Tell us your biggest rocketry related blunder.

eggtimer rocketry
Shop deals on ebay
The Rocketry Forum

Help Support The Rocketry Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.
prfesser said:
Not me but a product of the rocketry club in 9th grade, of which I was a member.

"Lane", supposedly the most experienced rocketeer in our club, decided to make a 4-stage...Lane was red as a beet, teachers were white, I almost pissed myself laughing.
Click to expand...

We built and launched rockets in the 7th grade. I was the only one in my class who had any rocket experience. Most everyone built an Estes Alpha or Yankee or whatever. In an effort to show off my street cred I built an Estes Space Shuttle. The launch went fine but the glider didn't separate from the booster, and the whole thing came down under chute as one unit. To the average viewer it was fine, but to anyone who knew how it *should* have performed (perhaps only me and the teacher) it was kind of embarrassing.

I realized the problem was too much paint on the lugs that held the glider to the booster. After sanding them down I successfully launched it properly at home a week later.
 
The first rocket I ever built was an Astron X-Ray in March/April 1968. I was 9 1/2.

For some reason that seemed to make sense at the time, I decided to sand lifting airfoils on all four fins.

I thought it was going to put it into an awesome stabilizing spin. But, somehow, I had all four fins glued on with the lifting force going in the same direction.

So, as soon as the rocket cleared the launch rod, it pitched into a huge loop, with the circle getting tighter as it picked up speed.

I think it finished about two full loops before the motor cut out and it augured straight into the ground.

Happily, in 50+ years since, I've never made THAT mistake again. Plenty of others, but not that one.
 
muddymooose said:
Last year I successfully launched my LOC Warlock on a CTI I218 (shakedown) and J293 (L2 cert). In October I stuck a J360 in it. The launch was spectacular with a big Skidmark behind that short, fat, heavy rocket. It got up over 1500 feet or so, weathercocked into the stiff breeze, and then...kept going. No motor ejection, no separation. The whistling "incoming bomb" sound broke my heart almost as much as watching it slam into the ground, and then a second later hearing the distant "boom" of the impact.

It landed in a corn field and in spite of wandering around for a bit I couldn't find it. I'll probably go look for it again at the first launch of the spring. If the field has been plowed since then I doubt I'll find much.

In retrospect I realize now I should have supplemented the BP ejection charge to compensate for the large internal volume. I'm guessing that I got lucky on the I218 and J293 flights. I'm guessing the cold weather on the failure day was just enough to affect the nose separation on a weak charge. The previous two launches were on pretty hot days.

Until that point I had a perfect record since I got back into the sport the previous year. But then *just like that* I lost a $200 rocket, $100 Altimeter 3, $130 JLCR, $50 chute, $125 in motor hardware, and odds and ends for a big $600+ loss.

I really don't want to do that again.
Click to expand...

Corn fields are really tough to find rockets in, even when the chute comes out. Good luck.
 
Well, it all started in 1974, with a Centuri Sure-Shot igniter, a car battery, an Estes Launch Control system, and a 1-lb. can of my Dad's Black Powder . . . LOL !

Dave F.
 
I forgot to attach the parachute to the shock cord so the rocket fell and the parachute drifted off.
 
Nytrunner said:
Tha is for sharing John! This gives us great insight to the days of rocket history before motor retainers were invented!
Click to expand...
That is probably 15 years ago. I've been using motor retention in my test stands ever since. ;-) Never did find that casing!

One other interesting feature of that video is the giggling. It belongs to a high school kid who is now a senior test manager at SpaceX.
 
1988 test flight of my Sunguidance rocket. Did a 2-stage flight, D12-0 to D12-5. Took off fine, steering at the sun, then staged. Well, did NOT stage, the D12-0 popped off but the D12-5 did not thrust. So it began to fall. But it wasn't ballistic. As it gained enough velocity for the nose fins to steer, it began to pull out from near vertical to an angle, hitting the ground a glancing blow at about 30 degrees and skidding to a halt. Before it hit, there was a sound and some flame and smoke that burned for about 2 seconds. Most of the nose fins were broken off but the guidance system still worked.

I was puzzled at WTF had happened. Then suspected, looked at the bottom of the model, looked at the nozzle... or LACK of nozzle. Then it all clicked. I had not installed a D12-5. I had installed a "5-21D". That is.... the D12 was in backwards, nozzle-up, ejection charge down. The D12-0 had ignited the ejection charge, the time delay burned for most of the descent, then the propellant burned from just before impact to shortly afterwards, causing the noise, flame, and big volume of smoke.

And.... that flight and post-crash realization is on video (30 years ago and 160 former pounds or so). Flight begins at 1:10.

 
Last edited:
The first time I attempted an L3 certification flight, back in 2002, I was using an Altaac2b altimeter with a Transolve P6 as the backup. I had used this particular combination 4 times before in 4" diameter rockets with J and K motors. Back in 2002 we were having a very hard time getting black powder, so I decided to save money by preparing 1 apogee charge and 1 main charge, and putting 2 electric matches in the same black powder charge, one from the Transolve and one from the Altaac2b.
Now, if you remember the Altaac2b at all, and read the instructions carefully, you remember that it had a very interesting safety feature: When the Altaac2b got to apogee it would do 2 continuity checks,and if either the main or the apogee electric match was open at that point, it would fire the other one, thus ensuring that your rocket would not come in ballistic. I read that particular paragraph, I understood it, I thought that was a pretty good idea, but I didn't follow through and analyze the whole scenario.
So, I launched the rocket, the Spork I, powered by the amazingly inexpensive AMW M1850GG, at apogee the Transolve fired a millisecond before the Altaac, burning up all the black powder and separating the two parts appropriately. Then, the Altaac sensed apogee and found that the apogee ematch connected to that altimeter had been burnt up by the black powder, so it fired the main charge, putting out the main parachute at apogee. (about 6000').
About a mile or two down the road, I found the Spork stretched out over a public road and a hog pen containing 2 very ill-tempered boars. L3 cert failure, lots of territorial disputes with profoundly non-neutered male hogs, and lots of rocket parts coming home with pig poop all over them. Not one of my better days.

Alan Whitmore
Prefect, Tripoli East NC
 
What a great thread.

On my L1 cert flight I was launching a 48-inch rocket with a quantum tube body and rail lugs. I took down the launch rail and started to load the rocket and before it was 10cm onto the rail, the aft rail lug popped right off, took no effort at all, just popped off.

I was embarrassed at having to concede my L1 attempt to such a boneheaded mistake, so I considered (silently) trying to launch it with just the top rail lug. After a few minutes I regained my level headedness and aborted. I did a walk of shame back past the RCO/LCO with my rocket in hand and told them what happened. They assured me if I could reaffix the lug I could try again.

Of course I'd lost confidence in the epoxy I'd used. I had an electric drill/screwdriver with me, but of course I had no appropriately sized screws. I had three people offer me hardware (screws) to fix the problem. I drilled the lug into place, went out to the launch rail again, and had a successful launch.

So, not only did I learn a lesson (secure the **** out of your launch lugs,) but got an appreciation for the friendliness of other rocketeers.
 
Steve Shannon said:
This is exactly why we minimize the number of people at the pad and require disarming all charges before working on a rocket.

Edit: I’m sorry. I didn’t intend to sound like I was scolding. This is the kind of accident that frightens me the most, an on the pad ignition or cato with a bunch of unnecessary people there to act as additional victims. I’m glad everyone was okay.
Click to expand...

No worries thats completely understandable. However it was while arming the electronics for flight. The altimeter was mis-programmed with a very low LDA. It was a windy day so it was discovered that a gust of wind triggered the altimeter into thinking the LDA was reached and the altimeter went into flight mode where it shot the charges off for the drogue at “apogee”.
 
conman13 said:
No worries thats completely understandable. However it was while arming the electronics for flight. The altimeter was mis-programmed with a very low LDA. It was a windy day so it was discovered that a gust of wind triggered the altimeter into thinking the LDA was reached and the altimeter went into flight mode where it shot the charges off for the drogue at “apogee”.
Click to expand...

Interesting, what altimeter, what bay volume, and what size ports were used?
 
Forgot to put the tracker in a rocket. Then talked myself into the fact that is was only going 3000-4000 feet so I don't need a tracker. That would have been true if it when straight up. Not so true if it goes at an angle.
 
LDRS Hartsel, CO. don't remember which one it was maybe 1989, or 1990. Built a LOC K-Load rocket, put a Sony Handycam 8mm Video Camera in the payload. Built it with fiberglass fins instead of the stock plywood ones for strength. Named the Rocket L-Load due to the L585 motor flown with. The mirror shroud caused spiraling during flight, about 1/2 sec before burnout the tube coupler failed and re-kitted the rocket into a parts cloud. After inspecting the wreckage which totally destroyed the $900 camera. The videotape cartridge was found, later was able to splice some of the tape into another cartridge to try to see what did show up before the shred...Turns out the camera failed before the rocket left the launch rod. I found out that rotational force effects the rotation of the video head, which the camera sensed as a problem and it automatically shut down recording...would have had no video if the rocket recovered perfectly. THIS event is what prompted me to insist to Gary Rosenfield that we make the tube couplers for all the Aerotech kits THICKER and better. Still to this day kit manufacturers use crappy thin tube couplers without a smooth glassine outer layer. Consider this a note to all paper tube kit makers...the coupler should be at least twice as thick as the airframe tube...
 
My personal biggest blunder was twofold. As I've said before, I never forget a mistake, so I can keep making them over and over...

About 20 years back, the first rocket accelerometer became available. The thing was about 10" long and just fit into a 38 mm tube. In addition to deployment it provided a nice time-thrust curve. (Very useful back in the days when we were measuring thrust with a Sharpie and paper mounted around a popcorn canister, driven by a rotisserie motor.) Expensive, but I bit the bullet and ordered one. Used it on a couple of flights and it worked great.

Then I decided to fly my 2.6" L1 rocket on a DPS F motor. Rather than go through the hassle of electronic deployment, I elected to use motor ejection. Stupid; the motor ejected the parachute just fine, except that it occurred after the nose was about 8" into the ground. Which turned my expensive accelerometer into silicon-and-fiberglass junk. I could have hooked up an ematch to eject just after apogee, but nooooo, I was in a hurry to push the button.

So I bought another one. Its maiden flight was in a 4" rocket on a DPS I-motor. It screamed to about 3000 feet. I screamed when it core-sampled. Accelerometers don't work so well when installed upside down.

That was my last electronic device for a good while...

Best -- Terry
 
My biggest mistake was right after I got my L1 I was all excited and decided to launch it again same day same motor but I forgot to put the spacer in let me tell ya not much left of a cardboard V2 when a Skidmark turns into a sparkler. I still have what remains in the rocket hanging in work room as a reminder to double check everything.
 
Nytrunner said:
Interesting, what altimeter, what bay volume, and what size ports were used?
Click to expand...

It was built 4 years ago so I don't remember the exact specifications off the top of my head however the ports were sized accordingly to the volume of the AV-Bay. We used an Eggtimer which had an LDA set at it lowest possible setting which I believe was 50ft and this error wasn't caught while programming the unit.
 

Similar threads

ShakyShane99
Estes Mercury Redstone build/update
Replies
1
Views
487
Lord Rory Gin
Lord Rory Gin
Bruiser
Aim-4 G Super Falcon Build
Replies
27
Views
1K
Bruiser
Bruiser
tsmmiller
On the other foot, The car from your past you miss the least!
2
Replies
54
Views
1K
icyclops
icyclops
Back_at_it
Rocketry Works Toobish XL Build
Replies
13
Views
671
Back_at_it
Back_at_it
stealth6
For the cyclists here (who might actually care about such things)....
Replies
22
Views
466
Kabulrocks
Kabulrocks

Latest posts

Back
Top