Yes I would agree. However, that rocket was a Apogee Zephyr and I have no plans on going real crazy on it.Threaded Plugged Forward closures are your friend...
Rookie HPR mistakes
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mperegrinefalcon
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Not reefing your shock cord enough
Forget to use motor case...
Citizen Baslim
Wife: No, you're burning money vertically.
Ouch. Good lesson material. Sorry about the rocket.
I am trying to figure out how this happened? CTI motor or pre-glued grains?
In aviation; I am just trying to learn from this mistake because we are all subject to error.
In my experience, usually it's a CTI motor when this happens. Unfortunately the reloads can be mistaken for ready-to-fire motors by people who are either inexperienced or are experienced but not paying attention.
That's what I was thinking and I use both Aero-Tech and CTI.
Not sure of the details yet as I had already left the event when this occurred. Wasn't my rocket. The finish on this rocket was flawless! As good as any custom car in a car show.
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Been there my friend !!
great thread, just read it again for the second time.
mustcomedown
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What does this mean in n00b speak, please?
It's a way of carefully arranging the cords so they deploy without tangling.
There are videos on parachute packing, check them out. People really care how it's packed if you are going to be hanging from it.
There are videos on parachute packing, check them out. People really care how it's packed if you are going to be hanging from it.
Being near the front-end of my (hopefully extensive) high power rocketry journey, I'm going to offer my insights into this while things are still relatively fresh in my head. I can almost guarantee that all of this has been said in this thread already. I apologize for the length of the post, but hopefully these items can serve as a resource to those interested in getting into HPR that may have found there way to the Rocketry Forum.
I have 2 general big takeaways, and a few bits of advice for those new to HPR:
Major takeaways:
An lastly, here are my few bits of advice I offer to new rocketeers:
I have 2 general big takeaways, and a few bits of advice for those new to HPR:
Major takeaways:
- Do not rely solely on your brain for anything at any point. Your body is capable of producing many chemicals that change the way your brain thinks, and for most of us, building rockets and launching them will create some of those chemicals, often times in mind-altering quantities. Do yourself a favor and create checklists and plans for things that you can follow. It's so easy to forget something small in the moment that may have a larger impact later on. While it may not be "cool" to be the guy at the pad with a clip-board and checklist, it's cooler than being the person unearthing their newly-25%-shorter rocket and freshly acquired core sample from your flying field.
- Assume all information is false until proven otherwise. The amount of knowledge and information in this hobby is vast, and as with all information, there is good and bad. Try to verify any information from multiple sources, and do your own research where practical to do so. Once you've found good information, don't just take what you need and move on; do your best to understand it well-enough that you could explain it to others, as you will probably have to do just that for an RSO if you're certifying HPR. If you want to spot check your understanding, pick any one item on a rocket, and ask yourself "why?" (or other simple questions) multiple times. You'll quickly determine your level of understanding within about 4-5 questions. Anyone can know something, but not everyone can truly understand it.
To give an example of this, let's look at an imaginary rocket's fins. The questions I'd ask myself are as follows, and here's a set of what I'll call not so great and great answers (not-so-great answer\great answer). The not-so-great answers are not wrong, but they do not demonstrate a good understanding:- What are those? Fins \ 1/4" Plywood Fins
- How are they mounted? With epoxy \ Using through-wall mounting and 2-part epoxy.
- What kind of epoxy? RocketPoxy \ G5000 RocketPoxy
- Why did you chose that epoxy as opposed to other adhesives? The instructions said to use epoxy and this one had "rocket" in the name. \ The tensile and compression strength of G5000 RocketPoxy are 7,600 psi and 14,800 psi respectively, which is more than adequate for this rocket. I personally prefer this epoxy in this situation because it makes really nice external fin fillets.
An lastly, here are my few bits of advice I offer to new rocketeers:
- Just because you planned a flight for a launch day doesn't mean you have to do it. If conditions aren't favorable, or something about the rocket is uncertain or concerning, don't launch it. Figure out what's wrong, and only launch something you're 100% comfortable and confident you rocket will operate nominally. We all get "launch fever." Don't let it be the reason you don't get a rocket back.
- Talk to people and ask questions, even if you think you know something and don't need to ask. Often times, other people will have valid opinions and insights, and it can make you a better rocketeer to gain other insights on things. (Also, for those of us who are typically anti-social, it forces us out of our comfort zones and gets us socializing. )
- High Power Rocketry is not a race to get all the certification levels as fast as possible. If you do "speed run" it, then you're only hurting yourself. The time spent between the levels is where you should be getting to know everything there is to know about that level. If someone wanted me to certify them level 2, I'd like to see that they've had at least 1 successful flight on a nearly-full or full impulse I motor.
- Surround yourself with rocketry media and people. There are a ton of rocketry groups and people on Facebook, Instagram, and many other places on the internet, as well as there being a lot of great folks/channels on YouTube doing rocketry (John Coker, RocketVlogs, BPS.space (Joe Barnard), Rockets Magazine, etc...). Even if you're just watching launch videos as opposed to in depth build guides, you can learn a lot just from watching. (Also, who doesn't love a good RocketVlog's CATO compilations?!) Many of the rocketry folks I communicate with on a regular basis are folks I discovered through Instagram.
- Support your local vendors at launches! They travel out to your event so you don't need to pay stupid-high shipping prices to obtain things. Supporting them at launches just makes them more willing to come back. Paying HAZMAT shipping is like losing an entire I motor with every order.
Spitfire222
I only lawn-darted once
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This is something I don't understand, and I've seen it in most hobbies I've participated in. Like the person who's never flown an RC plane but wants their first one to be a turbine jet. To me, those people aren't really interested in the hobby, just chasing accomplishments. And/or perhaps they don't realize that part of the aspect that makes those high-level things so cool and interesting is because of the journey it takes to gain that experience to successfully pull it off.
Do you regret doing your L1 and L2 two months apart? (No judgment from me, I'm just curious about the appearance of "do as I say, not as I do.")
I was almost hoping someone would mention it so I could elaborate, because I totally come across as a hypocrite.
I assure you it was not a "speed run" in my case, and in fact I had actually planned to wait longer before doing my L2, but sort of a perfect series of events lead to me going for it because I felt the time was right.I spent a while researching and learning everything I could about high power rocketry long before getting L1 certified. I've been flying low/mid power since I was kid (maybe 15 years total now), and moving into HPR was the next step, but it was a big/scary step. I'd need software for analyzing my designs, wood glue wouldn't be sufficient in all situations, rocket kits don't come with all the parts you need to fly them, motors aren't all disposable and have adjustable delays, etc... I told myself I'd research and learn everything I could until I no longer perceived it as scary, then I'd go for my L1. This involved basically attending launches, asking a lot of questions, wandering around this lovely forum, and using the L2 exam prep materials to gain knowledge. I basically had the L2 knowledge when I got my L1, and just didn't have any HPR flying experience. At the end of March, I made the rash decision to attend MDRA's Red Glare all three days, and I got quite a few level 1 flights in, working my way all the way through the L1 impulse range! I had flown my LOC Goblin on an AT I327 and it was a beautiful, straight flight! After seeing some other Goblin's fly on J motors at the event, I decided I'd use my Goblin for my L2 attempt, as bumping to a lower impulse J motor (AT J340) would only add about 500 feet to the altitude, and not increase the max velocity or acceleration too majorly. It seemed like an "organic" next step I was comfortable with taking, as opposed to rushing through things. Now that I have my L2, I'm going to slowly work my way up through the J-L impulse range in a way that I'm comfortable with (and is safe, obviously).
waltr
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I'm going for my L1, also on a LOC 4" Goblin, in a few weeks and like Aleks (akrachanko) I have been flying LPR & MPR rockets on reloads from D to G motors, Dual deploys, composite 2-stage airstarts and have been through both NAR & Tripoli L2 practice exams. Feel ready for L1 and L2 isn't far off.
Then do want to fly a range of H and I motors before L2. Earliest I see doing L2 is this autumn when MDRA is back at Higg's farm but may just be doing H & I flights then L2 in the spring. Was at Red Glare as an observer and crew for my local club members and did get the HP bug.
I have a few rockets that fly on an F67 as minimun but better on G's so want to fly these on H motors.
This is a great thread.
Then do want to fly a range of H and I motors before L2. Earliest I see doing L2 is this autumn when MDRA is back at Higg's farm but may just be doing H & I flights then L2 in the spring. Was at Red Glare as an observer and crew for my local club members and did get the HP bug.
I have a few rockets that fly on an F67 as minimun but better on G's so want to fly these on H motors.
This is a great thread.
This one is important. When I was flying RC airplanes we said "Take-off is optional, Landing is Mandatory". Same as flying a rocket.
Citizen Baslim
Wife: No, you're burning money vertically.
Glad you like it. I started it after not flying for a season (life got in the way) and when I came back I inadvertently placed the spacers under the motor instead of above it and watched a motor burn without creating pressure.
I would say this is conditional and each level is an accomplishment that should be sought after. I did my level 1 and 2 in the same day due to COVID-19 and after guidance from my club's president. If the method and knowledge level are at the right level I do not see why not. I am currently seeking my Level 3 but have talked with my TAP on what steps should be taken to get there. I like the idea of being mentored and providing mentorship to others. I am a pilot by profession so good CRM (Crew Resource Management) is the key to success in all things aviation with safety being priority. I think many folks get caught up in forgetting that we use an RSO and LCO. Going back to the theme of this thread the LCO saved my butt by a simple question "Did you power on your electronics?" Which went from a possible lawn dart to a beautiful parachute touch down.
I did my L2 a year after my L1. In the interim, I had still not launched many H motors and no I motors. So my L2 launch was pretty stressful. On the other hand, during the 3 years between my L2 and L3 attempts, I got a lot of experience with electronics and larger motors. As a result, my L3 was nearly stress free. I had a lot of confidence that things would work, and they did.
I have lost a few on the lines and I called entergy and they was happy to come get it down for me. All it cost me was a demo flight for the crew.
Not flying with backup charges. I ground tested ejection charges using a flight proven altimeter even had a flawless flight the day before. Then on the second flight the ejection charge, same size as the day before, didn’t push the drogue and main out all the way (I had a jlcr on the main). Not a lawn dart but hit hard enough to scare people and wreck a lot of the eBay including a featherweight GPS. I still can’t believe it.
I understand your concern, but I've been flying DD without backup for 15 years and although I've had an issue or two, it's never been a safety issue where something came down hard inside the flight line, which I consider a launch angle/wind conditions issue. If it comes in hard farther out than the launch pads, I consider that a definite issue, but not a safety issue since it was farther out than the safe distances. I certainly wouldn't consider that a rookie mistake. Just my thought on it.
Not a safety issue if it comes down further out?
Sounds like a dangerous game, relying on a probability distribution function as to whether to call something a safety problem or not. Redundant charges are good insurance.
14 second delays are not usually a good thing
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Need to make sure to thoroughly get the delay grain shavings out of the motor (hope I am saying that right) before adding the BP and not trust the RocSim 100% on the delay - well at least for the first flight. If the delay is 7 seconds or so - then that means it is not going to coast very much before it starts the descent The ejection charge blew after it hit the ground. No worries - my backup LOC 4” Goblin saved the day and I completed my NAR Level 1.
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I don't think that one needs to worry too much about getting all the shavings out of the drilled hole and the motor. It's an extremely small amount of propellant with a trivial amount of surface area when compared to the area of propellant exposed to the flame. Also, assuming that AT delays are still plain vanilla Black Jack, the shavings do not burn fast even under pressure, so overpressurization should not be a concern.
Edit: Apparently this may not be correct, see boatgeek's post #239.
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boatgeek
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I don't think that the shavings make a 7-10 second difference in deployment time, but they definitely can make a 1-2 second difference. Our TARC team found that clearing shavings made the delay times far more predictable.
Wow, I didn't expect that to be the case; thanks! And that gives another possible research project for anyone in HS/college: "Effect of delay propellant shavings on delay time in model rocketry". Thesis statement: Shavings left in a drilled delay decrease (or increase?) delay time due to <insert suspected reason>
Impress the teacher/prof by using the term "thesis statement." It's the specific hypothesis telling what shoulld happen, and why.
