Logos Technologies and Alta Motors come together to create an irresistible hybrid motorcycle concept, the SilentHawk Enduro.

First off, the cold, hard facts: The SilentHawk is not a production vehicle. It currently serves US Special Forces as a specialist Cross-Terrain motorcycle. As such, it is kept out of bounds by the government.

The SilentHawk is the brainchild of Logos Technologies, a defence and technology company based out of Fairfax, Virginia. Built especially for Special Forces, it is based on a Alta Motors Redshift MX eBike. The engine powering the bike is pretty nifty. Dubbed the ‘gen-set range extender’, the liquid-cooled rotary motor weighs just 4.5 kg. It produces roughly 15 hp and/or 6kW. It doesn’t matter what fuel is used, the engine adapts to it.  “Once the engine starts it will automatically regulate itself to all of that,” says Alex Dzwill, Logos’ lead engineer for SilentHawk. “It has a really complicated ECU.”


However, the internal combustion engine is a means to recharge the battery that powers the electric motors, which actually drive the Enduro; provided there is enough fuel in the 7.5-liter tank. Petrol, diesel, jet fuel, kerosene, it doesn’t really matter. Fuel efficiency does not change too much despite the type of fuel used, says Dzwill. The battery is a 5.8kWh unit, needing 2.5 hours of charging at 240V using only the rotary engine. The charging duration excludes any auxiliary equipment that is plugged in, for there are quite a few auxiliary plugs placed all over the SilentHawk.

The technique of using the IC engine as a generator for the electric propulsion unit has been in the automotive industry for a while now. The BMW i3 hybrid employs a small two-cylinder engine to keep the battery juiced up. Quite similarly, the SilentHawk uses its rotary engine to charge the main battery.


The party trick of the Cross-Terrain hybrid lies in its front hub. A 7 hp electric motor powers the front wheel, which is engaged via a switch on the console. It is a self-contained unit, separate from the principal drivetrain. Together with the Alta Motors-based motor for the rear wheel, the SilentHawk puts down 47 hp through its knobbly tyres. It weighs in at 158 kg, with a range of around 270 km on a single charge.

The applications for this kind of motorcycle out in the civilian world are huge. Here is a hybrid motorcycle that is rugged, minimalistic, runs silent (75 decibels max), and can hold almost 100 kph over varied terrain. While it is standing idle, it can charge any auxiliary equipment by itself (yes it can do that too!). The specs and features of the SilentHawk are impressive, to say the least. The only question remains whether the government will let it out of its tight fists.