Getting personal with the Jeep Hurricane concept
Most of the time, auto show "concept" vehicles are a bust. As a rule, they are made to look good on a display stand, and that's it. So it is unusual that a manufacturer would ask us if we would actually like to drive a few. Which is what Jeep did last March, taking us to a New Jersey parking lot on a grey, blustery spring morning for a little urban 'wheeling. There were seven past concept vehicles on hand for us to experience. We tried them all, but the Hurricane made the trip worthwhile.
The Hurricane is the real deal. If you had an unlimited budget to build a trail machine, a full year, unlimited manufacturing capability, and access to a team of very bright Jeep engineers and talented designers, you could end up with something like the Hurricane. And by "unlimited budget," we mean well into seven figures.
In essence, the Hurricane uses two coupled engines, fed into two transmissions, blended into one transfer case with four outputs direct to each wheel, all controlled by custom software. It has five different steering modes, excellent articulation, 14 inches of ground clearance, and five different steering modes. An aluminum spine holds it all together.
Looking at the Hurricane left us puzzled because every piece has been designed and fabricated-pretty much from scratch. There are no differentials, the wheels each carry 2.00:1 portal gears, and the brake discs are attached directly to the drivelines, tucked up under the spine.
There are no axles per se-just huge boxes that contain bevel gears to transmit power-and other than the engines, nothing is familiar. The body is gray carbon fiber, perfectly fit and exquisitely smooth to the touch.
We didn't get to drive the Hurricane ourselves, and we're not sure we could anyway. It takes 20 minutes sitting in the passenger seat just to gather in the instruments, levers, and controls, which are all unique and machined from billet. In this case, the offer was to get in, sit down, and shut up, which we readily accepted. We clambered in over the passenger-side door by stepping up onto a machined aluminum step plate. Our driver, senior design engineer Doug Quigley, is obviously a real Jeep guy. He pushed two green Start buttons, one for each engine, and the 5.7L Hemis roared to life.
Once on the move, the Hurricane feels just like any other good trail machine ... but with two V-8s and open exhaust, it is loud. Upon full throttle, engines roar like a drag boat, the hood rises upward, and the back end squats. The sound of twin 5.7L Hemi V-8s through open headers is something beyond the healthy roar that a muscle car makes at the drag races. It is euphoric. Both V-8s are multi-displacement engines, meaning the Hurricane can be powered by 4, 8, 12, or 16 cylinders, depending on throttle input. With all 16 cylinders under full throttle, the engines develop a total of 670 hp and 740 lb-ft of torque. With all but four cylinders shut down, it could probably get 20 mpg.
We got a few blasts down the parking lot, something like zero to 40 mph through light drizzle. There was no snow on the ground, but everything was damp. In the passenger seat, with just a brief windshield and open cabin, warmth from the engines wafting inward was a welcome blessing. With the throttle pinned, the feeling of acceleration compared to a good muscle car, maybe a little less savagely bruising than, say, an alcohol bogger. According to Jeep specs, the Hurricane can do zero to 60 in less than five seconds, and we suppose that's actually possible with the right tires on dry pavement.
You can sense good suspension travel by the way the Hurricane wallows around corners. There are two coils at each corner and 18 inches of total travel, 9 upward and 9 for droop. The shocks are adjustable take-aparts, and the coils can be swapped out for stiffer or softer ones. Today the vehicle is, overall, very lightly sprung. "You'd never want to drive it on the street this soft," Quigley told us, "but for conforming to different land forms, it's pretty good." For the fun of it, Quigley walked the Hurricane over a few concrete parking space bumpers, absurdly small obstacles given the suspension.
There is enough travel for the tires to easily contact the upper fenders. So the Jeep engineers put the fenders on hinges. They flip up when the tire gets jammed into the wheelwell: "With this tire size, with the jounce travel we have, by the time we got the fenders where they'd clear, it was looking stupid. So the solution was to have the fenders move out of the way."
Just from the feel of it, we think the Hurricane would ramp 750, maybe 800 on a 20-degree ramp. "And because there is no axle and no center diff, the lower control arms go almost to the center of the car. So when I go to full jounce and rebound, this tire is almost straight up and down-most of the tread is still on the ground. And we can transfer all the power to that one tire. Even if the other three are in slop, that one tire has enough tread on the ground and it just digs,"said Quigley.
Tires are LT305/70R20 Goodyear MTR (Military Tread Revised). "They cut the pattern specially for us, but it's basically an MTR tire they're working on. It's a hell of a tire. We've only got maybe six of these. So if we screw 'em up, I've got two more," Quigley apologizes, "and that's it." Ground clearance is more than 14 inches, and approach and departure angles of 64 and 86 degrees, respectively, are well into Top Truck Challenge territory. The crawl ratio, we're told, is about 38:1.
The Hurricane may not have insane travel, but the steering is the sickest thing we've ever seen. It can steer normally, like a car, via a fixed rack-and-pinion at each end. Tied to each rack is a worm-gear setup with position sensors. Drive the worm gears, you hear an electric motor noise as it brings the tires outward, front and rear simultaneously, to create "skid steer." In skid steer, all four wheels point outward, but at opposite angles on each side, so the Hurricane can grind a turn in its own radius. In skid steer, there is so much tire scrub that the Hurricane left a baffling, perfectly round doughnut-shaped rubber burnout print on the tarmac. On pavement, skid steer tears up the tires. In mud, it would be pretty handy, kind of like a tractor rotating by reversing the treads.
Then the Hurricane's tires can be pointed 46 degrees inward, for "toe steer," allowing the vehicle to roll freely in its own radius. A demonstration of this mode, as Quigley feeds in power, is something like the whirl-a-gig ride at the country fair, leaving us just slightly disoriented.
Then there is 4-Steer, which is regular four-wheel steer like GM has used on pickup trucks, and Crab Steer, where the rears go with the fronts, instead of the other way. The advantage there would be to move sideways without changing direction. Considering the trail potential of the various modes left us completely in awe.
While there is no plan to offer the public anything like the Hurricane, there are some practical applications to the technology. Instead of two V-8s, imagine combining one gas or diesel powerplant and one electric motor-a hybrid Jeep. And flip-up fenders could be built by anyone.