of improvement next time around.

This is what Traveler sees

One thing I want to note - this year we have had the largest rocket lab membership ever. Our first meeting of the year had easily 60 people present, and many of them have stuck around for the late nights in lab this semester. It's great that the lab has now grown to such a large size and is still functioning - we continue to educate ourselves and each other in each stage of the project and the process has been greatly rewarding.

Keep reading the website! Traveler will be up in the air as soon as paperwork is completed. It's just a matter of time at this point. We will continue work on improvements to the vehicle in the meantime, and possibly start up another interim project. Stay tuned.

Flight On!

Carmack Prize Submission

2011-08-31T02:05:00.000-07:00

We have submitted our project for the Carmack prize and will be flying Traveler to 100k+ feet on October 1st at BALLS!

Here is info on the Carmack Prize:

http://www.armadilloaerospace.com/n.x/Armadillo/Home/News?news_id=376

Basically we get money if we are the first group to fly a rocket to 100k ft and recover it. We have to get a GPS ping above that altitude.

Here are some quick specs:

The overall rocket is 8" OD and 160" long.

Motor case: carbon fiber, 8" OD, 120" long

Nose cone: S-glass with a titanium tip, 40" long

Fins: Carbon fiber, with carbon tip-to-tip retention

Motor

Propellant weight: 211 lbm

Peak Thrust: 4050 lbf

Configuration: 7.61" OD Bates Grains

Formula: Composite AP/Al formula, 82% solids, (10% metals)

Recovery:

Custom Kevlar and Nylon streamer measuring 180” long with an average width of 12”, deployed at apogee.

Flight On!

USC Rocket Lab

First of the Year Meeting

2011-08-25T19:17:00.001-07:00

TODAY, 8/25 IN GFS 101

BE THERE

RPL Documentary Snippet

2011-04-24T14:39:00.000-07:00

Oxamide, Del Grande, and Traveler

2011-04-11T11:59:00.000-07:00

Welcome back to our sporadic web updates! Here's what's been going on recently:

Oxamide testing - Back in February we built a small 3" diameter, two-grain motor case to characterize a new propellant formulation. We cast 6 small composite grains 72/10 AP and Al content, with an added 3% oxamide as a flame coolant with the hopes that we could see an appreciable lengthening in burn time as a result.

The motor case was all aluminum and we conducted three separate tests in one day. The difference between each firing was the throat diameter of the nozzle - it was constructed of an aluminum carrier with a removable graphite insert that had a different throat diameter for each burn, in order to hit 600, 800, and 1000 psi, respectively. It had hardly any diverging section, making it simply a sonic throat - we only needed chamber pressure and burn time in order to figure out the burn rate coefficients that we needed for modeling.

It was a first in the fact that Rocket Lab fired one motor three times in one day. This time we didn't have to worry about a thrust stand - we just dug a hole and threw the motor in the ground (reminiscent of some old static tests conducted by lab...).

We first put in nozzles that were supposed to give us 400 and 600 psi chamber pressures, but noticed that we were actually hitting startup pressures of 150% nominal pressure. We opted out of the 800 psi nozzle and went for a lower 300 psi nozzle we made as a back up just in case this problem happened.

With the biggest throat diameter, there was noticable chuffing in the motor - solid propellant combustion instability - caused by an incredibly low L* value (volume of chamber divided by the area of the throat) that caused the motor to resonate, similar to blowing over an open glass bottle and hearing a sound. We just had this nozzle lying around just in case we were worried about chamber pressure, and really did no Kn calcs with it - we just basically found a drill bit lying around and did the "eh...looks about right" calculation. But hey, we learned a lot. I put up just the one interesting video (chuffing) on youtube:

http://www.youtube.com/watch?v=S6ktfSXmSPE

(for some reason I can't get the video to actually display on Blogger so you will have to click the link)

Del Grande - We rebuilt Del Grande to fly it again this semester. We used a new kevlar nosecone (the mold/plug has been in the works for years now) with which we wanted to test a new nosecone mounted avionics system and CO2 recovery system. Everything else in the rocket was pretty much the same as before.

The upper airframe was repaired after the last flight which left a lengthwise tear in the airframe due to parachute deployment, and a new motor case and nozzle were manufactured. This rocket is an 8" diameter rocket with a 6" P6110 motor in an aluminum motor case.

We wanted to try a new GPS avionics system that would track the rocket and backup the data given from our ARTS board (from Ozark Aerospace). Unfortunately due to time constraints and a few hiccups with the live telemetry coming from the GPS system, and the fact that the on-site generator we were using to power our tracking computers failed just before launch, we were unable to get an active lock on the GPS system.

The launch was beautiful, even considering the weather conditions - it was incredibly windy. It was unnerving to watch the rocket sway back and forth on our launch rail as the bottom of the rocket was stacked precariously on a pile of bricks we found lying around. But the takeoff was amazing, as it was last time with this monstrous rocket. (We say monstrous because its so far the largest rocket we have fired, since this one was slightly longer than Del Grande 1). Video here:

http://www.youtube.com/watch?v=AH3Kdfcl6bM

Sims/past flight data say ~20k ft at ~mach 1.1 from a P6110 motor. It wasn't light. After the launch, Ian Whittinghill flew all over the site and was unable to find any trace of the motor:

Mojave Test Site

And the next weekend, a few members of RPL came out with a telescope and looked all over the Mojave desert, running from hill to hill, and getting sunburned the entire time. This is a time to learn and rethink some of our recovery methods, after the second failure in a row. This is something that we are turning our full attention toward, because our next rocket at Balls is REALLY going to need it, since our next project is...finally....Traveler.

ALSO - keep following our Picasa album... I am uploading more and more stuff. There's pictures from this last launch and I am starting to upload senior design projects by lab members. We have done everything from hybrid propulsion to electric to liquid flow tests. We don't call it Rocket "Propulsion" Laboratory for nothing.

http://picasaweb.google.com/uscrocketlab

New Year

2011-02-05T11:22:00.000-08:00

Hello loyal RPL followers,

Happy (belated) New Year from USCRPL! This semester we have a few exciting projects in store. But first off, we have come away from another static-fire setback. Our "lengthened Trunnion" motor did not perform as planned, and has sent us temporarily back to the drawing board. We were hoping for a success the first week back from winter break, but were instead scratching our heads over what went wrong and what we can/should do about it.

Rocket science is never easy.

We plan on having a third static fire of the modified motor (which WILL work!) this spring. Check for updates. I know we've been quiet about it, but when it works, everyone will know about it.

There is other work going on in lab, too. We are re-launching Del Grande with a modified propellant formula (still TBD), and it will be a testbed for our new hypersonic 8" conical nosecone and CO2 recovery deployment system. Still planning a ~20k ft altitude at >Mach 1, but it will be exciting to launch a rocket that has already flown before. We're planning a launch in the beginning of March.

The new freshmen have been a tremendous asset to Rocket Lab, and will soon carry the torch when some of us leave. Because of this, Del Grande (except for the nosecone) will be pretty much redesigned and rebuilt by the newer members of lab. This will be a great opportunity to become experienced with heritage RPL hardware and familiarized with a pretty straight forward rocket design.

One other thing I forgot to mention in the last RPL update:

Our recovery system did try to deploy, but the nosecone never come off of the rocket, as can be seen by the two accelerometer blips from the primary and secondary black powder charges. We placed 4 grams of BP in surgical tubing, and it didn't seem to have the necessary kick to pop the nose off. Therefore, the ARTS board was armed and working correctly, and the charges did deploy, but there wasn't enough BP combustion to produce enough force to break the shear pins holding the nosecone on. 50k+ ft recovery isn't easy. But at least it made for some good pictures (and we didn't have to chase down the rocket 10 miles away and miss dinner at Bruno's!)

One last thing: We'd like to send out a huge thanks to the RRS (Reaction Research Society) and Dave Crisalli in particular. We wouldn't be able to do almost any of this without the help of these guys, and they have been extremely patient with our static testing--we really appreciate it. And Dave, we still owe you concrete anchors. Those will be repaid in full.

Holiday Update

2010-12-19T07:36:00.000-08:00

Merry Christmas (and happy holidays) from the Rocket Lab!

Rocket lab has been busy up to USC's winter break, turning out tons of hardware for our next static fire that will be coming up in mid-January. It was originally scheduled just before finals but due to a few timing problems in the construction process and an overwhelming amount of work that we did not feel like rushing, we moved the static fire to the first weekend after classes start in the spring. We hope to solve some issues we had with the last firing and move right on to a new project right afterward, so this is definitely an exciting time in Lab.

Also, a CDR for our next vehicle should fall at the end of January, if all things go well.

In other news, we finally retrieved data off of our avionics board from Silver Spur 3! First off, we would like to thank the guys over at Ozark Aerospace for going through all the trouble of deconstructing our ARTS board and reading the data off of it for us. The ARTS board was a complete mess when we sent it to them (after the rocket impacted the ground at over Mach 1), and they managed to salvage all of the data from it!

We couldn't be more excited to find out how it actually flew.

See the following plot. Using the accelerometer data shown below, you can see that SS3 hit a top speed of 4,500 ft/s at approximately 9,800 ft. That comes out to an absolute speed of Mach 4.2! Rocket lab is now just on the verge of hypersonic flight!

Acceleration was exactly as expected, hovering around 39-40 g's for most of the burn. The motor burned for just over 4 seconds, and our max altitude (based on accelerometer data) is around 59,000 ft. This doesn't account for the fact that the flight may not have been 100% vertical, but tracing backwards to where the barometric altitude starts to pick up again on the falling end of the plot, a more accurate guess of the max altitude may be ~56,000 feet. Regardless, this still is the fastest, quickest accelerating, and highest flying rocket the lab has ever built, and something from which we have learned volumes.

Keep checking the blog for updates throughout the next few weeks!

Third Time's The Charm - With Videos!

2010-10-13T23:22:00.000-07:00

Just a quick update on the post below this one about Silver Spur 3 - videos have been added to the USCRPL youtube account:

Also, check out a high-speed (600fps) video of the takeoff. You might want to skip further into it if it's taking too long - the ignition time takes a while at this high of a frame rate. Thanks to Nathan Bergey for shooting this!

Also, additional pictures are being added to RPL's new Picasa account:

http://picasaweb.google.com/uscrocketlab

Be sure to subscribe and check back to the Picasa albums as more photos are added. I hope to get some 'real old ones on there, too. So alums--you might be interested.

Also, feel free to check out our youtube channel as well:

http://www.youtube.com/user/uscrpl

Flight On!

Third Time's the Charm

2010-09-27T17:39:00.000-07:00

In a little more than three weeks, Silver Spur 3 (a.k.a. Super Spur) was conceptualized, designed, built, and flown by USC's Rocket Propulsion Laboratory. As is usually the case with RPL, those three weeks were incredibly hectic and tiring, but any member that helped build Silver Spur 3 would say that every second was worth it. Because of this latest project, we have learned an enormous amount about our capability to design high-powered, incredibly high-speed rockets, and this information will be vital to our future endeavors.

Mitch and Alec busy machining

Silver Spur 3 was designed as a follow-up to the all-carbon motor case rocket, Silver Spur 2. We had many design objectives, among them:

- Design and fly a working composite motor-case rocket
- Increase max velocity from Silver Spur 2
- Reach as high a max Q as reasonable with our 4-inch hardware
- Design and test different thermal protection systems for the vehicle, both internal and external
- Break our previous altitude record
- Design and fly a vehicle that can withstand enormous initial and burnout G loads

All of these primary design objectives were met with great success. Even though both previous Silver Spur designs had failed in one way or another, we still wanted to push the design envelope, especially with our composites technology.

For a detailed look at SS3, let's start with the aft end and move forward:

SS3 Design
The nozzle was a hybrid 6061 aluminum, phenolic, graphite, and G-10 assembly. This general design had been tested before in our Trunnion series static fires, so this was the first iteration to prove flight worthy.

The fins were a first for Rocket Lab, and we are happy to say that our design proved to be very successful. Because of time and size constraints, we opted out of using any type of core material for weight savings and went with an 81-ply construction for each fin, using donated prepreg material. In an attempt to reduce the chances of fin flutter, the fins ended up being proportionally a bit smaller than the fins on previous RPL vehicles. But the "first" for RPL was the incorporation of an ablative leading edge - we machined pre-cured strips of linen phenolic into a tapered interface that would allow us to lay up each ply around the phenolic, holding the leading edge into place. We had never previously tested any leading edge material with a flight vehicle before, and as the photos at the end will show, they ended up working very well. The prepreg carbon fins were still in great condition when the rocket was recovered.

The layup proved a bit tricky, especially because our film adhesive bonding the carbon to the phenolic was a bit messy to work with. But after cure, they ended up looking better than we all thought they would. After machining and a little clean up:

The fins before they were scorched from mach 3+ flight

The four fins were then attached to the minimum-diameter motor case by a five-layer tip-to-tip carbon layup that cured in the oven the morning we left. Let's just say we sure know how to plan out our timing.

Above the forward motor bulkhead, we have the recovery section, which consisted of just enough space to house a 48" drogue parachute that would give near 100 ft/s descent rate. We were afraid of the rocket drifting too far and were pretty confident that it would be able to withstand a tough landing, so we opted for this approach. Not to mention, with the body being ~65" long, there wasn't too much room left over for a much larger parachute.

Avionics was mounted in the nosecone, which consisted of an ARTS board that was attached to a threaded rod extending from the nose tip. A G-10 bulkhead provided protection to the ARTS board from the ignition of the black powder charges. The threaded rod was attached through a bonded-in mount that held the nose tip on to the 8-layer wet-layup carbon nosecone.

And for the nose tip, we machined a ~1lb titanium death spike (nicknamed the "death nub" after further design iterations shortened its length and added a 0.25" radius to the tip). This was another first for rocket lab, as titanium had never before been machined for use in any other vehicle.

And the motor was an all-carbon motor case design that Rocket Lab has developed over the past few years. The motor was an O5000, with 7 six-inch long Bates grains housed in phenolic casting tubes.

Trip to Balls 19

On Thursday night, the whole lab was busy packing up everything we needed, thought we needed, and didn't think we needed into about 8 vehicles while the tip-to-tip layup was being cured in our oven. Most of us spent the entire night (and several nights earlier that week) awake, busy trying to get everything in order and finish any odd jobs that required attention. Shortly after the rocket was pulled from the oven at about 3 a.m., we all left for Balls 19 up in Black Rock, NV. This was a notable achievement for RPL - for once, we left to Balls mostly on time! This means that the dry lake bed was still barely lit by the setting sun once we got there, which didn't happen last year when we arrived at about midnight. This made a less hair-raising experience as we all roamed the enormous dry lake bed trying to find the flight line.

Integration/Flight Prep

We woke up at about 7 a.m. to begin prepping the rocket. We still had some things to do, namely, start sanding up the tip-to-tip layup, actually test-fit the grains into the case (and hope they fit properly), integrate the avionics and recovery system, attach the nose cone and shear pins, 5-minute epoxy the death "nub" onto the front of the nosecone, and assemble the launch rail.

Integrating the rocket out at Black Rock, NV

Well, at least this year the launch rail assembly was painless. Because we built the entire rocket so quickly, very little time was available before we got out to the desert to actually assemble the rocket and test the recovery system. This is one thing that separates us from the rest of the guys out at Balls every year. We are always frantically trying to assemble (and by assemble I mean build) the rocket that we don't know will even fit together properly out in the desert. But it always seems to work out well for us (minus last year - but the weather also played a large part in that one).

Rocket is fully integrated and being walked to the launch rail ~1/2 mile away from the flight line

Flight

David Reese was right - as long as it made it off the rail, it would fly.

And fly it did! There were so many things that we didn't know (or didn't think) would work, but we proved ourselves wrong after SS3 took to the skies. It came perfectly straight off the launch rail, and took off like a bat out of hell. The initial thrust of the rocket was enough to make a sizable crater in the ground and throw dirt clods 14 feet in the air.

The flight path was nearly perfect, minus a little bit of what looks like precession right near burnout.

But the one thing that didn't work as planned was recovery. The nosecone never came off the body, and thus the parachute did not deploy. As we were frantically panning the skies with the Rocket Hunter, a group of guys drove up to our group in their ATV saying that they saw a black rocket sticking about a foot out of the ground roughly a mile or so away. That would explain why we didn't get a signal from the avionics...

Amazingly, the fins survived intact. The best thing about them were the burn patterns and the completely scorched phenolic leading edges. They were charred completely black from mach 3+ flight. There was a little fraying from the tip-to-tip carbon, but they looked perfect besides that.

The rest of the rocket was a fun project to dig out of the ground. It took us a while (thanks for the shovels!) to get the everything out, but what we found was very interesting. The nozzle slid all the way up the body tube and stopped at the front bulkhead, making the hybrid nozzle look like a SolidWorks expanded assembly view. About 50% of the body tube was recovered, and the nosecone caved in on itself. But luckily, the carbon was just crushed enough to save most of the ARTS avionics board that we might be able to get some data off of it! And the best part was the titanium death spike. It survived flight at over mach 3 and ended up plowing into the ground over 6 feet at sonic speeds and never took a scratch. It will definitely be a permanent fixture in our RPL "museum" that we keep in lab.

- You can see the charred remains of the phenolic leading edges and the frayed carbon around them

Because we still need to wait on data, we can only approximate what the real flight path was. After analyzing video from the flight, the burn time was approximately 5 seconds, which was a tiny longer than we predicted. Backing out the acceleration from how many frames it took the rocket to clear the pad, acceleration was ~42 g's with a 2000lb initial thrust spike. The speed of the rocket, using these numbers, would come out to be roughly mach 3.3 at burnout, and max altitude around 50,000 feet. And the impact would occur 2 minutes later at 660 ft/s. But again, these numbers are speculative! Hopefully usable data will come out of the ARTS board in a few weeks, and the official stats will be released later.

All in all, this was the most remarkable project RPL has completed to date. The rocket was built at breakneck speed (as is usual) - but the best part is that it worked. All of our new implementations: our carbon case, our ablative LE's, our titanium nose spike, our 4-part nozzle - all worked! It's so exciting to have something like this come off as a success. And it will be vital to the continuation of our next high-altitude project, because we know we are capable of building a rocket that can survive incredible speeds and high altitudes, even if it lands a little faster than we expect. And we're working on that one, too.

Late-night digging party in the desert to get the rest of what was left out of the ground

-Flight On!

P.S. - expect more data/pictures soon. And an updated Projects page to the website.

Last Minute

2010-09-22T03:36:00.000-07:00

In advance, I apologize for the lack of updates. Usually I try to keep this blog up to date but recently things have been busy.

Very busy.

We have designed and (almost!) built Silver Spur 3, and plan on flying it in four days in Black Rock, NV. This will be our fastest, highest flying, and generally coolest rocket to date. Built entirely from carbon fiber (including the motor case), the rocket weighs about 23 lbs empty. We have developed an ablative leading edge technology that hopefully will keep the fins from being cooked off from near-hypersonic flight, and have fabricated a solid titanium nose tip to help keep the carbon nose a bit cooler.

Again, we produced 99% of this rocket in house. Machined and laid up the entire rocket - about the only thing we didn't make were O-rings and the ARTS avionics board. This is something RPL has always been proud of, and we are excited to show off this rocket at BALLS 19.

Well, it's about 4 days until launch and its 3:47 am and we are working on getting the fins attached. And touching up the nosecone... oh, and the nozzle has yet to be completed. Hopefully we will have enough time to get everything test fit together. I kind of wish we had time to paint it, but it wouldn't really be Rocket Lab rocket if we did. We are always pushing the clock before a launch, and that's something that makes this organization awesome. When the rocket is done, it makes the all-nighters worth it.

Let's just hope it flies!

Here's some eye candy. A lengthy post-Balls report will be posted in a week or two. Keep following the blog!

Meeting

2010-08-27T10:30:00.001-07:00

1st Meeting Fall 2010

Meet in GFS lobby - we will move to a room from there

4:00 pm 8/27/2010

Summer Update

2010-07-23T15:30:00.000-07:00

Happy Summer!

With the coming of warm weather and summer internships, Rocket Lab has slowed down its killer pace to gain valuable industry experience and reflect back on what has thus far been achieved. In May, we pulled together a full scale static fire to continue testing for our latest project Traveler. In a stunning three weeks of hard, treacherous work, Rocket Lab showed that its members are able to accomplish anything, even if it seems impossible.

Testing out at the Reaction Research Society site in Mojave, CA proved to be an educational trip where we experienced a rapid unscheduled dis-assembly. We consider this to be a successful test in that we gained valuable information about the nature of carbon fiber that have allowed us to re-evaluate several aspects of the design to make our rocket flight ready and successful. As Thomas Edison said, "I have not failed. I have just found 10,000 ways that won't work." The purpose of static fires is to test what we have done thus far and see what can be improved or changed before taking the final step and launching. We have done that.

We were also able to prove a new nozzle design, which we see as a great success.

So with happy hearts and energetic minds, we look to the Fall, when we will bring what we have learned from our respective internships this summer to the table to create some of the best rockets a university will ever be lucky enough to produce.

Keep your eyes on this site, because in the next few months, we hope to dazzle.

-Sarah Hester

On To The Six Grain

2010-04-09T14:38:00.000-07:00

We have finally fired Trunnion, and it was an amazing success. Our first 8" composite motor has fired, and we couldn't be more excited to move on to our next project - a full length, 8" diameter, 6 bates-grain flight motor. Despite being on April Fool's day, the static firing of our 2 grain Trunnion motor went without any major surprises.This test-fire was not just an ordinary motor performance test. Firing Trunnion was a demonstration of USCRPL's own composite motor case technology, and luckily it was a demonstration of its feasibility and effectiveness. Everything went to plan - the integration of our equipment on site, the data-acquisition setup, the assembly of the motor and its hardware, and the actual firing.

The data we acquired looks great. The thrust curve looks beautiful (classic flat Bates-Grain profile), and within ~60lbs of our theoretical thrust calculations. The pressure and temperature data are also all within a safe range, and we believe that we are more than ready to move on to construction of our planned high thrust flight motor, which will be three times the length of this one. One note: The main difference between this firing of Trunnion and the one last November is the nozzle construction. The last design won't be flown because it was designed with a significant factor of safety and is therefore much too heavy.

On to photos of the launch!

A nice view of one of the bates grains

Jordan attaches an insulator plate to the top of the grain

This is Alec and Mitch's baby. The carrier is all steel, and you can see it heat up white-hot in the video below

Fitting the liner with the grains into the motor case

Ian Whittinghill and Dave Crisalli inspect the assembly of the motor

Joe readies the data acquisition hardware. We had three thermocouples, one pressure sensor, and one strain gauge

Assembling the thrust stand (informally known as "Jordan's Last Stand")

Mach diamonds!

Success!

2010-04-01T22:13:00.000-07:00

After setbacks and weather delays, Trunnion was successfully static-fired today. Countless hours of work went into this project, and we are ecstatic that everything went to plan.

Now on to the 6-grain......

We still have quite a bit of data to go through, so there will be more posted soon.

Work Goes On

2010-02-28T22:57:00.000-08:00

Rocket Lab lately has been a busy place. The largest time-consuming element of our work as of now has been Trunnion, but that is about to change. We are nearing completion of the rebuilt Trunnion, even though our firing date has been moved back several times. Unfortunately for us, Mojave has been inundated with enough water from recent rains that it would be too difficult to drive out there to test-fire Trunnion. And it doesn't seem like it is going to dry up too soon if we keep seeing the weather we have been lately. This means that even though we are ready to fire, we are simply going to have to move on to other projects.

But the rebuilding has so far been a success. Since we haven't been as pressed for time as we originally planned for, Alec and Mitch have been able to let quite a few other members try their hand at machining parts on the lathe. And the cleanup/preparation of the motor case has gone smoothly. The only thing left to do is to finish machining the nozzle carrier, and we will be ready to go (see pictures below).

Otherwise, we are getting steadily closer to launching Del Grande. The upper section of the body has been layed up, and we used a hi-temp mold release that more easily facilitated the fiberglass' separation with the mandrel. Also, we have finished work on the nosecone mold plug, which will soon be used to create a new nosecone for Del Grande.

Here are a few photos from lab:

Cutting our fiberglass casting tubes:

An insulator plate from the last firing: notice the aluminum droplets that condensed from the aluminum in the propellant.

A close-up of the droplets:

The nosecone mold plug being trimmed on the lathe:

Finished nosecone mold plug after a layer of fiberglass and tons of Bondo:

A newly-machined aft motor case bulkhead:

Del Grande in the background and the newly created body tube section ready to be joined together:

Machining the steel nozzle carrier:

Del Carbon is now hung up! Doesn't it look beautiful?

Tim, Vlad, Scott, and Jordan discussing Mach Madness designs:

Vlad working on a mach madness fin mold:

Trunnion and Other Projects

2010-01-25T17:51:00.000-08:00

As of now, Rocket Lab is mainly working on rebuilding Trunnion for a second test-fire in mid February. We will be using a new nozzle design that minimizes the effects of tensional stresses during the ignition stage of the burn. We will be using the same case as our previous static fire, which means we have to take apart and thoroughly clean the case before our next test, while also checking for damage from our last firing. Preliminary checks are looking good.

We also are nearing completion of the nosecone mold plug for Traveler. We plan on testing the nosecone design and manufacturing processes by flying it on the body of Del Grande, along with some changes in the avionics and recovery systems. Updates will follow as work progresses.

We finally have some photos of the Trunnion firing! (Thanks to Ian). Please enjoy:

Our thrust-stand setup, along with data collection system:

Static fire:

Now for some more recent photos: Mitch working on 8" nosecone plug:

Jordan attaches the thrust collector to a winch to pry out our de-pinned nozzle bulkhead:

Using mother nature to our advantage! (the trees were perfectly unharmed) - they helped us pry out the thrust bulkhead.

New Semester, New Lab, New Leaders

2010-01-12T22:30:00.000-08:00

The spring 2010 semester at USC has begun, and RPL has been busy unpacking materials from a move that occurred during winter break. We have moved one room over in RRB into a larger space, which is a blessing for RPL as it continues to grow in both project and member size. But with moving comes a lot of work. Our lathe was slightly damaged during break and we are short of space for our 8" mandrel, so machining parts and laying up fiberglass or carbon will have to be put on hold for the time being. Not to mention we still have to organize the lab and get everything unloaded from boxes and put back on shelves.

Hopefully we will have the lab back in shape within the week so we can continue work on the new nozzle for Trunnion. Also, Mach Madness rockets are in the process of a final design review and actual building will commence as soon as the lab is organized. Also, Del Grande will be fixed up and ready to fly within the semester.

We also have new leadership. Jordan Forness and Scott Macklin have taken the helm as Jordan Olliges and Chris McNutt have graduated from USC. We wish the best of luck to Jordan O. and Chris in their future endeavors--they provided invaluable leadership to lab this past semester and helped us get where we are today. We hope to continue where they left off.

Also, the USCRPL website has been updated. You may notice new header in the front page and the Projects and Media section have been changed a bit. More images will follow in the media section as soon as possible.

Flight On!

Trunnion Static Fire

2009-12-16T13:59:00.001-08:00

On Dec. 5, Rocket Lab traveled to the Mojave test area to static fire the Trunnion motor, a 1/3 scale version of Traveler's motor. The static fire included a brand new, scratch built thrust stand, the largest propellant grains ever made by the lab, and our all composite motor case.

Integration and assembly began early in the morning and proceeded without any problems. It was the smoothest, most problem-free integration the lab has ever experienced. Credit for this goes out to the lab for all their hard work, and to Chris and Jordan for their leadership and foresight to anticipate problems.

Most rocket lab launches remind me of eager little kids curiously playing with fireworks on the fourth of July. But this launch was decidedly different. We took a short break from our zealous experimentation to do real science. Our in-house built DAQ recorded thrust, chamber pressure, chamber temperature, and motor case temperature at key areas.

Trunnion performed beautifully, surviving intact through burnout. The entire lab gained invaluable experience fabricating Traveler components. All that needs to be done is redesign the nozzle retention, cast a new motor and we will be back out to try again.

Nothing can stop us from our goal!

-Jordan Forness

Del Grande Launch Video

2009-12-06T18:32:00.000-08:00

The video of the Del Grande launch back on October 17th, 2009 at the MTA.

Trunnion and Mach Madness

2009-12-01T11:43:00.001-08:00

Rocket Lab has been a busy place lately. Since our launch in October, we have begun (and almost completed) work on Trunnion, a roughly 1/3 size motor based off of the design for the Traveler motor. It is our first 8" diameter motor and should be a very impressive firing this upcoming weekend at MTA. Work is also progressing on our own custom-built thrust stand that will accommodate the enormous motor.

The design for the motor case is based off of research carried out by Rocket Lab in the past few years into composite motor case design. The case is comprised entirely by carbon fiber fitted with aluminum bulkheads.

This upcoming weekend during the static fire, we plan on monitoring the external temperature of the casing and the thrust produced by the motor with our thrust stand. We plan on thoroughly checking the casing for any deformities as a result of the firing that may need to be addressed before the test fire of the full sized motor.

If all goes well, we will start work on our full-sized motor, test-firing it by early 2010.

Work will also soon commence on getting Del Grande back into flying condition. We will need to re-cast propellant, machine a new nozzle, re-build a roughly 3 foot long section of fiberglass tubing that will replace the torn tubing as a result of the shock cords from last launch, and construct a new nosecone. Plans are to test the nosecone for Traveler by building Traveler's nosecone and flying it on Del Grande. This will also be a good practice run for our nosecone construction process - we will be using a mold this time as opposed to fiberglass wrapped around a foam core. Also, we expect to mount cameras in the body of Del Grande for some interesting aerial photography.

And lastly, Mach Madness. We have divided the majority of Rocket Lab into teams of 3-4 people that will be competing to build the fastest possible rocket they can from a limit of 5lbs of propellant per rocket. The design process is for the most part over, and the teams will soon commence building. We hope to launch these rockets sometime next semester.

As you can see, Rocket Lab has a lot on its plate. And with the upcoming departure of Chris McNutt and Jordan Olliges from RPL, we may have a few challenges ahead. But it's nothing we can't handle.

Photographs:

Jim Green is working on beveling steel sections of the thrust stand that will soon be welded

Alec Leverette is getting ready to machine a retention ring for the motor

Sarah Hester prepares to weld supports for the thrust stand

Close-up picture of the 8" composite motor case

Ian Whittinghill pays a visit to RPL, helping guide the construction of the thrust stand

Mitchell Kaundart machines the steel thrust collector plate that will be fitted to a strain gauge to measure Trunnion's overall thrust

Success!

2009-10-21T14:29:00.000-07:00

Del Grande finally took to the skies, leaving behind it an ecstatic group of USC engineers and a massive plume of white smoke. It was an enormously successful maiden flight, and we here at RPL couldn't be more pleased.

This is our first launch since fall semester of 2008, and it was an event long overdue. After our disappointment at Balls, we have been anxious these past two weeks to get this thing off the ground. But we are glad we waited, because the results were worth it.

Since we had about 2 weeks of down time between our trip to Balls and our launch at MTA in the Mojave, we decided there was still a large amount of work we could do on Del Grande to ensure it flew as perfectly as possible. Because of some errors in construction, we noticed at Balls that the position of the Cg was far enough aft to cause some concern. Jordan Olliges machined a large solid aluminum slug to fit into the nosecone, which helped balance the rocket. The nosecone was also a little uneven in parts, as was the fiberglass that was layed up along the sides of the fins where they connect to the body of the rocket, so we filled in these areas with Bondo (a hardening polyester resin that can be sanded to a smooth shape) for mainly aerodynamic purposes. Additionally, the rocket was painted a glossy jet black (possibly the most exciting change from Balls).

The weather at MTA was perfect. Here are some photos from the launch prep process the morning of launch:

Here, Scott and Vlad are readying the recovery system: particularly, the ejection charges for the nose cone ejection and parachute deployment

The rocket is readied for the insertion of the motor casing

Chris stands by the motor grains with Dave Crisalli, president of the Reaction Research Society and in charge of operations out at the MTA

The motor case is secured inside the rocket:

Joe Laurienti readies our avionics system, the "ARTS2" (manufactured by Ozark Aerospace - the only thing on this rocket not made by RPL besides the parachute), which will take care of the data acquisition and chute deployment at apogee. It is equipped with an electric ignitor for the ejection charges, barometric pressure sensors, and accelerometer. We also have equipped a radio emitter for our range finder (to locate the rocket once it has landed)

Ian Whittinghill is constructing a home-made ignition system, composed of an e-match and scrap propellant.

Pezhman Zarifian shows off the nosecone. Composed of a foam core wrapped in a fiberglass shell topped off with a 3" sharp aluminum tip, it is easy to see why it is usually referred to as the "death spike" among RPL members.

Del Grande being loaded onto the launch stand:

Del Grande finally in liftoff position. This rocket is enormous--easily the largest rocket RPL has ever built at around 15 feet tall. The launch stand was tilted approximately 10 degrees toward the west to make for an easier recovery near the road leading to the entrance of MTA.

Prepping the rocket went smoothly and we were ready to launch at around 11:30 am. Everyone headed for the bunker about 100 yards away to nervously await takeoff. And takeoff it did.

With approximately a 6 second burn time, Del Grande achieved a maximum speed of around Mach 1.28 and reached 22,900 feet, reaching Mach 1 at just 3.19 seconds after liftoff. Not bad for such a massive rocket.

Here are some more flight photos:

The flight path was gorgeous - almost perfectly straight. The weaves in the smoke trail are due more to wind shear layers than the actual flight path.

Here is ejection shortly after it reached 22,900 feet. It is actually that small speck right in the dead center of the photo - enhanced in the next image:

What's amazing to think about is the fact that the whole ensemble of rocket, shock cord, and parachute is well over 50 feet in length, and it looks so small at that altitude. The smoke at the top is the smoke from the ignition of the ejection charges.

A closer photo of the recovery phase

The rocket landed roughly 1.5 miles away - astonishingly close if our launch angle, prevailing winds, and altitude achieved are all taken into account. The rocket survived with minimal damage to the lower half but moderate damage to the upper half. The lower section looks used but barely has a scratch - the fins held up to the forces of the landing and the only evidence of supersonic travel is the peeled-back USC Viterbi bumper stickers.

We were less fortunate with recovering the nose cone. The nosecone was sheared off of its base (you can see from the foam and the protruding aluminum slug in the center), presumably at the ejection phase, and was not recovered.

Additionally, the shock cords "zippered" their way down both sides of the body of the rocket. Amazingly, the kevlar shock cords were in perfect condition after ripping their way through multiple feet of fiberglass.

All in all, it was an enormously successful flight. Del Grande exceeded everyone's expectations in both its flight, recovery, and condition upon landing. All of our hard work has finally paid off.

A full technical report on the construction, launch, recovery, and data analysis of the flight is underway and should be completed within a month.

Flight on!

Del Grande Launch

2009-10-18T16:45:00.000-07:00

Successful Flight!

Max altitude: 22,900 feet
Max Speed: 1,413 feet/second

More to come....