Cessna Citation CJ2 with Tamarack Winglets

Natural beauty often inspires creativity—sometimes even genius. Take northern Idaho. Its Lake Pend Oreille is a 43-mile-long, 1,159-foot-deep wonder protected by the Selkirk, Cabinet, and Bitterroot mountains and magnificently rimmed by evergreens and tamaracks. Not coincidentally, perhaps, the adjacent 46-mile corridor from Coeur d’Alene to Sandpoint is home to several small and medium-sized aerospace companies run by renegades who bristle at the status quo and are always looking for a better way to do things. 

This is the ground that legendary aircraft designer Burt Rutan now calls home, where the late medical equipment and aerospace inventor Dr. Forrest Bird devised more than 50 aircraft supplemental type certificates and 200 patents, and where the Quest (now Daher) Kodiak turboprop took shape and is still built. “We’re not just a bunch of rednecks from north Idaho,” jokes Tamarack Aerospace CEO Nick Guida.

Located in Sandpoint, Tamarack manufactures “active” winglets that allow older jets to perform as well as or better than their new-production counterparts. At present, the winglets are available for retrofit only on Cessna’s Citation CJ series of light jets, but Guida’s company hopes to expand its product line to include versions for more makes and models. Called the Atlas system, Tamarack’s offering differs in several important ways from the conventional passive winglets you’ve seen on aircraft for several decades.

How Winglets Work

Any winglet works by increasing the aspect ratio of the wing—its ability to increase lift over drag. But passive winglets require the addition of significant structural reinforcement to carry additional wing loading from the winglet during maneuvering or gusts/turbulence. This adds weight to the aircraft and limits their fuel-saving potential to around 4 to 5 percent. 

The Atlas system can reduce drag by up to 30 percent and achieve fuel savings near 33 percent because it doesn’t need all this additional wing structure and weighs less. Rather than adding structure, Atlas has a “load alleviation system”—basically a small flap at the end of the wing—that automatically activates when the aircraft hits turbulence and/or loading above 1.5G. The flap disrupts the flow of air to the winglet and “unloads” the wing, thereby eliminating the wing loading problem. The Atlas system increases the wingspan on the CJ2 by six feet to 55 feet, 10 inches. 

The improved performance that Atlas delivers on the Cessna Citation CJ2 light jet is particularly dramatic. The CJ2 (also known as the Model 525A) is basically a CJ1 with a 33-inch cabin stretch. Cessna built approximately 243 CJ2s between 2000 and 2006 and another 224 of an upgraded model, the CJ2+, between 2006 and 2014. The two differ in that the 2+ adds full authority digital engine control (FADEC) to the Williams FJ44 engines with more thrust, integrated Collins Pro Line 21 avionics, and an upgraded interior. According to the aircraft valuation service Vref, prices range from $1.9 million to $2.4 million for the straight 2 and $2.75 million to $3.85 million for the 2+. Several maintenance plans support the aircraft, including Cessna’s Pro Parts and Williams’s TAP. 

What a CJ2 Offers

A stock CJ2 is already a solid small-cabin jet, offering a range of a little over 1,3000 nautical miles with four passengers, a maximum cruise speed of 410 knots, and good short-field performance—it’s easily able to use runways as short as 3,500 feet (sea level, standard temperatures). Power comes from a pair of Williams FJ44 turbofans, 2,400 pounds of thrust each on the 2 and 2,490 pounds on the 2+. The extra thrust on the 2+’s engines facilitates faster climbs and more payload, enabling missions of about 1,450 nautical miles with four passengers under most conditions. 

Up to seven passengers can crowd into the 243-cubic-foot cabin with six single seats. (An additional lucky soul can occupy the belted potty if the aircraft is so equipped. The CJ2 can be purchased with either a blue water bowl commode or the electric flushing variety. The belted potty is available only with the latter.) The last row of single seats is best left to children and small dogs. Overall, the cabin measures a somewhat less than capacious 14.1 feet long by 4.8 feet wide by 4.8 feet tall. Baggage capacity is 74 cubic feet distributed between the nose and the aft cabin. 

Both aircraft can be flown single-pilot. The avionics package on the CJ features components from a variety of manufacturers—Collins, Universal, Honeywell, King, and L3. The panel on the CJ2+ is more streamlined with the Collins Pro Line 21 system. Cessna’s attempt to peddle a 2+ with an integrated Garmin G3000 integrated glass panel avionics system upgrade failed to gain market acceptance mainly due to cost—$900,000. (That retrofit became factory equipment on the new, somewhat shorter Citation M2.) Collins Aerospace offers a three-screen Pro Line Fusion avionics update for the 2+ for considerably less—in the $300,000 to $400,000 range, depending on options selected. Given hull values of straight CJ2s, this kind of an upgrade may not make economic sense. 

How the Atlas System Helps

Atlas installed on the Citation CJ2 weighs around 75 pounds but enables an 800-pound jump in zero fuel weight (400 pounds on the CJ2+)—basically the amount of stuff you can put on an airplane before fuel is added—for a total payload of 2,200 pounds. The increase is the result of enhanced performance from the winglets, and on the 12,375-pound (maximum takeoff weight) CJ2 their impact is dramatic. Benefits include faster time climbs—less than 30 minutes—to 45,000 feet without the need to step climb, the practice of burning off fuel in order to climb higher; and the ability to use even shorter runways and ones in high altitude/hot temperature conditions. The winglets also allow for lighter braking, smoother dispatching of in-flight turbulence, more stabilized approaches, and less chance of runway overrun due to overspeed. 

Tamarack also claims a CJ2 with Atlas burns just 675 to 700 pounds of fuel per hour at cruise speed and altitudes, compared with up to 900 in a stock CJ2, for a fuel savings of around 25 to 30 percent. This can increase range, depending on aircraft load, by up to 300 nautical miles, according to Tamarack performance charts. Depending on fuel prices, Atlas can pay for itself in two to four years of average aircraft use, according to Guida. He adds that the price of Atlas instantly accrues to a concomitant increase in aircraft value, but that the real value is in the extra performance the modification generates. He also claims that additional savings could be generated in the form of reduced insurance premiums, adding, “We’re starting to educate insurers on the increased safety margins the system provides.”

Tamarack winglets do undoubtedly make the CJ2 a better airplane. Installation of the system, which retails for $249,000, can be completed in eight calendar days.