A 4 vane air engine model uses a cylindrical housing with a rotating rotor and four sliding vanes that trap and expand compressed air to produce steady rotary motion. For a DIY or prototype build, M-Seal is recommendable for sealing gaps, fixing vanes, and reinforcing joints because it hardens airtight and handles moderate pressure well. To safely use it with actual compressed air, the circular base should be covered with a thick acrylic plate, tightly bolted and sealed, so you can see the motion while maintaining pressure integrity. Acrylic adds visibility and rigidity, while proper sealing prevents leaks and sudden air loss.