Thank you Cris!!! Yes, I suggest watching the clock for 25 seconds and
thinking, do we wait this long?
And, some people use really small drogues. My rockets come down close to 200
fps. Adding the time when the rocket is no longer seen and bumping over apogee
it’s like a minute before you would see it again. Would it hurt getting hit by
a 5 lb. rocket going 200 fps? This is why rockets must take a significant
trajectory away from people and all their stuff. If people are not always
doing this, then it must be assured.
The Board is doing things to help with this, and I know it. I appreciate it.
I don’t think it’s enough. A long time ago when I played football, my coach
used to say I wasn’t trying enough. I thought, dang, really! But, that was a
football coach and this is me. ;-). Is there any wonder why there’s resentment
at times when I bring stuff like this up.
This is important. The consequences are too great. Like TRA President Steve
Shannon said, “Don’t accept as conventional wisdom that rockets are going to
cross the flight line."
Richard Dierking
On Dec 17, 2018, at 11:33 AM, Cris Erving
<cris.erving@xxxxxxxxxxx<mailto:cris.erving@xxxxxxxxxxx>> wrote:
From the (fortunately few) ballistic recoveries that I have had, I have been
able to get altimeter data from them and the terminal velocity of the rockets
was in the 400 fps range. So, your rocket coming down ballistic from a 10,000'
apogee would be down in something a bit more than 25 seconds... that's a lot
more than 10 seconds, for sure.
Eggtimer Cris
________________________________
From: roc-chat-bounce@xxxxxxxxxxxxx<mailto:roc-chat-bounce@xxxxxxxxxxxxx>
<roc-chat-bounce@xxxxxxxxxxxxx<mailto:roc-chat-bounce@xxxxxxxxxxxxx>> on behalf
of R Dierking <applerocketry@xxxxxxxxxxx<mailto:applerocketry@xxxxxxxxxxx>>
Sent: Monday, December 17, 2018 11:23 AM
To: roc-chat@xxxxxxxxxxxxx<mailto:roc-chat@xxxxxxxxxxxxx>
Subject: [roc-chat] Re: Range Management and Complex Rockets
Yes, I agree. And, if we had more reassurance that rockets took trajectories
away from the spectator area (people!) then that would help.
Think about this; if rockets were consistently positioned that they took
trajectories away from the flight line even night launches would be safer. If
you saw rockets flying away from the spectator area all day, wouldn’t there be
more comfort with the night launches?
And, this goes for all rockets including model rockets.
Here’s what I do and I’m curious what other people do. I’ve confirmed that it
works btw by predicting then comparing with the result. I use trig to figure
out the launch angle. Yes, you have to start with a stable rocket and not
launch under some crazy condition. I think that launching when the wind is
around 20 mph is crazy. My maximum is 10 mph. First, I think about how far
away from the pad I want the rocket to be at apogee. Say, 400’ or 500’. Then,
I look at the sim’d altitude, say 8000’. Using these two estimates and the
arctan function, you can calculate the angle of the rail away from the flight
line. (You can also use arccos(x) btw, I just used arctan(x)). You will find
that the angle is probably more than you would guess. And that’s just it.
When you ask someone to lean the rod/rail away from the flight line and they
use 2 degrees or miss completely because it’s difficult to judge if you are not
used to it.
I’m disappointed that no one answered the question of how long it takes for a
rocket to descend from 10,000’ without deployment. I’ve been at launches just
like the rest of you when a rocket is launched and disappears with no event and
people wait like 10 seconds (I’ve counted) and say “well, it’s down by now.”
Hum, really? How about, it could be really accelerating right now so everyone
should be focused on the sky above them.
Richard Dierking
On Dec 17, 2018, at 10:51 AM, Duvall, Rick
<RDuVall@xxxxxxx<mailto:RDuVall@xxxxxxx>> wrote:
Richard,
My point is that generally a rocket with a fully deployed recovery system does
not need to be watched all the way to the ground. Once there is an unverified
deployment, we wait until it is verified or enough time to return to earth.
Large rockets under chute heading to the spectator area would pause launching
as well.
I believe we are basically in agreement. An “as expected” launch away from the
spectator area does not need to hold up other launches.
Rick
From: roc-chat-bounce@xxxxxxxxxxxxx<mailto:roc-chat-bounce@xxxxxxxxxxxxx>
[mailto:roc-chat-bounce@xxxxxxxxxxxxx] On Behalf Of R Dierking
Sent: Thursday, December 13, 2018 7:28 PM
To: roc-chat@xxxxxxxxxxxxx<mailto:roc-chat@xxxxxxxxxxxxx>
Subject: [roc-chat] Re: Range Management and Complex Rockets
Good question Rick.
I would be more concerned with rockets that were not under drogue/main. How
about this for a partial answer; just because a rocket goes out of sight
doesn’t mean you can launch the next one.
I believe there is a lot of pressure to launch fast. But, if safety is truly
first, the pace of launching is based on how fast rockets can be safely
launched and tracked, not how long the line is. So, if a rocket is launched
and goes out of sight, everyone should be focused on watching for that rocket,
not diverting their focus to the next launch. If many people are looking for
the rocket that was launched, and it happens to be coming down hot in the
spectator area, there’s a much better chance it will be spotted and people
alerted to the danger.
And, how long does it take for a rocket that goes 10,000’ to come down when
there isn’t any deployment? It takes longer than many people guess.
Here’s my analogy. I have a 50# bow and probably could shoot an arrow straight
up to about 400’. If I did this, the arrow would disappear around apogee. If
I shot one up, and immediately said after, OK, now watch this next one,
everyone would think that was really dangerous, right? So, what’s the
difference? Does anyone think an arrow would be more dangerous than a rocket
coming down hot?
I believe that this is the kind of thing that Steve Shannon was speaking about
when mentioning how people start to accept things that are really unacceptable.
Richard Dierking
On Dec 13, 2018, at 4:33 PM, Duvall, Rick
<RDuVall@xxxxxxx<mailto:RDuVall@xxxxxxx>> wrote:
Richard,
Under Launch Management: What do you consider “knowing the fate” of the rocket
being flown? I consider the fate “know” when there is a safe recovery
deployment and a safe decent rate. Would you agree with that determination? I
pride myself on being able to say that as LCO I have had 8 individually
launched rockets safely descending under chute at the same time.
Rick “the lurker” DuVall
From: roc-chat-bounce@xxxxxxxxxxxxx<mailto:roc-chat-bounce@xxxxxxxxxxxxx>
[mailto:roc-chat-bounce@xxxxxxxxxxxxx] On Behalf Of R Dierking
Sent: Wednesday, December 12, 2018 8:55 AM
To: roc-chat@xxxxxxxxxxxxx<mailto:roc-chat@xxxxxxxxxxxxx>
Subject: [EXTERNAL] [roc-chat] Range Management and Complex Rockets
I suggest you read the From the President article by Steve Shannon in the Fall
2018 Tripoli Report. It’s good, and I agree with most of the things that Steve
said, but there’s one thing he states that kind of re-ignited my ‘passion’ for
safety, and why we need to change our view. In the article in regards to pad
management, Steve states, “Put a slight tilt on the rails to launch away from
the flight line.” I get what he is saying, but this is not quite correct, and
I believe this has created some confusion. I believe it’s best to say to
position the rail at significant angle so that the trajectory will not be over
people. Here’s why there’s an important difference. Rockets tend to have a
dispersion of flight angles when they leave the pad and rail. It varies with
the rocket, motor, pad, and of course, conditions. I have heard that the rail
was leaned slightly away from the spectator area, but the rocket still flew
over the area. This doesn’t mean that leaning rockets doesn’t work. It only
means the rail was not tilted enough.
I know that people don’t like long chat posts, so I’m going to summarize a bit
and look forward to comments.
Range Management: It’s particularly important at launches that are attended by
unexperienced flyers and spectators that pad rails be leaned away so that
rockets don’t take trajectories over people. This may mean leaning rockets at
angles that people are not used to. This should be continually monitored and
adjusted if necessary. The objective is that a rocket taking a trajectory over
people is a rare occurrence. Further, if leaning away from the spectator area
is not consistently working, someone needs to take a close look at the pads and
rail construction and length.
Launch Management: A new rocket should never be launched until the fate of the
current rocket being flown is known. To launch one rocket right after another
is an extremely dangerous practice.
Complex Rockets: All complex rockets should have a written check off list.
More complex, then longer more detailed list. This should be required at
rocket inspection prior to pad assignment. If a complex rocket must be
recycled, this should only be done under the supervision of the RSO.
Personally, I always consult my check off list first if my rocket needs to be
recycled.
Don’t just say safety first, don’t except things that are not safe, and speak
up when you see something that is wrong. We all make mistakes and need to know
that others are watching out for us. And, sorry if this is raw, but you will
never idiot-proof rocketry, but you can control the idiots.
Richard Dierking
TRA 11366, L3
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