New rocket engine: feedback & proposals

[SamLogan]

Biodiesel Engine: great addition, but it needs non-cryo oxidizers and some built-in storage to truly bridge mid-game rocketry

The new biodiesel engine looks fantastic, and I love the idea behind it. As I understand it, its role is to sit between the petroleum engine and liquid-hydrogen rocketry. The moment players reach the petroleum/LOX stage, though, they’re usually only one step away from LH/LOX—if you can make LOX, you’re often producing LH alongside it. That’s why the petroleum/oxylite rocket still has a clear niche, while petroleum/LOX tends to be a short stop on the way to LH/LOX. Replacing petroleum with biodiesel to “save oil” is a neat concept on paper.

In practice, the biodiesel rocket feels too niche. Even if, at equal tank count, it can reach a longer range than my LH/LOX test builds, it’s slower and—more importantly—leaves very little height for other modules. Rockets that are 90% fuel/oxidizer tanks and have no room left for cargo, research, or drillcone are frustrating to fly. By contrast, the steam rocket (thanks to its internal storage) is still the most convenient workhorse for me, followed by radbolt.

For me the biggest issue is the hard LOX requirement with no alternative. If you want more players to benefit from biodiesel, it should become the natural step right after steam, using biodiesel + a solid oxidizer. You could support three oxidizers—peat, wood, or oxylite—with performance that scales by quality. A smaller “petroleum-style” variant could also work, but it would be a pity to limit such a cool engine to a tiny niche.

The second issue is the lack of internal tanks. The steam rocket’s strength is exactly that: integrated storage. Giving the biodiesel engine built-in capacity for fuel (and some oxidizer) would free valuable height for mission modules and make it far more attractive to beginner/intermediate players as a stepping stone toward late-game rockets.

On uniqueness vs. reuse:
It’s also a bit puzzling to ship a brand-new engine when the same gameplay gap could have been closed by simply letting the petroleum rocket burn biodiesel. That choice raises the bar for distinctiveness: if biodiesel warrants its own engine, it needs a clear identity beyond “petroleum, but greener.” Without that, it risks duplicating the petroleum path while consuming more tank slots. Concretely, giving it non-cryo oxidizer options (peat/wood/oxylite), some integrated storage, and a different exhaust/heat profile or unique module synergies would set it apart and justify it as a true mid-game bridge.

In short: let biodiesel accept non-cryogenic oxidizers and give the engine some integrated storage. It would become a compelling mid-game bridge that stands on its own, while LH/LOX remains the fast, long-range end-game option.

P.S. Could you consider adding ladder anchor points—or an integrated ladder channel—to the rocket platform/launchpad structures? Squeezing ladders between adjacent rockets is painful and usually ends up looking awkward. I get that you want to encourage more Jet Suit usage, but a small QoL ladder option on the pad/tower would make base layouts much cleaner.

Edited November 1, 2025 by SamLogan

[Tigin]

There's no hard liquid oxygen requirement 

 

[SamLogan]

4 hours ago, Tigin said:

There's no hard liquid oxygen requirement 

 

Oh interesting 

[Gurgel]

I disagree. Making LOX is easily possible with gaseous Hydrogen as coolant. Making liquid Hydrogen is somewhat hard without supercoolant. Yes, you can use a small packets-do-not-liquify-in-pipes solutions, but I prefer not to. Hence I usually have LOX some time before having liquid Hydrogen. 

 

[bleepbloopinato]

sidenote wood and peat are like the opposite of oxidizers lol