While Rocketry Planet Forums and the Rocketry Forums are great places for rocketry information, the chatter is dominated by model- and mid-power rocketeers (nothing against that – I’m just more interested in high power) and high power wannabes (that’s me). On the other hand, the guys at Tripoli Quad Cities have some serious projects on their forums.
Here’s a great example: Terry Leright’s Gladys, a minimum diameter N-3180 to N-1100 two-stager. Terry documents the construction, including kevlar and carbon reinforcement on the tubes and fins, the stage coupler (the sustainer motor casing, which has a flush rear closure, extends backwards into the booster airframe). Here’s the interstage coupler:
The finished rocket (actually, he built two of them, but that’s another story):
On the launch pad at Black Rock Desert – I swear I’m gonna make it there someday:
And here’s the liftoff on the N3180 (photo by Ken Adams):
One of the coolest aspects of this flight is that Terry’s electronics – an R-DAS (the same unit I obliterated in my second USLI rocket) – maxed out on its pressure and flatlined the altitude. Terry knew the flight went a lot higher because the R-DAS data showed the rocket was still going 1200 feet per second when the altitude flatlined – that’s over 800 miles per hour.
Rocketeer and math whiz David Schultz took a look at the data and calculated that Gladys maxed out at about 70,000 feet. His methods are definitely worth a read!
Finally, here’s video of the flight, showing just how massive the acceleration was (Gladys flies around 3:40):
(Construction photos by Terry Leright, launch photos by Ken Adams)
Lee Scott just posted a link to the onboard video from his L3 rocket, the Cylcone, on his website. The video doesn’t appear to be on YouTube so I can’t embed it, but it’s one of the best quality onboard videos I’ve seen from a high power rocket so it’s definitely worth downloading.
When it grows too cold for rocket launches to be endurable, much less enjoyable, we rocketeers are inevitably drawn to rebuilding our fleets for the coming flying season. Unfortunately it’s a bit hard to use epoxy or spray paint when it’s freezing out, but hopefully over the next couple months I’ll have a chance to work on these projects:
From left to right:
PML 2.1″ AMRAAM (29mm motor mount) – this one lost the front of its main body tube a while back (windy, underpowered launch on a chuffing G33). I simply need to graft some phenolic tubing onto the front, and finish it to cover up the surgery.
My 2.6″ Fat Boy has a 38mm motor mount and is basically a fiberglassed version of the Estes kit. The reinforcement on the fins and parts of the nose cone is a bit spotty (fiberglassing plastic = poor choice) and I need to figure out how to pull off recovery and nose weight, so this one will require some work.
Above the Fat Boy is the body for a 1.6″ diameter Mosquito (the “Arkansas Skeeter”) with a 29mm motor mount – not the most sane of projects, and no clue when I’ll get it done and feel comfortable risking my hardware.
LOC Aura (painted black).I completely forgot that I had ever built this rocket until I went home to Arkansas for Christmas. I mailed it (along with some of these other rockets) up to DC so I could figure out a recovery system and start flying it – seems like it will be great for F, G, and H flights.
The short, dark tube with a long white tube is the genesis of a new project. The bottom section was originally to be an Estes Big Daddy – but with 4 29mm motor mounts. However, I’m not comfortable enough with my ignition skills to want to explore composite clusters on a rocket this short, and I’m not really that partial to the Big Daddy design. So, I’m going to extend this into a more traditional length 3″ diameter rocket. Maybe I’ll build in a timer bay so I can do air starts – maybe liftoff on 2 H128’s with 2 G64’s starting after a delay.
The next three tubes are for my as-yet-unnamed 3″ project. One potential name is I Lied About the Motor – just for the laughs I’d get at the flight line, and the uneasy questions I’d get at the RSO table. On the left is the remains of the crashed booster section, and on the right is the main parachute bay and nose cone – significantly shortened from a nasty zipper that’s been mercifully amputated. In the center is a 3″ coupler and a section of grey tubing I discovered while home in Arkansas for Christmas. Very luckily, this is a section of tubing that was reinforced with the same wraps of fiberglass and epoxy as the other tubes, but cut off to reduce excess length and then saved. I was quite happy to find this piece as it will make the rebuild much simpler, as this tube is already the same diameter as the other two.
Finally, on the far right is a scratch-built rocket I have yet to fly. It’s 2.6″ in diameter, built from LOC components, and has a 38mm motor mount and plywood fins. The unique aspect of this design is that it’s missing a section of the 2.6″ tubing above the fins. The 38mm motor mount has a total of four centering rings – two attached to the lower body tube and two bonded to the top, main body tube. More on this project later, but one potential name (with a paint design that would play off the rocket’s gaping hole) isZombie Bite – Grab the Vaccine! It’s going to be a good winter building season!
Since I last catalogued my rocket supplies, the Christmas season has come and gone. I got a Dremel, and various gift certificates that led me to get a new motor and a new toolbox. Then I turned around and bought another motor, so my hardware supply has increased a lot lately:
From bottom to top: Aerotech 24/40, 29/40-120 (both black and gold), 29/180 and 240 casings, 38/240, 360, 480, 600, and 720 Dr. Rocket Aerotech casings (all red), Aerotech 54/1706 casing (black), and the 54/2800 Loki Research casings (blue). The largest casing can contain 70x as many Newton-seconds of total impulse.
The two new 54mm casings were both acquired used for good prices. The 54/1706 can hold a K185 (for Lunch Money or my 3″ project) or a K550 (for the 3″ project only – I don’t trust Quantum Tubing enough for that treatment).
The blue Loki casing – my first – holds three reloads: the 7-second burn, 2500 Ns K350, the K830 Spitfire (2287 Ns, 2.7 sec burn), and the L1400 (2850 Ns, 2.0 sec burn), one of the largest 54mm motors on the market. Hopefully my 3″ project will be sturdy enough to handle the K350, which should take it to ~13,000 feet, but I’ll just have to build something a bit larger to take those other reloads.
This is a post about the most expensive rocket I’ve flown – and the most expensive rocket I’ve crashed. And this will also hopefully be the first of many posts chronicling the rebuilding process.
In college I worked on a few projects with Dr. Ed Wilson at Harding University, with most of my time spent on research involving the use of spectrometers to look at hybrid rocket motor exhaust plumes. So when we heard about NASA’s University Student Launch Initiative (USLI) – a systems engineering contests where university teams designed and built rockets to fly scientific payloads – we decided we wanted to compete.
For the first year of our participation in USLI (2007) we flew a 4″ diameter rocket with a hybrid K motor. However, our design kept getting heavier and heavier, so by launch day there was no chance we’d get close to the target altitude of one mile. The first flight was relatively successful – a solid flight on a K hybrid with safe recovery – but a connection between our spectrograph and the onboard R-DAS flight computer came loose, so we did not get any data. Onboard video from the flight is here.
For the second year of USLI (and my last year of college) we tried to improve on our previous design. Because our previous design was too heavy, we made our 2008 rocket 3.1″ in diameter instead of 4.0″. Because our many stressful hours working on our electronics payload were complicated by a difficult-to-access avionics bay, a major feature of our 2008 rocket was a new, easily-accessible (and see-through) bay design, pictured at left. [Note that some of the labels in the diagram are incorrect - that's an RDAS, not a Gwiz, for one - because this was an early version of the diagram before all the labels were corrected.]
Because the telemetry component of the R-DAS caused so many headaches in the 2007 rocket, and since we didn’t get data from it anyway, we decided to forego the telemetry unit in our 2008 project. Instead, we wired our custom spectrograph directly to the R-DAS, which was to store the data. All in all, it was a pretty complex payload, and in addition to the pricey R-DAS unit, the parts for the spectrograph cost over $1k.
From top to bottom, the 2008 rocket consisted of a 3″ nose cone, parachute section (separation at apogee, followed by release of the main chute by a ChuteTamer unit some time later), see-through electronics bay, spectrograph bay (sealed off from light), and the 48″ long 54mm motor mount. The spectrograph attached to a fiber optic cable that ran down the length of the motor thorugh an aluminum wiring conduit and emerged at the top of one of the fins. From there the fiber optic cable was taped (using high-temp electrical tape, I believe) to the outside of the fin until it was positioned to point directly at the exhaust plume.
Scientifically, the goal was to gather spectra from the flight that would be analagous to spectra obtained in ground testing, as a proof-of-concept for more intensive onboard spectroscopy experiments, which might eventually be useful as non-intruive inflight combustion diagnostics. You can learn a lot from the spectral data, including combustion temperature, propellant components, and the presence of uncombusted particulate matter.
Pictured above are the pre-flight prep and the pre-flight USLI safety check.
As the weight of the project crept upwards, we switched plans from using a Contrail 54mm J hybrid to the 54mm K555, the same motor used for the 2007 projected.
Two major lessons from my participation in USLI were: A) Everything takes longer than expected; and B) Test everything possible before risking expensive electronics in-flight. We had originally planned to finish major airframe construction approximately 2 months before the launch in Huntsville, Alabama. That would give us time to attend two launches with the Mid-South Rocketry Society in Memphis, TN (two hours’ drive east of our school in Searcy, Arkansas). We finished up construction and electronics work too late to make it to the first launch, and the second launch was rained out. So instead of flying the rocket first on a hybrid J or an Aerotech J350 – without the spectrograph on board – our first flight of the launch vehicle was to be a fully loaded flight for the competition in Huntsville. (Our crash, and that of another, larger project in 2008, probably contributed to NASA’s [wise] decision to require previous test flights for all competition rockets starting in 2009.)
The lift-off was perfect on the Contrail K555. The red and black rocket lept off the pad and flew straight up into the blue sky. My biggest concern prior to launch was whether our see-through, easily disassembled electronics bay design would survive the stresses of flight. When she hit burnout without shredding, I felt a surge of relief and let out a whoop. And then things went wrong.
I didn’t fly many rockets between LDRS in Argonia in 1999 (when I was 15) and the first year of NASA’s University Student Launch Initiative competition (when I was in my fourth of five years in college). I also didn’t keep up with the rocketry hobby/industry online as much during that time, so I missed some pretty outstanding projects.
One of the most extraordinary amateur rockets flown in the last decade was the Civilian Space Exploration Team’s Go Fast rocket, the first amateur rocket to reach space. It flew 72 miles at a max speed of Mach 5. (Documented at Derek Deville’s website.)
The Go Fast rocket was 10″ in diameter, 21 feet long, and weight 724 lbs, of which an impressive 435 pounds was propellant. In hobby terms, the motor came out to an S50150.
To get an idea of how high 72 miles is, check out this diagram, which shows the highest commercial airliners, highest military aircraft, and how high Go Fast went. Wowser.
Many projects this size are never recovered, or end up buried far underground. Go Fast’s payload section was fully recovered. The manpower involved in finding the space vehicle is covered at Stratofox, along with some fascinating analysis of the sonic booms created on reentry.
The video on YouTube includes these technical details from Derek Deville:
The motor produced a peak thrust of 16,000 lbs accelerating the vehicle at 23 g’s. At 10.5 seconds into the flight the vehicle was at about 40,000 feet and traveling at 3,420 mph (Mach 5) setting an amateur speed record. After motor burnout at 49,000 feet the rocket continued to coast upwards for an amazing 330,000 feet over 145 seconds before reaching apogee. All portions of the vehicle were recovered.
I just saw a few videos posted on The Rocketry Forum by Bob (see his YouTube channel). The basic idea is to launch a rocket (in this case, an Aerotech Mirage kit) with an onboard video camera either immediately before or after another rocket is launched, with the goal being to catch the other rocket in flight. Here’s the first attempt, with the “chase rocket” rather hard to see because it uses an Aerotech H220 Blue Thunder motor, which is nearly smokeless:
It gets better. Bob tried again and caught the smoke trail of another rocket flying on a longburning 54mm J90W.
But the best footage came from a flight of the Mirage on an H180, followed closely by a rocket from a Steve T on a Cesaroni green K motor. The results are impressive, making you feel like you’re in the video rocket with a much larger rocket being launched directly at you:
And here’s the slow-motion version of the same footage:
I’ve never seen anyone try onboard video with chase rockets before, so Bob and Steve may just have invented a new niche for high power rocketry. I hope we see many more of these. And eventually – if this becomes the next cool thing – maybe we’ll all get to see the chasing rocket shred, or even a highly improbable mid-air collision… but not with Bob’s rockets we hope!
[I guess I have basically two types of posts around here -> ones about the cool stuff I'm building/flying, and ones about the really cool stuff other people are flying. This is the latter.]
I’m slowing going through YouTube and the interwebs to find all the awesome projects that were flown somewhere, sometime that I’ve never heard of before. First, check out the Pershing flown at LDRS 27 in Argonia, Kansas. Interestingly, the put the frame on the pad, installed the motor, and then installed the skin over the frame. Some answers about why they built it they way they did (without any structural carbon fiber or fiberglass) are in this ROL Forum discussion. The description of the flight is great too: “there was an issue and the landing was hard.” Pretty cool project, but I still think the Pershing is an ugly rocket.
And here’s a video of a Q-powered flight at BALLS 2004 in the Black Rock Desert. Shadow Aero has this to say about the project in its gallery:
“Dave Triano of ShadowAero designed and built the amazing ‘Interstellar Overdrive’ Q motor project for Mike Hobbs and Randy Helmonds. The rocket was powered by a 8′ ‘Q’ motor by Frank Kosdon, and flew September 11, 2004, to an altitude of 100,000′. The minimum diameter rocket was a study in simplicity and efficiency, using an all-carbon fin can and nosecone created with special resin systems and ablative coatings. The deployment system worked as designed. It was composed of redundant XTime units intiating dual patent pending gas generators designed by Dave Triano.”
“The Frank Kosdon, Mike Hobbs, Dave Triano Q motor rocket was one of the most memorable flights. The 325 pound rocket was flown out of a halo tower and had about a 14 second burn with a long delay grain. Due to the extreme altitude that the rocket was flown to it looked like it was on a long arc, even though it was still climbing to well over 88,000 feet. In typical Balls fashion and typical Fran Kosdon fashion the rocket was only recovered on a 6 chute. They figured it would come back at about 135 MPH and they weren t worried about the condition after it landed, they just wanted it back. The Q project choose #1, they lost the rocket. Speaking with Dave Triano after the flight was interesting, the bottom line is that s how we do it out here . He had a track on it for over seven minutes and knows it is out there, someplace. He did say that they have a way of turning up again. We wish him luck.”
Greg Smith has one of the best blogs out there to feature high-end high power rocket projects.
For the last few months Greg chronicled the construction of Em-Sem-Fifty, a minimum diameter carbon fiber rocket designed around full-M motors. The second flight of Em-Sem-Fifty (after a warm-up on an L) was a drag-race on – what else – M750’s. The M750 is a long-burning Aerotech 98mm motor – 12.7 seconds of thrust! – and Greg’s flight topped 20,000 feet.
Here’s Greg’s time-elapse video of the flight prep and launch:
And Greg’s co-racer Frank Hermes’ video of the same flights:
The successful attempt followed repair work from some nasty zipper’s sustained on the first attempt. Greg also has some great failure analysis too – after all, knowing why your rocket failed is the first step to preventing future failures.
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