Scratch Express Mail Original Design / Scratch Built

Scratch - Express Mail {Scratch}

Contributed by Drake "Doc" Damerau

Manufacturer: Scratch
(Contributed - by Drake Damerau - 03/30/05) (Scratch) Express Mail

Brief:
Mid power rocket made with free Priority mail boxes, parachute recovery.

Construction:
To build this rocket, you will need two triangle priority mail tubes, packing tape, wood glue, and a hobby knife.

The first step is to make the body. Cut the end flaps off of one of the tubes (picture below-left).

Peel the self stick tape off of the side flap and seal the box. Set this aside for now (picture below-right).

The next step is to make the nose cone. Cut about 9 inches off the end of one of the boxes. Use the end that has the flaps. Now cut the self stick flap from the side. This is the trickiest part of the build. You will need to trim the sides and "work" the fold in the middle to make it fit into the other box. The fit has to be good to ensure that the pressure doesn't leak out and fails to blow off the nose cone. When you get a good fit, use packing tape to close the end and side.

Flaps Tape

(Scratch) Express MailNow you can make the motor mount. I used an 11" x 17" sheet of paper wrapped around a couple of E engines and secured it with some packing tape. Soak the paper liberally with CA to stiffen it up. I did this to keep it a free paper rocket, but you can use a MMT if you wish.

Now make two centering "rings" (centering triangles really) out of the leftover tube. You can use your motor tube to draw circles to cut the holes. You will need to cut a hole for the tube now in the box you made for the body tube. Glue the motor tube assembly in the rocket as you would with any other rocket.

(Scratch) Express Mail Cut three fins out of the remaining box. I chose to glue them to the sides but you can arrange them any way you wish. Launch lugs were made from a discarded Aerotech igniter tube. Recovery can be installed using any system you wish.

The finished weight without recovery was 15.6 oz.

Finishing:
I chose not to finish mine. If you wish to finish yours, I would recommend two coats of primer to seal the cardboard before painting. Another idea would be to just seal it with a clear coat to prevent the cardboard from soaking up moisture.

Flight:
The first flight was on an E16-4W. It looked like it went to about 500 feet. The delay was good but the flight was underpowered. This is an F powered rocket.

Recovery:
I used a 24" paper parachute for this flight. The recovery was good, but it landed in a stream. By the time I got to it, it was soaked beyond repair.

Summary:
This was a fun rocket to build. The price was right and its nice to do something unusual.

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