THE “VISION” THING . . .
Take a close look at Cirrus Design’s prototype SJ-50 “Vision” jet–and then glance at Alan and Dale Klapmeier’s original VK-30 from the 1980s and the similarities are impossible to miss.
The sleek, five-seat, low-wing, composite airplanes are true to the same design philosophy with technology that’s 20 years apart.
“This is the natural maturation of the same exact idea,” said Mike Van Staggen, Cirrus Design’s vice president for advanced development, a leader in Vision design and testing. “Both airplanes were meant to be the ultimate in personal transportation machines.”
There are plenty of differences in the planes, too.
The Narwhal-like Vision has wider curves for more interior space, a thicker wing with greater area for a slower, 61-knot stall speed, and a distinctive V-tail to accommodate the biggest difference: a single, top-mounted, Williams FJ-33 jet engine.
Cirrus CEO Alan Klapmeier said he and brother Dale first met with engine designer Sam Williams in 1989 seeking a jet to power their kit-built VK-30. But nothing was commercially available at the time that was small or fuel efficient enough to fit their airplane.
Two decades later, however, the advent of new materials and the profusion of “Very Light Jets” have created a market for tiny turbofans.
Cirrus has taken $100,000 deposits for more than 450 Visions so far, and the company plans to sell them for $1 million each. The prototype made its first flight on July 3 in Duluth, Minnesota, one year after the company revealed its original design mockup.
The design goals for the Vision are:
A 300-kt TAS
61-kt stall speed
Same wingspan as a Cirrus SR-22 (38 feet 4 inches)
Snorri Gudmundsson, chief aerodynamicist for the Vision, said the plane has been meeting performance expectations so far–but the company has set ambitious goals.
The engine’s high thrust line, for example, requires redirecting the tailpipe, and bending the airflow is sure to decrease thrust by some, as yet unknown, amount. The Vision’s humungous tail surfaces are meant to provide lateral stability (avoid Dutch roll), and enhance control authority at low speeds. But they also increase drag and weight at the extreme rear of the airplane.
Gudmundsson said he made thorough measurements of every V-tailed aircraft he could find before Cirrus built the Vision prototype. The Fouga Magister, a French, twin-engine, military jet was the most similar, and the Global Hawk unmanned aerial vehicle, F-117 Nighthawk stealth fighter, competition sailplanes, and Beech Bonanza also provided useful data.
The Vision also is meant to share the same handling characteristics as the SR-22. Both use side-stick controllers, and they are meant to have similar approach and stall speeds.
“So far, our test pilots are saying that the Vision’s actual performance matches our expectations–and that’s extremely important,” Gudmundsson said. “It confirms the validity of our initial methods and projections.”
Van Staggen said Cirrus has developed a simple value equation that compares the Vision’s cost, seats, and speed with competitors such as the Eclipse 400, Diamond’s D-Jet, and others. Cirrus’ conclusion:
“The world doesn’t need another $2 million airplane,” he said. “The world needs a $1 million airplane that offers super high value. It won’t be easy. But the closer we can deliver the Vision to $1 million, the better.”
Cirrus engineers took hundreds of measurements inside high-end automobiles and other aircraft before setting the internal Vision dimensions. The curvy airplane is meant to maximize interior space.
“Cubic inches inside create a sense of value,” Van Staggen said. “Minute dimensional proportions make a huge difference.”
Cirrus also surveyed potential buyers to see if there was such a thing as “V-tailphobia.” Early Bonanzas had a bad reputation for coming apart in flight after series of high-profile structural failures, and Van Staggen was concerned pilots would avoid any plane with that distinctive design feature.
“We found that people have so much faith in Cirrus and our reputation for safety that V-tailphobia never materialized,” he said.
Tags: Dave Hirschman