Xponential 2018: 3W Kit Concept Enables UAV Engines to Be Customized

SP-55 single-piston engine Credit: Lucien Miller, Innov8tive Designs

May 14, 2018      

DENVER — At AUVSI’s Xponential 2018 show here earlier this month, numerous exhibitors displayed the latest technology for unmanned aerial vehicles, or UAVs. For example, 3W Modellmotoren GmbH introduced a single-cylinder piston engine and a two-cylinder piston engine as all-new customization options for UAV engines.

The commercial drone market will grow from $541 million in 2016 to $17 billion by 2024, predicts Global Market Insights Inc. Similarly, BI Intelligence, the research wing of Business Insider, expects commercial drone shipments to reach 805,000 units by 2021 at a compound annual growth rate of 51%.

Applications for commercial UAVs include infrastructure inspection, precision agriculture, and real estate, let alone drone deliveries.

Hanau, Germany-based 3W‘s new offerings for UAV engines are part of a “kit concept” intended to enable operators to define many characteristics of engine features and performance. They can tailor them to precisely match the conditions faced in real-world applications.

UAV engines included single-piston and twin-rotor engines.

Wankel twin-rotor engine in 3W’s booth at Xponential 2018.

In addition, 3W’s booth at Xponential 2018 included a full line of internal combustion two-stroke engines, from 35cc up through 370cc.

The kit concept opens up a wide variety of customization options to end users. They can pick a motor block and add carburation or fuel injection, various prop hubs, telemetry, and a wide range of communications and control systems.

All the UAV engines shown in Denver featured dual ignition with independent redundant ignition systems, i.e., two spark plugs per cylinder. Two sparks per cylinder gives cleaner combustion and more power, said 3W representatives.

Moreover, if an ignition system goes out, with two plugs, the engine will continue running. 3W also showed both single and twin-rotor Wankel engines equipped with dual spark plugs.

Customizing UAV engines in the hangar

3W makes virtually all of its components in-house, which enables the company to produce these custom systems. Other companies buy OEM, off-the-shelf components from leading engine vendors such as Desert Aircraft, but 3W designs and manufactures its engines in Germany, from the ground up.

The 3W sales engineer at Xponential proudly noted that everything 3W offers is manufactured to its exacting specifications. Because of the time 3W can devote to product development at its plant in Frankfurt, a very high level of engineering quality is guaranteed, he claimed.

“We allow your engineers to achieve the highest degree of specialization for your unmanned aircraft, by allowing you to choose the fuel system, whatever size generator you need to provide for electronics, and if it is a standalone system, to provide energy for propulsion electric motors, as well,” the engineer said. “Our kit concept offers the full gamut of customization and specialization and is unique in the industry.”


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Sky Power aims for efficiency

“Thanks to the construction-kit principle, we can quickly and graphically illustrate to the customer the components of which his future engine will consist,” stated Karl Schudt, managing director of Sky Power GmbH, a 3W service provider, before the show. “An adaptation of the engine to the application area can thus be quickly visualized.”

“We’re convinced that an efficient, sustainable engine application can only come through application-specific engine designs,” he added. “3W-International’s basic engine always stands at the center here. We illustrate the overall principle on the new SP-110 FI TS engine.”

At Xponential, Sky Power announced its ECU030 injection and ignition system, which is compatible with all of 3W’s gasoline and heavy fuel (diesel) UAV engines. The Bad Homburg, Germany-based company designed the new systems to reduce fuel consumption and enable fine-tuning of the engines for specific applications.

The ECU030 has four ignition channels with two separately adjustable injection nozzles, and it electronically moderates pump pressure. It automatically adjusts fuel mixture to best match cylinder temperature, air pressure, and external temperature.

All engine data can be monitored via an intuitive PC display and read out via a CAN-BUS interface, according to Sky Power. Test runs demonstrated that fuel reductions were achievable at constant power with the 3W-110i B2 TS FI, and a fuel consumption reduction of more than 20% was reported at 5,500 rpm.

3W overview

3W has been supplying two-stroke piston engines to the modeling market for over 35 years. The company develops and manufactures one-cylinder to six-cylinder model engines for hobby and competition radio control pilots.

3W's FITS UAV engine at Xponential 2018

SP-110 FITS twin engine

All 3W engines from 55cc’s and up can be delivered as twin-spark versions, with both ignitions working independently of each other. This allows these UAV engines to operate quieter and at low idles, with increased reliability.

If one ignition fails, the engine will continue running at a slight reduced RPM.

The company provided the following list of milestones on its site:

  • 1985: Market launch of the first 2-stroke 3W-60 gasoline engines specially designed for airplane models.
  • 1986: Development and production of the 3W-40 and 3W-80B2 opposed-twin engines.
  • 1989: Development and production of the 3W-70B2 as well as the first 4-cylinder 3W-240B4 and 3W-160B4.
  • 1991: Development and production the 2-cylinder 3W-120R2 in-line engine as well as the 3-cylinder 3W-120R3 in-line engine.
  • 1995: Grant of a patent for the first 3-cylinder radial engine, with integrated planetary reduction gear.
  • 1997: A generation of engines with new pistons and cylinder technology begins with the i-series.
  • 2000: 3W develops a 4-cylinder flat engine with 546 ccm/33.32 cu in on behalf of a customer.
  • 2002: Patent application for a new muffler system in Europe and the US. Development and production of the 4-cylinder 3W-212iB4 flat engine.
  • 2003: Completion construction design for the 5-cylinder radial engine 3W-256STR.
  • 2004: Meanwhile 3W produces engines between 24 and 684 cubic centimeters. The range of engines encompasses twenty-two different displacements in forty-seven different designs.
  • 2007: Development and production of the new 3W-210 Xib2.
  • 2008: Development and production of the 3W-110iR2 in-line engine.
  • 2009: Development of the kerosene/heavy-fuel engines (HFE) with carburetor.
  • Since 2010: Intensive further development of HFE engines.
  • 2013: Development and production of engines with reed-assembly control.

About the Author:

Tom Atwood is executive director of The National Robotics Education Foundation (NREF) and a director of the Florida Peninsula Chapter of the Association for Unmanned Vehicles International (AUVSI). Lucien Miller, CEO of Innov8tive Designs, also provided assistance in the development of this article and with photography. More coverage of Xponential will come soon.