Rookie HPR mistakes

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I'm not trying to hear that!

Having worked decades at a job with unnegotiable crazy deadlines, I hear ya...actually I personally rushed my L2 build which was also very complex to make the last launch for the season at my club; however you adjust things according to your goals. I rushed some parts, but then made extra checks and I also didn't bother to paint/finish my rocket. I did it though and have no regrets since sometimes the biggest achievements are the ones that are the biggest challenges. :) 👍

However I'd like to get L3 one day, but in no rush to do so...I'd like to gradually work my way up and will make sure I first enjoy the rockets along the way.
 
Not resetting the Raven correctly to abort the air starts if things are not going as planned. Click on the picture to go to the flicker page and scroll down for more pictures and comentery by Steve Jurvetson. Steve is a regular at the launches and does quite a bit to promote rocketry!!!!



Is that your Giant Kraken????
 
And a near-miss:
-If an altimeter seems flaky, don't fly it. Pull it off the flight line and fix whatever's wrong. That saved a flight for me.
(I'm just starting this thread, so I'll have some comments on early posts as I go.)

As a corollary to this is the following advice: ask yourself, if the flight should go wrong, what's the first thing you'll check? If there is a ready answer to this question, check and fix it now.
 
Mine is:
-Never use an eye screw through a plywood bulkhead for chute retention, no matter how small the rocket is. Pulled out on the first flight. Fortunately, the airframe fell on soft sod without damage and the nose cone and chute were recovered a mile away.

There's nothing quite like watching the nosecone and chute drift away. The paper, z-fold, and glue shock cord attachment for a small Estes rocket failed. Builder error I'm sure.

No tracker. Yeah, I had installed a "tracker" but it was really just an altimeter (it's important to know, or in my case pay better attention, to your electronics... definitely had a derp moment). It was in a contest rocket (modified Aspire with a 60n or less limit).
It made it to almost 4,000' and that's where I discovered that using the wrong ejection charge ignitor<-- ematch makes a rocket a lawn dart. I had set it up as dual deploy (no motor ejection). We lost site of it pretty quickly. I found it two months later by estimating the track and distance with the simulation. I literally passed within 5 feet of it, walked about 10 yards farther, turned back to start a grid search and walked right to it. Luck counts. It was in the desert for 2 months, during monsoon season, but I recovered everything, stripped the parts out of it, and the second version is ready to fly next month. We redid the contest because of the 3 that launched, none came home. I "could've" won since I found my altimeter but I'm not all that competitive. We added the initial wager to the pot and we'll see who can get the highest altitude next month. Hopefully all three, maybe four, launch and return properly.

One thing I'm finding out about rocketry in general, every launch has a lesson.
 
How about forgetting to install the CTI Pro38 Motor into the Aluminum Casing BEFORE loading it into my Model.................
The day after my Cert Flight.......... at BONG Recreation area. VERY ROOKIE
I bet THAT is a mistake ..... a person ONLY MAKES ONCE !!

Here it is on a CTI PRO-38 H143 Smokey Sam WITHOUT the Motor Casing.............. Oops
Wow, I'm up to post #40, and this is the third or fourth time I've read that same thing. I'm amazed it's such a common mistake. The liner without the case would be a really loose fit in the motor mount, and doesn't have the thrust ring. Even without a checklist, how about just paying attention?

Probably the worst rookie mistake I have seen is not taking the advice of experienced Rocketeers at the field or, worse, actually arguing with the person that is going to do your cert.
Well... I agree, but not all advice from experienced flyers is made equal. I have a friend who took such advice - You should do it this way instead of what you've designed, analyzed, and carefully built - and in the post mortum it was exactly that change which led to the dirt dive.

So listen to advice. Take it seriously. But after many low and mid power flights, don't switch off your own good judgement.

More great assistance, thank you, gotta love TRF. It's the people people that turn a fun hobby into an obsession! I got my L1 and L2 with single deploy/motor eject rockets, and my current build is a dual deploy Darkstar 3, so this is all very helpful.
And therein lies another (avoided; well done) pitfall: thinking that HPR is fundamentally different and needs to have all the complications. You can often build a rocket with same materials and methods as many MPRs (or sometimes even LPRs) and fly it successfully on an H motor. Don't do this without due consideration of maximum forces, flight profile, etc., but also don't think of HPR as a whole new world of mystery wherein every flight must have electronic dual deployment, epoxy and fiberglass construction, etc.

@FlyBy01 I think Plugger is referring to that fact some people think JB weld is the gods of glue, and will use it on their whole model.. Like, everything! including generous fillets!!
Any why not? No, it's not the god of glues, or the glue of the gods, but it's pretty good stuff up to a point. It's what I used for my entire L1 rocket, a modified Big Daddy, with no problems at all. No, I don't use it for everything in all cases, but that time it was what I had and it worked just fine. Don't overthink things, and don't bother spending a small fortune on 17 different kinds of glue.

(OK, after writing this response to post #64 and then reading on, I see that the JBW question has been beaten to death before I arrived. But I stand by the last sentence of that paragraph.)

Well, that's enough for now. I'll move on to page four of the thread in a while.
 
Wow, I'm up to post #40, and this is the third or fourth time I've read that same thing. I'm amazed it's such a common mistake. The liner without the case would be a really loose fit in the motor mount, and doesn't have the thrust ring. Even without a checklist, how about just paying attention?

In reference to CTI 38mm loads being inserted into the rocket WITHOUT the casing......it's SUCH a common issue that, at this point, when it happens I put at least half of the blame on the RSO who inspected the rocket and signed off on the flight.
 
The original JBWeld product, the one that goes by that name alone and something like "JB Plastic Weld" or "J-B Kwik" or some such, is a goopy liquid or runny paste (whichever you'd rather call it). You undoubtedly had one of the other products.

Oh yeah, one more rookie mistake.

Asking "what is the best epoxy to use?" on any rocketry forum in the known universe. 😉
Even outside of a forum, ask ten rocketeers which is the best glue and you'll thirteen different answers.

Excuse me, do you have a moment to talk about our lord and savior, [insert your favorite epoxy here]? :headspinning:
No. No I do not.

Please forgive me, but I just can't helpmyself.
c. got distracted talking to a bystander prepping my rocket
Why was a bystander prepping your rocket?

But really, this is a discussion for another thread.
Is it? One rookie mistake worth mentioning is expecting to go two miles high and Mach 3 right out of the gate. HPR certification, at any level, is just a marking point on a continuous path to bigger, higher, and/or faster, not a sudden jump.
 
It's not hard to break Mach 1 and survive. But things get quickly out of hand above Mach 2 and Mach 3 seems be like a brick wall. But really, this is a discussion for another thread.
...<snipped>...
Is it? One rookie mistake worth mentioning is expecting to go two miles high and Mach 3 right out of the gate. HPR certification, at any level, is just a marking point on a continuous path to bigger, higher, and/or faster, not a sudden jump.
This thread is about rookie HPR mistakes and I was talking about construction techniques to go past Mach 2 and beyond. While wanting to do so may be a rookie mistake, my point was that the actual design and construction techniques to do so probably belong in another thread. To me, the appropriate discussion would be to have the rookie start with traditional HPR rockets and learn those techniques first, and then step up to Mach 2 and beyond. To try and incorporate all that in a rookie HPR thread just seems like a bit much.


Tony
 
I understand. It's not so much building wrong that's a rookie mistake as it is expecting, as a rookie, to use that information.

True that may be. The one I bought had two "film canisters" held together with a paper tube (potential rocket?). Just like in the 60s. There was no label indication on what consistently to expect.
Are you sure that was JBWeld? It sounds like PC7.
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Wow, I'm up to post #40, and this is the third or fourth time I've read that same thing. I'm amazed it's such a common mistake. The liner without the case would be a really loose fit in the motor mount, and doesn't have the thrust ring. Even without a checklist, how about just paying attention?
The 38mm Cesaroni reloads have the thrust ring built into the reload. It would be possible to install one into a rocket with an Aeropack retainer and not see anything amiss from the outside. Fortunately most people only make that mistake once.
 
We added the initial wager to the pot and we'll see who can get the highest altitude next month. Hopefully all three, maybe four, launch and return properly.

One thing I'm finding out about rocketry in general, every launch has a lesson.

Update... I rebuilt the first contest rocket that I called a lawn dart in the post above. Come to find out, it wasn't a lawn dart, even though the chute never came out. Compared to the arrival of rocket #2 anyway. The second iteration was a lawn dart. That's quite a site to see even if it is a little 29mm rocket. I hope I don't see another one. The second time was not a charm. She came in just as straight as she went up. The only survivable part was the fins. I sawed them out and installed them on my 3rd Aspire. I sent the TeleMini off to Keith and he recovered the data from the TeleMini even though it was not flyable anymore. The curve is kind of pretty in an OH s$&% kind of way. I posted it over on the MP forum.

I'm toying with the idea of launching Aspire #3 (though it will have enough mods that it's an Aspire only in name) with a 29mm I205. It'll have redundant dual deploy if I do. Club rules and all things considered, I'm fine with that. I don't have a good sim yet. I won't launch with out it...

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Going through the trouble of carefully folding a chute and carefully wrapping the hair-tie around said chute for the JLCR and then launching the rocket only to watch it descend with a neatly tied up chute bundle all the way to the ground realizing YOU FORGOT TO TURN ON THE JLCR IN THE FIRST PLACE.

I may not be a rookie but I sure felt like one at that point...


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Going through the trouble of carefully folding a chute and carefully wrapping the hair-tie around said chute for the JLCR and then launching the rocket only to watch it descend with a neatly tied up chute bundle all the way to the ground realizing YOU FORGOT TO TURN ON THE JLCR IN THE FIRST PLACE.

I may not be a rookie but I sure felt like one at that point...

Watching your L2 cert flight*, seeing a beautiful deployment and descent, and the relief when the JLCR open the chute - a beautiful flight. You walk to the rocket and everything's in great shape - except there's no JLCR. You forgot to secure it...

*OK not a rookie mistake... but dang I felt like one
 
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A couple of weeks ago I launched a rocket and as it was climbing out I realized I hadn't turned on the altimeter. Fortunately the motor ejection charge got the drouge out so it didn't come back ballistic.
 
A couple of weeks ago I launched a rocket and as it was climbing out I realized I hadn't turned on the altimeter. Fortunately the motor ejection charge got the drouge out so it didn't come back ballistic.
I‘ve done that. It’s why I use a checklist. Every. Single, Time.
 

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I used to use threaded rods glued to the side of the MMT for motor retention. Then place something on the rod with a nut hooked over the motor. One time I used a screen clip that hooked perfectly over the end of the motor of a Minnie Magg I used to have. Unfortunately it protruded too far over the end of the motor and actually interfered with the thrust and created a vectoring situation. This caused the rocket to veer off the rail much like rod whip. It veered so hard that it shattered both rail buttons and scratched the crap out of the body tube. More facepalm once I realized what I did wrong.
 
My favorite Rookie mistake was "After joining an R&d group at a major medical company, I was building test equipment to make Gamma detectors that could be near an MR.
I left a working piece of equipment we wanted to use, along with some huge power supplies on a cart, with a sign saying !!this can't be in the MRroom!!
On it, running, on a 30 ft extension cord. The other guys were at lunch. So, I set everything up, and go to lunch. :)
I return from lunch, to them prying the cart out of the bore of the mr, and the powersupplies were a smoking mess, lol.
I learned two things: Switching power supplies don't work in a 3 Tesla magnetic field, and PhD's don't read signs. :)
 
Avoid using "special" threaded fastners, esp. things that will need to be used at the pad or in the field. If you're using a bolt/screw/dohicky that needs a special connector, or needs a special driver bit to turn it, and you drop it and lose it, that could be then end of your launch before it gets off the ground. Yeah, a left-handed titanium metric tri-wing screw is really neat, but you're not going to find one at the local Ace. Standardize as much as possible; make them as simple as possible. Use straight slotted head screws instead of Phillips head if possible - you can use almost anything to turn them. And, as much as possible, use industry/hobby standard parts/connectors - you might have to borrow something out in the field. Pack spares for these as well!
 
Great thread idea!

Flew the "Remove Before Flight" flag attached to the arming key.

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