Detonation Propulsionat Illinois

Resonance

A liquid oxygen and liquid methane rotating detonation rocket engine, being designed and built by students at the University of Illinois.

See the engineWork with us
How it works

Why detonation

A conventional rocket burns its propellants in a steady flame. A rotating detonation engine burns them in a shock wave that runs around a narrow ring, thousands of times a second.

The shock compresses the mixture as it burns it, so the same propellant does more work in far less space. That means a smaller, lighter engine for the same thrust.

Top view of the annular combustion channel with one detonation front travelling around it

At that speed one lap takes about 0.13 ms. The animation runs roughly 20,000 times slower.

3–14%more specific impulse
The theoretical gain over a conventional engine, depending on propellant (Purdue).
½the chamber length
The Air Force Research Laboratory cut its methane engine's chamber from 76 to 38 mm and measured the same performance.
10×faster combustion
A detonation finishes burning about ten times faster than a flame, so the same thrust comes from roughly a tenth of the chamber volume.

Sources: Heister et al., 2022, Bennewitz et al., 2021, NASA Marshall, 2024.

Resonance, our first engine

Resonance injects both propellants as liquids, the way a flight engine does, and both of its walls are water-cooled so it can fire for seconds at a time.

See the full design
Thrust
2 kN class
Chamber pressure
271 psia
Propellants
LOX and LCH₄
Channel
85 × 5 mm
Detonation hold
5 s
Conceptual section of a water-cooled annular detonation engineAn injector and manifold feed a cylindrical annular combustion channel between two cooled walls. The centerbody widens near the annular throat, then tapers into a truncated plug outside the outer wall. A second view shows the ring-shaped channel. This illustration simplifies proportions and passages and contains no manufacturing dimensions.Longitudinal sectionExhaustAnnular cross-sectionCombustion channelWater coolingSectioned metal

Conceptual section. Proportions and passages are simplified.

  1. Preliminary

    Feeds liquid oxygen and liquid methane into the channel.

  2. Preliminary

    The ring the detonation runs around, between the outer wall and the centerbody.

  3. Preliminary

    Deionised water will cool both walls, from a supply we are building ourselves, for the whole firing of about seven seconds.

  4. Preliminary

    An annular throat and centerbody plug guide the exhaust out of the engine.

  5. Set

    Starts combustion so we can study whether the wave keeps going on its own.

  6. Preliminary

    Build the electronics for pressure transducers and data acquisition, and help capture high-speed footage of the engine.

Where we are

The design is in review. Hardware comes next, then cold flow, then a first firing that has to show two things: the wave keeps rotating for five seconds after the igniter is off, and the hardware can fire again. Thrust is recorded on every run.

  1. 1

    Design and review

    Finish the first design and get someone else to review the numbers before we build anything.

    In progress
  2. 2

    Build and inspect

    Machine or print the copper hot section and CT-scan the cooling channels.

    Next
  3. 3

    Cold flow and checkout

    Run water and stand-in fluids, then check the valves, sensors, and abort.

    Planned
  4. 4

    Hot fire

    Fire the engine, write down the measurements, and inspect the hardware afterward.

    Planned

Work with us

We are looking for students who want to own a part of the engine, and for partners who can help us build and measure it. If you want to join or have any questions, just email us.

See what we needEmail the team