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Tamarack Aerospace has received STC approval from both EASA and the FAA for its active winglet system for the Cessna Citation 525, the Sandpoint, Idaho-based company announced today. These approvals cover installation of the winglets on the Cessna CJ, CJ1, CJ1+ and M2 in the U.S. and Europe.
The company’s winglet system includes a wingtip extension and winglet, as well as load-alleviation technology that counteracts and alleviates gust loads and maneuver loads, negating the need for structural reinforcement of the wing. By eliminating structural reinforcements, the Tamarack winglet “dramatically reduces,” installation time, said the company.
According to Tamarack, performance benefits of the winglets include fuel-burn reduction and range increase of up to 25 percent for the CitationJet and CJ1 and up to 13 percent for the CJ1+ and M2; higher initial altitudes; faster climbs; a 400-pound increase in zero fuel weight; 12- to 15 percent higher single-engine climb gradients; better high-hot performance; and increased stability.
“We have a long list of orders, and our customers are actively working with our partner, Cessna Aircraft, on scheduling installs," said Tamarack CEO Nick Guida. He added that the technology is scalable and can be installed on any aircraft type. Additional airframe programs are already in development.
The Citation 525 series of business jets is the springboard from which Tamarack Aerospace intends to launch its Atlas active winglet technology into an upgrade market that it believes could extend to airliners and military aircraft. According to the Idaho-based company, the system will deliver fuel and range improvements of between 13 and 25 percent for the smaller Citations, which it claims represents a three- or four-fold improvement over the scale of benefits delivered by existing passive winglets already installed on other aircraft.
Last month the FAA validated the supplemental type certificate that the European Aviation Safety Agency had issued last year for installation of the winglets on the CJ, CJ1, CJ1+ and M2. The modifications, which take just under three weeks, are being offered through an exclusive partnership with Cessna, with the CJ1/1+ priced at $239,000. The price for the M2 has yet to be determined, but it will likely be closer to $300,000.
Tamarack CEO Nick Guida believes that subsequent approval processes for other aircraft will be completed more swiftly and on this basis he is actively pursuing options for retrofitting other business jets, either through partnerships with airframers or maintenance, repair and overhaul organizations. His team has held talks with the U.S. Air Force about an application for C-130 military transports, and UAVs are in Tamarack’s sights as well.
For the CJ/CJ1/CJ1+, Tamarack extends the wingspan to 52 feet 6 inches from 46 feet 5 inches. For the M2, which already has modest winglets in the standard version, the wingspan grows to 52 feet 6 inches from 47 feet 3 inches. The company says that the Atlas active winglet technology overcomes the need to strengthen the elongated wing with more metal, which it claims can result in weight penalties of up to 500 pounds for a bizliner-class aircraft.
The active technology centers on a trailing-edge device that can reduce load on the wing, essentially by counteracting and alleviating gust and maneuver loads. This Tamarack active camber surface device is electronically controlled and monitors the load on the trailing edge, keeping the pilot informed at all times.
“When you are developing a passive winglet the stress guy is always going to be fighting the aerodynamicist, who wants the best possible wing shape, and generally the stress guy has to get his way,” Guida told AIN. “We can allow for an extended wing, and a winglet, with lower loads, which is unparalleled. Aircraft can get to higher altitudes faster. We can get rid of the yaw damper and deliver better hot and high performance with about 640 pounds [for additional fuel or payload] in the CJs.”
Other improvements for the Citation light jets include a 400-pound increase in zero-fuel weight, significant range increases (see chart), higher initial altitudes, a 12 to 15 percent boost in single-engine climb gradients, improved stability and extended wing life as a result of reduced fatigue.
After almost five years of development work, Tamarack is entering what has proved to be a lucrative market still dominated by Aviation Partners (API) with its blended winglets for the Hawker 800/800XP, Dassault Falcon 2000, 900 and 50, as well as the Boeing Business Jet line. These have delivered range and fuel burn improvements of the order of 5 to 7 percent. More recently, the company has introduced the split-scimitar winglet, promising even greater benefits in performance and operating economics.
According to API, its winglets boost performance mainly by reducing drag from vortices generated around the wingtip resulting from the pressure differences between the upper and lower surfaces of the wing that generate lift. The blended winglets feature a high aspect ratio for lower cruise drag while also maintaining buffet margins and favorable low-speed characteristics.
Winglet Technology developed its elliptical winglets for the Citation X and X+ (priced at $415,000) and says that it expects to earn an STC for the Citation Sovereign next month. For the Citation X, the upgrade boosts speed by 20 knots in ISA + 10-degree C conditions (just over a 4 percent improvement), extends range with four passengers by between 220 nm and 550 nm, allows higher initial flight levels, significantly reduces time-to-climb and raises hot-and-high payload by up to 1,270 pounds.
Winglet Technology says its technology optimizes lift distribution across the full span of the wing. It also claims that the design is superior to other winglets in delivering less interference drag around the transition point between the wing and the winglets, improved alignment of the winglet with the leading and trailing edges, and greater drag reduction across a broad range of speeds.