Airborne Engineering Ltd has developed and demonstrated Snark, a deep-throttling (5:1 ratio) liquid bipropellant ablatively-cooled engine in the thrust range 300N-2kN using nitrous oxide and isopropyl alcohol. The propellant valves were under digital control using an Arduino microcontroller.

"The propellants are nitrous oxide and isopropyl alcohol. The maximum thrust level is 300N. Throttle ratios of up to 5:1 have been demonstrated without the engine showing any signs of instability. In this test, the throttle valves were digitally controlled using an Arduino microcontroller."

"The Snark engine is of a modular design which can be configured for different thrust ranges. The example shown here is at the low end of the thrust spectrum. Thrust levels up to 2KN are possible in this form-factor (3 inch diameter chamber) by using a larger nozzle and injector."