‘The C-2 was based on the E-2, with a mandate to keep as much commonality as possible. Multiple smaller rudders work perfectly well even if you don’t “need” them,’ Andy Burns, US Navy Surface Warfare & Flight Officer
The E-2 Hawkeye is the US Navy’s all-weather, carrier-based tactical battle management airborne early warning, command and control aircraft. The E-2 is a twin engine, five crewmember, high-wing turboprop aircraft with a 24-foot diameter radar rotodome attached to the upper fuselage.
As a derivative of the E-2 Hawkeye, the C-2 Greyhound has a common wing with the Hawkeye but has a widened fuselage and a rear loading ramp. The interior arrangement of the cabin can accommodate priority cargo like jet engines, passengers, litter patients and critical spare parts.
Why do the E-2 and C-2 require multiple vertical stabilizers?
Andy Burns, former US Navy Surface Warfare & Flight Officer, explains on Quora;
‘The E-2 requires multiple vertical stabs because of the airflow around the pylon supporting the rotodome, and because of the height of the pylon-done structure. In order to get enough “clean” airflow and sufficient rudder authority, the choice was either one really tall rudder, or multiple smaller ones. A tall rudder would have required a folding mechanism, like that on the S-3 Viking, in order to fit on the hangar decks of 1960s-era carriers, which would have added weight and complexity and extra demands on the hydraulic system. Multiple rudders was actually the simpler design.
‘The C-2 was based on the E-2, with a mandate to keep as much commonality as possible. Multiple smaller rudders work perfectly well even if you don’t “need” them.’
Burns adds;
‘Fun trivia fact: due to how the air flows around the empennage and the propeller wash, the port inboard stab doesn’t actually do anything. Unlike the other three, it doesn’t have a movable rudder. It’s mostly there for symmetry and to even out weight distribution, but both the E-2 and C-2 could fly perfectly well without it.’
Photo by PHAN JUSTIN BLAKE and PH1(Aw) Shawn P. Eklund, U.S. Navy