Brush fire in Palm Bay’s ‘Compound’ was accidental, caused by rocketry enthusiasts, officials say

[jsdemar]

Based on actual information from the folks involved, much of what is reported here and in the article is incorrect.

They had permission to test, had a fire suppression plan, extinguishers, and called 911 as soon as the fire started.

Not everything on the internet is true.


Tony

That's what I was told as well. Permission was given to the team lead via email. The SRA club president is also employed as an advisor for the department. The nozzle blew on their hybrid test. (They were also there a week ago and only got cold flow). The students reacted quickly and called 911. The fire department was there within 10 minutes and put out the fire. The college is doing an investigation. Could have been worse.

 

[SolarYellow]

Screen cap from the org's home page linked earlier. Lots of potentially burny stuff not very far away from the burning stuff.

 

[Kelly]

Lots of potentially burny stuff not very far away from the burning stuff

Like, for instance, asphalt.

 

[NateB]

Like, for instance, asphalt.

The immediate area looks good with the asphalt but the brush is close. If it is dry and windy, it doesn't take much to set off acres. Up here, Spring can be deceiving because even damp ground can host dry grass and brush while it is still dormant. Sparks from a hot cigarette can start fires and I've seen sparks from brush fires jump across 4 lane highways and spread flames.

If it is true they only have a few ABC extinguishers, then that is not enough and not really the right type for the application. Indian packs are great, water cans you can recharge with an air compressor work well, or even a small tank and pump on a golf cart if you need to get somewhere more remote would be a good idea.

 

[Hobie1dog]

I thought all static tests were on a horizontal motor mount about 3 ft off the ground?

 

[rharshberger]

I thought all static tests were on a horizontal motor mount about 3 ft off the ground?

Not always, just depends on the test stand, I have seen some done vertically (up or flight orientation and down facing though admittedly few downward facing motors) and some horizontal. I do not however know how much difference there is in results based on orientation.

 

[jsdemar]

I thought all static tests were on a horizontal motor mount about 3 ft off the ground?

This was a hybrid motor test. Typically nozzle down in flight orientation.

 

[mjennings]

An unfortunate event for sure. I flew with Spaceport 15 years ago now. Great people and a good club then. As stated above research motors weren't a thing with SRA when I flew and I'm sure that was part of the call. Glad that no one appears to have been injured! Hopefully this won't cause bad will to the club.

 

[tim cubbedge]

Screen cap from the org's home page linked earlier. Lots of potentially burny stuff not very far away from the burning stuff.

View attachment 640780

That's a 99% O motor which is why our president denied KXR permission to static fire. We are very skeptical when we get requests for N motors due to safe distance rules. No way could we have accommodated the O motor.

 

[OzHybrid]

That's a 99% O motor which is why our president denied KXR permission to static fire. We are very skeptical when we get requests for N motors due to safe distance rules. No way could we have accommodated the O motor.

I had this discussion with Alan Whitmore years ago and he confirmed that safe launch distances do NOT apply to a non flight motor test. But obviously, safety does apply and there should be a barrier, or motor in a 20ft container used as containment or some safety mitigation plan in place.
The launch safety distances are not enforced by TRA for testing.

 

[jsdemar]

I had this discussion with Alan Whitmore years ago and he confirmed that safe launch distances do NOT apply to a non flight motor test. But obviously, safety does apply and there should be a barrier, or motor in a 20ft container used as containment or some safety mitigation plan in place.
The launch safety distances are not enforced by TRA for testing.

(Unhiding OxHybrid momentarily from my ignore list...)

The Tripoli Unified Safety Code applies to all static test firings at a Tripoli sanctioned launch. This includes safe distances and cleared distances. If you're not at a Tripoli launch, you are on your own insurance-wise and conforming with all AHJ requirements.

Tripoli members can read the discussion on the Tripoli website at:
https://tripoli.org/content.aspx?page_id=2155&club_id=795696&item_id=1466585

 

[cerving]

Yup, it doesn't make sense to me that a static firing wouldn't have the same safety guidelines as a flight. If anything, the chance of a cato is higher with a static firing... you're trying to see if it's going to work, right?

 

[3stoogesrocketry]

Yup, it doesn't make sense to me that a static firing wouldn't have the same safety guidelines as a flight. If anything, the chance of a cato is higher with a static firing... you're trying to see if it's going to work, right?

If* the motor catos..... how far will the individual prices travel? If a K motor at 300 feet blows vs a O motor at 2000 feet, who is in more danger? Non flight motor tests are very different then flight motors tests (launches) . Imagine in a far off land, If you take a skyripper 38mm H motor, and hook it to a 20 pound bottle on a test stand till the grain disappears and the case fails. Is this a H motor? I motor? K motor? M ? I know I am one of only a few who know, but sometimes further away is more dangerous.

 

[OzHybrid]

(Unhiding OxHybrid momentarily from my ignore list...)

The Tripoli Unified Safety Code applies to all static test firings at a Tripoli sanctioned launch. This includes safe distances and cleared distances. If you're not at a Tripoli launch, you are on your own insurance-wise and conforming with all AHJ requirements.

Tripoli members can read the discussion on the Tripoli website at:
https://tripoli.org/content.aspx?page_id=2155&club_id=795696&item_id=1466585

That's recent Feb/March 2024 and interesting, but not actually specified in the unified code as a test is NOT a launch.
From the Rules....
As needed, the Tripoli Board of Directors (BoD) will announce updates in the Tripoli Report that shall be considered official even before a new version is published. As per the boards directive, any change to the rules shall be notified through the Tripoli magazine or a change to the the rules on the website.

The forum is a discussion area. Not a rule change notification. @jsdemar
The unified code refers to research flights. There is NO reference within it to motor testing, where no flight occurs.
I'm not covering whether it is or is not insured, however as it is not specified, it would seem to be an UNINSURED activity. Launching a research motor is an insured activity provided the safety distances are maintained.
Also, I note that the previous doubling of the safety distances for research motors has been REMOVED from the current regulations without any prior notification or discussion here that I've seen. So as the RULES stand and are notified currently, a research motor has the same safety distance as a commercial tested motor.
While I recognise that updating a set of rules is a thankless task and was done mainly by one person, we all have to make sure that we know where to go to for any rule changes. And that they should be correct in that place.

@jsdemar ((Unhiding OxHybrid momentarily from my ignore list...)) learn to type. OzHybrid. not OxHybrid.

 

[Art Upton]

If* the motor catos..... how far will the individual prices travel? If a K motor at 300 feet blows vs a O motor at 2000 feet, who is in more danger? Non flight motor tests are very different then flight motors tests (launches) . Imagine in a far off land, If you take a skyripper 38mm H motor, and hook it to a 20 pound bottle on a test stand till the grain disappears and the case fails. Is this a H motor? I motor? K motor? M ? I know I am one of only a few who know, but sometimes further away is more dangerous.

I was at a Texas LDRS almost 2 decades ago where a large O motor Hybrid CATOed just off the pad being flown by the hybrid maker.

I could feel the concussion in my chest well beyond the distance line. It tossed Shards some distance away.

I saw that the Hybrid builder had blast shields for static tests, was posted on here long ago before the crash.

 

[kramer714]

Ok, again I dont know the details about the failure, this is more of a general comment....

Engineering students , need to act well, like engineers. If you are building a rocket motor case,

• Do you know the estimated pressure you will reach,
  • how did you validate it
  • What margins in pressure are to be expected.. and how did you come up with them.
• What margins have you designed for?
  • What justification do you have for the margins
  • yield is failure... really
  • how are you proving it?
• What are the material properties you are designing around?
  • Real design allowable properties, from something like MIL-HDBK-5 Rev. J
    • Yield Stress
    • Fatigue Limits
    • K1C
    • Bearing Yield
    • Effects of temperature on the materials?
• Do you REALLY know how to determine the strains in a pressure vessel
  • When to treat it as a thin wall vs a thick wall?
  • How are you proving it?
• Do you know how to account for multiple tests?
  • Is the motor case 'instrumented' to really know the loads it saw in the test?
  • Do you have an extra case, be able to NOT USE one that has seen a load beyond what it should have.
  • Are you recording the loads at each test?
  • Are you monitoring the temperature at each test?
• End Attachment
  • Do you really know how to design around a bolted end?... and use the appropriate margins... and have manufacturing tolerances in you analysis.
  • Do you know how to design around fracture toughness for a snap ring or groove? The bending moment and stress concentrations at the corners?
    • understand and validate the manufacturing tolerances as designed, AND AS BUILT.
• Test Plan - Do you have a plan for testing the motor case?... in writing... with a worksheet... and a way of recording the results..
  • Do you have a criteria for passing (no it inst just it didn't fail).
  • Do you understand about strain and yield as a criteria for testing?
  • Did your analysis show that you are not causing a failure in subsequent test by the way you load the part in this test?
    • Understand missing fastener testing as part of your test plan?
  • Do you know how to use water to test the motor case?
  • Do you know how to use a strain gauge? That can survive test launches? and are properly temperature compensated?
  • How to measure the yield by weight of water in the motor case before and after?.. and have a pass fail criteria?
• Safety - for testing do you have a way of containing the failure?
  • For quick test in the past I have used steel pipe (down well pipe works for small diameter) wrapped with chain link fence and canvas tarp jelly roll style as a spall protection.

Sounds like a lot of work. less work than failing at a launch....

This group may have done all that, again I am talking in general, but when I hear they spit a nozzle... I start thinking about a failure analysis.


Mike (if ya wanna be an engineer....) K

 

[jsdemar]

Ok, again I dont know the details about the failure, this is more of a general comment....

An update from someone who was there, the motor didn’t fail.

 

[kramer714]

An update from someone who was there, the motor didn’t fail.

I didn't want to make any assumptions about what happened, my 'bullet list rant' is more about, with college teams, they need to think about becoming engineers, during school they should start thinking like engineers.

At the local launch last weekend I ended up talking to a couple of different college teams, both had a strange reaction when I started talking about calculating things not just launch and see what happens. A good example was what is the load on the shock cord when a drogue comes out. We walked through the steps on how to calculate, validate and test this, quickly without launching a rocket. Quicker Cheaper, and lower risk than launching something and seeing if it fails.

The good thing was both groups didn't get defensive just the opposite, they started asking better and better questions, encouraging. I told them both (yeah old guy stories) something a prof of mine said in college. He said you really dont need engineers, if you want to build a bridge across the grand canyon, just get a lot of people with shovels and fill it in.... now if you want to do it quickly and cost effectively that's where you need engineers to design a bridge.

 

[tim cubbedge]

An update from someone who was there, the motor didn’t fail.

So what caused the fire, flammable materials not removed to a safe distance?

 

[ntsgators]

I am a current UCF student and I know a couple of the people that were involved in this incident, and they provided me with some information.

From what I have been told the combustion chamber had recirculation occurring at the top and bottom of the chamber and had a peak in pressure, which caused the casing to fail in a couple of spots and fire started spraying out the side with molten ABS plastic since their fuel grain were part ABS. The motor was theoretically a 99% O.

According to the Tripoli safety codes, you would need a radius of 62.5 feet that is cleared of flammable material and the team was made aware of that beforehand. The minimum radius the team had when conducting the test was 20-25 feet. The fire equipment they had was 2 ABC extinguishers and 1 D class. It was supposedly a very windy day also when they conducted the test.

Also to clear up any confusion with SRA’s president, they are employed by UCF as an advisor for senior design rocketry projects and does not have any oversight into UCF clubs that deal with rocketry.

 

[jsdemar]

I am a current UCF student and I know a couple of the people that were involved in this incident, and they provided me with some information.

From what I have been told the combustion chamber had recirculation occurring at the top and bottom of the chamber and had a peak in pressure, which caused the casing to fail in a couple of spots and fire started spraying out the side with molten ABS plastic since their fuel grain were part ABS. The motor was theoretically a 99% O.

According to the Tripoli safety codes, you would need a radius of 62.5 feet that is cleared of flammable material and the team was made aware of that beforehand. The minimum radius the team had when conducting the test was 20-25 feet. The fire equipment they had was 2 ABC extinguishers and 1 D class. It was supposedly a very windy day also when they conducted the test.

Also to clear up any confusion with SRA’s president, they are employed by UCF as an advisor for senior design rocketry projects and does not have any oversight into UCF clubs that deal with rocketry.

This is contrary to the information we received directly from a non-KXR person who was there.

I suggest the admins close this thread until the university completes the investigation.

 

[Clo_swampchild]

This is contrary to the information we received directly from a non-KXR person who was there.

I suggest the admins close this thread until the university completes the investigation.

Sorry to bother you with this reply, but I have a few friends that are apart of KXR and the reply that was made was accurate for the most part.

I’m not heavily involved with KXR due to personal reasons but I worry for my friends who could’ve gotten hurt from combustion chamber failure. It’s almost like an out of control game of telephone with the information being spread.

 

[OzHybrid]

I was provided this video as well

Probably best not to post that publicly.

 

[NateB]

It’s almost like an out of control game of telephone with the information being spread.

Then it is probably best to not discuss until an official statement and investigation is made before rumors get out of hand.

 

[kramer714]

I am a current UCF student and I know a couple of the people that were involved in this incident, and they provided me with some information.

From what I have been told the combustion chamber had recirculation occurring at the top and bottom of the chamber and had a peak in pressure, which caused the casing to fail in a couple of spots and fire started spraying out the side with molten ABS plastic since their fuel grain were part ABS. The motor was theoretically a 99% O.

According to the Tripoli safety codes, you would need a radius of 62.5 feet that is cleared of flammable material and the team was made aware of that beforehand. The minimum radius the team had when conducting the test was 20-25 feet. The fire equipment they had was 2 ABC extinguishers and 1 D class. It was supposedly a very windy day also when they conducted the test.

Also to clear up any confusion with SRA’s president, they are employed by UCF as an advisor for senior design rocketry projects and does not have any oversight into UCF clubs that deal with rocketry.

Standard disclaimer, generic info not specific to this failure....

Any 'off the shelf' safety code should be used as a starting point. Not to say it is a reference only but, when doing a serious project like this, a serious safety assessment is warranted. What are the failure modes, what are the consequences of those failure modes, then you rate them for ' how possible is it', if it happens, 'how severe is it' , and 'can you detect it / prevent it'. A failure of the case was always a possibility, with flaming fragments, or hot shrapnel going a distance over 62 feet (certainly over 25 feet) a very 'non zero' possibility.

This type of analysis ,would be part of a PDR,CDR. FRR , and any additional safety reviews. If you are a college team and dont know what a PDR, CDR, and FRR is, you should.

Um, basic 'engineering'.....

Mike (kids these days.......) K

 

[SolarYellow]

The first Tripoli launch I went to around here, there was a college team with an EX motor on a test stand. Looking at the motor, looking around, there wasn't a person I could see who was far enough away from that thing to be safe if it CATOed. And all the kids were, for as near as it mattered, standing right next to it while they tried to light it.

 

[Peartree]

Thread locked until the release of official investigation.