Postal Tube Project

[Rat]

I've done some searching both here and on EMRR and can't find what I'm looking for. I'm sure it's there somewhere.

Anyway, I've been collecting tubes of all sorts from work but I have an especially nice 2.75" mailing tube (@ 72" long) that I would like to use as a base for a scratch built scale/semi-scale sounding rocket project. Something along the lines of a Nike, Corporal, Black Brandt. The tube has 1/8" thick walls. Is this too heavy for use? Is there some sort of "rule" regarding wall thickness vs. OD?

This will be a first large scale scratchbuild but I spent many years as a scale modeler so I am comfortable with various materials.

Does anyone have any links to a build thread or website that could be of help. I really don't know where to start.

Thanks!

+EDIT+
Just reread this post. What I'm looking for are builds that specifically use postal tubes. Just to clear it up a bit.

Thanks Again!

 

[Stefan_Jones]

I've used postal tubes for special projects.

There are two drawbacks.

One, mailing tubes vary in quality. Some are made of low-grade paper and / or have wraps that aren't well bonded. You can overcome this by treating the tube with Minwax Wood HArdener, which adds a lot of strength and weight. I guess you can use epoxy to coat the ends as well.

Second, you will need to make all of the accessories that are tube-size-related.. Nose cones, centering rings, and couplers / bulkheads.

You can have BMS make the cone and rings, but be prepared to pay a lot.

 

[brianc]

Originally posted by Stefan_Jones
you will need to make all of the accessories that are tube-size-related.. Nose cones, centering rings, and couplers / bulkheads.

I've used Staples mail tubes too.

https://rocketryforum.com/showthread.php?s=&threadid=23334

https://rocketryforum.com/showthread.php?s=&threadid=21558#post240766

The 3" Giant Leap 5:1 plastic cone fits nicely!

https://rocketryforum.com/attachment.php?s=&postid=264407

https://rocketryforum.com/showthread.php?s=&threadid=25689

 

[rstaff3]

I like the mailing tubes from The Container Store. They have full length telescoping tubes (aka couplers) and are good quality. If you are picky about smooth finished, they will take some work - instead of spirals to fill, there are ridges to knock down. The 3" and 4" work well with 'standard cones', but require a little tape.

 

[hokkyokusei]

Originally posted by Rat
I've done some searching both here and on EMRR and can't find what I'm looking for. I'm sure it's there somewhere.

Anyway, I've been collecting tubes of all sorts from work but I have an especially nice 2.75" mailing tube (@ 72" long) that I would like to use as a base for a scratch built scale/semi-scale sounding rocket project. Something along the lines of a Nike, Corporal, Black Brandt. The tube has 1/8" thick walls. Is this too heavy for use? Is there some sort of "rule" regarding wall thickness vs. OD?

+EDIT+
Just reread this post. What I'm looking for are builds that specifically use postal tubes. Just to clear it up a bi

Welcome to the way of the tube

Scratchbuilding, using mailing tubes is very satisfying, but as others have said, it can be a lot of work, if you want a good finish. If you want to do scale, you have the added hassle of finding complementary tubes of the right diameters.

I don't have any specific tips, but you might some inspiration here: www.nsrg.org.uk/projects/tb3

 

[Rat]

Sounds like I'm in for a challenge. Just the way I like it!

Making nose cones sounds like the hardest part. The good news is I can use that as an excuse to finally buy myself a drill press!

Thanks for the links and suggestions.


BTW. brianc - The second link in your list is broken.

-Jim

 

[brianc]

Originally posted by Rat
BTW. brianc - The second link in your list is broken.

THANX! Fixed now.

 

[Rocketcrab]

Last October at the Steel City Smoke Trails launch, a fellow was there who flew a scratchbuilt Mercury Redstone, built from 3" mailing tubes. Flew great on a G64. It planted the seed in my mind to build something outof the numerous mailing and other similar tubes that I've collected over the years. I'm leaning towards a sport-scale 3" diameter Viking, the first version with the Redstone-like fins.

 

[Rat]

Where do I find information on motor lift capabilities? Specifically G and under.

Also, is there some kind of safety margin regarding lifting power. For example if a motor will lift 10oz max do you only build to 8oz leaving a 20% "margin for error"?

Some of these tubes I have seem awfully heavy.

 

[brianc]

Originally posted by Rat
Where do I find information on motor lift capabilities? Specifically G and under.

Also, is there some kind of safety margin regarding lifting power. For example if a motor will lift 10oz max do you only build to 8oz leaving a 20% "margin for error"?

Some of these tubes I have seem awfully heavy.

https://www.info-central.org/propulsion_selection.shtml

https://www.info-central.org/resources_thrustweight.shtml

 

[rstaff3]

My experience is that with up to three inches, it is quite easy to design a wide range of rockets (from 3FNC to oddrocs) that will fly on Fs & Gs. At 4 inches you will need a bit more planning. Two 48" tubes will get heavy fast.