Sorry to continue the off-thread distraction but I think I can help fill in some of the holes...
Archived Media Articles by BRETT SHIPP, WFAA-TV
FRIDAY, DECEMBER 07, 2007
DALLAS, Texas USA - Six weeks after a toy rocket nearly killed her son, a North Texas mother is struggling to help pay the bills needed for his recovery.
Our local media was pretty weak on facts about this whole thing, at least in regards to facts that would interest us rocketry geeks. They pushed hard on the 'poor little kid was injured by the boy scouts and then abandoned by them' aspect of the story
I was asked to serve as a subject-matter expert witness in this matter. I was given access to much of the deposition material and many photographs of the model rocket that were taken after the accident. The following description includes factual information as best I can remember (my files are put away somewhere), without exaggeration or personal slant. Any comments or opinions of my own have been noted.
The launch was conducted at a scheduled church-scout group weekend campout. The group had done this before and had experienced people on hand. Organizers had made reasonable efforts to encourage kids to get beginner-level kits. Launches used A-B-C-class low power motors. Hobby-standard launchers were used (plastic legs, 1/8-diam launch rods, etc). Range and launch operations seem to have been reasonably well organized and controlled; scouts stood in line, experienced scouts and adults supervised preps and launches, crowd control was effective, etc.
Launch facility was reported to be on a flat portion of terrain, near a building, with downrange terrain dropping away (downhill) and covered with scattered bushes and small trees. Scouts who had already launched their rockets were downrange searching for retrieval. Apparently none were expecting any trouble (my opinion: I think this is an entirely reasonable expectation that we all would have made)
Weather and launch conditions were OK; broad daylight, dry, some wind noted by some eyewitnesses but apparently not enough wind to cause experienced leaders to call for halt.
A plastic model rocket had been brought by one scout (NOT the victim) at his request because he already had it. This was apparently approved by the group leadership. (My opinion: although the product recall had been issued, I question whether it is reasonable to expect someone other than a rocket-nerd to have knowledge of such a recall). This specific rocket is reported to have been launched at least twice earlier that same day and apparently had a normal, uneventful, safe flight each time. This plastic model rocket had a sharply pointed NC shape, made of hard styrene plastic, and contained a metal ballast weight.
The final launch of the plastic model rocket reportedly experienced a severe, abrupt change in flight path just above the launcher. The rocket was turned toward a horizontal flight path just above the end of the launch rod, at just about the same instant that the motor reached maximum thrust. It is my assessment that some combination of factors (modroc weight, motor power, launch rod strength, possible wind gusts, etc) resulted in an unfortunate rod-whip incident that reached a worst case (rod tip lateral velocity) condition at the moment when the modroc separated from the launch rod, causing severe tip-off.
The modroc reportedly traveled in a horizontal flight path, only a few feet above the ground, across the launch area and over the edge of the surrounding hill. Apparently the normally expectable curving descent of such a flight path was also a near-perfect match to the local terrain. Various witnesses described the altitude of the flight path to be around five to ten feet.
The victim was downrange at the time, searching for his own model rocket, and was unaware of the launch problem or of the approaching model rocket. The victim described only seeing the approach at the last moment, and hearing a whoosh noise. The victim was struck under his arm. The model rocket was still in the coast phase of the motor burn. The complete model rocket broke several ribs and pierced the chest cavity and lung, followed immediately by discharge of the ejection charge inside the chest cavity. The NC penetrated within a few inches of the victims heart.
Paramedics called to the scene cut the shock cord and separated the body of the modroc. The victim was evacuated by helicopter to a regional hospital. Surgeons removed the parachute, nose cone, and (presumably) ejection wadding. The victim has apparently made a full recovery since this incident but I would not be surprised if he was not a big fan of model rockets.
From the photographs made available to me (and they were ridiculously extensive) there was no sign of any kind of obvious damage to the plastic model rocket that would begin to explain this flight behavior or raise any suspicion of failure of any kind. There were no bent or misaligned fins, no nicked or misshaped leading edges (or any other edges), no sign of cracks, no broken launch lugs, no off-axis nozzle holes, no motor case side burn-throughs
nothing. The plastic model rocket appeared to be in good enough condition (after shock cord repairs) to quite safely prep and launch again. I think that without the recall notice, if I handed this model rocket to any of you, you would have no suspicion of a problem and no reason not to launch the thing yourself.
In my opinion this was a one-in-a-million (billion?) event, purely an accident. This was The Perfect Storm. Each of the factors leading to this incident were freak occurrences;
1) Launch rod tip-off of such severity to cause a radical, early change in flight path (while under full thrust)
2) Resulting height of flight profile
3) Perfect match of descending ballistic flight profile to local hillside
4) Perfect direction of tip-off toward victim
All of these factors together, at the same time, I would normally have called IMPOSSIBLE. But it did happen.
Is the probability of a repeat event (with this specific model rocket design or any other) high enough to warrant changing our ways, finding a better way to inspect and launch? Thats a good question. I dont think so, but then again I never would have expected anything like this to happen in the first place.
I will admit that when I first heard of this accident on the local TV news I was immediately suspicious that some kids had been recklessly misusing model rockets, deliberately launching them at each other something along the lines of that stupid Jack### show. Nothing could have been further from the truth. This was NOT an instance of Joe-Bob and his drunken friends. This accident could have happened to any of us. Thank God that when it did occur, there were scouts and other people present to help this kid, get proper emergency care, and get him to a hospital. If this had happened to an individual out by himself, launching alone, there is a sizeable chance that he would have bled out and died.
WRT The Product Recall
The recall had been previously issued but these folks seemed to be unaware of it. The plastic model rocket had been legally, properly, etc purchased prior to the recall at a major chain store which until recently had also sold several other model rocket products, none of which would have raised any suspicions on our part.
Further, the product recall was issued for a completely different reason. This product had experienced several instances of failure-to-eject, followed of course by ballistic flight and hard terminal impact. Suspicions were that the ejection gas was leaking out through the molded launch lug holes, or through separated/split upper and lower halves of the plastic body, or due to separation of the plastic tail ring securing the motor case (allowing the motor to kick out instead of the parachute). This recall was not related to any instability of this model rocket, whether known, suspected, alleged, or anything else. Whatever the cause of the recall, this modroc was history
..literally.
Lastly, I would like to thank Art Upton one more time for his support and his loan of equipment.
Sorry for my part here in continuing the derailment, I promise no more from me about this unless someone wants to start a separate thread.
