Rocket Challenge on Discover

Doug Sams wrote in news: snipped-for-privacy@flash.net:

Neither of these sound plausible to me. BP doesn't require pressurization to ignite, and once ignited, the ambient air pressure is irrelevant. Nor does it require air to "conduct the heat". The particles are in contact with one another!

len.

Reply to
Leonard Fehskens
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I guess you haven't been to many large NAR or TRA launchs. Sounds like many I heard when the first time they saw HPR in the 80s.

news:...

Reply to
AlMax714

Some of us lucky ones saw it in the 70's. :)

Reply to
Jerry Irvine

they are referring to extreme altitudes, where the atmosphere is so rarified and the temperature so low that BP and the matches used to ignite it do not burn normally

- iz

from

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Reply to
Ismaeel Abdur-Rasheed

This from a guy who says he won't follow a car down the road if someone is smoking in it.

No agenda here...move along...nope, none at all...

Even got in the obligatory TRA boo hoo shot.

Reply to
Kurt Kesler

Points well taken, Brett. Thanks for posting some specific concerns.

The solutions to the propellant issues are self-evident and are really beyond policies/practices for an organized launch itself.

I've been trying to reconcile your ballistic and large model recovery safety concerns with the actual intent of an LDRS-type event; to launch AND witness (simple spectators present) large, legal rockets. For terminology sake, I will call flyers and spectators, participants. A successful rocket flight is one which remains within the TRA safety guidelines and stays within FAA restrictions and TRA launch field dimensions; the "flight envelope".

Your recovery concerns seem to fall into two categories; large, heavy rockets performing within the envelope, and out-of-envelope flights.

Presumably, all entities within the launch field dimensions are participants, or have given their permission for the launch to occur. Participants accept the risks involved with any activity, be it rockets, sports, or driving down the highway. Insurance carriers, for instance, offer liability insurance to HPR launches based upon statistical evidence that the certification practices and safety guidelines of the sponsoring organizations reduce the safety risks to an "acceptable" level. It can be argued that the existing safety record of HPR is the direct result of certification practices and safety guidelines and not a result of avoiding disasters through sheer luck. Statistically, someone will, God forbid, eventually be hurt in an HPR accident/landing, just as hundreds are hurt/killed daily pursuing an infinite number of other activities commonly recognized as "harmless". For participants, the dangers inherent to an HPR launch are relative, not absolute, and the emphasis is on damage mitigation, not risk elimination, which is impossible in any endeavor.

However, your point concerning non-participants is absolutely valid. An out-of-envelope flight endangering a non-participant is completely unacceptable. The obvious solution is to increase the flight envelope parameters to contain a worst-case ballistic trajectory and/or the descent flight path of a large model under a (reasonable) recovery system.

Given that participants are aware of and accept the risks of a launch, the focus now is on minimizing the hazards without minimizing the activity itself. You spoke of amateur sites with overhead protection and blockhouses. That's fine for sites capable of implementing those features. Unfortunately, most HPR sites are located on property that does not belong to the rocket organization and permanent fixtures are not an option. Overhead protection from ballistic recovery becomes an issue of portable shelters and flight progress monitoring and warnings. Protection from a horizontal flight/land shark is more problematic and primarily involves flight monitoring and warnings.

I can imagine a flight-line where vehicles are arranged around a "safer zone" to provide some protection from horizontal events. Protection from darts and prangs would require a portable roof-type shelter of some kind. Large models under recovery impacting in/along the flight line are a monitoring and warning issue only at reasonable descent rates.

Assuming an HPR launch is meant to promote and encourage the SAFE launch and recovery of even very large models, do you have any specific recommendations which would ease your concerns and enhance safety?

Reply to
Gary

Actually, it's more complicated than that. While you can usually get the the BP to light initially, the lack of atmosphere prevents heat transfer and thus the particles blow apart from the initial flame--and there's no atmosphere to provide conduction and convective transfer of heat to the now-leaving BP particles.

Reply to
Marcus Leech

False. The Tripoli (and thus NFPA-1127 and NAR HPR) guidelines are arbitrary and totally unrelated to safety guidelines worked out with decades of actual rocket flights by experts shooting rockets on the weekends.

But that should not free launch organizers to setup the range in a way to promote in-crowd lawn darts, which is precisely how, for example, LDRS-Lucerne (TRA) was setup.

It canbe argued wronglyand rely purely on anecdotal evidence and nothing else.

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Jerry

Reply to
Jerry Irvine

Soooooo....... and he also start vely furst grue thread. : )

Randy

Reply to
Randy

Bob Kaplow wrote: > ... I'm refering to smoking while prepping, or in the prep > areas. .... at a big launch I always see people violating that rule. > And it's ALWAYS the TRA folks, even at an NAR launch.

Come on, Bob, look a little bit harder. At a mixed NAR/TRA launch recently I (as RSO, but I would have done it whether RSO or not) sternly asked two people to stop smoking near the flight line; one of them I nailed on two separate occasions. Both are NAR members, not TRA.

Reply to
Steve Humphrey

bet the dads aren't thinking that

I also wonder how many people are now wandering around hardware stores thinking "that pipe could fly..."

:)

Reply to
tater schuld

Bob, I can't find any law or regulation that prohibits smoking at launches. Perhaps you can point it out to me?

The BATFE reg concerns smoking near magazines.

--------------------------- Sec. 555.212 Smoking and open flames.

Smoking, matches, open flames, and spark producing devices are not permitted: (a) In any magazine; (b) Within 50 feet of any outdoor magazine; or (c) Within any room containing an indoor magazine.

-------------------------------

I don't think we need to worry about (a) and (c) so (b) is the problem. In order to enforce this, you would have to either impound every match, cigarete lighter etc., or rope off an area around the magazines. If the flyers told you about them.

NFPA 1122 and 1127 say nothing about smoking. I can't find anything in the NAR safety code either.

But it is still pretty stupid to have an ignition source of any kind near rocket motors, igniters, ejections charges, etc.

Bob Kaplow wrote: > In article , "Joel Corwith" writes: >

Reply to
David Schultz

The only time drag force is significant is at precisely those times that you do not want to eject a parachute: when the rocket is moving fast.

At or near apogee the drag force is so low on all but the lightest and dragiest of rockets that the rocket is essentially in free fall. No matter what the altitude is.

Micro gravity effects combustion by removing convection currents that bring in fresh air and remove combustion products. Important for burning something that requires the air as an oxidizer but probably not significant for BP.

James Steven York wrote: > Interesting. One more factor that may make a difference, and that > isn't mentioned. These things may be effectively burning in zero (or > micro) gravity, which does strange things to combustion. In thicker > air, the rocket may be decelerating due to air drag fast enough to > cancel out these effects, but when you're going very high... >

Reply to
David Schultz

All the best explosives guys I know smoke and do so near explosives. They also determine what it is by taste!

Ewwwwwww.

Jerry

Reply to
Jerry Irvine

The law is called "The Law of Natural Selection". Unfortunately, it can sometimes take a few generations to take effect...

David Erbas-White

Reply to
David Erbas-White

I have posted drag force charts here before.

Reply to
Jerry Irvine

Curtis Reynolds wrote in news:3FAFB6AD.9925FEB9 @tctc.com:

Yep, I've seen the results of FOI requests. They blacked out everyting except the words "yadda" "blah" and "murmur."

It would be nice to know their definition of "rocketry related materials" is as well. That could include plastic, paper, wood, cloth, etc. etc. etc.

Reply to
David W.

John DeMar wrote in news: snipped-for-privacy@removethis.syr.edu:

Any coverage except cloud coverage :-)

Reply to
David W.

I agree completely! Showing that we are prepared for things to go wrong, and that things CAN go wrong without endangering anyone, is exactly the message we need to present!

Reply to
RayDunakin

And once again Jerry proves that he can turn any topic into an attack on TRA.

That's great Jerry, but how much of that is simply luck? I saw plenty of things at the Lucerne launches in the late 80's that _could_ have resulted in injuries

-- just as I have seen them at a great many other launches since then.

Using safe distances, etc reduces the risks but can't eliminate them completely. There's always the chance that an individual might be in the wrong place at the wrong time, or make some stupid mistake, regardless of which person or organization is running the launch.

Reply to
RayDunakin

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