I frequently use 1/4-20 all-thread in the nose cone to attach weight as
needed. I havent had any trouble with the weight coming loose.
I still haven't seen any explanation of why metal weights are bad.
David Smith
NAR 78668, TRA 15803
Amateur Extra: W6DPS
On Jan 30, 2017 15:05, "R Dierking" <applerocketry@xxxxxxxxxxx> wrote:
Hum a rod in the nose…
I understand the reasoning. But, I think there’s a solution that still
would be safer.
*From: *Adrian P. Bailey <adrian@xxxxxxxxxxxxxxx>
*Sent: *Monday, January 30, 2017 2:55 PM
*To: *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@
freelists.org] *On Behalf Of *Michael Klett
*Sent:* Monday, January 30, 2017 2:49 PM
*To:* ROC Chat <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> 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>
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>
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 <xsive.guy@xxxxxxxxx>
*Sent: *Monday, January 30, 2017 2:15 PM
*To: *ROC Chat <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>
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 <allen.farrington@xxxxxx>
*Sent: *Monday, January 30, 2017 1:59 PM
*To: *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> 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*
