Spraying responsibly at 20 mph. You may remember the white-knuckled, seat-of-the-pants spray jockies. These legendary heroes raced the weather and drove the razor's edge between speed and accuracy, boom bounce and good enough spray coverage. Today, the few crop cowboys who've survived say they don't much care for modern spray rigs. The sheer barnstorming adventure is gone, what with 90-ft. booms, smooth hydrostatic transmissions, GPS guidance systems and technologically advanced suspensions. Driving one is more like piloting a jumbo jet down a runway - all speed, size and push-button controls. And like the jet pilot, today's sprayer operators ply their trade more on knowledge than adrenaline, getting a smooth ride and maximum efficiency for every gallon they apply.

Cleared for takeoff. Now taxiing up the runway is the 4710, John Deere's biggest, fastest and most sophisticated sprayer ever. The company claims that, compared to its 4700 predecessor, the 4710 has 8% more horsepower, 20% faster spraying speeds, 11% more fuel capacity, 7% more solution tank capacity, 17% faster road transport speeds and 11% more underframe clearance.

Much of that advantage comes from a 200-hp, 6.8-liter John Deere Powertech engine. Paired with a four-range hydrostatic transmission, the sprayer cruises through the field at working speeds up to 20 mph, with road transport speeds up to 29 1/2 mph. If it lugs down in muddy or loose soils, the turbocharged engine delivers a 5% power bulge at 1,800 rpm (up to 210 hp). Optional traction control delivers power to the ground if one wheel starts to slip. For quick stops, hydrostatic braking and a service brake provide additional control.

Landing gear. To attain a smooth ride at high speeds, the 4710 uses a large strut and air spring on each wheel along with a scissor-type linkage to keep the wheels tracking properly. Deere says the design is based partly on the landing gear of an F-18 fighter jet. The suspension system is built around a 4- x 8-in., high-strength welded frame. Axels are made of 8- x 8-in. structural steel with 1/2-in.- thick walls.

For variable row widths, the 4710 has an optional hydraulic tread spacing feature that moves the low-pressure 46-in. tires between 120- to 152-in. centers at the push of a button.

What it can do. Deere claims the 2-mph advantage the 4710 has over its nearest competitor translates to an additional 21.8 acres/hr. Underframe clearance is 60 in. A 25-ft. turning radius helps avoid lightbulb-shaped turns on headlands, even when running a 90-ft. boom.

Boom suspension reduces bounce and improves spray accuracy with a hydraulic accumulator in the lift cylinder controls. Center pivot roll suspension keeps the boom level with the ground on terraces and sidehills. Yaw suspension ties the left and right wings together around a pivoting central axis to prevent the boom from flapping on turns. Deere says its boom control technology allows the operator to make minor speed adjustments without the boom tipping erratically.

Stealth spraying. Standard lighting and lighting kit add-ons make it easier to spray at night, allowing the operator to take advantage of calm nighttime breezes. An optional parallel tracking system pinpoints the sprayer's location to an average accuracy of 10 in., using a monitor and audible beeps to guide the operator down rows or across fields. Deere says parallel tracking is especially useful in situations where foam is less visible, such as solid-seeded crops, preemerge applications and at night.

Base list price for the sprayer is $127,000. Boom prices are $10,500 for 60 ft., $18,000 for 80 ft., and $19,300 for 90 ft. An optional 820-gal. stainless steel tank is $5,700. For more information, contact John Deere North American, Dept. FIN, 11145 Thompson Ave., Lexena, KS 66219, 913/310-8324, www.deere.com.