Conducting Launches For A Crowd

[VinceC]

Good Afternoon,

Well, I am not sure where to post this so we will try here. Vince here, co-Advisor of the Onteora Rocket Club. Relatively new at over seeing a Club - two plus years. During my "previous life" safety was a big concern so incorporating safety into every aspect of what the Club does is not a foreign concept. Not necessarily easy but not foreign - lol. We follow the NAR Model Rocket Safety Code and work to develop our own "Enhanced Safety Code."

Now for the question - and we may already have a good idea what the answer is but are looking for some guidance.

The Club has been asked to put on a demonstration at halftime of one of the schools football games. Maybe even launch during the National Anthem - "rockets red glare". Of course the Club would love to do this, would love to show off, and would love the exposure.

The main issue? There will probably be a "small crowd" of 100-200 folks attending the game. The football field is in a pretty tight space. Surrounded by a track with woods on two sides, a little more open space on one end, and the school buildings on the other. The stands/bleachers separate the field and the school buildings.

Depending on the weather that day our maximum separation from the crowd would come by us launching from the furthest corner of the field away from the stands.

My aggressive, we can work this out, let's put on a show attitude says lets do some thing really cool. Like conduct a five rocket simultaneous launch. The students of course are pumped up! The want to do this especially since they are "stigmatized" as the typical nerdy "rocket club." Even though half the Club members are student athletes and the Club always draws a small crowd when they conduct launches on school grounds - lol.

Then my Advisor, practical, safety conscious, "boring" side kicks in and goes - "oh what about the safety?" Safety of he crowd? And possibly some parked cars?

Best case, the rocket(s) land in the football field. It is good even gets lost in the neighboring woods, the Club is prepared to lose what they launch. Bad case is the rocket has a safe recovery and "lands in the stands." Of course kind of neat - if no one gets hurt. Worst case is the parachute does not deploy and we have a crash landing into the stands. No so good.

So what do you all think? Has anyone ever done any thing like this before? Can anyone share the extra safety steps put in place to to conduct a launch near a crowd? Are we being overly cautious? Is this one of those things that sounds great but you just do not do? Or can it be done?

Thanks in advance for any suggestions or guidance anyone may care to offer.

Vince
Onteora Rocket Club

 

[Antares JS]

Angle your launch rods ever so slightly away from the crowd and don't launch if it's too windy. Other than that, let 'er rip.

 

[dr wogz]

What size rockets?

What 'shape' of the crowd? (Will you be surrounded? will they all be on one side or another?)

Safety wise, be mindful of where the wind is, and where your 'ballistic zone' will be. if you are launching from 'center field', and you will have spectators all around, I wouldn't.

Launch away from everyone, preferably into / towards a 'dead zone': no people or "things" that will get damaged..

launching some Alpha III on B6-4 are one thing. Launching a 3" Darkstar on a K is another.. Remember your safety distances to people & property

 

[PayLoad]

The idea sounds cool. However there’s something just not right about launching in the middle of a few thousand people who can’t move Out of the way

 

[bobbyg23]

The idea sounds cool. However there’s something just not right about launching in the middle of a few thousand people who can’t move Out of the way

Um, you should read the post. 100 - 200 people. Not thousands.

 

[Sooner Boomer]

Is this going to be day or night? Is it possible to launch from an end zone and angle away from the field (no more than 15 degrees off of vertical)?

The audience needs to be aware these are hobby rockets with recovery systems, not fireworks (my main concern). They don't explode into pretty colors.

 

[Grog6]

Large diameter, fairly heavy rockets with larger motors look cool for a crowd. The big thing is to do a rehersal, and work out everything before the show. Be sure to tell the audience that they should keep an eye on the rockets, that way everyone sees and enjoys the rockets, and is looking the right way if one moves unexpectedly.

 

[mh9162013]

I guess one factor is the number of rockets and the relative danger they pose to the crowd.

For example, if you wanted to launch a more powerful rocket (F impulse or w/e) with a pointy nose cone, maybe launch just 1 of them. But if you're thinking about 5 rockets, maybe use smaller and lighter rockets using 1/2A engines that won't do as much damage if their recovery systems don't work properly.

Basically, if something goes wrong, it's a lot easier for a crowd to track 1 or 2 rockets as opposed to 5. Isn't that how that guy died a few months/years ago? He was doing a drag race launch and while looking for one rocket, he ignored or lost track of the second one which came down on a ballistic trajectory and killed him. I could be remembering that incident wrong...

Another thought: modify the rockets so that if they go ballistic, damage/injuries will be minimal or nonexistant. So maybe replace the tip of a plastic or balsa nose cone with foam, like the foam you find on the nose of those stomp rockets. Then make the fins out of the thinnest balsa possible, and do not do anything to them to make them stronger, such as papering them.

Just some of my thoughts.

 

[smstachwick]

Your main concern is drift distance. If I were you’d I’d limit your altitude by flying larger rockets with small motors, then installing streamers in place of parachutes. Estes Big Berthas flying on B4-2s to 250ft or less and then deploying 2”x20” streamers would be workable.

The suggestions to soften a rocket may be viable. Just remember to check your stability margins and verify that everything is strong enough for flight.

Arrange for the crowd to be made aware of the impending flights prior to the start of the music. Make sure everyone on the field is made aware of misfire protocols so that a rocket experiencing a “hangfire” can’t take off in a linebacker’s face.

 

[lakeroadster]

I think the entire idea is a liability lawyers dream. But as long as @VinceC has an adequate liability insurance policy.. have at it.

@VinceC, are you a NAR member?

 

[mh9162013]

I think the entire idea is a liability lawyers dream.

Especially because any lawsuit will include the school, school district, superintendent and other government officials with insurance policies with limits in the 8 figures...

But I think if the OP is careful, the chances of something bad happening is minimal.

 

[boatgeek]

Assuming this is you...



You can reasonably claim a minimum site dimension of 500' if you include the woods, which gets you up to D motors. I was hoping to be able to get to an E or F motor so you could get a red motor, but no dice. Assuming the crowd is in the white area, then I'd launch from the red X, angling the launch rod well away from the crowd, kind of in the direction of the red arrows. You'll want to check the winds to make sure that the rockets under chute don't land in the crowd. It might be worth checking with NAR to see if you can fly a higher impulse rocket that doesn't go high (spool or saucer) on a 500-ft field.

Larger diameter, high drag rockets will put on a better show. You definitely want to keep the altitude down, probably in the 200-300 foot range to keep rockets on the field.

 

[boatgeek]

Adding on to what other people have said, there are foam "TARC nose cones" out there for BT-80 size tubing. That would probably work pretty nicely for a 200-ish foot flight on a D12.

I think it's really cool that the school wants you to participate in a football game!

 

[dhbarr]

Adding on to what other people have said, there are foam "TARC nose cones" out there for BT-80 size tubing. That would probably work pretty nicely for a 200-ish foot flight on a D12.

I think it's really cool that the school wants you to participate in a football game!

I do confirm that a d12-3 hefts a bt80 foamy tarcy about 60ft with an eggload. I think your estimate is pretty close for a d12-5.

EDIT: and don't simultaneously launch more than 10 or you may have to jump down to C's depending on expected altitude.

 

[Tyeeking]

Unfortunately today’s world is very litigious. Guests at launches sign waivers for a reason.

 

[techrat]

Larger diameter rockets with large wide fins lift off more slowly, and make for a better show. Try and avoid high impulse motors. In other words, if you're flying 24mm, use the smallest 24mm motor that'll get the rocket off the pad, like a C11, or like another poster mentioned, use a Big Bertha with a B6-4, and yes, streamers so that the rocket comes down almost straight from where it lifted off (assuming no wind). You want to avoid hundreds of feet of drift.

 

[cls]

Larger diameter rockets with large wide fins lift off more slowly, and make for a better show.

That's a good point. As experienced rocketeers, we have learned to follow very fast launches. New folks have trouble seeing the fastest and smallest rockets.

 

[Mushtang]

When rockets launch the loud sounds and seeing the rocket shoot up are the most exciting parts for people who don't build them. Watching them come down slowly and silently on parachutes doesn't really match the launch.

My advice is to launch a bunch of loud rockets that give off a lot of smoke on their way up to really boost the experience for them. And at the conclusion, launch a few really big mortar fireworks (the balls that are in thick tubes that shoot way up and make a loud explosion) for a satisfying ending.

I'm assuming it's a day launch so the light from the firework ending won't be seen, only heard. Still would be a more exciting ending than some parachutes.

 

[neil_w]

Also: slow launches are more likely to weathercock. I'd want to stick with higher speeds off the rod to improve the chances of a straight flight.

You could also throw in a saucer and/or a helicopter recovery rocket, both of which are interesting to folks who haven't seen rockets before (heck they're fun for everyone else too). And they'll be a bit more reliable at coming down close to the pad.

 

[georgegassaway]

Large diameter, fairly heavy rockets with larger motors look cool for a crowd.

Absolutely the WRONG type of rocket to fly for a crowd. We are not talking of a crowd showing up at a rocket launch, we are talking about a rocket launch showing up at a football game with a crowd.

No need for anything bigger or heavier than a Big Bertha.

IIRC, the first known R/C airplane fatality, late 1970's, was a plane being flown during halftime at a football stadium. It crashed into the stands and killed a person.

 

[CoronaDuke]

Try this. Foam cups, paper streamers, goes 90 ft.

 

[CoronaDuke]

Or this. Any small rocket, Estes C6 motor, 80 ft crepe paper streamers. Attach two streamers to each rocket, one per fin.

 

[loopy]

Personally, I'd go with a Big Bertha - they can see it, and you can keep it low/slow and still safe since it's a light model. If you want to be impressive, do a saucer on a composite. Will stay very low, and won't drift much.