Standing next to a remote airstrip Marines key a supply request into a small tablet computer and hit Send Button.
The demonstration is the latest development in an ambitious effort by the Marine Corps to use unmanned aircraft to resupply troops in the field. This demonstration, tests what the military calls a “pilot in a box.”
The Marines already have made headway in using pilotless aircraft. In recent operations an unmanned K-MAX helicopter was used to deliver supplies to remote outposts.
Sensors mounted onto the nose of the aircraft scan for obstacles. The computer steers the helicopter away from power lines and other hazards.
Although the current system requires visual contact between the ground controller and the aircraft at takeoff and at the point of delivery, cameras feed the necessary information to the controller during flight.
In addition to explicit ground control, the K-MAX can autonomously recalculate its route to avoid sudden hazards or no fly zones and deal with other problems that arise during missions.
Military commanders say the technology will allow them to send multiple unmanned aircraft into a battlefield to deliver supplies. If the enemy shoots down some of them, others will make it to the destination and units will not take any losses.
To avoid mountains of steel on the beach, Marine Corps wants to build a system where sensors in vehicles and other equipment determine when a part is needed and transmit the information to a headquarters, which delivers the replacement. A system like that will avoid having to stockpile a lot of parts during an operation.
The technology will allow the Marines to reduce the number of troops in logistics support, freeing up more for combat. You don’t want to assign war fighters to things that could be assigned to unmanned technology.
Marines deployed the K-MAX unmanned cargo delivery helicopters using experimental systems to carry tons of supplies to troops.
Now we’re getting them upgraded and retrofitted to get them back flying again. We hope to get them back soon, and that will allow us to go back and experiment more with autonomous systems."
The K-MAX is capable of carrying up to 6,000 pounds of cargo at a time, making it a logistics "workhorse, burning just over 80 gallons of fuel per hour during lift operations, making it the most efficient lift-to-fuel ratio of any helicopter in its class.
"We are hoping this research project will really help us get into the autonomous part of that particular system."
Marines want to develop a single, common data link to talk to anything unmanned "so we don't get into the situation where we have to have 10 different data links."
"When we talk about 'where we are going forward,' K-MAX opens up our ability to take whatever comes -- so that vehicle can be quickly integrate it into the weapon system.”
The simple, straight-forward design that uses fewer aircraft systems, shortens the load path between the engine and rotor system, enhancing the airframe's ability to handle the stress loads generated between the rotor system and cargo hook assembly during repeated lifting exercises.
K-MAX helicopter has dual-crossing rotors for increased precision.
The K-MAX uses a unique double rotor system where the two rotors cross each other called "intermeshing rotors." Its opposing rotors eliminate the need for a tail rotor. This makes the K-Max lighter, less costly to maintain and allows all of the power generated by the engine to turn the main rotors.
The two intermeshed rotors, which rotate in opposite directions at a slight angle so their blades don’t collide, greatly increase lift capabilities.
In fact, such design provides a one-to-one lift ratio so the K-MAX can carry up to 6,000 pounds, more than its own weight. This design also improves the vehicle’s stability in high altitude and hot temperature conditions and limits the noise signature of the craft.
Flaps, like those on a plane wing, are built into each rotor. They give the K-MAX more control than a conventional helicopter.
The key to the K-MAX helicopter's efficiency is an oversized intermeshing rotor system with servo-flap control. Operating without a tail rotor, all engine power is transferred directly to the large counter-rotating main rotors.
What's more, the K-MAX maintains its power and performance at high altitudes and temperatures and requires less maintenance than helicopters with the traditional tail rotor configuration.
The trolley system allows the cargo hook to move back and forth across the belly of the aircraft, enhancing load stability. The curved track in which the cargo hook rides is part of the heavily reinforced structure that delivers repeated and reliable lifting.
Teams were assigned to improve reliability and lifting capacity, hauling 6,000-pound loads at sea level and 4,000 pounds at 15,000 feet, with the strength partly thanks use of two intermeshing rotors on top of the aircraft.
K-MAX has intermeshing rotors eliminating the need for a tail rotor. These opposite-spinning rotors lend the K-MAX a natural tendency to hover, making it more stable for precision lifting and placing.
The setup eliminates the need for a tail rotor, which is usually needed to keep the aircraft from spinning uncontrollably, but sucks up about 30 percent of the engine’s power. Dropping the blades in back preserves that juice for lifting power. It also keeps the aircraft’s center of gravity over its payload hook, so carrying heavy loads is easier.
Outfitting the uncomplicated K-MAX—one engine, one transmission, no high-pressure hydraulic system, no tail rotor—for autonomous flight wasn’t overly difficult.
Compared to self-driving land vehicles which have to navigate on the ground, helicopters don’t come across many obstacles.
There was “not a lot of hardware that we had to add.
We tossed in actuators to physically move the controls in response to electronic commands, mission computers to tell them what to do, and a 3D imaging system to look out for suitable landing spots.
Past operations have required line of sight communication, meaning the transmitting and receiving stations can’t have any major obstacles between them.
During most missions, K-MAX was used at low altitudes and in mountainous regions, so maintaining a good connection wasn’t feasible. A ground controller can, however, use satellite communication and a laptop to change the mission at any point during flight.
K-MAX has flown thousands of delivery missions in combat, mostly at night, and lifted more than 4.5 million pounds of cargo. “We are experimenting with K-MAX ability to airlift the unmanned Squad Mission Support System into a mock hostile territory, to see if it’s possible to take troops out of danger altogether.
K-MAX uses a mission management system to translate the ground operator commands into viable mission plans and provides any necessary guidance while the craft is in the air. A ground controller uses a handheld tablet to interface with the K-Max as necessary.
K-MAX aircraft drew strong praise from enlisted Marines and top brass, but a decision was made to ground them so they can be have outfitted with advanced autonomous pilotage systems.
“What we have found is although you have logistics that you need to get to the right place at the right time, you also need a workhorse that just does this automatically. We’re hoping this research project helps us really get into the autonomous part of that particular system.”
“Sometimes there’s nothing unmanned about unmanned. “Some of our most precious assets right now are the folks that fly our unmanned systems. So, autonomy is key to try to alleviate the human link.”
Technologically, K-MAX is just plain useful. It started as a small one-man chopper before it was converted to a remotely piloted vehicle.
Tactically, K-MAX allows delivery of supplies to forward outposts by air, without risking human pilots or, worse yet, sending ground convoys through the gauntlet of ambushes.
“What stood out for many Marines was the permanent scorch marks burnt into the earth up and down ‘ambush alley. So many improvised explosive devices had gone off in one narrow mountain pass, an unavoidable chokepoint for supply convoys often times that stretch of road continually had scars marking where explosions had scorched the earth.
“Every piece of cargo flown via K-MAX is one piece of cargo that doesn’t need to put personnel in harm’s way going by ground convoy. Unlike manned choppers, “since it was an unmanned system, we were able to conduct flights during inclement weather when other helicopters couldn’t fly. “We flew during the night, in the rain, dust and high wind.
In the future, U.S. forces are likely to be spread more thinly on the ground, the distance and danger truck convoys must cover will only increase, and aerial resupply – especially aerial resupply with no pilots exposed to danger will only become more attractive.
That said, K-MAX is not a silver bullet for logistics. First of all, it’s not a truly autonomous robot: It requires a pair of human operators running it by remote control from the launch site and a third person at the destination to direct it where to drop the cargo, either by remote control or by placing a hockey-puck-sized homing beacon. In between, it flies automatically along a pre-set course, although the operators can always take back control to evade enemy fire or other hazards.
K-MAX is less expensive than manned choppers, according to the Navy admiral overseeing the program for the Marines. K-MAX cost “less than $1,500 per flight hour, an order of magnitude less than other manned rotary wing assets in the inventory.”
A big part of that low cost is that K-MAX has required less than 90 minutes of maintenance on the ground for every 60 minutes in the yet remained mission-capable over 90% of the time.
While K-MAX is cheaper than manned helicopters, it still carries a lot less cargo per dollar than old-fashioned trucks taking about 3 times the amount of flights than truck loads.
But those ground convoys aren’t so cheap because they require escorts and sometimes get blown up anyway, at a terrible cost to property and troops.
In the future when Marines will be pitted against a better-armed enemy than has been the case for almost two decades – one with shoulder-fired anti-aircraft missiles or even just a lot of heavy machineguns – an unmanned aircraft might not be able to evade enemy fire.
Maybe that’s why the Marine Corps has not ordered a great deal more K-MAX aircraft than those now in service. Nevertheless, on any planet, robots are getting ever better at extending human capabilities, without risking human lives, in some very hazardous places.
Marines go to battle today with more equipment than any time in history. An average infantry battalion has about 8,400 pieces of equipment, up from 3,200 15 years ago. The weight each Marine carries in battle averages roughly 100 pounds, more than three times what a Marine carried in World War II.
“Infantry battalions have gotten a lot bigger and heavier,” said a Marine Corps statement.
The extra weight has made the Marines more lethal and increased their ability to protect troops on the battlefield.
But the need for all the equipment makes supply lines vulnerable and slows the mobility of Marines, an expeditionary force that likes to travel light.
Recent experiences drove home the need to streamline logistics support: Troops were distributed across vast areas, and threats made supply lines vulnerable.
“Whether the need is nighttime aerial firefighting, resupplying troops in austere locations, the next generation of the unmanned K-MAX will likely continue to demonstrate its unmatched readiness and efficiency no matter the requirement.”