My most horrific model rocket crash.

[Dr.Zooch]

In flying model rockets since 1969, today I had my most horrific crash ever. It was at the monthly MDRA launch.

The model was the two stage D to E launcher that is often seen in my videos. The payload was my AOB (Ants OnBoard) flying TV studio. It consisted of a cam from boostervision.com, a mirror, a stage light, two ant-stronaut couches and two ants in their F4-B ant spacesuits. Below the studio was the 9 volt battery for the cam, some button cells for the stage light and the needed switching equipment and wiring.

The ants were working on my next spoof video and had just flow in my up-scaled Orbital Transport glider while being videoed. They did a great job. Where some ants just cower down in the F4-B, these two were faces and feelers out the visor looking directly into the cam- very active. So I decided that on the next flight, they'd do the AOB- which I've flown a dozen times.

I loaded them up with the most active one being closest to the cam (this rig has a side-view arrangement) and the launch went... As the rocket cleared the rod it very clear that something was wrong. The D12-0 was boosting poorly and the climb was way weak. It arced over and I thought it was simply not going to stage- instead, it staged, pointing almost horizontally downward and about 30 feet off the ground. The SRBs fell away and the second stage pile-drove into the ground under power and continued to thrust for a second or two, then it did the delay and exploded.

Since I had a cam going, they'd launched me first- so I had to wait until the low power and high power racks had been launched before the feild was safed and I could go out and get the pieces. While I was waiting and watching the wreckage smolder out there, I thought to myself "Those were two good little ants. They worked well with the cameras... right up to the point where I drove them into the ground under rocket power."

When I got to the crash site- it was bad- REALLY bad. :y:The impact had squished all of the tubing. The nosecone where the studio was contained was like half a smashed eggshell with the entire workings of the studio smashed into the end of it. The 9 volt battery was mangled as if someone had taken a pair of pliers to it. The engine compartment saw the E engine shoved about 6 inches up the tube and the resulting exhaust had burned away most of the fin area. It was a nightmare that I scooped up and took back to my table.

I went digging for the ants among the wreckage....

What I found was amazing. The first ant was still in his F4-B suit which was rattling around in the nosecone's remains, and was alive and well! The second one was still in the couch, and was also alive and well!

It's amazing- the entire rocket totally smashed and burned, and the only parts that were undamaged were the most fragile of all... the ants.

I have no idea why that D12 burned so poorly, nor why the staging was so strange. The engine nozzle appeared intact, but there was a good deal of unburned propellant in the forward end of the engine. In reviewing the onboard video I have seen some motions imparted on the ants that seem out of place- additional study of the frame-by-frame will be required.

When I got home tonight I released the ants where I'd caught them- they seemed fine... but I went out later and dropped a Tylenol near the nest... just in case someone may need it.

 

[shreadvector]

It is impossible for a D12-0 or any other black powder booster motor to have unburned propellant left in the casing. If any of the propellant burns, the rest will burn. if the grain ejected out the top it would be completely consumed like a roman candle ball. If the casing split, the grain would fly out and generally upward like a roman candle ball.

If the nozzle eroded (was it the white powdery "Poopy Clay" from manufacturing year A or B ?) then you could have had a serious loss of thrust. if it eroded asymmetrically then you would have loss of thrust and it would force it off course or unstable.

If you really think you have unburned propellant in the booster casing, simply take it to a BBQ grill and try to ignite that propellant. You can also inspect the alleged propellant first by removing it and seeing it it crushes and what it looks like.

One way or another, it's M.E.S.S. report time.

 

[shreadvector]

2 more things:

1) You can also get really poor performance if a BP motor is soaked in 100% humidity for many days. The total impulse remains the same, but the thrust level goes way down and the burn time gets longer.

2) This thread should be moved to Mid Power. :2:

 

[RangerStl]

All the goop I've seen left over in a casing has been ash of some kind, either from the propellant or from the couple layers of paper that get charred off the inside.

The only way there could be unburnt propellant stuff in there is if the propellant slug was almost all carbon which means Estes somehow left out the KNO3.

That seems pretty unlikely. :confused2:

Could you investigate the leftover crud further perhaps by dissection?

 

[Dr.Zooch]

It is impossible for a D12-0 or any other black powder booster motor to have unburned propellant left in the casing. If any of the propellant burns, the rest will burn. if the grain ejected out the top it would be completely consumed like a roman candle ball. If the casing split, the grain would fly out and generally upward like a roman candle ball.

If the nozzle eroded (was it the white powdery "Poopy Clay" from manufacturing year A or B ?) then you could have had a serious loss of thrust. if it eroded asymmetrically then you would have loss of thrust and it would force it off course or unstable.

If you really think you have unburned propellant in the booster casing, simply take it to a BBQ grill and try to ignite that propellant. You can also inspect the alleged propellant first by removing it and seeing it it crushes and what it looks like.

One way or another, it's M.E.S.S. report time.

First off- I was incorrect in using the term "a good deal of unburned propellant" that is a good deal of propellant by the standards of someone who has flow THOUSANDS of dash zero boosters and NEVER before seen anything like it. What was there was a crescent of material ~1/8 wide that arced about 1/4 the inside diameter of the motor. I pushed on it with my finger to see if it was soot or burned material. It was hard and would not chip away.

Next- I tossed the spent motor.

Next- I know all about "poopy clay"

Lastly- I try to never use the word "impossible." To do so, as it was used, in this thread implys that I am publishing a lie. As a person who makes a habit of not lying, I find that opening remark provocative. I sincearly believe that is not what you were trying to do... correct?

 

[shreadvector]

First off- I was incorrect in using the term "a good deal of unburned propellant" that is a good deal of propellant by the standards of someone who has flow THOUSANDS of dash zero boosters and NEVER before seen anything like it. What was there was a crescent of material ~1/8 wide that arced about 1/4 the inside diameter of the motor. I pushed on it with my finger to see if it was soot or burned material. It was hard and would not chip away.

Next- I tossed the spent motor.

Next- I know all about "poopy clay"

Lastly- I try to never use the word "impossible." To do so, as it was used, in this thread implys that I am publishing a lie. As a person who makes a habit of not lying, I find that opening remark provocative. I sincearly believe that is not what you were trying to do... correct?

Correct that I was not trying to imply that you were lying. You would only get that by incorrectly inferring.

I would testify in court that it was impossible for there to be leftover black powder propellant in a black powder motor. I have no doubt that you saw something and you just added that it was hard. No problem. I have no idea waht it was, but Black Powder propellant cannot possibly survive inside a motor casing after it has fired - only combustion remains and 'crud'.

Something went wrong with that motor. You posted the agonizing details here and all I was doing was trying to assist you in figuring out what went wrong. My advice to everyone - not you, but everyone, is to retain the casing from any motor failure so that once it has been reported to the NAR and the manufacturer, any follow up questions can be persued. For instance, in this case, if Estes wanted the casing returned to them for analysis or if they requested digital photos, having the failed casing would be very helpful with their efforts to identify the failure mode and try to prevent it from happening again.

 

[Dr.Zooch]

Correct that I was not trying to imply that you were lying.

That's what I was sure of.

I would testify in court that it was impossible for there to be leftover black powder propellant in a black powder motor. I have no doubt that you saw something and you just added that it was hard. No problem. I have no idea waht it was, but Black Powder propellant cannot possibly survive inside a motor casing after it has fired - only combustion remains and 'crud'.

You are very correct- I have no real proof that it was actuall "Propellant" and I should have done what you said and retained the motor rather than just tossing it. All I really know is it was "something hard" because I tapped on it with a launch rod and it did not budge.

I was just highly bummed at losing two of my main workhorses (the booster and the flying TV studio).

Your advice is well taken by me.

 

[Peartree]

I was just highly bummed at losing two of my main workhorses (the booster and the flying TV studio).

We *will* see them again won't we?

[YOUTUBE]HofoK_QQxGc[/YOUTUBE]

 

[RangerStl]

Well, this I find intriguing... :eyepop:

Hard junk that didn't come out when prodded, wonder if the big "E" is grinding up Kingsford briquettes for their propellant fuel.

If the powder was contaminated with enough OIL it wouldn't burn, but then again it wouldn't be hard, either.

If there were excessive KNO3 in the mixture (like LOTS) it might remain unconsumed, melted from the heat, and crystallized in the case. This would also reduce the burn efficiency.

Do they use an organic adhesive binder like Guar Gum in the propellant? Maybe somebody misplaced a decimal point when mixing that batch...

I have six D12-0 boosters in my stash. I'll keep an eye out for similar behavior.

N

 

[Dr.Zooch]

Keep in mind that the deposit of stuff I found could mean nothing.

My biggest issue is the under powered boost and the delay in staging. It was so apparent that immeadiatly following the crash, several very experienced rocketeers came up and told me that I'd blown a nozzle- because that's what it looked like. The nozzle, however, looked very normal. Additionally, I've had D12-0s blow nozzles twice before and both times they failed to stage because the pressure needed to force the hot gasses in retrograde is released through the opening where the nozzle should be.

Currently- this is just a big question mark. My problem is to now re-build the flying video studio. Even the wrecked boostervision.com cam had been crashed once before and was a survivor- so it's a fair write-off. Since, like a moron, I tossed the expended booster.

 

[powderburner]

When I got home tonight I released the ants where I'd caught them- they seemed fine...

You may want to think about moving a few times. Might make it a little more difficult for the attorneys (representing the antstronauts) to find you.

My sympathies on the loss of your carrier vehicle. I crashed a camera rocket a few years back, and in my rocky soil, it was ugly. I still haven't spent the money to replace it.

 

[Dr.Zooch]

I still have 3 booservision.com gear cams that are yet to be used or comitted to a set up. So, I'm doing okay there... of course I can do 3 crashes in a single MDRA launch, so you never know.

 

[foose4string]

Wes, seems like all of your troubles have been with the D12-0. Two blown nozzles and one that was a wimpy excuse for a D12. Have all of these been out of the same pack? Where did you obtain them? I know you don't worry too much about reporting motors, but after trashing some nifty rockets and replacing cameras, I think it's high time you should. If these are a bad lot, I think Estes should know about it.

 

[wilsotr]

You need to give up on this model rocketry stuff, Dr. Z, and take up spacesuit design. Apparently, you build some tough suits.

 

[Dr.Zooch]

Wes, seems like all of your troubles have been with the D12-0. Two blown nozzles and one that was a wimpy excuse for a D12. Have all of these been out of the same pack? Where did you obtain them? I know you don't worry too much about reporting motors, but after trashing some nifty rockets and replacing cameras, I think it's high time you should. If these are a bad lot, I think Estes should know about it.

These were all from different packs, in fact were bought in 3 different years. I think it's just bad luck rather than bad Estes. Foose- you saw that launch- what'd you think?

 

[Dr.Zooch]

You need to give up on this model rocketry stuff, Dr. Z, and take up spacesuit design. Apparently, you build some tough suits.

Too bad I designed it when I was 15 years old

 

[Dr.Zooch]

Here are some shots of the flying video studio...

 

[Dr.Zooch]

Here's what's left...

Note the Antstronaut's couches next to the battery :eyepop:

 

[foose4string]

These were all from different packs, in fact were bought in 3 different years. I think it's just bad luck rather than bad Estes. Foose- you saw that launch- what'd you think?

What do I think? I think a Mercury Atlas kit would be terrific!


Oh wait- you mean about the motors.

Looked very much like the other flights I witnessed with the blown nozzles- except this one actually staged. I'm assuming nothing changed with regards to design or weight or anything? I dunno, pretty strange. I don't recall hearing anything about a high failure rate with the D12-0 motors and I don't have any personal experience with them either. I have flown plenty of them with delays and never had a single problem. Three times bad luck with the same motor designation seems very odd.

 

[Dr.Zooch]

Nope- no changes in weight, etc- in fact the same booster flew in April at Red Glare, in the same config. and if flew like a champ. Like I said... I think it's just rotten luck, but I look on the bright side... I can probably now fly D12-0s for the rest of my life without another failure. I mean... what are the odds? Right?

 

[Mikus]

For instance, in this case, if Estes wanted the casing returned to them for analysis or if they requested digital photos, having the failed casing would be very helpful with their efforts to identify the failure mode and try to prevent it from happening again.

Are we thinking about the same company named Estes?!?!?! :eyepop:

 

[luke strawwalker]

In flying model rockets since 1969, today I had my most horrific crash ever. It was at the monthly MDRA launch.

The model was the two stage D to E launcher that is often seen in my videos. The payload was my AOB (Ants OnBoard) flying TV studio. It consisted of a cam from boostervision.com, a mirror, a stage light, two ant-stronaut couches and two ants in their F4-B ant spacesuits. Below the studio was the 9 volt battery for the cam, some button cells for the stage light and the needed switching equipment and wiring.

The ants were working on my next spoof video and had just flow in my up-scaled Orbital Transport glider while being videoed. They did a great job. Where some ants just cower down in the F4-B, these two were faces and feelers out the visor looking directly into the cam- very active. So I decided that on the next flight, they'd do the AOB- which I've flown a dozen times.

I loaded them up with the most active one being closest to the cam (this rig has a side-view arrangement) and the launch went... As the rocket cleared the rod it very clear that something was wrong. The D12-0 was boosting poorly and the climb was way weak. It arced over and I thought it was simply not going to stage- instead, it staged, pointing almost horizontally downward and about 30 feet off the ground. The SRBs fell away and the second stage pile-drove into the ground under power and continued to thrust for a second or two, then it did the delay and exploded.

Since I had a cam going, they'd launched me first- so I had to wait until the low power and high power racks had been launched before the feild was safed and I could go out and get the pieces. While I was waiting and watching the wreckage smolder out there, I thought to myself "Those were two good little ants. They worked well with the cameras... right up to the point where I drove them into the ground under rocket power."

When I got to the crash site- it was bad- REALLY bad. :y:The impact had squished all of the tubing. The nosecone where the studio was contained was like half a smashed eggshell with the entire workings of the studio smashed into the end of it. The 9 volt battery was mangled as if someone had taken a pair of pliers to it. The engine compartment saw the E engine shoved about 6 inches up the tube and the resulting exhaust had burned away most of the fin area. It was a nightmare that I scooped up and took back to my table.

I went digging for the ants among the wreckage....

What I found was amazing. The first ant was still in his F4-B suit which was rattling around in the nosecone's remains, and was alive and well! The second one was still in the couch, and was also alive and well!

It's amazing- the entire rocket totally smashed and burned, and the only parts that were undamaged were the most fragile of all... the ants.

I have no idea why that D12 burned so poorly, nor why the staging was so strange. The engine nozzle appeared intact, but there was a good deal of unburned propellant in the forward end of the engine. In reviewing the onboard video I have seen some motions imparted on the ants that seem out of place- additional study of the frame-by-frame will be required.

When I got home tonight I released the ants where I'd caught them- they seemed fine... but I went out later and dropped a Tylenol near the nest... just in case someone may need it.

Cool!!! Did the little buggars get hazard pay??? :neener:

I've had some BP engines that did stuff like that. Despite shread's assertions that it's IMPOSSIBLE for BP motors to NOT burn fully, I have seen it myself and experienced some motors that were WAY underpowered, like you said. I think the most likely culprit is the propellant batch having a 'lump' in it or something so that it is not homogenously mixed or gets some type of contamination as the motor is being manufactured, like some extra clay dumped in after the nozzle is pressed, or something like that. If the BP mixture isn't homogenous, you could end up with part of it with the wrong proportions, and if it runs out of fuel or oxidizer first, the remaining oxidizer (or fuel as the case may be) WILL end up unburned because there is nothing to support combustion. I haven't seen but one or two of these, but I HAVE seen them!

The most likely probability though is moisture contamination. How old was this D12 and where did it come from?? If it absorbed a bunch of moisture somehow, that will SEVERELY reduce the burn rate and power of the motor. Something to consider, anyway. If it was still in the package with the other two and they fired fine, I'd say you got a contaminated or non-homogenous motor.

One thing I DO know-- the quality control on motors is WAY worse now than it was on the motors I was flying 20 years ago! I've flown a BUNCH of those old motors and they are a LOT more consistent and dependable than the new motors. I've seen quite a few D12's and E9's with spit nozzles, CATO's, and weak or shotgun ejections. I had one recently come back with about 75% of the clay cap still in place AFTER the ejection charge! Luckily the chute deployed, but I still wonder how!

Later! OL JR

 

[Dr.Zooch]

I keep all of my engines in the same place- right in a plastic tool box under my work bench here in my office.

 

[JAL3]

A few months ago I some problems with Estes 24mm motors. In one day I had 2 blown nozzles and one WAY underpowered flight. That was with 2 different C11s coming from different lots and a D12. There some pics and vids on my Fliskits Morning Star thread.

BTW, your camera work is FIRST RATE and the editing is even better.

 

[Medaforce649]

Ive had one failed launch, I was at the park with my friend and we were gonna try out the F4-B in my shenzhou booster from apogee. I had flown it once before and lost the engine block, so I was trying to launch it on one that I designed. With the ant loaded in the cockpit of the shenzhou, the engine ignited and the rocket went 30 ft in the air, but then my engine block failed and the engine went inside the body tube sending the rocket into a horizontal trajectory towards a nearby forest. I recovered everything, the rocket was a total loss but the nose cone and shenzhou, with the ant were fine. It all happened in like 2 seconds xD

 

[CharlaineC]

All I can say is i'm glad the ants survived un harmed. proves that your made some great suits for them. but I am sorry for the loss of you rocket.

 

[Dr.Zooch]

Keeps me off the hook from PFWLA (People Finding Weird-os Launching Ants)... they've been after me for years.

 

[jorpet]

Did you fail to name your ants at least two episodes before their flight?

Did you give one of them a red button?

:roll:

 

[Dr.Zooch]

Hey... have you been reading "The Program?"

 

[luke strawwalker]

Did you fail to name your ants at least two episodes before their flight?

Did you give one of them a red button?

:roll:

Hey, they COULD'VE pulled the abort handle...

Steely-Eyed Missile Ants...

You can call the vid, "The Right Arthropods".... No squirming hatch-blowers there eh??

:roll::roll::roll:

Later! OL JR

PS... I recently watched "The Right Stuff" after not having seen it in probably 20 years and I laughed out loud during the 'squirming hatch blower' scene... thought of you Doc... OL JR