Rookie HPR mistakes

[boatgeek]

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.

That would be an interesting research topic. It would be a challenge to get consistent enough shavings to give repeatable results. My operating theory is that the shavings get blown into the hole and delay ignition of the delay in the drilled hole.

 

[dhbarr]

Would expect S formula AT delays to show any such effect more than regular, and CTI delays to be between the two. Could be a fun hypothesis to test since you don't actually need to buy AT motors to buy AT delays.

 

[Neutronium95]

Would expect S formula AT delays to show any such effect more than regular, and CTI delays to be between the two. Could be a fun hypothesis to test since you don't actually need to buy AT motors to buy AT delays.

Aerotech delays are all the same formulation. The shorter delays are just physically shorter. Both Aerotech and Cesaroni delays burn at about 1/32" per second at atmospheric pressure.

 

[timster68]

If I may update my lesson learned, the true root cause of this flight failure was probably the motor selection. The AT H283 DMS has the lowest Total Impulse of the 38MM HPR DMS motors. Any other H motor would have been a better choice, even the H100 has 10% more Total Impulse than the H283. Again, if I have to drill out 8 seconds of the delay charge out of a motor, I probably need to choose a motor with more thrust to get more coast time - more altitude and some more forgiveness on the delay charge. I was soley using RockSim to select the motor, but with this experience I understand (like many other things) that I need to use other references (like the Aerotech Master Motor Index) to provide a complete reference for the motor selection.

 

[dhbarr]

Aerotech delays are all the same formulation. The shorter delays are just physically shorter. Both Aerotech and Cesaroni delays burn at about 1/32" per second at atmospheric pressure.

AT also has a slower formulation, as seen in e.g. the HDK23 found in F22-7J, G33-7J. The HDK22 and HDK23 are both .75 long, but you get an extra two seconds out of the HDK23 in those two reloads.

 

[Biodragen]

Welp, I still consider myself a rookie only being in this hobby for 2 years and being L3. I still am learning things as I go. many tweaks to what I already know.

I flew my LOC 5.5 Ultimate Buzz Dubbed the "Psychotic" on MWP this year. I had done the AV-bay set up previous day and all I had to do is connect the charges to the terminals and connect quick links.
While getting ready for flight I was having a conversation that actually caused me to be off my game in checking but a rocketeer friend even asked me if I checked the quick links. I also planned not to use the Drogue this time so it was tapped up.
With this flight I was using the Marshall GPS system and getting acquainted more.
For this round I used a K700 reload.

FWIW, Braden Carlson has this flight on video on Part 2 at minute mark 14:57. Flight went great and had a great whistle to it. It was the recovery that didn't go so well.
The booster separated and the rest went another direction and was about a mile apart.

What I walked away with is several things.
1- All was recovered and not one bit of damage to the booster (if you look for my build thread you can see why)
2- Use GPS on both halves just in case
3- Pay attention to what you are doing better and if distracted start over and check again and again if need be. Checking often can't hurt, sure its a pain but rewarding to say the least when you get your rocket back to launch again.
4- The more skilled you become the more confident you are which leads to cockiness and that is when mistakes happen

Mistakes happen more to the skilled or veterans than the rookies. The rookies are more careful in trying to make sure they did everything correct.

 

[RocketmanAleks]

Welp, I still consider myself a rookie only being in this hobby for 2 years and being L3. I still am learning things as I go. many tweaks to what I already know.

I flew my LOC 5.5 Ultimate Buzz Dubbed the "Psychotic" on MWP this year. I had done the AV-bay set up previous day and all I had to do is connect the charges to the terminals and connect quick links.
While getting ready for flight I was having a conversation that actually caused me to be off my game in checking but a rocketeer friend even asked me if I checked the quick links. I also planned not to use the Drogue this time so it was tapped up.
With this flight I was using the Marshall GPS system and getting acquainted more.
For this round I used a K700 reload.

FWIW, Braden Carlson has this flight on video on Part 2 at minute mark 14:57. Flight went great and had a great whistle to it. It was the recovery that didn't go so well.
The booster separated and the rest went another direction and was about a mile apart.

What I walked away with is several things.
1- All was recovered and not one bit of damage to the booster (if you look for my build thread you can see why)
2- Use GPS on both halves just in case
3- Pay attention to what you are doing better and if distracted start over and check again and again if need be. Checking often can't hurt, sure its a pain but rewarding to say the least when you get your rocket back to launch again.
4- The more skilled you become the more confident you are which leads to cockiness and that is when mistakes happen

Mistakes happen more to the skilled or veterans than the rookies. The rookies are more careful in trying to make sure they did everything correct.

One thing I've started doing and recommend everyone else consider is taking closeout pictures on your rockets while prepping your rocket for flight. First, make a diagram of your recovery system including all hardware/chutes/shock cords/nomex/etc... and make note of everything that is supposed to happen during deployment. When prepping your rocket, take a picture of each component as you complete preparation on it and put it in the rocket. If you fold a chute, take a picture, then load it in the rocket. If you close a quick link, add a torque line and take a picture of it, then load it in the rocket. Before heading up to the RSO, I will step through my diagram I made with my pictures I took and ensure everything is in the right place. I can make sure all quick links are connected to everything they're supposed to be connected to, and that everything is ready for flight.

I was lucky in that the incident that lead me to this was losing a Nomex blanket. At like $8, I consider it one of the cheapest lessons I've learned in this hobby.

 

[Handeman]

I pulled a good one at the last launch. Never turned on the JLCR. I have it in one of the protectors so you don't see any of the lights unless you open the protector. I attached it to the quick link, folded the chute, hooked up the JLCR, but never opened the protector and turned it on. No damage to the rocket so all was good, but that is probably something I won't do again, at least for a long while.

 

[dhbarr]

I pulled a good one at the last launch. Never turned on the JLCR. I have it in one of the protectors so you don't see any of the lights unless you open the protector. I attached it to the quick link, folded the chute, hooked up the JLCR, but never opened the protector and turned it on. No damage to the rocket so all was good, but that is probably something I won't do again, at least for a long while.

I write "JLCR?" on the tape I use to attach the igniter to the nosecone.

 

[Biodragen]

I pulled a good one at the last launch. Never turned on the JLCR. I have it in one of the protectors so you don't see any of the lights unless you open the protector. I attached it to the quick link, folded the chute, hooked up the JLCR, but never opened the protector and turned it on. No damage to the rocket so all was good, but that is probably something I won't do again, at least for a long while.

Been there done that. To one up you and its costly, it all works great but I have forgotten to tether my JLCR and lost it.
My mentor has done it too.

 

[KenECoyote]

Been there done that. To one up you and its costly, it all works great but I have forgotten to tether my JLCR and lost it.
My mentor has done it too.

I've spotted one falling separately from my friend's rocket and found it for him. I've also forgotten to secure one once.
Usually you won't forget the second time since it's a very expensive lesson.

 

[Tom Flint]

Using too small of a drogue which allows the rocket to fall with the booster above the nose cone section due to the drag of the booster's fins. Then when the main fires, it fires downward and deploys underneath all the other rocket parts causing the booster to fly into the main parachute, collapsing it.

 

[bschultz32]

When I volunteer as an RSO safety-inspecting rockets for flight, I often ask the flyer "Are you reasonably sure that everything that SHOULD be connected really IS connected?". The deer-caught-in-the-headlights looks I see are precious. It's not uncommon to hear the flyer respond "Now I'm not so sure. Gimme a minute to check." And it's not uncommon to hear the returning flyer say "Glad you asked, I found that X was not connected to Y." It can be an unforgiving hobby. You live and you learn.
Bob

 

[Antares JS]

On 38mm Aerotech reloads, the nozzle fits neatly in the nozzle o-ring. The forward o-ring fits neatly onto the lip on the aft end of the forward closure.

 

[Switch]

How does trying a 27 core 2 stage 1:65th scale Falcon Heavy as my second High Power Rocket qualify?

 

[bad_idea]

Congrats on getting it into the air (and on L1)! Better luck on the next flight.

 

[conneryc]

Mine was.... First dual-deploy after my Level 2 cert flight (J350 pictured over there <-----) was with a K550. Flight was great. Only problem was that I failed to ground test my charges, so only the drogue deployed. After falling from 3500' on just the drogue, a broken fin was the only damage which was soon repaired. Thankfully luck was with me that day as the rocket (RDS Northstar 6"x9' tall) fell into the staging/parking area and missed all of the cars and awnings.

 

[soopirV]

I've been out of the hobby for 4-5 years after obtaining my L2 followed by a divorce. I'm looking forward to getting back in to it, and have enjoyed this thread immensly...I've had a less-than-stellar track record, but am so thrilled to see that all of my mistakes have already been covered by page 2. I'm the type of guy who perseverates on things, and that last flight I took before hanging up my spurs that came in ballistic isn't that unusual. Thanks!

 

[Choco_mint]

Flight testing prototypes for my L1-L2 combo rocket (yeah its a bit unorthodox, there's a thread on it on this forum), had flown on a less powerful motor the week before, tried it again with more power to fine tune the DD, but didn't change the deployment altitude values on my SLCF... Drouge deployment at 300 feet and the main deployed at around 70... Safe to say that prototype never flew again.

 

[jmasterj]

Flight testing prototypes for my L1-L2 combo rocket (yeah its a bit unorthodox, there's a thread on it on this forum), had flown on a less powerful motor the week before, tried it again with more power to fine tune the DD, but didn't change the deployment altitude values on my SLCF... Drouge deployment at 300 feet and the main deployed at around 70... Safe to say that prototype never flew again.

Why wasn't the drogue set for apogee?

 

[Choco_mint]

I had set the drogue manually for the low-power test, according to what my simulation told me to expect (that's a rookie mistake of its own isn't it), instead of apogee... Clarification as well, the main opened at 70, not deployed.

 

[Seatechnerd83]

Was helping a freind with his DMS motor delay on his cert, accidentally used the drilling tool backwards and drilled out 2 seconds instead of 6, thankfully the chute deployed about 300 feet off the ground, but it almost came in ballistic into the ground.

 

[spigalau]

Not mine but someone local... large 2 stage rocket (M to N), 2nd stage used an aerotech 12v ignitor with pyrogen. Problem was local flight computer had a 3.7V LIPO. Guess what didn't ignite...

 

[fyrwrxz]

I'm calling this a rookie mistake, aggravated by flyitis. Super happy with my new bird, except I needed a 5 grain Cez case. Had the load already. Nope, no such luck. Seeing my delimma, Charley Savoy (Aerotech) steps up with one of the new (at the time) 38 DMS smokey, my fave flavour. My buddy, who stores every thrust curve known to man in his head, sez "that'll work". Hmm, free motor to demo, slides right in. What could go wrong? It did. Due to my custom construction, the retainer nut/washer/bulkhead/eyebolt was right against the ejection well. The bird had been already completely assembled and packed, and I didn't check the new motor clearance. Got a nice little extra boost thru the nozzle after burnout on a picture perfect lift off. Charley standing right next to me. We both said "Nice Smoke" then he walks off. I tell the chap next to me I'm looking for a chute at +9 seconds and he valiantly volunteers "It's already down". Diplomatic speak for cratered. Parachute and kevlar the only survivors. Rocket and pride in the dust. I feel stupid to this day for not checking a change of plans at the last minute. Total rookie move.

 

[KenECoyote]

Using a big drill bit on a thin piece of unsecured wood...especially in a bay with electronics behind said wall.



I should know better, but I was rushing because I had to leave for an errand and tried a grab and go, but ended up a grab and NO.

Ripped the bulkhead apart and broke off a terminal block on the dd altimeter I had just tested.

 

[Banzai88]

Using a big drill bit on a thin piece of unsecured wood...especially in a bay with electronics behind said wall.

View attachment 574540

I should know better, but I was rushing because I had to leave for an errand and tried a grab and go, but ended up a grab and NO.

Ripped the bulkhead apart and broke off a terminal block on the dd altimeter I had just tested.

I did something similar, and the drill bit went right into the lipo battery that I had just painstakingly mounted onto the sled. Wow, that thing flared up FAST, and I was lucky that I was able to grab it off the work bench and throw it outside into a bucket. BIG fire, total loss of the sled and electronics.

Certainly not my finest moment.

 

[AfterBurners]

Well, last month I was oblivious to the changing and increasing winds. I was so obsessed with flight prep and going "HSF" (high, straight, fast) that I overlooked the warning signs that the transmission lines were now in play. The launch angle was actually downwind a little so it would weathercock back to vertical. Lost 2 cameras, an RRC3, a JLCR, brand new CTI 6XL case and spacers, Aeropack tailcone, and a Marco Polo tracking unit.
View attachment 467638
View attachment 467640

wouldn't the city / county retrieve it?

 

[AfterBurners]

I've been out of the hobby for 4-5 years after obtaining my L2 followed by a divorce. I'm looking forward to getting back in to it, and have enjoyed this thread immensly...I've had a less-than-stellar track record, but am so thrilled to see that all of my mistakes have already been covered by page 2. I'm the type of guy who perseverates on things, and that last flight I took before hanging up my spurs that came in ballistic isn't that unusual. Thanks!

I've been out of it as well for about the same amount of time. Picked up Modern High Power Rocketry and it bleed the excitement back in me. We all must make time for the things we enjoy. This can be taxing when you are busy with other obligation, but having build goals help.

 

[mynameisfinn02]

Some of these tips also point to another big one I forgot in my first post...

-Don't start out in HPR. Fly at least a dozen LPR's of varying sizes and types before trying your first HPR. That experience will really help you avoid the dumbest mistakes.

I can at least honestly say that most of my early HPR problems stemmed from using materials I wasn't used to and not realizing I needed to supply motor retention separately. Spoiled by Estes!

Disagree (kind of), my first ever rocket was a cardboard + 3D printed thing on an I205. Recovered half on the same day then the other half a month later. It was dangerous but a fantastic learning experience.

 

[Voyhager3]

Using 5 min/not enough epoxy on the motor adapter!
(It's mostly fine)