Scratch built "Priority Mail"

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smiler82

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Hello all, I've lurked here for a while, but decided I needed some input before a build...

I did lots of LPR as a youngster, and I am now getting back into this great hobby as my kids are getting bigger. My brother knows this and gave me a Priority Mail shipping tube thinking I could built a rocket out of it... hence the name Priority Mail.

Any of you who have handled these tubes know that they are fairly stout, maybe even too heavy. The tube I have is about 30" long, 2" diameter, and I'd estimate the wall thickness at over 1/16". My plan was to build this for 24/29mm and try to keep the budget as close to 0 as possible; hand made nose cone, motor mount, bulkhead(s), recovery, etc. I've never done MPR before, so I have/will be trolling these pages for info. My goal is not altitude or speed, just a very durable rocket that can be launched over and over, and be built on the cheap.

Now onto my ?'s:

I have some 1/4" pine stock laying around, and I was thinking about using this for some very stout fins. Any downsides to this? Weight is the first one I can think of...

I have not yet played with any Sim programs, so I'm wondering if my motor choices are right. I have lots of experience with Estes BP motors, and I have plenty of E9-4's laying around. My plan is to build this for 29mm and then adapt it down to 24mm for the first few flights.


Thanks in advance for any input...

Brian
 
Try Openrocket, it is a free sim program. I love it, and play around on it a lot.
 
1/4" is way to big and heavy. You could easily get by with 1/8" stock.

Kevin
 
Yep, you don't need 1/4" fins unless you'e flying it on 38 or even 54mm HPR motors. Your 1/16" tube also sounds like way overkill. It'll work, but the rocket is going to be extremely heavy. If you want to fly it on 24mm motors, you need to get some single-use composite motors. An E9-4 just won't have enough kick, unless you make an interchangeable motor mount with the option to cluster three 24mm motors. (Believe me, that can get expensive fast. 29mm is definitely your best option here.)
Here's the link to OpenRocket: www.openrocket.sourceforge.net
If you want to use a mailing tube, there are much thinner walled ones available. In fact, if you don't mind the extra drag, you can get 3" mailing tubes that are so much thinner that they probably weigh less than your tube.
Good luck with your project! :)
 
Thanks for all the info shared; I am playing with OpenRocket now and I am liking it. It's clear that I need more measurments before going any further...
 
smiler82 said:
Hello all, I've lurked here for a while, but decided I needed some input before a build...

I did lots of LPR as a youngster, and I am now getting back into this great hobby as my kids are getting bigger. My brother knows this and gave me a Priority Mail shipping tube thinking I could built a rocket out of it... hence the name Priority Mail.

Any of you who have handled these tubes know that they are fairly stout, maybe even too heavy. The tube I have is about 30" long, 2" diameter, and I'd estimate the wall thickness at over 1/16". My plan was to build this for 24/29mm and try to keep the budget as close to 0 as possible; hand made nose cone, motor mount, bulkhead(s), recovery, etc. I've never done MPR before, so I have/will be trolling these pages for info. My goal is not altitude or speed, just a very durable rocket that can be launched over and over, and be built on the cheap.

Now onto my ?'s:

I have some 1/4" pine stock laying around, and I was thinking about using this for some very stout fins. Any downsides to this? Weight is the first one I can think of...

I have not yet played with any Sim programs, so I'm wondering if my motor choices are right. I have lots of experience with Estes BP motors, and I have plenty of E9-4's laying around. My plan is to build this for 29mm and then adapt it down to 24mm for the first few flights.


Thanks in advance for any input...

Brian
Click to expand...

Hi, Brian. My local club had a contest a few years back, "El Cheapo", to build a rocket out of non-rocket parts as cheaply as possible. I used the three sided Priority Mailing tube as the body and nose cone, and flat-sided Priority Mailing boxes (doubled up) for the fins. It flew on a cluster of 3 D-12's, but the three second delay was about 2 seconds too long. The good news is it is easily (and cheaply) repairable.

To answer your question about stout fins, IMHO, they would be way overkill. Thin fins are just fine, they'll be plenty strong for the relatively low speeds these fat tubes will achieve. Looking forward to following your build.

Sather
 
Yeah, forget the 1/4" pine and go with 1/8" birch plywood. Good luck on sticking with the "cheap" budget though.
 
Your 1/4 inch stock is a bit thick but that doesn't mean it won't work for you. If you're determined to build to keep the cost close to zero I can see no reason why the pine stock won't work. Frankly I'd probably use the pine to build a bird house but I like birds.

A quick and dirty 3fnc Open Rocket design using a 30x2x1/16" tube and 1/4"pine fins shows about 1000ft and good speed off of a 4 foot rod using a F50 motor.

What were you thinking about for a nose cone? Look at your dollar store for an umbrella=$1 dollar parachute. While at the dollar store pick up a long nylon dog leash=$1 shock cord.
 
Priority Post - when it positively has to get there.

This model was constructed from a 2.5" mailing tube, using a standard LOC cone. I had to peel a bit of the inside of the tube at the forward end to accommodate the nose shoulder.

John
 
I have a couple of pictures of two rockets I built using mailing tubes. The Pershing is made with a 3.75" diameter tube and the Nike Apache is a little over 3". I made custom nose cones and the transition for the Apache to fit the tubes. They both have a 29 mm motor tube and fly very nicely.

Pershing 1A #.jpgNike Apache.jpg
 
SteveL said:
I have a couple of pictures of two rockets I built using mailing tubes. The Pershing is made with a 3.75" diameter tube and the Nike Apache is a little over 3". I made custom nose cones and the transition for the Apache to fit the tubes. They both have a 29 mm motor tube and fly very nicely.

View attachment 98821View attachment 98822
Click to expand...

Those are some very nice rockets!
 
SteveL said:
I have a couple of pictures of two rockets I built using mailing tubes. The Pershing is made with a 3.75" diameter tube and the Nike Apache is a little over 3". I made custom nose cones and the transition for the Apache to fit the tubes. They both have a 29 mm motor tube and fly very nicely.

View attachment 98821View attachment 98822
Click to expand...

They both look awesome!
 
Here's a rocket I made with a 2" mail tube and a plastic kids meal toy. It has a dual 24mm motor mount. I called it Cloudy with a Chance of Turbulence. The wrap was made with white adhesive paper that I printed clouds onto.

DSC01122.JPG

DSC01123.JPG
 

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Mailing tubes are great for rockets. I built the "Going Postal" using 2 - 2" tubes from Staples, the Estes upscale that I'm doing is based on a 1 1/2" mailing tube.
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