Big Tube

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cryoscum
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Big Tube

Postby cryoscum » Sat Jun 15, 2013 7:17 pm

Hi All

This thread is actually not too specific, but it is relevant to scratch building stuff, so I thought I'd document it.
I've been making 6-ish inch tubes for some time, but they've been rolled on PVC pipe mandrels, making them a non-standard size (approx 6.1" I think) and accordingly you cannot use a standard NC on it. This has never bothered me as I make the NC's too, but it's not ideal for general usability of the tubes. Hence I got some phenolic coupler tube from Blake to make a long & properly sized mandrel, suitable for a 6" minimum diameter project :twisted:

I don't think you can get 6" coupler stiffener tubes (i.e. fits inside coupler tube) so I had to make something that'll do the trick. Ten minutes on the computer and 30 seconds on the laser made this:
1.JPG
1.JPG (42.33 KiB) Viewed 2967 times

This "coupler stiffener" was glued into the 2 tubes right on the joint with epiglue. Similar centering rings were made for the ends and 2 more intermediate positions along the total tube length. After the assembly was carefully aligned and fully cured I gave it a bit of a sand and a coat of laminating epoxy to ensure it isn't effected by moisture. This mandrel is 2.45m in length, so we'll aim to make a 2.4m long tube...
2.JPG
2.JPG (48.25 KiB) Viewed 2967 times
AMRS L3 | NAR L3 | QRS 089 | MDRA 224
AMRS Technical Advisory Group

Total impulse for 2016: 32,458 Ns (thus far)
Total impulse for 2015: 84,231 Ns
Total impulse for 2014: 40,757 Ns
Total impulse for 2013: 62,927 Ns

BerowraRocketBoy
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Re: Big Tube

Postby BerowraRocketBoy » Sat Jun 15, 2013 7:22 pm

nice :)

Your work is always ingenious.
MPR cert: Grey Dot on an F52-8T

Level 1 cert: Ok... so maybe I was a little optimistic putting this in. But if I do do it, then it'll be something fast.

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Re: Big Tube

Postby october sky » Sat Jun 15, 2013 8:27 pm

Such great work again Nic !hmmmm, 6" min diam. rocket.....I have a gut feeling about this what motor might go into something like this.... :P

Ps. and can of bundy there...naturally ! :wink:
QRS Inc. NO: 003

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TRA #11616 L3

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cryoscum
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Re: Big Tube

Postby cryoscum » Sat Jun 15, 2013 9:14 pm

october sky wrote:...and can of bundy there...naturally...


Of course! It makes you smart, strong, cool, ambidextrous, virile, legit, beautiful and confident! Oh yeah, and humble :)
Not to mention: a Queenslanda! (sorta :) )
AMRS L3 | NAR L3 | QRS 089 | MDRA 224
AMRS Technical Advisory Group

Total impulse for 2016: 32,458 Ns (thus far)
Total impulse for 2015: 84,231 Ns
Total impulse for 2014: 40,757 Ns
Total impulse for 2013: 62,927 Ns

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Re: Big Tube

Postby BerowraRocketBoy » Sat Jun 15, 2013 11:41 pm

Hmmm, lets see....

Nope, I'm afraid to say I cannot see any evidence supporting this theory.

Sorry Nic, but I'm just not going to be able to trust you from now on.

:wink:
MPR cert: Grey Dot on an F52-8T

Level 1 cert: Ok... so maybe I was a little optimistic putting this in. But if I do do it, then it'll be something fast.

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CATO
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Re: Big Tube

Postby CATO » Sun Jun 16, 2013 7:46 am

Funny, I was doing the very same thing yesterday...

Nics_School_of_Big_Tube_Rolling.jpg
"In thrust we trust"

AMRS 21 L3
TRA 07459 L3

Impulse:
2018: 14,767 Ns (44% N)
Ns 17: 5,973; 16: 34,558; 15: 35,955; 14: 6,016; 13: 10,208
PB - Gorilla N2717WC, H: 10,260', S: 1.14M

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cryoscum
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Re: Big Tube

Postby cryoscum » Sun Jun 16, 2013 9:36 am

Nice! :)
AMRS L3 | NAR L3 | QRS 089 | MDRA 224
AMRS Technical Advisory Group

Total impulse for 2016: 32,458 Ns (thus far)
Total impulse for 2015: 84,231 Ns
Total impulse for 2014: 40,757 Ns
Total impulse for 2013: 62,927 Ns

Kryten
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Re: Big Tube

Postby Kryten » Sun Jun 16, 2013 2:48 pm

I can't see the can of Toohey's in that pic
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Re: Big Tube

Postby CATO » Sun Jun 16, 2013 3:36 pm

Opps, yes, forgot, sorry, don't have any Toohey's...

Back to the "Nic Lottering School Of Big Tube Rolling"...
NLSOBTR_1.jpg

NLSOBTR_2.jpg

NLSOBTR_3.jpg

NLSOBTR_4.jpg

NLSOBTR_5.jpg

NLSOBTR_6.jpg
"In thrust we trust"

AMRS 21 L3
TRA 07459 L3

Impulse:
2018: 14,767 Ns (44% N)
Ns 17: 5,973; 16: 34,558; 15: 35,955; 14: 6,016; 13: 10,208
PB - Gorilla N2717WC, H: 10,260', S: 1.14M

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Re: Big Tube

Postby ROCKet STAR » Sun Jun 16, 2013 4:14 pm

CATO wrote:Opps, yes, forgot, sorry, don't have any Toohey's...


How about Canadian Club? :twisted:
Chris Barnes

AMRS# 29 - L3

UKRA - L3

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cryoscum
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Re: Big Tube

Postby cryoscum » Sun Jun 16, 2013 4:28 pm

Heheh, looks like that trick just works everytime! It also works for friction fitted motors with too much masking tape!

The real truth is that THIS is the reason why you need to build your rockets ultra-strong :)
1.jpg
1.jpg (234.6 KiB) Viewed 2873 times

2.jpg
2.jpg (225.99 KiB) Viewed 2873 times
AMRS L3 | NAR L3 | QRS 089 | MDRA 224
AMRS Technical Advisory Group

Total impulse for 2016: 32,458 Ns (thus far)
Total impulse for 2015: 84,231 Ns
Total impulse for 2014: 40,757 Ns
Total impulse for 2013: 62,927 Ns

User avatar
cryoscum
STOP... Hammer Time The Prodigy
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Posts: 1802
Joined: Wed Oct 06, 2010 2:54 pm
Location: QLD, NSW & VIC

Re: Big Tube

Postby cryoscum » Mon Jun 17, 2013 5:27 pm

Given that the temp in the shed is currently 6 deg C and dropping, there's little point to mess around with anything using epoxy, so I thought I'd post something about the table extension I made yesterday. I very much need the flat & open table space during the rolling process, so a mandrel longer than the table becomes problematic. An add-on & collapsable section to the table makes the most sense as you don't want to lose the floor area. $20 of 16mm white board, some off-cuts I had lying around and 1.5 hours had it ready...
1.JPG
1.JPG (39.42 KiB) Viewed 2842 times

2.JPG
2.JPG (41.88 KiB) Viewed 2842 times
AMRS L3 | NAR L3 | QRS 089 | MDRA 224
AMRS Technical Advisory Group

Total impulse for 2016: 32,458 Ns (thus far)
Total impulse for 2015: 84,231 Ns
Total impulse for 2014: 40,757 Ns
Total impulse for 2013: 62,927 Ns

BerowraRocketBoy
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Re: Big Tube

Postby BerowraRocketBoy » Mon Jun 17, 2013 9:40 pm

And the mandrel extends too! Very smart indeed.
MPR cert: Grey Dot on an F52-8T

Level 1 cert: Ok... so maybe I was a little optimistic putting this in. But if I do do it, then it'll be something fast.

Jase69
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Re: Big Tube

Postby Jase69 » Thu Jun 20, 2013 7:26 pm

Cyro, I had the same tube dia problem with my first build. The way I overcome it was to take another length of tube the same size and Dremal one cut top to bottom, then I rolled it to fit inside the tube, mark and cut off the excess. I would then CA+ Med the tube back together, sand slightly and epoxy a layer of 3/4oz cloth to the outside. A strip of 3/4oz was cut 25mm wide and epoxied over the join on the inside. It turned out perfect and was very quick and easy to do.

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Re: Big Tube

Postby Jase69 » Mon Jun 24, 2013 8:02 pm

Cryo would you still consider building a foam core tube like you did in your Maverick build for this sized tube?


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