Gifted Engine: MM-H-38

A article all about the recently received MM-38 rocket motor, featuring dimensions, a banana, and a design or 2 of my own

I recently got into contact with a veteran experimental rocketeer, who generously provided his help with my rocketry program

He generously provided help designing my own engine (more on that later), lent us a Emco Unimat 3 lathe to build that engine

He also provided me with a engine I have christened MM-H-38 (Metal Motor, H Class, 38 mm)
I might name it something else, for example H280-38 (H Class, 280 Newton Seconds, 38 mm) or 280H38 (280 Ns, H Class, 38 mm, with the H acting as a dash)
Nothing is set in stone (or metal) yet, so we shall see what it ends up being

Its 38 millimeters in diameter, has a nozzle of stainless steel, and a impulse of 280 newton seconds! (56 times as powerful as R-7! which was 5 newton seconds)

Here are some pictures:

LeathermanⓇ Wave+ for scale
Banana For Scale, as is tradition
Disassembled Engine with Scale Banana and LeathermanⓇ Wave+
Bulkhead (Bottom)
Bulkhead (Top), With holes drilled about 1cm down to save weight and ease removing (I think)
It even has threads!
Stainless Steel Nozzle
Soot from previous use
Steel Retaining Rings
Steel Retaining Ring Groove

Edit: I also designed and 3D printed some wall brackets to store and display this new engine, pictures follow

Proudly Asymmetrical

Here are some Dimensions:
MM-H-38 is (roughly) 29 cm long including the nozzle, and 38 mm in diameter
Other measurements removed due to being boring
The casing is 38mm in diameter, 1.5mm thick, and 26.3 cm long, or 28.8 cm including protruding nozzle
The Bulkhead is 3cm long
The Nozzle is 4.6cm long, and both it and the Bulkhead are 34.5 mm in diameter

I also got a bag with spare O-Rings and Snap Rings in case they get lost or deteriorate

Mass (Dry)Grams
Snap Ring3.2
Dry Mass is mass without fuel, Wet Mass is currently unknown

Now, since this rocket is gifted, I don’t yet know a lot about it
For now, I will be focusing on digitizing this engine (done), and developing fuel grains and the supply chains to make them

I also, as mentioned before, got access to a Emco Unimat 3 tabletop metal lathe to develop my own engine

Very Fancy
Now, before you can make a engine, you need a design
I have also been working on that:


V2 is the current version as of time of writing (28/05/2021)
It has a lot of work needed still, mainly the nozzle is imperfect and none of the parts have sealing yet
More explanation will be provided when its actually finished

Now this article was mostly just posting pictures and giving a slight update on new tools and developments, but once more stuff has been done it will of course get more in depth explanations

I would also like to thank this fellow rocketeer for the great help, resources, and kind gifts, they are very much appreciated!

3 thoughts on “Gifted Engine: MM-H-38”

Leave a Reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.

By continuing to use the site, you agree to the use of cookies. more information

The cookie settings on this website are set to "allow cookies" to give you the best browsing experience possible. If you continue to use this website without changing your cookie settings or you click "Accept" below then you are consenting to this.