Microturbine Jet Engine

If you are looking for high power in a small package - nothing beats the microturbine. This simplified, miniaturized jet-engine fits in the palm of your hand and produces high levels of thrust. A microturbine that weighs 3.5kg can easily produce 425N at full throttle, this equates to a 12:1 thrust-to-weight ratio. For comparison, modern military jet-engines like the Pratt & Whitney F100 produce almost a 10:1 thrust-to-weight ratio but only with the addition of an afterburner.

Originally microturbines were used on radio-control hobby aircraft, for the purposes of simulating real jet-engine noise and operation. At its heart, the microturbine is the simplest form of a jet-engine: one turbine stage driving a compressor stage through a single shaft. As time went by and the technology evolved, these engines became more affordable, easier to use, and running on a variety of heavy fuel (Kerosene, Jet-A, Diesel). Today microturbines are used in a wide variety of applications that extend far beyond the hobby-world; these include hover-boards, jet-packs, and even flying single-seat aircraft. I too have begun a company in 2016 (FusionFlight) to exploit the advantages of microturbine propulsion for vertical take-off and landing (VTOL) drones. Due to their small size, vehicles can be built with multiple redundant microturbines to ensure safe operation. Installing thrust-vectoring systems on these engines allows the construction of a variety of stable aerial configurations.

Of-course there are several disadvantages to consider. Microturbines utilize a portion of the fuel to cool-down the bearings in the shaft. To keep cost and weight minimal, microturbine suppliers opt to dump the fuel from the bearings directly into the nozzle. As a result, fuel efficiency is low. However, straightforward upgrades are available to reroute the hot fuel back into the combustor to alleviate this loss in efficiency. Since the engines rotate at speeds of up to 140,000RPM, the noise level is fairly high (115db at the source from a 100N engine), so applications requiring quiet operation would need additional noise suppression systems that are currently in development.

Ultimately, a VTOL aircraft powered by microturbines should not be used to hover above a single location. Instead, it should accelerate to cruise velocity right after performing vertical take-off; this is the most fuel-efficient method and ensures we use the microturbines to their full potential.

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