[roc-chat] Re: E-bay machine screw ?
- From: "Lesnick, Mike" <mikel@xxxxxxxxxxx>
- To: <roc-chat@xxxxxxxxxxxxx>
- Date: Sat, 28 May 2011 12:48:33 -0400
If the only purpose of the screws is to hold the upper air frame on and all of
the pressure will be against the nose cone ( the ejection charge is designed to
blow the nose cone off), eight 4-40 screws should be more than enough.
I just flew a mad Cow Pyron dual deployment kit for the first time last month.
This is an all cardboard airframe kit. I mounted 4 “blind nuts” (brass
inserts) 6-23 thread size in the forward bulkhead of the electronics bay and
used 4 6-32 screws to attach it. Worked perfectly, and as far as I can tell
there was no stress on the upper air frame.
I like being able to take the upper air frame off to have easier access to the
upper end of the electronics bay and the ejection charge holder.
If you have more detailed questions cal me714-323-5968
Mike
Michael Lesnick
Axiom Healthcare Group
18135 Santa Lauretta Cir
Fountain Valley, CA 92708
714-594-5720 - Office Phone
714-323-5968 - Cell
714-968-7076 - Fax
MikeL@xxxxxxxxxxx
From: roc-chat-bounce@xxxxxxxxxxxxx [mailto:roc-chat-bounce@xxxxxxxxxxxxx] On
Behalf Of John Howard
Sent: Saturday, May 28, 2011 8:48 AM
To: roc-chat@xxxxxxxxxxxxx
Subject: [roc-chat] E-bay machine screw ?
Hi All,
I've been a ROC member for a couple years and lurking on roc-chat for about the
same. I am finishing a 4” fiberglass Madcow Nike Smoke for NSL/ ROCstock and
have a hardware question.
The Nike is one of two L2 rockets I am bringing with the hope of dong my L2
Cert flight. I have split the airframe in half and added an electronics bay
built from a fiberglass coupler tube. I am hoping to connect it all together
with machine screws. To load the ejection charge, I’ll unscrew the upper
airframe, load them, then re-attach. The charge will eject the parachute out
with the nosecone. Everything is built and ready to paint. I have drilled 8
pilot holes to mount the coupler tube to the bottom half, and four for the
upper half.
Do you think 4-40 machine screws will be strong enough, or should I use 6-32?
Looking on the web, it looks like 4-40 screws would have enough strength, plus
there will be 8 on the bottom screwed into standoffs/nuts. I could also epoxy
the E-bay in, but I also have a open coupler tube with the same pilot holes so
I could launch the rocket with a motor and motor ejection charge. The “keep it
simple stupid” version.
Thanks ahead of time, and see you in two weeks!
John Howard
Sent from my iThing
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