hmm since I'm a composite guy I'm thinking about a combo of;
https://midwesttungsten.com/tungsten-bucking-bar-bb-1-1-64-lbs-5-8-x-1-x-4/?gclid=CNOG5LyL69ECFQNrfgodvnkHlA
http://unitednuclear.com/index.php?main_page=product_info&cPath=16_17_69&products_id=89
Should make everyone unhappy that way.
Lets start with making sure the pads are tilted away from the range then
go from there.
Mike (wow this is a great endorsement for a forum) Kramer
On 1/30/2017 3:56 PM, Gregory Lyzenga wrote:
Jeez, I can’t leave you guys alone for one afternoon without filling my inbox! I literally could not delete messages faster than they were coming in! ;-)
I don’t have too much to add, but just one “old guy” comment…
From a historical perspective, it was always my impression that a primary (if not only) rationale for the “no metal” rule was to avoid shrapnel in the event of a motor cato. Explosive catos were a much more common event in the early days of amateur rocketry, but seem to be thankfully very rare with today’s modern motors and casings. In that context, I think I come down more on the side of treating all massive components as potentially dangerous when traveling at high speed, regardless of whether they happen to have a free electron above the valence band.
- Greg
On Jan 30, 2017, at 3:22 PM, R Dierking <applerocketry@xxxxxxxxxxx <mailto:applerocketry@xxxxxxxxxxx>> wrote:
Ok, might be a little off-topic. But, this kind of thing (discussion/consideration/thinking out of the box), is not only interesting, but necessary. Otherwise, it goes like, incident, rule, incident, rule. How much fun would that be. Or, how about, let’s do the same damn thing all the time.
Remember, some people were discussing the current condition of the lakebed and it’s not even February. Sorry, but come on guys! You all have been going to the lakebed enough times to know this is kind of pointless now.
OK, I’m a pain. I’m actually being nice. I have hundreds of these topic things. 😊
One thing that I know, when you bring something up that flies in the face of established dogma, watch out! And, the reasons people will stand on to defend; OMG.
For example, I once said that it was dangerous launching one rocket after another without knowing the fate of the previous rocket. And, people said, “what about the line of people waiting!” So, I replied, I have a bow, not a powerful one, but I will stand by the low power pads, and shoot one straight as possible into the air, and then immediately fire another. “You can’t do that!” “That’s dangerous!”
I’m accumulated a list of things. But, I don’t keep track.
So, did the lakebed dry a little while we were chatting?
*From: *R Dierking <mailto:applerocketry@xxxxxxxxxxx>
*Sent: *Monday, January 30, 2017 3:07 PM
*To: *Michael Klett <mailto:xsive.guy@xxxxxxxxx>; ROC Chat <mailto:roc-chat@xxxxxxxxxxxxx>
*Subject: *[roc-chat] Re: Prohibiting Metal for Nose Weight
Not taking feathers. Considering the differences between pieces of metal material and particles of other solid materials. Or, even water.
*From: *Michael Klett <mailto:xsive.guy@xxxxxxxxx>
*Sent: *Monday, January 30, 2017 2:49 PM
*To: *ROC Chat <mailto:roc-chat@xxxxxxxxxxxxx>
*Subject: *[roc-chat] Re: Prohibiting Metal for Nose Weight
Yes, they weight the same but their volume can be very different. If the volume difference is significant (lead vs. feathers) you may need more weight to counteract the location of the CG of the weight.
On Mon, Jan 30, 2017 at 2:37 PM, David Smith <davew6dps@xxxxxxxxx <mailto:davew6dps@xxxxxxxxx>> wrote:
Mike,
An ounce of BBs weighs the same as an ounce of sand.
Mass is Mass.
Dave
On Mon, Jan 30, 2017 at 2:34 PM, Michael Klett
<xsive.guy@xxxxxxxxx <mailto:xsive.guy@xxxxxxxxx>> wrote:
No, mass is not mass. If I needed 4 oz of weight at the tip
I would need a pound at the middle (depending the length of
the rocket, placement of CP an CG etc. The point is the
lever arm.) With lead I can get really close to the tip. With feathers I'd need a lot more volume and the cg of the
mass would not be near the tip so I'd need perhaps a pound of
feathers to be equivalent to the 4 oz in moving the rocket's
CG. The length of distance between the center of Mass of the
rocket without the weight and the center of mass of the added
weight determines how much weight you need to add. At the
tip "less is more".
But to your other point. Once I add the epoxy to keep the
sand in place it in fact becomes "trash" on the playa because
of the epoxy. And if I've used the epoxy and things come
apart a 4 oz blob of sand/epoxy is going to hurt just as much
(probably) as a 4 oz blob of lead/epoxy.
Sorry, I don't see any benefit to changing materials
currently. Although I must admit your idea of using water for
ballast on the way up and letting it drain out on the way
down to reduce weight at landing has always fascinated me.
Thanks,
Mike
On Mon, Jan 30, 2017 at 2:19 PM, R Dierking
<applerocketry@xxxxxxxxxxx
<mailto:applerocketry@xxxxxxxxxxx>> wrote:
Sorry Mike. I believe you have not considered other
things and went to what you knew first.
Yes, mass is mass. I don’t think anyone needs a high
density material for nose weight. It’s just not that
critical.
However, it would probably be impossible for me to
convince anyone that insists on metal material. But,
what the heck, I’m trying anyway.
Richard
*From: *Michael Klett <mailto:xsive.guy@xxxxxxxxx>
*Sent: *Monday, January 30, 2017 2:15 PM
*To: *ROC Chat <mailto:roc-chat@xxxxxxxxxxxxx>
*Subject: *[roc-chat] Re: Prohibiting Metal for Nose Weight
Richard,
My ballast of choice is lead BBs. They seem safely
captured in epoxy. I would also argue that by using lead
they occupy less volume so I can get the center of the
mass of the BBs further in to the tip of the nose cone
and so I need less weight. Less weight is safer. If I
tried to put the weight in the AvBay for instance, I'd
need a lot more weight to balance the rocket and the
additional weight would reduce the safety some.
Thanks,
Michael
On Mon, Jan 30, 2017 at 2:05 PM, R Dierking
<applerocketry@xxxxxxxxxxx
<mailto:applerocketry@xxxxxxxxxxx>> wrote:
Then why do even people with model rockets use metal?
The RSO wouldn’t want someone with an aluminum nose
cone on a HP rocket but accepts rockets with a nose
containing bolts or lean shot. And, having taken a
nose apart that had bb’s set in 5 minute epoxy, the
epoxy cracks and releases the bb’s.
*From: *Allen Farrington <mailto:allen.farrington@xxxxxx>
*Sent: *Monday, January 30, 2017 1:59 PM
*To: *roc-chat@xxxxxxxxxxxxx
<mailto:roc-chat@xxxxxxxxxxxxx>
*Subject: *[roc-chat] Re: Prohibiting Metal for Nose
Weight
Tripoli has an official statement on using
metal...you can find it on their website here:
http://www.tripoli.org/Portals/1/Documents/Safety%20Code/Metal%20in%20Rocket%20Construction%20v2.0.pdf
<http://www.tripoli.org/Portals/1/Documents/Safety%20Code/Metal%20in%20Rocket%20Construction%20v2.0.pdf>
Allen
Sent from my iPad
On Jan 30, 2017, at 1:50 PM, R Dierking
<applerocketry@xxxxxxxxxxx
<mailto:applerocketry@xxxxxxxxxxx>> wrote:
Next time the NAR and TRA safety rules are revised,
there should be something about what kind of nose
weight should be used or how about shouldn’t be used.
Don’t the codes already say something about
minimizing the use of metal? Why add it? There’s no
good reason why metal has to be used; there are
other things that would work fine.
And, just to get ahead of the one response that’s
going to ask if a rocket with other types of weight
could hurt someone just as bad. Yes, I realize
that. But, again, if you think through the various
failure scenarios, metal (bolts, lead shot, bb’s,
what ever…) is a poor choice for nose weight.
What other things could be used? Things that would
be even better for both safety and performance.
Richard Dierking
--
*Justice shall flourish in his time, and fullness of
peace for ever.*
*Psalm 72*
--
*Justice shall flourish in his time, and fullness of peace
for ever.*
*Psalm 72*
-- David P Smith
NAR 78668, L2
Amateur Extra, W6DPS
--
*Justice shall flourish in his time, and fullness of peace for ever.*
*Psalm 72*
----------------------------------------------------------
Gregory A. Lyzenga <lyzenga@xxxxxxx <mailto:lyzenga@xxxxxxx>>
Dept. of Physics, Harvey Mudd College (909) 621-8378 <tel:%28909%29%20621-8378>
Claremont, CA 91711-5990 mobile (626) 808-5314 <tel:%28626%29%20808-5314>
