Cessna’s Amazing CJs

In some cases Cessna’s competitors have tried, with limited success, to create an alternative vision of the light jet paradigm that Cessna seems to have both invented and perfected.

That original CitationJet was a wonder. At a top cruise speed of 380 knots, it was between 30 and 40 knots faster than its predecessor, and it was lighter while having similar payload numbers. It was also a single-pilot airplane from the start, and its solid and predictable handling qualities made it a realistic step-up airplane for all kinds of pilots.

Today the CJ lineup includes three airplanes, the CJ2+, the CJ3 and the flagship CJ4. The derivatives started coming in 2000, when Cessna delivered the first CJ1, an improved CJ with updated avionics — Collins Pro Line 21, the current standard across the CJ line — and higher maximum takeoff weight. More notably, the CJ2, which featured a stretched fuselage, more powerful engines and better range, was a roomier, faster, more modern CJ. The CJ3, an immediate hit, came four years later. It was stretched even more and was even faster, to the point that it began attracting customers that Cessna never figured would be asking for a CJ, including fractional providers. The ultimate expression, at least so far, is the CJ4, a 2,000 nm, 450-knot airplane. Cessna delivered the first CJ4 just last year. Today, every CJ is outfitted with digitally controlled (fadec) engines, which makes single-pilot flying safer and easier.

There are relatively few truly significant product introductions in the short history of the entry-level business/personal jet, yet most of them have been pioneered by one company, Cessna Aircraft out of Wichita, Kansas. The certification in 1971 of the Citation, the CitationJet’s inspiration, was one such event.

The airplane was originally called the Fanjet, for the Pratt & Whitney JT15D-1A turbofan engines that powered them. Though the Fanjet moniker was soon abandoned, Cessna’s instinct to focus on the fan was right on the money. The Citation’s light jet competition at the time, the Lear 24, was a whole different animal. It was a true turbojet; it featured a moderately swept wing; it was much faster, and it was demanding to fly. The new Cessna jet, on the other hand, was anything but a barnburner, a fact that some had fun with, calling it the “Slow-tation” or the “Nearjet.” But the truth was that Cessna turned the airplane’s performance into a selling point. The Citation handled easily and could use runways considerably shorter than the Lear could.

Customers chuckled at the jokes and still bought the airplane. That original Citation was, as you probably know, a huge hit. Cessna sold many hundreds of them. It also established a product niche, the straight-wing entry-level jet, that Cessna had pretty much to itself for the next decade and a half. Truth be told, there’s little competition today.

The one area in which the Citation was no better than a Lear was that it too needed to be flown by a crew, a situation remedied by Cessna in 1977 with the introduction of the single-pilot Citation I/SP. While the two-pilot airplane gave turboprops a run for their money, the single-pilot version, it could be argued, put most of them out of business. The only twin turboprop produced in any numbers that survived the ’80s was the Beechcraft King Air.

While Cessna evolved the Citation into a number of different larger models, some of which are still being built today, it ended production of the original entry-level jet in 1985, due in large part to the high relative cost of building the jet — it cost almost exactly as much for Cessna to build the Citation I as to build the higher-priced and higher-profit-margin Citation II and its spinoffs.

Despite shelving the Citation, the fact is that Cessna never wanted to be out of the entry-level jet game, so soon after the end of its Citation I program, it began development of a new jet, one designed to be less expensive for the company to build and less expensive for the customer to buy and operate, while at the same time being a realistic single-pilot airplane. If that sounds like a tall order, you’re right.

The result was an all-new model that Cessna announced at the National Business Aircraft Association Convention in 1989. The jet, the Model 525 CitationJet, made its first flight a year and a half later, in April 1991.

From the beginning, Cessna planned to give clean-sheet treatment to the CitationJet.

There wasn’t really a choice; Cessna knew it couldn’t simply tweak the Citation and get where it knew it needed to be. No company is better at getting the most out of its lineup. If it could have made the Citation 500 work, it would have done it.

(And in case you were wondering, the airplane has been informally called the “CJ” since the outset. For the past decade, since the launch of the CJ1, all of the 525 descendants are simply “CJs.”)

In conceiving that new airplane, Cessna looked at the desired outcome from every conceivable angle and in fact wound up doing nearly every conceivable thing differently. The CitationJet ended up with a mostly new fuselage and a revolutionary new wing along with a new fuselage-to-wing fairing design, new engines and a new tail, as well as a new cabin.

There was some degree of risk involved with every one of the clean-sheet choices that the company made, but without a doubt the biggest gamble was Cessna’s selection of a new airplane engine from a brand-new manufacturer. The 1,900-pound-thrust Williams International/Rolls-Royce FJ44-1A was exactly what Cessna was looking for: a light, economical and small turbofan of approximately 2,000 pounds of thrust. At the time, there were no alternatives. To be fair, Williams wasn’t new to building turbofans, nor was the basic FJ44 design a new engine. The Michigan-based company had been building engines for the military for years. This might have been more reassuring except for the fact that Williams’ engines all wound up in cruise missiles. As long as the TBO was at least five hours, an observer quipped, everyone was happy. The involvement in the process of commercial engine manufacturing giant Rolls-Royce must have been a comfort. In fact, Rolls did much of the development on the high-pressure turbine, which was seen as a critical step in making the engine fuel-efficient and reliable enough for the manned aviation world.

With 1,900 pounds of thrust, the FJ44s sacrificed 600 total pounds of output compared with the 2,200-pound Pratt & Whitney JT15Ds. But they were substantially smaller in diameter than the Pratt & Whitney engines on the Citation, cutting down on drag. The FJ44s had better specific fuel consumption than the Pratts, and they were 14 percent lighter. To top it off, they were far less mechanically complex than the Pratt & Whitney engines. The FJ44 features, to name two noteworthy parts-saving components, a one-piece titanium fan that requires no internal cooling and a single fuel-slinger ring that feeds the combustion process instead of individual injectors. The Williams engine has about 70 percent fewer parts than the JT15D.

Another major piece to getting better performance on less weight was the wing, and here Cessna took another risk, coming up with a natural laminar flow (NLF) airfoil that cut drag and boosted speed. The wing on the Citation had relatively little laminar flow (the airflow that adheres to the wing instead of separating and becoming turbulent), but the new wing, designed by Cessna and NASA, had laminar flow to an impressive 31 percent of chord — a modified version was tested, believe it or not, mounted on a Cessna 210. Once the NLF wing made it to a jet, it became clear that, despite the smooth flow, it also maintained good handling qualities, another critical part of the equation in creating a new entry-level jet; after all, what good does it do to have a lighter, faster entry-level jet if entry-level pilots can’t fly it? Like the engines, the new wing worked.

The wing also had the advantage of mating to the fuselage from below, which eliminated the pass-through spar on the Citation, giving more headroom in the CitationJet, especially in the aft cabin. The foresight in this one expensive design choice has allowed the CitationJet (which was a few feet shorter than the Citation to begin with) to be stretched three times in its 20-year lifetime.

Another design choice was the T-tail, which seems the distinguishing feature of the CJ line. The cruciform (cross-shaped) tail of the original Citation was strong and effective, but the new vision seemed to demand a new look, and the T-tail was adopted. Cessna made it work too. By the time the CitationJet was being drawn up, aerodynamicists were able to prevent the deep stall threat, and the higher-mounted, smaller horizontal tail allowed both a simpler design — trim tabs on a stabilizer instead of a trimmable tail — and a smaller rudder to boot.

One of the stickiest wickets for Cessna was trying to figure out how to deice the airplane. Here, again, it hit a home run by going with a heated wing, engine inlets, bleed air and alcohol for the windshield, and pneumatic boots for the horizontal tail. The system gave the jet a reliable anti-icing system, and the heated wing allowed Cessna to keep the upper surface of the leading edge of the wing smooth, maintaining the advantage of the natural laminar flow airfoil.

Unlike the original Citation, the CJ was designed from the ground up to be a single-pilot airplane (though it can be flown as a crewed airplane too). Everything critical and frequently used is put within easy reach of the pilot. Even the circuit breakers are segregated, putting the ones most critical or most likely to be pulled on the pilot’s side, though even the right-side breakers can still be reached in a pinch.

Despite its smart, pilot-friendly design, the CitationJet is still a jet and requires solid training and professional technique, as does any jet. The truth is that, while the CitationJet is less complicated than a lot of jets, even for pilots transitioning from turboprops, there are a lot of challenges in store. Not that they can’t be met; they can be. In fact, with the possible exception of a couple of very new quite-light jets, the CitationJet is arguably the ideal airplane in which to make that transition.

The need for a new, entry-level Cessna jet is, of course, old news. While not a CJ in name, the Mustang is a CJ in spirit. With that 340-knot, sub-10,000-pound, single-pilot turbofan, Cessna again redefined the light jet scene. The lineup runs from the Mustang, at right around $3 million as typically equipped, to the CJ4, at around $9 million. Cessna discontinued the CJ1+ a few months ago, and there has been some speculation about what airplane might fill the niche just above the Mustang and below the CJ2+. Will it be a bigger Mustang or an all-new CJ? Time will tell.

Check out Ken Wolf’s accompanying piece, “I Finally Married a Jet.”