[roc-chat] Re: Shock cord attachment advice
- From: R Dierking <applerocketry@xxxxxxxxxxx>
- To: "roc-chat@xxxxxxxxxxxxx" <roc-chat@xxxxxxxxxxxxx>
- Date: Sun, 5 Jan 2014 15:17:40 -0800
Jack did you mean the motor will not be ejected with the Aeropack? :-)
Also, I'm trying to follow this; is the rocket 54 mm minimum diameter, or a 38
mm mount like a stock Vulcanite?
From: jackgaribaldi@xxxxxxx
To: roc-chat@xxxxxxxxxxxxx
Subject: [roc-chat] Re: Shock cord attachment advice
Date: Sun, 5 Jan 2014 14:21:16 -0800
No worries just remember if you choose the Aeropack retainer you cannot use
motor ejection any more in that rocket so you also could glue another centering
ring in like a 54mm with a 29mm hole on top of your other one with an eyebolt
in it too Jack G From: roc-chat-bounce@xxxxxxxxxxxxx
[mailto:roc-chat-bounce@xxxxxxxxxxxxx] On Behalf Of Dave M
Sent: Sunday, January 05, 2014 1:25 PM
To: roc-chat@xxxxxxxxxxxxx
Subject: [roc-chat] Re: Shock cord attachment advice Thanks guys. (For some
reason I never got Cliffs message until I saw Jack's response -- nothing in my
spam folder either. Yahoo malware??) Jack -- I'm going to contact you about the
Aeropack retainer. Dave From: Jack Garibaldi <jackgaribaldi@xxxxxxx>
To: roc-chat@xxxxxxxxxxxxx
Sent: Sunday, January 5, 2014 12:51 PM
Subject: [roc-chat] Re: Shock cord attachment advice
Hi Dave
If you have to fly motor ejection then Cliff's way is good or the Estes way
and glue some Kevlar to the side of your airframe, if you don't use motor
ejection and use electronics then Aeropack has minimum diameter motor
retainers with an eye bolt on top or you can make something custom like the
anchor point with holes for motor ejection they both epoxy into your
airframe.
Jack G
-----Original Message-----
From: roc-chat-bounce@xxxxxxxxxxxxx [mailto:roc-chat-bounce@xxxxxxxxxxxxx]
On Behalf Of Cliff Sojourner
Sent: Sunday, January 05, 2014 12:20 PM
To: roc-chat@xxxxxxxxxxxxx
Subject: [roc-chat] Re: Shock cord attachment advice
hi Dave, I've had good results in this situation using about 20 feet of 1/4"
kevlar. tie a slip-knot at one end and wrap it around the back of the
motor, lead the loose end through the MMT, in to the airframe and tie on the
nose cone. the friction & loop are solid enough, the long length gives a
soft enough thwak that it won't break anything.
personally I have given up on pistons.
Cliff
On 2014-01-03 17:53, Dave M wrote:
> I have a 2.1" diameter Vulcanite that was built per LOC directions where
you glue a loop of string down inside the aft tube and then attach the
elastic cord. This worked a few times until the elastic cord snapped in two.
I replaced the elastic with a Kevlar cord and it worked great. However, I
noticed later that one side of the loop of sting that was glued inside the
tube had almost broke free (the glue had separated from the tube). I've
never built a minimum diameter rocket, but I'm thinking there are better
ideas than this to attach the shock cord. Are the min diameter rockets using
a piston design i.e. PML? The centering ring for these rockets are too small
to make any kind of attachment.
>
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