Carolina Seaplanes' "Super Seabee"
First Impressions: The Seabee is not a plane that floats, but a boat that flies! Words without pictures cannot adequately describe the Republic RC-3! The Seabee is a conglomeration of an airplane, a boat, and a Volkswagen bus. The result is an undeniably cool machine. Load up the family, pack your fishing and camping gear and head out to the lake for a weekend of adventure!
Background: Percival “Spence” Spencer (1897-1995) was the son of Christopher Spenser (1833-1922), who invented the highly successful Spencer Repeating Rifle and Spencer Pump-Action Shotgun. Percival, like his father, was a creative innovator but his attentions were clearly captured by airplanes (specifically amphibious airplanes)
The heritage of the iconic RC-3 is the Spenser-Larsen SL-12C, which, beginning in 1937, was developed in partnership with engineer Vincent Larsen. After that partnership was dissolved, Spenser developed and flew his two-seat Spencer S-12 Air Car Amphibian in August of 1941. After the attack on Pearl Harbor just three months later, Spence placed his Air Car in storage and became a test pilot for the Republic Aircraft Corporation, flying acceptance flights on P-47 Thunderbolts. After leaving Republic in 1943, Spencer sold the corporation his Air Car design. Wanting to diversify from their military-only contracts, Republic foresaw a civilian market for the Air Car Amphibian, as well as a military market for light air-sea rescue applications. Republic originally anticipated 5,000 Seabee orders, but delays in tooling, cancelled orders, and a smaller than anticipated market led to a relatively short manufacturing run for the RC-3. In the end, 1,060 Seabees were manufactured, which is a respectable number for the first low-cost, single-engine amphibian. While only produced for two short years, they are highly sought after, and their owners consider themselves caretakers.
Design Characteristics: The RC-3 is an all-metal, four or five-seat amphibious taildragger with a top-mounted, rear-facing engine and a pusher propeller. The fuselage, wing, and tail sections use hull and skin strength to minimize weight. The hull is formed with five bays, eliminating the large number of wood bulkheads found in the prototype. Each wing has three spars and only three ribs each! Most of the strength and rigidity of the wings and stabilizers is due to the wrapped, corrugated aluminum skin.
Brett James, owner of Carolina Seaplanes, has a near-immaculate 1947 RC-3 with all the desirable mods, including an extra-thick aluminum keel runner, hull strakes, Southwind cabin heater, extended baggage compartment, underseat storage compartments, and a Simuflight extra-wide spray rail around the sides of the keel. Another major modification is 16-inch wing extensions that lengthen both the ailerons and flaps.
Powerplant: For seaplanes, the ability to get “on step” quickly means less water “runway” needed and less vulnerability while in “boat” mode. RC-3s originally came with a 215-horsepower, 6-cylinder Franklin engine. Brett’s Super Seabee has a IGSO-480. The gearbox’s 77:120 reduction ratio turns 340 horsepower into low-end torque, which is then translated into thrust via the 88-inch, three-bladed Hartzell propeller. The propeller can reverse pitch, which is a super handy feature for a seaplane. Reverse-pitch is selected with a guarded handle in the overhead panel. Fuel is held in a single 81-gallon fuselage tank and is pumped to the engine via an engine-driven fuel pump and electric backup pump. Expect a 21 to 22 gallon-per-hour burn rate.
Pre-flight/Pre-float: As with any seaplane, preflight inspection must also incorporate a “prefloat” inspection. Ensure that all five bilge plugs and two sponson plugs have been removed and drained. Don’t forget to reinstall the plugs after draining! With the engine on top of the aircraft, there are naturally some preflight differences. First, two pushbuttons unlatch the cowling. Next, climb on top of the aft part of the fuselage, reach through the prop and push the “clam shell” cowling open, which is accomplished with assistance from gas-powered lifter arms. When preflighting ashore, you can drain and check fuel from the sump immediately behind the keel “step” on the left side. If your Seabee is in the water during preflight inspection, turn the bilge pump on and cycle the bilge selector valve between all five bilge compartments. Any water will be pumped overboard through a port on the left side behind the door.
Takeoff (Land): Set takeoff trim with 4.5 counterclockwise turns of the overhead trim knob. After lining up on the runway, lock the tailwheel by pushing the tailwheel lever full forward. Flip on the fuel boost pump, check the instruments one last time, and smoothly add full power, being careful to not overboost the cylinders with supercharged air. The forward visibility is absolutely fantastic on the ground, in the air and in the water. On land, the three-point sight picture appears very flat. In very little time you will feel the nose of the Seabee rise, just as though it’s getting up “on plane” in the water. This rise is the oleo struts decompressing as the wings begin producing lift. There is no need to push the tailwheel off the ground or change the pitch attitude. Simply hold what you have and the Republic Aircraft Corporation will have you flying in no time! Raising the gear decreases drag minimally. The main landing gear simply rotates aft about 120 degrees to keep the tires well away from the waterline. The tailwheel, located right behind the aft part of the keel, rotates counterclockwise to bring the tire above the keel line, so it won’t interfere with the “step” for water landings or takeoffs.
Takeoff (Water): Ensure landing gear is retracted, point into the wind, and smoothly add throttle, while holding the yoke full aft. This is where the IGSO-480 really makes money! The “Super” Seabee wants to jump “on step”! Be diligent to keep the wings level in order to avoid dragging a sponson. The “Super” Seabee won’t stay “on step” long before you’ll feel the lunge that indicates you that you have “unstuck” from the water.
Flight Characteristics: The Seabee is a flying boat, and yes, it flies like one. The Seabee will happily move and respond to the pilot’s inputs - just in slow motion. A “bicycle-chain” gear in the yokes control aileron movement. The co-pilot’s yoke is removable to access the starboard bow hatch (nautical jargon for the front right door on the nose). Because the right yoke is removable, it tends to have more “play” than the left seat yoke. At cruise power setting with 30 inches of manifold pressure and 2600 RPM, the RC-3 gives an honest 110 MPH. Of course, when you’re in a seaplane, you naturally want to explore every water feature you can find, always scouting for waterways and hidden coves. Seaplane pilots are adventurers, and the Seabee allows you to take your family and friends along for an airborne-aquatic exploration.
Landing (water): Select 30 degrees of flaps by moving the flap lever on the floor forward. This lever is a manual valve to direct hydraulic pressure. Then depress the “hyd actuate” button on the instrument panel to energize the hydraulic pump. Most flying boats have outboard sponsons under the wings. These sponsons are meant to keep the wings out of the water at taxi speed only. They are not intended to absorb landings. In fact, most sponsons are designed with a shear point, should they absorb too much energy. Brett says that if you ever happen to shear off a sponson, add power, and get back off the water. Without a sponson, when the aircraft slows, the sponson-less wing will drag in the water. You will then begin a slow-speed “tail-rotorless helicopter” maneuver that will likely lead to an emergency water egress and a very bad day. Keep your wings level with the ailerons and make it easy on yourself by landing directly into the wind, which is usually an option in a seaplane.
Once in “boat mode”, you can water taxi to your favorite beach - or open the bow door, throw out the anchor (yes, it was standard equipment) and fish or swim until the sun starts getting low. An interesting feature is the water rudder never needs to be lowered or retracted. It is protected in the “afterbody length” behind the hull “step-up”. When beaching and docking, the reversible propeller is useful to control your approach, or even stop and back out.
Landing (Land): To configure the Seabee for a runway landing, lift the landing gear handle on the floorboard, then push it forward, ensuring the handle is pushed down again. The landing gear handle mechanically actuates a valve, redirecting hydraulic pressure in the same fashion as the flap handle. Next, push the “hyd actuate” button, energizing the pump. You should see a single green light on the instrument panel when all three landing gear are down and locked. A hydraulic wobble pump is available to supplement the hyd pressure if required to receive “down and locked” indications. With landing checks complete, set-up for a stabilized 75 MPH approach. As with any taildragger, lining up straight is a good way to begin the landing adventure. Even with a perfect “squeaker” landing, the two main landing gear oleo struts always seem to compress at different times, which translates to a small swerve. Never fear- the huge rudder is plenty effective, even at slow speeds. There is nothing particularly difficult about a runway landing, but it’s important to remember that there’s a lot of mass to keep tracking straight.
Wrap-Up: The Republic Seabee is truly a classic, and the experience of flying one to the lake is sure to imprint a memory that you will cherish. It’s no wonder Seabee pilots are enthusiastic about their machines and love sharing that experience with others!