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Commercial flying boat "Rohrbach-Rocco". Aviation 1927
The new commercial flying boat "Rohrbach-Rocco" is built as a monoplane with support floats and is powered by 2 Rolls-Royce "Condor" engines of 650 hp each with traction propellers. A strongly keeled, ship-shaped hull with a high cruiser bow is equipped for the reception of 10 clever guests, luggage, crash and 3 men crew, along with the equipment necessary for smart operation. Behind the driver's seat cutout, the wings are detachably attached to the upper edge of the fuselage and supported by 2 struts each on the fuselage side. All the fuel is stored inside. The vertical stabilizer is mounted on the rear end of the fuselage for removable use, while the horizontal stabilizer is attached to the side fin and supported downwards by a strut. Parallel to the hull are the boat-shaped support floats, which are attached to the blade by removable struts. High above the blades, the two engines are mounted freely on special support frames on both sides of the fuselage, so that the propellers work completely free of splash water. Due to this arrangement, the smart boat has an extraordinarily good seaworthiness. It can take off and land perfectly with the full weight in seas 4-5. The extremely keeled shape of the bottom ensures a favourable distribution of ground forces, soft insertion during watering, reduction of shocks during take-off and repellency of splashing water. The sharp cruiser bow cuts through the approaching high seas at the start without much increase in resistance.Good manoeuvring is possible even at high wind speed (12 m/sec.) due to the lateral engine arrangement, and even if one engine fails, the boat can easily be kept on course by slight rudder deflection. Due to the shape of the boat and the support float arrangement, a great longitudinal and lateral stability on the water is achieved, so that the boat can drift safely even in storms. An auxiliary sail can also be provided with which the aircraft can reach the next port as a sailboat in an emergency. The flight characteristics are very good due to the good weight balance, the correctly arranged and dimensioned tail unit and the V-position of the wings, as well as the stability conditions for every type of flight, so that the machine can be flown easily and effortlessly even in very gusty weather. The recovery of the flying boat is done with the help of salvage vehicles. Two floating, two-wheeled recovery vehicles can be easily and quickly attached and removed under the wings. The end of the plug-in hull is supported on an easily mountable tail carriage. The flying boat can roll into the water and ashore on this wagon under its own power on a natural shore.
The aircraft, like the other Rohrbach constructions, is made entirely of duralumin, only the fastening fittings and bolts of the removable parts as well as the struts are made of steel and the fuel containers are made of sheet brass. Light metal was processed only in the form of smooth sheets, strips and open profiles. This type of construction makes it easy to check and protect all parts against corrosion, so there are no grooved profiles and no inaccessible
cavities at junctions, etc. All rivets can be freely controlled on both sides. The toll plates form smooth surfaces and are full which, in addition to aerodynamic advantages, results in a simplified hauling style due to the elimination of the truss diagonals and still a robust hauling style. The fuselage and wings are walkable, the possibility of damage on the part of the crew is greatly reduced due to the stronger load-bearing skins, and the service life of the whole machine is thus considerably extended. Due to the light metal construction without the use of fabric or wood for covering, etc., the flying boat can remain at the buoy for a longer period of time, unaffected by the weather. Any repairs can be carried out easily and quickly with the simplest tools, as only sheet metal and angles, connected by free rivets, are used everywhere; for the repair material, therefore, only a very small storage of a few parts is necessary. Since steel parts rust and duralumine corrode due to seawater, all parts are extremely carefully provided with a seawater-resistant protective varnish. The hull and float are sealed in all parts absolutely seawater-proof. A further protective coating on all sides, which the machine receives after its completion, enhances the elegant appearance of this flying boat. The ship-shaped hull is built in two stages with a strongly keeled bottom and is designed as a box girder. Individual main frames, some of which are designed as watertight bulkheads, and numerous intermediate frames for bracing the bottom, all of which are connected by 4 longitudinal spars and a keel angle, form the hull structure to which the smooth outer skin plates are riveted watertight. The latter are fully called upon to absorb forces. The top of the fuselage is walkable. There are no inaccessible cavities on the entire construction, all nodes and rivets can be freely controlled on both sides.
The boat is divided into so many watertight compartments by means of bulkheads with watertight closing doors operated by central locking that the aircraft remains buoyant even if two adjacent compartments leak. All hatches and windows can be closed watertight. The lateral stability on the water required in the landing position is ensured by the lateral swimmers, as in a normal swimming position. But even in the event of total float damage, the aircraft is protected from capsizing, as the wing tips are equipped with watertight compartments, so that the passengers are not endangered in any case, no matter how unfavorable. All departments can be drained by a special bilge device, and there are also special drainage compartments in the soil of each department for drainage from land.
The individual hull compartments are arranged as follows: The collision compartment, at the front of the boat tip, is accessible through a large round, watertight hatch in the hull ceiling. Space is provided here for the on-board and sea equipment, such as anchor lines, etc., with which the boat is equipped in the transport company as required. Behind the collision compartment is the driver's cab, which has two seats side by side for the drivers in the fuselage cut-out protected by a windshield in front of the propeller plane. Due to the fact that the seats are located in the front very high part of the boat, the guides have a very good view to all sides and are well protected from splashing water.. Dual control allows
the operator to be relieved by the fitter or navigator. All control levers for engine and radiator control, as well as the actuations of fuel taps, fire cocks and other equipment are located in the driver's cab and can be operated by both the driver and the fitter. In front of the driver's seats, the flight and navigation instruments as well as the instruments necessary to control the engine system are visible to both. The instruments can be illuminated in groups. The electrical system is powered by a WindpropeIIer generator. An electric control panel, permanently installed fire extinguishers with lines to the motors and a hand pump complete the equipment.
Between the driver's cab and the guest compartment is the radio room with a length of Ü/J2 in, a width of 1.51 m, waterproof side windows and a round hatch with a watertight lid in the ceiling. In addition to the table and seat of the radio operator and the radios, the auxiliary machine system is also housed soundproof in this room. It consists of the Bristol starter motor, which can operate both a radio generator and a bilge pump by means of special couplings. From here, a door leads to the guest room behind it. This is 6.8 m long and 1.7 m wide and has full headroom. It is divided in the middle by a bulkhead with a watertight closing door, in the front part there is space for 4 people, in the rear part for 6 people, access is through an access hatch in the ceiling at the rear end of the guest room. The dining room itself is equipped with elegant, sound-absorbing room cladding made of leather and fabric. The leather-covered chairs with adjustable backrests are securely attached to the carpeted floor. Large, round, easy-to-open and watertight side windows at each seat allow a view that is not obstructed by any part of the construction. The artificial lighting of the room is provided by individual small lamps attached to each passenger seat, while luggage nets, coat hooks and grab handles on the ceiling complete the furnishings of the guest room. In the back corner of this room is the washroom with toilet, washing device and electric lighting. From the guest room, another door, also watertight, leads to the cargo hold below, which is accessible from above through a large hatch with a watertight lid, is 1.50 m long and 1.30 m wide on average. A special lashing device allows the luggage to be securely attached.
The other equipment of the boat consists of cleats, tow shackles, fittings for heating the aircraft, salvage vehicle fittings and the bow. Rear and position lights. The shape, arrangement and V-position of the wings can be seen from the overview sketch. The wings are attached to the fuselage with 2 steel bolts each and supported against the fuselage by 2 struts each. Each wing consists of a hollow box-like wing carrier with full-bearing smooth skins. In this carrier. To complement
the wing profile shape, sheet metal-covered ribbed boxes are easily hinged at the front and rear, some of which are designed as fuel tanks. The ends of these wing carriers are waterproof and have watertight hand holes. The ouerrudders were also built with load-bearing Bskin and is deposited on the outer end rib boxes. The wings are accessible to the end, so that it is easy to fill up the fuel tanks
and to easily check the ribbed box attachments before each flight. Easily fold-down rib boxes allow a quick, easy and thorough inspection of the entire inside of the wing. Any repairs to the wing can be easily carried out without having to dismantle the entire wing. Damaged rib boxes can be easily removed, repaired or replaced with replacement pieces. The entire tail unit is attached to the end of the fuselage by means of 4 steel fittings with easily controllable steel bolts. The side fin and the elevator halves, which are suspended from it by means of steel fittings and bolts and supported by easily removable struts, consist of box girders, attached, fold-down rib boxes and rudders, as does the wing construction. Here, too, there are the same easy repair and inspection options as with the wing. The rudders have been designed in such a way that they can be folded down by loosening a single bolt on each rudder bearing without the need to loosen the bearing bolts and the steering linkage. They are operated from the driver's seat with double control by rods, whereby the elevator is operated by 2 coupled control columns that can be swivelled forwards and backwards around a horizontal shaft, on which the handwheels for the aileron operation are located at the same time. The entire control linkage is located inside the fuselage and wings, but all levers and bearings are easily accessible and controllable. In order to protect the guides from fatigue in the event of an engine failing or in the event of a possible incorrect trimming position, adjustable elastic bands are installed to relieve the load. The floats were arranged on both sides of the fuselage and supported against the wings by easily detachable rods. They are
built like a boat with a sharp stem and keeled bottom and are shaped in such a way that they produce a good take-off buoyancy without throwing up splashing water, furthermore give the aircraft a good outer stability, are little endangered in strong seas and cause little resistance in the air. The structure of the floats is similar to that of the hull. They are divided into watertight compartments by bulkheads in such a way that the necessary lateral stability of the aircraft is always maintained in the case of leaks. The individual compartments are easily accessible through watertightly sealed hand holes. They can all be emptied from a point above the waterline when the aircraft is in the water. On land, the drainage is carried out by drainage screws located in the testicles of each compartment.
The engine consists of 2 water-cooled Rolls-Royce "Condor" engines of 650 hp each with four-bladed wood screws that work as traction propellers. The engines are, as you can already guess, mounted on a strut frame completely free above the wings and surrounded by an easily removable fairing. The fuel system has been designed with fire safety in mind. All fuel tanks are attached to the wing box carriers at the front and rear as ribbed boxes outside the fuselage, so that in the event of leaks the gasoline flows into the open air and prevents the formation of dangerous gasoline vaporsThe No fuel line goes through the closed fuselage spaces. Furthermore, fire extinguishers with lines to both engines, which can be easily operated by both pilots, are planned, with extinguishing nozzles on the carburettor and on the engine pan. In front of each carburetor, there are also fire cocks installed, which can be operated from the driver's cab. The fuel is pumped by motor pumps from a collector that is connected to all fuel tanks. The lubricant reservoirs are stored in each engine compartment behind the engine. The oil is supplied by tubular coolers arranged on the side of the engine frame. For water cooling, two large tubular coolers are mounted under the wings, whose cover flaps can be operated by linkages from the driver's cab.
Likewise, the entire engine regulation is carried out from the driver's cab by levers and linkages, which, running within the fuselage and the wing, are guided to the engines in a specially covered strut. The engines are started by a "Bristol starter" which is located near the driver and with which both engines can be put into operation in a short time from the driver's cab.
In the transport company, the flying boat is equipped with perfect sea equipment. This includes a heavy anchor as the main part. It is mounted at the front of the bow and is operated by a special winch. A drift anchor, anchor lantern, anchor and slip lines, fenders, boat hooks, hand lamps, mouthpiece, tool boxes, signal flags, life jackets, life belts, etc. complete the extensive equipment required by the ship-like character of this flying boat.
The guide has a combined altimeter and speedometer as well as 2 compasses of different constructions installed on flight and navigation devices. In addition, a gyrorector with an artificial horizon allows safe flying at night and in fog. To control the engines, both 2 mechanical and 2 electric rev counters were installed: the lubrication and cooling of the engines are monitored by remote thermometers and pressure gauges. The respective petrol supply in the tanks is indicated by petrol grandfather gauges. The Frde is used to transmit continuous traffic by a radio for telephony and telegraphy with a range of 150-600 km. The necessary transmitter energy is generated by a generator, which is driven by a wind propeller and attached to the fuselage. If the boat is lying on the water, radio can be transmitted with an auxiliary antenna, which can be stretched from the crank-out mast to the wing tips, whereby the necessary electricity is generated in the special generator, which is controlled by the .. Bristor starter motor is driven. This makes it possible, even from a boat drifting at sea, to communicate permanently with ships and ports and, if necessary, to call for help in distress at sea, so that passengers are protected as far as possible from serious danger in every situation. These facilities also contribute to making the "Rohrbach-Rocco" flying boat a safe and pleasant means of transport.