Let's learn from our mistakes.

Two more mistakes on the same rocket!
1. I attached an 808 camera to a full sized GI Joe, around his belt. Like that would hold it upon ejection. Dumb! that camera is gone and probably has some wicked footage.
2. Second flight. I forgot to arm the Chute Release concerned it would time out before it made it to the launch pad when I we prepping it. GI Joe came out perfectly. The rocket however shattered one fin. Dumb Dumb Dumb.

In the future, if I do another camera, a tie wrap will go around the GI JOE Waistline.
IF I wait to arm the Chute Release, I will have a tag hanging off the rocket which will need to be removed prior to launch. Even if taped on as a reminder since the thing doesn't beep.

rstaff3 said:

By far my worst case involved not connecting all the recovery components AND not listening to my wife (which is always a bad thing).

My RocketMan Freedom to Fly came with a very short harness. Evidently he thinks shorter is better vs the uber long ones that seem to be in style. I had decided to add a longer section. I was prepping the altimeter and connecting everything together. In front of me was a bunch of parts that had to be hooked together. As I started, she asked, "should that be hooked up"? Well, I was looking a few loose items and responded, "yes." I proceeded and her attention moved either to a conversation, the rocket dog, or whatever. I stuffed it all in and flew it. Unfortunately, she was talking about another connection that I overlooked. The phenolic tube shattered and was replaced to good old cardboard.

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Similarly, I failed to hook up part of the recovery system because someone was talking to me while I worked on it. Since then, I try to be more careful about talking to others while they prep their rockets or talking while I prep mine.

Another lesson learned is to be very careful with two-part expanding foam. It always expands more than you expect.

-- Roger

When attaching a shock cord to the nosecone in a zipperless design... Make sure that the nosecone and the recovery bay are securely attached to each other.

My PSII based Cherokee D separated at the nosecone and recovery bay, leaving the parachute stuck inside the bay. I got lucky though, at probably the last possible second, the parachute pulled free and deployed (of course my camera's battery cut out at that exact moment)(I think the camera couldn't take the stress and passed out). My witnesses were many though... OROC's launch last September in Sheridan Oregon.

[video=youtube;3qrm-fAsqLI]https://www.youtube.com/watch?v=3qrm-fAsqLI[/video]

Thanks to the camera failure, you don't get to hear my next line... "I *MEANT* to do that!"

Not a problem I had out on the range, but one I'll try to save you from nonetheless...

For rockets with a payload section that uses either a balsa block, or an Estes-type blow-molded transition to secure it to the rocket... Seal the holes (either the single big one in the bottom of the plastic transition, or all the small ones in the balsa transition.

I've tested to see the parachute deploy on a couple of my rockets with just such an arrangement, only to watch as the nosecone (without shock cord or parachute) pop off. Had this happened in flight, the results would have been very bad. I was stunned when it happened with the balsa transition, and pissed too, the nosecone wouldn't have hit the hard surface it did has it been attached to the shock cord (I had to repaint it).

I learned the hard way that it doesn't take much torque to break a Missileworks rotary switch. When we clear-coated the nosecone the flush-mounted switches got coated. When I went to break the first one it turned past the detent breaking the switch. It was surprisingly easy to do - needless to say I was much more careful on the second one.

Even if you carefully label and draw arrows for the connections to your electronics for the main and drogue it won't matter if you don't bother to read them.

Getting main/drogue backwards wouldn't normally be too catastrophic unless...your main charge is weak, fails to get the main out at apogee, but then drag is sufficient to get the airframe kind-a separated into three sections, and then the drogue/main/whatever/second charge blows past the other chute. L2 failure.

Fortunately, the rocket survived and made a successful L2 flight a year later.

--David

I found it wise on fins with a similar length root, trailing, and leading edge to mark the root,trailing, and leading edge BEFORE glue up.

I like to mount my shock cord to the motor mount. seems when I slow down I remember to do that before the motor mount is glued in I don't have to reinvent shock cord mounts.

Every time I remember to attach a launch lug before painting I feel like celebrating. I haven't forgotten one yet, but I have come close and feel like it's inevitable....

jpbell said:

I forgot to put a launch lug on a rocket and didn't realize it until I got ready to launch it for its maiden voyage...not a deal break by any means but a huge disappointment when I realized it...

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HAhA! I've been there! It's a real WTF moment out on the pad, especially if they are waiting for you to rack. Walk of shame.....almost as much fun losing the igniter somewhere between the RSO and the pad. Yup, been there-done that!

fyrwrxz said:

HAhA! I've been there! It's a real WTF moment out on the pad, especially if they are waiting for you to rack. Walk of shame.....almost as much fun losing the igniter somewhere between the RSO and the pad. Yup, been there-done that!

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Yeah, I did that once. Not a club launch, just a local field with the family. Still, very frustrating!

jadebox said:

Another lesson learned is to be very careful with two-part expanding foam. It always expands more than you expect.

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Oh, my gosh! I wish I had taken pictures when I put that stuff all down the sides of my rocket onto the basement floor!

I haven't had enough experience to have any really bad screw ups, and they've all been inexpensive low power kits, so it hasn't been too much of a disaster. But on just about every build, I do something that makes me swear out loud, because I didn't mean to do it.

First time I installed an ejection baffle (3-D Rocketry Nautilus II), I was so nervous about getting it built solidly and in the right spot, that once it was in there, I realized I had forgotten to tie on the Kevlar shock cord. I peered down at the screw eye, now mounted on the baffle but serving no purpose.

I just got some elastic and made a teabag mount, which lasted the life of the rocket (two launches, before it ended up in a tree).



Apart from that, it's been a little CA on the fingers, a few chipped fins, and a few crooked fins. Also, launching too high in windy conditions. It's like I couldn't stop myself. I've gotten better at that.

During the night when your prepping rockets for next day launch, skip the cocktails. You forget what was done and have to recheck everything again. Actually a good habit I have is to put post its on the fins stating what was done, what needs to be done and what motors are going to be used.

My most recent Rocket related mistake was not understanding the concepts of gearing ratios needed for lathing things.
What makes it doubly sad is that I actually used to make small parts on a metal lathe sometimes, so I should have remembered some of the basic stuff.
It was just like the time I mixed a "too Large In The Same Mixing Container" Batch of BSI 15 minute, then blamed the Epoxy for going Chernobyl on me.
I'de made that mistake before, and attributed it to my eyeballing the measurements incorrectly. Many a batch was wasted before I settled on just eyeballin' it but in only tiny batches.
Turned out, I was just a fool for "Eyeballin" it at all. Cavecentral set me straight with graduated measures of appropriate scale and aspect, along with Pipets, resembling turkey basters. I had seen these for sale on Amazon, but until I started using them, I did not even know how much epoxy I was wasting. They are now a Required Item on the Required Items Checklist.

Many rockets I started and I made many mistakes. But most I regretted when it turned out that the memory card of the phone is full and interrupted the filming of the flight
Another big problem is impatience.On the other hand, and the large waiting is not good. For example do a rocket two weeks and finally it turns out that it does not fly properly. Also a big disappointment.
P.S.Some enjoy the process of construction or design. I am glad only one-rocket flight. If there was any deal instead of me, assembling and I just launch and then watch the video would be great

FYI- A motor tube does NOT need the spirals filled and sanded. Too many tubes on the build pile from too many rockets caused this one. I guess i coulda marked it or something....:bang:

What I learned today: When building a more complex model like the Cosmic Interceptor, finish/paint the pieces as much as possible before final assembly. Going to be 10x easier than having to try and sand all those nooks and crannies.

fyrwrxz said:

FYI- A motor tube does NOT need the spirals filled and sanded. Too many tubes on the build pile from too many rockets caused this one. I guess i coulda marked it or something....:bang:

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Oh, that reminds me .... don't confuse a coupler tube for a motor tube. A 98mm motor won't fit in a 98mm coupler! (I had to make the rocket use 75mm motors.)

-- Roger

I papered some fairly large fins with Avery label paper. This worked very well for smaller fins on sport rockets but this time it wasn't so good. A few days after the fins were glued in place and fillets completed, I noticed the paper lifting in spots. Annoying as heck considering the rocket was semi-scale. I'm not sure if there is a fix for this so I'm letting the spots be. It's only cosmetic after all. My advice though, would be to either use wood glue with paper or simply use a balsa filler such as aerogloss and sand the heck out of the fins.

The day before yesterday, August 13 did the dumbest flight in my life. I taped wires coming out of the rocket with tape so as not to move during transport. At the start I forgot to come off. Accordingly, the rocket remained tied for the guide and took off. 14 yesterday did more stupid flight. I put the rocket 2 Onboard cameras.
But do not attach enough and momentum still in the active part of trajectory one comes off. This modify the trajectory of the rocket directed toward the ground. 2 cameras , one was totally destroyed both microcards destroyed.Recovery system destroyed, nose destroyed. Engine and fins no damages.

SaturnV said:

The day before yesterday, August 13 did the dumbest flight in my life. I taped wires coming out of the rocket with tape so as not to move during transport. At the start I forgot to come off. Accordingly, the rocket remained tied for the guide and took off. 14 yesterday did more stupid flight. I put the rocket 2 Onboard cameras.
But do not attach enough and momentum still in the active part of trajectory one comes off. This modify the trajectory of the rocket directed toward the ground. 2 cameras , one was totally destroyed both microcards destroyed.Recovery system destroyed, nose destroyed. Engine and fins no damages.

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That sounds like an awful weekend. :wink:

You have simple rocket and must be connected only 3-4 cable or only push 1-2 buttons? You need the checklist!
1. do this
2. do this
............
Otherwise this will happening.
[video=youtube;7mwvGyDQa5w]https://www.youtube.com/watch?v=7mwvGyDQa5w[/video]