UST008

with 4 Gbytes of onboard memory for

data logging in a compact and robust

package rated to IP68 for deployment in

harsh environments.

Slovenian company C-Astral

provided a preview of the Advanced

Technology Light Acquisition System

(ATLAS), a new hand-launched fixed-

wing UAV that it plans to unveil at the

InterGeo geospatial event in October,

along with a higher end system, the

Bramor gPX.

Available from the fourth quarter of

2016, ATLAS is intended as a competitor

for lower-end ‘entry level’ systems

from the likes of SenseFly and Delair,

providing longer endurance and a

compact ground control station that can

be installed in a car and used with any

computer.

The mission planning software enables

multiple missions on the same flight, and

combines its functionality with situational

awareness-enabled mission flight control

software, along with common C-Astral

features such as full mission re-planning

and system control in-flight, and multiple

flight geometries and terrain-following

for stable ground sampling distance

maintenance.

With a 155 cm wingspan, ATLAS

is 82 cm long, weighs 2 kg on take-

off and packs down small enough

to be checked in as airline luggage,

C-Astral’s Marko Peljhan told us.

electric motor and a two-bladed tractor

propeller, it offers up to 70 minutes

of flight time and a range of 60 km. It

is autonomous from hand launch to

parachute landing, is designed to be

rainproof and to resist 30 knot winds

and operate in temperatures from -25

to +45 C.

Like C-Astral’s other vehicles, the

structure is made from composite

materials reinforced with carbon, Kevlar

or Vectran fibres, with Kevlar underneath

for toughness and RF transparency for

the integrated antenna system, and CFRP

for lightness in the wings, which have

magnetically attached winglets and an

easily replaceable pitot tube.

Payload and battery modules are under

the top cover and lift out on handles.

Wiring is integrated into the structure

to minimise the risk of breakages and

shorts. Typical payload modules are EO

and multi-spectral sensors.

Hirth now offers a range of six

off-the-shelf gasoline and heavy fuel-

burning two-stroke engines for UAV

applications, covering the 8-100 bhp

range, Dietrich Kehe reported;

UST

profiled the company’s 183 cc air-cooled

twin in issue one. The current smallest,

lowest-power engine is an 8 hp air-

cooled 100 cc twin; its largest, highest

powered unit a 100 hp water-cooled

939 cc inline three. The respective

weights are 3.4 and 47.5 kg.

Lee Estingoy reported that a new

development from Hacker Motor is

a range of servos that have two-way

communications yet are “standard price”

rather than high end in terms of cost.

They feature a digital encoder, he noted.

Established supplier of generators

for UAV applications, Sullivan, is

now involved in developing hybrid

powertrains for multi-rotor use. James

Hudson explained that the concept is to

use an internal combustion engine solely

to drive a generator that in turn supplies

the electric motors powering the four or

more rotors.

In this series hybrid arrangement,

the IC engine and electric motors

are linked by an appropriately sized

Sullivan generator and associated power

management unit, which means that no

battery is required.

Quadcopter and similar UAVs are

notoriously energy-hungry. The upshot of

the hybrid solution, said Hudson, is that

the craft can fly further for a given take-

off weight. That is not only because the

fuel for the IC engine is far more energy-

dense than a state-of-the-art battery but

also because as the mission proceeds

its weight diminishes, whereas that of a

battery is consistent.

An alternative is to use a small battery

to fill the gap between a system sized

for average power and the peak power

requirement for take-off. Hudson told

Unmanned Systems Technology

| June/July 2016

The power management unit for

Sullivan’s hybrid powertrains