Hydrogen Thruster is unrealistic currently.

With the latest release of Hydrogen Thrusters. I have to say the Engine designs themselves are very nice. BUT, There are a number of features that are either missing or seem weak.

Reference Video for bullets 1 & 2: https://youtu.be/E4yvQtsOSkk?t=512 Nasa video test of RS-25 engine from the Space Shuttle Program which burn Hydrogen.

1. No Mach Diamonds. Extremely common on all Chemical burning engines. These are the main illuminators of the gas as its the highest point of pressure outside of the engine. The Mach diamonds themselves are very bright, should be able to "overblow" the white on screen, where the only color comes in as ambient depending on liquid being burned. The only way you wouldn't see a Mach diamond is if you're burning something that resembles RP-1. See Firefly's Engine in Slo-Mo for this reference. https://youtu.be/0srs5jZ1qdg?t=93.

2. Frost should develop around the engine base when in atmosphere (could be a texture update) as the engine runs for longer periods of time.

3. Thrust plumes should be very long and should grow in length the more engines that get put into an area. To explain in simple terms, the surround air speed (or lack of surround air for vaccum) is what allows the plume to be short, but when you push alot of engines into a small area like in SE1 or SE2, the engines towards the center should have longer plumes. SpaceX Starship launch shows almost 300ft plumes due to the density of engines. https://youtu.be/b28zbsnk-48?t=37

4. Damage to engine bell should not affect the performance nor impact the formation of the mach diamonds. While this is counter-intuitive, there is recent precedence for this. https://youtu.be/S5TdVYSgqr4?t=19 - Commentary of an exploded rocket nozzle on a test stand.

5. Color reference is pretty goodfor Hydrogen plume, but the Mach diamond should be emitting blue color at the engine bell with red color being the color of flame much further from the engine. Reference the Nasa video above. RP-1 (Kerosine) matches more closely with the color that the current models show.

I was going to put my Hydrogen system review here, but will open a different topic: https://support.keenswh.com/spaceengineers2/pc/topic/48042-hydrogen-system-overall-se1-critique-for-se2