Swivel Engine

Lore & Background

The Swivel Engine was developed by the Kerbal Space Center's propulsion division as an upgrade to the basic LV-T30 'Reliant' engine. Its key innovation is the gimbal mechanism, which allows the nozzle to pivot up to 3 degrees in any direction, enabling precise control without relying solely on reaction wheels or RCS. This made it a staple for early orbital missions and Mun landers, where efficient steering is critical. The engine's design was inspired by real-world gimballed engines like the RL-10, but with a distinctly Kerbal flair for simplicity and reliability.

Reader's Guide

The B7 RS 4 differs visually from the standard B7 S4, by having even wider flared front and rear wheel arches (fenders), to allow for a wider axle track. Over the B7 A4, it also includes two larger frontal side air intakes (for the two additional side-mounted coolant radiators). Constructed from fully galvanised steel unibody, the B7 RS 4 uses aluminium for its front wings (fenders) and bonnet (hood). The saloon version features a drag coefficient (Cd) of 0.31, from a frontal area of 2.17 m2.

In the saloon, luggage space measured according to the VDA 'block method' is 460 litres (16.2 cu ft) with the rear seats in the upright position. Kerb weight of the saloon variant starts at 1,650 kg (3,638 lb). To achieve maximum body stiffness with controlled deformation crumple zones, the B7 RS 4 features laser beam welding of major seams of the high-strength steel body shell. Two-stage driver and front-seat passenger frontal airbags are standard, as is Audi's "side guard" head protection curtain airbag system.

The Recaro shell-type RS race bucket seats (not available in North American markets) include electrically inflatable upper and lower side bolsters and adjustable lumbar support.

Did You Know?

• The Swivel Engine is one of the first engines in the tech tree to feature thrust vectoring, making it a favorite for beginners learning to control rockets.
• Despite its name, the Swivel Engine does not actually swivel in a full circle; its gimbal range is limited to ±3 degrees.
• In real life, gimballed engines like the Swivel are used on many launch vehicles, including the SpaceX Merlin engine.
• The Swivel Engine's model features a distinctive red and white color scheme, making it easily recognizable in the VAB.