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The military needs stealth modes of transportation, and electric motorcycles are just the thing to travel without noise or much of a heat signature.

Logos Technologies, a defense technology company based in Fairfax, Virginia, recently won its second award from Darpa (the Defense Advanced Research Projects Agency) to continue development of the SilentHawk, a military hybrid-electric motorcycle.

Logos Technologies is working with Alta Motors (formerly BRD Motorcycles) and using Alta’s RedShift MX as a basis for the bike. The RedShift is a pre-production electric motorcycle that weighs 251 pounds, produces 40 horsepower, and runs on a 5.2-kilowatt-hour battery.

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It was supposed to be produced in 2012, then Alta pushed back the production date to mid-2015, at a price of $15,000.

For comparison, the 2015 Zero FX electric motorcycle weighs 281 pounds, has 44 hp, and its 5.7-kWh battery is good for about 54 miles of combined highway and city riding. The FX costs $12,340.

Logos Technologies plans to pair the RedShift with its hybrid-electric drone engine, presently in development.  The resulting SilentHawk would have about half the all-electric running time of the RedShift, but it could be refueled using standard gasoline, diesel fuel, military jet fuel (JP8), or even “other fuels”.

The ability to use multiple fuels enables operators to scavenge fuel from whatever sources may be available.  For example, an MH-47 special-ops Chinook helicopter that carries fuel for other helicopters could also fuel up a fleet of SilentHawk motorcycles without having to carry a separate tank.

Darpa’s definition of a “silent” motorcycle is that it must produce less than 55 decibels of noise operating in electric mode. At that level, a motorcycle would barely make more noise than its wheels would produce while riding over gravel.

While running the engine, Darpa permits up to 75 decibels–roughly similar to a vacuum cleaner.

The original Darpa grant was awarded to Logos Technologies last April, to test the idea of pairing the hybrid engine with the RedShift frame.

After demonstrating that the engine could power the motorcycle, Logos earned the second award to produce a working prototype–due in Summer 2016.

Historically, the idea of a hybrid motorcycle has usually been dismissed due to the extra weight and volume of carrying an engine on an electric motorcycle.

Motorcycles with either an internal combustion engine or an electric motor and lithium-ion battery pack already have frames filled to capacity with necessary parts.

How does Logos intend to take a small electric motorcycle, add an engine and fuel tank, and make it tough and nimble enough for offroad use?  Would the fuel be carried in saddlebags?  How would that affect balance?

But the plans for the SilentHawk go beyond making it a regular off-road hybrid motorcycle.

“Quiet, all-wheel-drive capability at extended range in a lightweight, rugged, single-track vehicle, said Wade Pullman, manager of advanced concepts at Logos, “would support successful operations in extreme terrain conditions and contested environments.”

Motorcycles with both wheels driven are incredibly rare indeed, but such a capability would give it even more grip in challenging terrain.

“An innovative design approach, including a unique field-swappable power system concept,” Pullman continued.

It “will allow unprecedented customizability of the bike while still meeting and exceeding the government’s challenging requirements.”

The question remains, what does “field-swappable” mean in this context?

Darpa is known for pushing the boundaries of technology in multiple disciplines.

While a silent, off-road, hybrid, all-wheel-drive motorcycle sounds like a futuristic sci-fi vehicle indeed, we may see one roaming the woods as early as next year.

This story originally appeared on Green Car Reports. Copyright 2015

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