Indestructible Rocketry parts, Good or bad?

For those who are content to get the same thrill (without the extra cost) of the High Power Peple
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Rocket Babe
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#11 Re: Indestructible Rocketry parts, Good or bad?

Post by Rocket Babe »

All I'm going to say is there used to be a thing called common sense :roll: but now common sense is a rare thing indeed and is considered by many as a superpower. :USA:
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#12 Re: Indestructible Rocketry parts, Good or bad?

Post by Ez2cDave »

Yes, I realize thi thread is 8 years old . . .

I found a couple of pics of the liftoff of the two "drag race" rockets, one of which struck scoutmaster, Michael Bentley. I believe the rocket on the right is the one involved in his death.

Dave F.
LIFTOFF PHOTO.jpg (62.68 KiB) Viewed 1014 times
LIFTOFF PIC - CROP - LARGE.jpg (174.53 KiB) Viewed 1014 times
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luke strawwalker
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#13 Re: Indestructible Rocketry parts, Good or bad?

Post by luke strawwalker »

That's why materials are supposed to be frangible, meaning they disintegrate and absorb the impact rather than staying intact and putting that energy into destroying whatever they hit. I've seen some HPR 'cardboard tubes' that had close to a quarter inch wall thickness- at that point it's really not much different from being made of fiberglass or aluminum for that matter, it's solid enough and strong enough it's going to impart most of the impact energy into whatever it hits rather than disintegrate, crumple, break up, etc.

I attended a pretty good number of HPR launches when I got back into rocketry about 20 years ago or so... I was interested in it since it came about not long after I graduated high school in 89 and really gained popularity in the early/mid 90's. I have to say I was not impressed with what I saw. Entirely too much "hold my beer and watch this" sort of attitudes, along with a lax safety culture. Saw one guy nearly get gutted by his dual deploy setup when a breeze blew across the active sensor, causing a pressure drop across the port due to the Bernoulli principle and then a rise in pressure in the tube as the breeze stopped, causing the altimeter to fire the BP ejection charge. Blew a 4-6 inch nosecone about a foot long that was VERY pointed, and it flew right behind the head of the guy sitting at the folding table I was watching assemble his reload motor... had his lawn chair been a foot back, he'd have taken that thing right to the side of the head, quite possibly fatally, given that it was dragging a six foot chute behind it at high speed as well. The "kickback" blew the tube and altimeter board back into his gut, snapping it off before the tube hit him in the gut, leaving a near perfect ring and slash (like the ghostbusters sign) imprinted into his stomach. Knocked the wind out of him and he was carried to a motorhome to recuperate, took and hour or so and he's back on his feet, BUT it could have been much worse.

At the same launch, saw a 4 foot 2 inch-ish diameter upper stage of a HPR rocket streamline in after staging failure... We were in the process of leaving, my wife sitting in the back seat of the pickup chatting with another lady while everyone started screaming "heads up!" I watched the thing streamline into a tree in a fenceline about 30-40 yards away, and so I went over to it to inspect the damage-- a fiberglassed fin has cut a branch off like a razor and it had embedded itself a foor or so deep in the ground before it finally had too much resistance to continue and the tube basically exploded... even the 9 volt batteries powering the staging electronics shattered and scattered baby batteries about.

Then I've read about plenty of other incidents, from HPR rockets impacting a motorcycle rear wheel and destroying it, while someone was on the bike. The staging malfunction on the pad that caused the electronics to fire the upper stage on the pad once it was leaned over to be worked on, and it flew between 2 people on the same four wheeler, burning them both. A foot either way it would have killed one or the other of them.

Then there was the HPR that streamlined in and buried itself just off the road in a ditch next to a field that some Amish were working in, IIRC... the rocket buried itself several feet deep, only a thin hole was visible in the grass. They tried to dig it out, had to dig several feet deep just to get the reload casing and electronics, and pretty much gave up on the rest of it because it was buried too deep. Obviously if it had hit one of the field workers or one of the many Amish riding their bikes past that field, they would have been dead, without doubt.

Then there's the whole sparky motor thing, where a club violated their own rules against sparkies up in North Texas because a stupid TARC team had only bought and brought sparky motors all the way from El Paso, and could only launch their rocket at a certified launch and they HAD to get the flight in to make the deadline for the TARC competition. The sparky motor ignited the field, burned off a bunch of acres of pasture, and almost set fire to a several hundred acre ripe wheat field (which would burn like gasoline) just across the fence. The club lost their launch site after that when the landowners decided it wasn't worth the risk, particularly when being pressured by the neighbors whose crops nearly burned. That could have been hundreds of thousands of dollars of loss right there.

Then I read about stupid stuff like bowling ball lofting, and countless articles bragging on how to make your tubes and parts slathered in fiberglass or carbon fiber to make them into "anti-tank rounds". Added weight?? NO problem, just increase the motor size! No elegance of design, no thought to safety, just "Make it bigger and stronger and shove a bigger motor in it!" That's @ss-grabbery, not rocketry IMHO.

Then the club I was hosting on the farms started pushing for HPR on the farm. Started looking at setback distances and talking to the neighbors. After a little more research and thought, I pulled the plug on that idea... too much risk IMHO... my house, my family, my barns, my animals and equipment, were going to be the ones perforated if someone made a mistake or did something stupid. I wasn't willing to take that chance.

I've not seen anything different in all these years to convince me otherwise. Even when I suggested, having seen one accident and read about others that could have been prevented with the use of safety pins or shunts to either open the circuit between the electronics and the ignitor or ejection charge, rendering it safe BEFORE any work on the rocket was performed, and the safety pin or shunt was the last thing removed on the pad and the first thing inserted in the event of malfunction, plus better range control (such as keeping idgits on four wheelers out of the immediate path of the rocket or out of proximity of the rocket being worked on, for instance, but that only goes SO far-- it does NOTHING to protect those outside the immediate vicinity of the launch operations or even outside the range where the rocket might potentially crash... such as the house outside the fence that a HPR dual deploy failed on and took out their sunsetter awning by turning it into a taco shell or horseshoe when the rocket crashed into it in the adjacent neighborhood off the property of the NASA JSC campus...

Of course when you suggest such things, you're instantly ATTACKED for being a 'nervous Nellie" or "trying to ruin someone's fun" or other such nonsense. They can't be bothered to install or use even such simple safety devices, just to enhance safety, and anyone who suggests they should is some sort of "rule Nazi" and thus MUST be opposed and attacked.

For ALL those reasons, I didn't allow HPR on the farms, and won't. Nothing I've seen or read over the years has done anything but reinforce that position...

Later! OL J R :)
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