Most of us interested in inertial propulsion eventually find themselves imagining their own version of a “Universal Drive” — a mechanism that could produce thrust using only internal motion. So I’m just curious… Hypothetically… What kind of mechanism have YOU been thinking about? Would it use rotating masses, reciprocating masses, or something else entirely? Where would the asymmetry come from? Would it produce a continuous push, or a pulsed impulse? No need for a finished design — sketches and/or half-formed ideas are welcome. Some of the most interesting discussions I have had start with the machines people have only been dreaming about.

I want to welcome Thorsteinn Olafsson (@thorsteinn-olafsson-3775). I have been in touch with Thorsteinn for a while now and he has some great ideas for propulsion producing designs. Unfortunately, academia and industry has not wanted to entertain his ideas (something many of us have experienced). Thorsteinn, I hope you will share some of those ideas here where you can get honest and respectful reactions and support.

Thanks so very much to Tim Ventura for inviting me to present at the 4/11/2026 live APEC conference! I was pleasantly very surprised by the article about the presentation and the propulsion system itself, the "PIE" system. Read the article here: https://www.altpropulsion.com/bryan-st-clairs-pulsed-inertial-engine-past-present-future/

The video "Math in Motion" is just under 4 minutes and is now online on my YT channel. Thanks again to Denny O for allowing me to use clips from his channel. Feel free to comment here and on YouTube. Here is the link: https://www.youtube.com/watch?v=Pe9SHTSgDHU

Hey folks, As of today, I released a new publication which attempts to rigorously formalize spatial mass displacement system (colloquial known as inertial displacement systems) into 3 fundamental categories, in terms of the Mach formalism I put forward back in August. It was mostly written in response to folks who keep saying that this field is dead, and genuine thrust based systems remain an impossibility. Its titled:"A Short Historical and Technical Examination of Fundamental Spatial Mass Displacement Systems" You can can read my working version here: https://www.researchgate.net/publication/403702161_A_Short_Historical_and_Technical_Examination_of_Fundamental_Spatial_Mass_Displacement_Systems Even though it says its a "short" “examination”, this field is far too broad, containing all manner of nuance, for me to cover every system with extreme analytical rigor. That being said I place a number of well known systems in "the hot seat" and try to give fair and tactful treatments. The good news is, now that I've finished this, I can probably work on making lesson plans/scripts for skool that covers such items in more detail! This work ended up being about 100 ish pages, and when I started 4 months ago I thought it would only be around 40-50 at most. I'm still in the midst of small final edits—it in terms of writing— but as is. it contains very important information for enthusiast and builders alike. I'm human like anyone else, so I'm not the all knowing final word on this matter. I just hope it pushes the field forward. Nam qui curat