You support it with a bracket across the bulkhead to which the shock cord is
attached…
From: roc-chat-bounce@xxxxxxxxxxxxx [mailto:roc-chat-bounce@xxxxxxxxxxxxx] On ;
Behalf Of richsilv@xxxxxxxxxxx
Sent: Monday, January 30, 2017 3:16 PM
To: roc-chat@xxxxxxxxxxxxx
Subject: [roc-chat] Re: Prohibiting Metal for Nose Weight
One must be really careful when coming up with these removable mass
devices/features… And make sure that (now likely smaller mounting point) will
stand up to the stresses you are going to put them under… I can easily see
where a “Bolt” epoxied into a Nose Code could much more easily rip out than
that same mass of BBs (say… Or feathers if you like… Packing peanuts) epoxied
into the Nose…
From: roc-chat-bounce@xxxxxxxxxxxxx<mailto:roc-chat-bounce@xxxxxxxxxxxxx>
[mailto:roc-chat-bounce@xxxxxxxxxxxxx] On Behalf Of Adrian P. Bailey
Sent: Monday, January 30, 2017 2:56 PM
To: roc-chat@xxxxxxxxxxxxx<mailto:roc-chat@xxxxxxxxxxxxx>
Subject: [roc-chat] Re: Prohibiting Metal for Nose Weight
I went looking for advice on this a while ago. I didn’t want to epoxy lead shot
into the nose as that’s permanent but I did want something dense that I could
position as far forward as possible, to avoid adding unnecessary mass. A steel
threaded rod, epoxied into the tip of the nosecone, could be used to add custom
weights as necessary.
From: roc-chat-bounce@xxxxxxxxxxxxx<mailto:roc-chat-bounce@xxxxxxxxxxxxx>
[mailto:roc-chat-bounce@xxxxxxxxxxxxx] On Behalf Of Michael Klett
Sent: Monday, January 30, 2017 2:49 PM
To: ROC Chat <roc-chat@xxxxxxxxxxxxx<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
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
