What makes the bike so good for special forces is the hybrid electric engine. For normal use, traveling far from sensitive areas, the bike can use diesel, gasoline, or jet fuel, scavenging fuel as need be on missions far from base. When needed, the electric part of the engine ensures that the bike runs silent—or nearly so. DARPA’s goal is for the silent mode to ring in at 55 decibels. That's quieter than a normal conversation. The bike's louder mode could reach up to 75 decibels, which is slightly louder than the average vacuum cleaner.
SilentHawk is based on Alta Motor’s RedShift MX bike. Last year, Logos tested RedShift bikes with their new hybrid-electric engine. Now, for Phase II of testing, Logos says they plan “to proceed with an aggressive Phase II program plan, with the goal of developing and testing the first operational prototype in only 18 months.”
Special Forces toyed with the electric Zero MMX external link concept a couple years ago, but ditched it due to battery concerns
Motorcycles with both wheels driven are rare but would give the motorcycle better grip in challenging terrain.
The rotary motor can run on diesel, JP-8, gasoline, or a mix of the three, so anything the operator can get their hands on during a mission will work. It’s installed in a series hybrid configuration, so it simply generates electricity and doesn’t provide direct drive to the wheels. It was designed to be removed in less than 30 minutes, making the bike all-electric and lighter for specific missions, but even when the engine is running, the SilentHawk currently produces just 75 db of noise, compared to over 100 db for a typical motorcycle. DARPA wants to make take it below 55 db. This would be another 100 times quieter.
The total range is 170 miles, with 50 of those in “silent drive” battery-powered mode. It weighs approximately 350 pounds and has a top speed of 90 mph. It also features a small, hub-mounted motor in the front wheel that gives it two-wheel-drive for added off-road capability.
Logos Technologies says the price per unit should be “affordable,” thanks to all of the off-the shelf componentry it uses. A production RedShift MX currently retails for $14,995.
SOURCES - Popular Science, Defense Industry Daily, Fox News