Unmanned Systems Technology 016 | Hydromea Vertex AUV | Power management systems | Unmanned Space Vehicles | Continental CD-155 turbodiesel | Swift 020 UAV | ECUs | DSEI 2017 Show report

October/November 2017 | Unmanned Systems Technology 60 Dossier | Continental Motors CD-155 I4 turbodiesel additional coatings in view of the jet fuel’s lack of lubricity. Otherwise the engine was unchanged, aside from the mapping of the FADEC having been set to suit both fuels with no recalibration necessary when switching. In fact, the user can even mix the two fuels in the tank. The engine glow plugs are as effective with jet fuel as with diesel, although the user needs to remember that whereas jet fuel can be cold-started down to -30 C, diesel will only do so from zero. The dual diesel/jet fuel capability of the CD-155 is particularly attractive to military users who often want to run everything on the latter (and steer clear of Avgas). Compared with an Avgas-fuelled (spark ignited), more conventional engine of the same horsepower as measured at sea level, the CD-155 is about 40 kg heavier. However, it offers a 30% improvement in fuel consumption, so for a given range the take-off fuel load is correspondingly lighter. Moreover, the conventional engine is naturally aspirated. Mundt notes that the CD-155’s turbo-supercharger really comes into its own at flight altitudes above 13,000 ft (4000 m), compensating for the thinning atmosphere. In addition, the use of water cooling and turbo-supercharging, together with a low operating speed relative to a comparable spark ignition engine, reduces noise. Inflight shutdown (IFSD) rate is a good indicator of engine reliability, as it records instances where more than 20% of horsepower is lost. FAA IFSD statistics for piston-engined aircraft show an average of ten shutdowns per 100,000 flight hours, whereas the CD-135 has averaged 3.21 over its lifetime and 1.74 over the past year. Currently under development at Technify Motors is a V6 turbodiesel, likewise derived from an automotive engine. This will be known as the CD- 300 since its power output will be in the region of 300 PS. It has now been certified, and at the time of writing, the first examples were soon due to be en route to customers. Meanwhile, across the CD-135 and CD-155, Technify Motors has shipped more than 5000 units, proving the wisdom of its approach. Indeed, it is significant that much of the CD-155 is manufactured in-house, and with other components sourced from the original tier one suppliers (and below) it will inevitably have a far longer lifespan in the aviation world than its parent will in the automotive one. Aviation places far more significance than automotive on time-proven power unit technology; in the latter case designs have a lifespan of years rather than the decades characteristic of aircraft engines. Technify will be able to continue producing the CD-155 for as long as it wishes, and one imagines it will have a very long life. The CD-155 has a three-ring piston The CD-155 has a cracked con rod cap The CD-155’s intake and exhaust camshafts