What Makes the CJ4 Different?
With seats for up to 11 occupants, the Citation CJ4 Gen2 is definitely on the top edge of the single-pilot spectrum. And size isn’t the only thing that makes the Gen2 stand out from its 525-type brethren.
The CJ4 Gen2 has a closed-center hydraulic system, which operates at 3,000 psi versus 1,500 psi in the other CJs. This system enables the modular feature of the speed brakes and allows for the use of multiple hydraulic functions simultaneously. The open center system of the other CJs only allows for one function at a time. The CJ4 was also the first in the 525 series with a single-point refueling system and an electrically heated windshield, enabled through the airplane’s electrical system, which has two alternators. But the main difference is in the wing. All of the other CJs have straight wings of various lengths based on size, but the CJ4 Gen2’s have a 12.5-degree sweep. In fact, the wing design is closer to that of the Citation Sovereign. Boundary-layer energizers at the leading edges help maintain laminar flow over the wings, and two stall strips at the wing roots help reduce the stall speed by causing the root of the wing stall first. Like the Sovereign, the CJ4 Gen2 has three speed-brake panels on each side. The design team also incorporated other features from the Citation Sovereign’s wings that allow for slower approach speeds. So, even though the CJ4 Gen2 is a bigger, heavier airplane, the VREF speeds are comparable to or slower than the other CJs.