Category: High Power Certification

Having successfully obtained my level 1 certification at the June launch of the Big Sky Rocketry Association, I began to plan for my level 2 certification.

I decided to use the same Wildman Darkstar Jr rocket that I used in my Level 1 certification, but decided to go with electronic duel deployment for recovery during the level 2 flight.

The motor I selected, an Aerotech J270W-14A, showed a simulated apogee of 6283 feet, which it would reach in 17.4 seconds at a maximum velocity of 86.3 ft/s.

I did a detailed inspection of the rocket to ensure that it hadn’t been damaged in any way during the level 1 flight, and found that everything was in working order, and aside from a bit of dirt and dust on one of the fins, the rocket appeared as new.

Having flown the Quantum in the level 1 flight, I was a bit more comfortable with its operation and began researching ejection charges in detail. I then began testing various charge amounts in live tests for both the payload and booster sections. After a number of tests, I determined the optimum charges were XX grams for the booster section, and XX grams for the payload section. The nylon shear pins I had purchased also performed correctly in all of the tests, giving me confidence they would work during the actual flight.

The last bit of prep I conducted was experimenting with various methods of folding the main chute to fit it in the payload section along with the Eggfinder GPS locator. The 50″ chute I used during the level 1 flight was a tight fit in the booster section during the original flight, but with some careful folding and compression, I found it would fit cleanly in the payload section and eject consistently.

I had been studying for the level 2 test for about a month before my level 1 flight with the intent to certify and then complete the written test after the flight, but due to circumstances outside of anyone’s control, the person with the tests had to leave the launch early so the test still had to be completed. My studying system involved memorizing all of the questions in the NAR level 2 Exam testing pool, and then taking the on-line practice tests for Section A, Section B, Section C, Section D, and Section E at least once a day requiring a 100% on all sections. Using this method, it wasn’t long until I could quickly answer all of the questions in the testing pool correctly, and I was confident I would have no issue with the test itself.

Having completed all of these preparations prior to the July launch date, I was very disappointed, but understood and agreed with the reasoning behind the decision, when the July launch was cancelled due to fire dangers. As the summer unfolded with one of the worst fire seasons in the history of the state, I was unsurprised when the August and September launches were also scrubbed. Finally, with some much needed moisture finally arriving in the September, the October launch was confirmed as a go. The night before the launch, the weather forecast warned of winds exceeding 20 mph shortly before noon and continuing to increase throughout the afternoon, so I made sure I had as much of the rocket prepped as possible with the intent to arrive, take the test, finish prepping the rocket and launch as soon as possible to avoid the distinct possibility of the launch having to be cancelled due to the winds.

My son and I then got up very early on Saturday morning to make the 4+ hour drive to the launch location. The drive was uneventful, and the day dawned clear and sunny. The wind was fairly steady throughout the drive, but appeared to be staying around 10mph.

Once at the launch site, and having checked in with the launch organizers (who I had already contacted to ensure that someone would have the written test available, and to let them know I was planning the cert flight), I soon found myself sitting at a table with a copy of the test. My son, who is currently in school, found it funny that “dad” had to take a test just like he did, and he wondered if I would remember how to do it. When I completed the test less than five minutes later and got a 100%, he decided that I must have been pretty good at taking tests.

With the written test out of the way, it was time to prep the rocket and get in line to fly. There were three other flyers attempting certification flights that day, two for level 1 with one planning a level 2 flight if he was successful, and one going for his level 3. Having done most of the prepping the night before, it didn’t take long to complete my checklist items, connect the blackpowder charges to the Quantum, connect all the batteries, and prep the rocket motor.

After watching three other rockets launch with out issue, it was my turn and I headed out to far pad. The rocket slid easily onto the rail, but it took a bit of time finding the right size rocks to position the nozzle of the blast plate. After arming the Quantum, and ensuring that I heard the proper sequence of beeps, I then inserted the ignitor, hooked it up (after confirming that the clips were not powered), and confirmed continuity.

 

It was then back to the line where I announced the rocket and motor details, and my son counted down and pushed the button. The rocket motor ignited very quickly and the rocket left the pad leaving a large circle of exhaust. The flame coming out of the motor was as long as the rocket itself, and while the sound wasn’t as good as an M, N, or O, it was still very impressive.

The rocket boosted straight up, and despite the steady winds, didn’t seem to be effected at all.

 

 

 

 

 

As the rocket continued its ascent, everything appeared to be proceeding as planned and the motor burnout was observed.

The rocket was visually tracked to apogee, and the two halves separated with the drogue shoot appearing shortly thereafter. The rocket was tracked throughout the descent, and the second ejection event was observed with the main appearing quickly and slowing the rockets decent. During the entire descent, the Eggfinder receiver was receiving GPS location details from the rocket, and the location continued to update until the rocket disappeared from view behind a nearby hill.

After entering the location data into my phone, my son and I began the hike to retrieve the rocket. After a small detour to help another flyer locate their rocket, we arrived at the location shown on the Eggfinder as the last known location. The rocket was not visible, but after holding the Eggfinder over my head, it began receiving updated location information, and the new location coordinates led us straight to the rocket.

The rocket was undamaged and a quick inspection showed that all of the components were present and appeared to have functioned as planned. After downloading the flight data from the Quantum, I repacked the chutes, put the rocket back together and began the walk back to the line.

Once we were back, Steve Shannon inspected the rocket and confirmed that it was in flyable condition. He then signed off on my NAR Level 2 High Power Certification Application.

After mailing in the certification paperwork to NAR HQ, I again received an updated card and then a level 2 pin. The pins are pretty cool, but I’m not sure where I’m going to end up putting them as I would hate to have them damaged.

 

 

The road to my level 1 HPR certification began with an impulse buy of a Wildman Darkstar Jr kit during a Black Saturday sale. The kit was fiberglass, looked awesome, and the price was low enough that it seemed like too good of a deal to pass up. Once the kit arrived, it looked even better than the on-line photos, and all of the various bits and pieces fit together nicely. Then the reality that I had no experience building fiberglass kits or what would need to be different when compared to more traditional low power kits sat in, and the kit went back into its box.

After obtaining and reading the book Modern High-Power Rocketry Vol 2, combing the internet for build threads, tips and tricks, and basically satisfying myself that I would at least have a general idea of what would  be required to build a high powered rocket, I pulled the kit back out of the box and began to contemplate my build.

The details of the kit from the Wildman website were as follows:

This fiberglass dual deployment rocket features a 38mm motor mount, making it a great L1 or L2 certification kit. Standing nearly five feet tall and measuring 2.1″ in diameter, it weighs just 4.5 pounds and can be flown on motors from H through J impulse.

This Kit Includes:

1 Fiberglass booster airframe

1 Fiberglass payload bay

1 Fiberglass coupler

1 Fiberglass avionics bay switch band

6 Fiberglass fins

2 Centering rings

2 Single-piece stepped avionics bay lids

38mm fiberglass motor mount tube

Filament-wound nosecone

 

I knew from the beginning that I would not be focusing on performance or any sort of “Wow” factor. I wanted to build the equivalent of a flying tank that would be able to survive as many mistakes as possible and remain in a flying condition. With that in mind, I began assembling the various components I would need for the build.

I decided to follow the steps outlined in a post I located on the rocketryforum.com website, where member Crazy Jim, AKA Jim Hendrickson, went into exquisite detail on how to build not only a fiberglass high power, rocket but this exact kit! The tips, tricks, various methods, and other details found throughout the thread, along with the step by step directions, including pictures, made the whole process seem less complex and by breaking it all down into small steps, it suddenly didn’t seem to be as overwhelming as it had in the beginning. The thread can be found here.

I had purchased an Aeropack 38mm motor retainer, appropriate lengths of kevlar, rail buttons, and some Rocketpoxy epoxy when I originally bought the kit, so it I had to decide on what hardware I would need to hook everything together, electronics, and finally parachutes for recovery.

I decided to attach the booster recovery harness directly to the motor mount using epoxy rather than trying to fit some sort of U-bolt or eye bolt into the tiny space between the 38mm motor mount tube and the 2.2″ body tube. After cleaning, sanding, and dry-fitting all of the parts together for the booster section of the rocket, I carefully labeled and marked the position of all of the centering rings, fins, fillet pull lines, rail button locations, and vent holes. I then followed the steps in the thread and the motor mount and fins quickly went from loose pieces of fiberglass to the complete lower half of a rocket. When it was all assembled, the fact that booster section alone was larger than any of my current low power or medium power rockets brought home the fact that this was going to be quite the rocket when it was completed!

The nose cone and payload section went together without any issues. I decided to make the nose cone bulk head removable and epoxied a piece of all-thread into the tip (it would have been nice to have a threaded aluminum tip, but my generation of the kit didn’t ship with one), and then secured the bulk head to the all thread using multiple bolts and lock washers. I then installed a u-bolt to all for the recovery harness attachment.

This left the e-bay section as the final piece to complete. It would have likely been completed earlier, but there were so many different ways of putting it together, and each had benefits and downsides, that it took quite a while to decide how to proceed. After reviewing multiple methods of constructing the section, and checking the price on the required hardware for each method, I settled on using a single piece of all-thread running down the center of the section with a u-bolt on both ends. Although this method wasn’t as elegant as some, it was cost effective, and all of the required hardware was available locally.

Now that the rocket itself was complete, I began to contemplate the actual launch and obtaining a motor for my certification flight. For those that may not be aware, many HPR motors are required to be shipped as hazmat, and the roughly $30 fee can easily double the cost of a single motor. Because of this, I contacted Steve Shannon with the Big Sky Rocketry Association to determine if their launches ever were attended by a vendor, or how their members purchased their motors. Steve explained their system of group ordering (the hazmat fee is the same if you order 1 or 100 motors) to save on shipping, and advised me that their annual group order was fast approaching. After making arrangements to be contacted when the ordering process began, I went back to planning for my level 1 cert flight.

Using the freely available rocket simulator software, OpenRocket, I created the virtual model of my rocket, updating the various section’s weight and center of gravity details, and began to “test” various motor options. Although I originally planned to use Aerotech reloadable motors, the costs of the motor cases and the lower price of the singe use motor began to make that option more appealing. After numerous hours tweaking various settings in the simulator and testing various motors, I decided on the Aerotech H-283-W single use motor. The simulation showed an expected altitude of 1232 feet with an 8.72 second time to apogee. This would keep the entire flight easily within eye sight, and would allow me to use the motor’s ejection charge rather than rely on an electronic device for deployment.

Having the motor selected gave me the final weight needed to determine what parachute to use for recovery. After trying various sizes of basic, flat, parachutes (or more accurately parasheets) in the simulator, I determined that a chute about 50″ would bring the rocket down at a safe 18 feet per second. The parachute was ordered and I began the process of constructing the recovery harnesses for both the booster and payload sections. Although I wouldn’t be using the payload section for recovery during this flight, I planned to attach the recovery harness to avoid any unexpected separations or other issues. I had originally planned to use kevlar for both harnesses, but I did not have enough on hand to provide the lengths I wanted for both harnesses, and after reading about the benefits of nylon (stretches, doesn’t zipper as easily), and discovering a method of using masking tape to provide burn resistance, I decided to construct the booster harness from nylon webbing and use the smaller kevlar webbing in the payload section where space was limited.

Although I had originally planned to fly the rocket naked (no paint), I had time to spare so I planned out and rattle canned a basic neon-green and black paint job. I also used Future floor polish to give the rocket a clear coat. It didn’t turn out too bad, and from launch distance, it looks awesome!

The final assembly pieces to come together before the launch were an Eggtimer Quantum flight computer and an Eggfinder mini GPS locator. Although the flight would use motor eject for recovery, I wanted to test out the Quantum and become comfortable with its operation for my eventual level 2 certification. I also planned on flying the rocket with the Quantum activated and an ejection charge loaded as an extra piece of insurance incase the motor ejection had some sort of failure. After assembling, testing, and familiarizing myself with both devices functions and basic operation, I mounted the Quantum in the e-bay and built an enclosure for the Eggfinder that attached to the payload recovery harness.

I then obtained some FFFF black powder and began ground testing my ejection charges. I researched methods of determining the amount of black powder required for the size of rocket I was attempting to separate and began the tests. It appeared that 1.2 grams of powder were sufficient to separate the booster from the front of the rocket without the nose cone hitting the end of the recovery harness.

The week before the launch date arrived, but the ordered parachute had not. The vendor stated that the order should arrive in time for the launch, but when it didn’t arrive on the day before the launch, plan B kicked in and a quick trip to the fabric store provided the nylon, while the local farm and ranch store provided a small diameter rope for shroud lines. After reading a few sites that detailed how to construct a parachute, I managed to build one and still get a few hours of sleep before leaving for the launch.

The launch was held at the Big Sky Rocketry Association’s Twin Bridges location, which is about a four hour drive! The launch was held on June 24, 2017, and the day was clear and warm.

After arriving at the launch site, checking in with the launch organizers, paying my motor bill and my membership in the Big Sky Rocketry Association, I began to get things ready for the launch.

I had created a check list to make sure that everything was completed, and in the proper order, and after confirming that the only item that needed to be witnessed was the motor assembly, I found a qualified witness, Andrew Horton, and completed the very simple assembly for the single use Aerotech motor under his observation. Once the motor was installed, I put the rocket together, confirmed everything was working properly and had power, had the rocket inspected by the RSO, and then proceeded to the launch pad.

The rocket went onto the rail without an issue (and I was thanked for using rail buttons rather than launch lugs), and after receiving a quick tutorial in how the club’s launch system functioned, the ignitor was installed, continuity was confirmed, and it was back to the launch control table.

After announcing the certification flight, the rocket and motor details, and the expected altitude, I began the count down and pushed the button! The motor ignited quickly and the rocket quickly left the pad only slightly weather cocking as it hit winds a few hundred feet up. The rocket was tracked to apogee and the two sections were observed to have separated and the main chute deployed. The rocket was then visually tracked during the descent while audio confirmation could be heard from the Eggfinder Receiver that the rocket’s on-board GPS tracking device was functioning properly. The rocket hit a few thermals on the way down, but stayed with-in line of sight until it landed a few hills over.

Once the rocket was down, I grabbed the Eggfinder Receiver, plugged the coordinates in to my phone’s mapping application, and proceeded to walk towards the last location where the rocket was observed. As always seems to be the case, the rocket was actually further away than it appeared, but the Egg finder system worked properly and updated the final location when I got close.  Using the phone’s mapping app, I was able to walk right up to the rocket.

The rocket did not have any visible damage, and after checking all of the fins and other components, I determined that nothing had been damaged during the flight and descent. I also could see that the Quantum had fired the ejection charge, and later review of it’s logs confirmed it had been fired shortly after apogee. After connecting to the Quantum with my phone, it showed the rocket had reached 1112 feet in 8.6 seconds with an average acceleration of 6.24Gs, and had landed 107.6 seconds after launch detection.

After returning the rocket, it was inspected by Andrew Horton and Dale Emery who agreed that it was undamaged and signed off on the NAR High Power Certification Application completing my Level 1 Certification.

After disassembling the rocket and cleaning out the booster and rear of the rocket, I watched a few more launches, discussed returning the next month to take the level 2 test (there had been some confusion and they didn’t have one available at the launch that day) and possibly do my level 2 flight, then packed the car and left for Idaho.

A short time after submitting the paperwork to NAR HQ, my new Level 1 card arrived in the mail, then shortly after that I received an unexpected surprise of a Level 1 pin.