The  Heinkel Amphibian (Flight 1931)
Dr. Ernst Heinkel is one of Germany's pioneers, and his name has. almost from the very earliest days, been associated mainly with the twin-float seaplane type of aircraft. In this connection it is perhaps worth while recalling thai before he formed his own company Dr. Heinkel was associated with the Hansa - Brandenburg lirm. whose machines were not unknown to British pilots during the war. In the main. Dr. Heinkel has remained faithful to his earlier ideals, but this has not prevented him from producing from time to time machines other than float- planes. He has produced some very good landplanes. and at Stockholm he showed an even later type, the H.E.57, which is a boat-type amphibian, designed for passenger-carrying.    A model was published in Flight of December 12, 1930. At Stockholm the Heinkel H.E.57 Amphibian arrived from Warnemünde (where the Heinkel factories are situ- ated) piloted by Herr von Gronau. the German pilot who flew from Germany to New York, via Iceland and Green- land, on a Dornier Wal last year. The advantages of the amphibian were demonstrated in a small way at once, in that Herr Gronau was able to alight on the water outside the exhibition and taxi on to the slipway, and then, with wheels lowered, bring the machine right up on the shore just outside the main exhibition hangar.
The Heinkel H.E.57 is a strut-braced high-wing monoplane amphibian flying-boat of mixed construction. The hull is mainly built of Duralumin, while the monoplane
wing is largely of wood construction. Although of the two-stepped type, the hull of the H.E.57 differs in its lines very materially from the majority of British flying-boat hulls, even from those of the well known SARO boats with which the Heinkel may best be compared, because of its flat-sided hull. It is true that the   Heinkel resembles other British  boats in that it has two steps (the SARO boats having but one), but the general layout of the machine is more than that found in the boats of Mr. Knowler's design.   The forward main step of the Heinkel is very like those found  on  all British flying-boot hulls, with a fairly pronounced vee. but the rear step is of totally different design, in that it resembles more the heel of a seaplane float, terminating in a vertical stern post   which  merges  into the  bottom  of  the rear. cocked-up portion of the main hull     This vertical stern post carries a water rudder bv means of which the machine can be manoeuvred while taxying, and also forms a tail skid when the machine is used as a landplane.
Constructionally. the boat hull is fairly orthodox, the flat sides simplifying the construction of the frames and planking  The bottom. from the bows to the rear step. have a pronounced vee, that ahead of the main step being a vee with curved planes while aft of the main step being a vee of the straight-lined  type.    Two watertight bulkheads divide the bout in three compartments, of which the one in the middle forms the cabin of the machine. In the forward compartment  is stowed the marine gear, etc.. and this part is reached  either through a hatch in the forward deck through a watertight door in the cabin bulkhead.
The rear part tne hull aft of the rearmost bulkhead. does not  contain any load or equipment but a watertight door in the bulkhead gives access to it  for purposes of inspecting controls and the interior of the boat hull. In the middle  part of die interior of the hull is arranged the cabin  and cockpit equipment, which consists of the usual chair seats with a gangway down the centre. There are seats for four passengers, and  the two seats for the crew are placed side by side, and not separated from the
passenger cabin. In the roof there is a celluloid skylight, while in the sides of the cabin are rectangular glass windows. Around the sides and front of the forward part of the cabin are also glass windows of unsplinterable glass, the side windows being arranged to open and serving, in case of accident, as emergency exits for the crew and passengers. The cabin is reached through a hinged hatch in the deck, visible in one of our photographs. The land undercarriage consists of a tripod on each side, axle and radius rod being hinged to the sides of the hull, while the telescopic leg is attached near the top, at the point where the front wing spar fitting is mounted on the hull. The telescopic leg is of the oleo type, and raising the wheels is accomplished hydraulically by means of a hand-operated pump in the cockpit, "next to the pilot's seat.

The  monoplane  wing  is  of  mixed  construction, withwooden spars and duralumin ribs, covered with fabric The wing is braced by a pair of vee struts on each side, the lower end of the vee being attached to the sides of the hull approximately at waterline height. This position might be expected to make the boat slightly " dirty " during take-off. but, as we did not see the machine take off during our stay in Stockholm, we are unable to state from personal observation whether this surmise is correct or not. Wing-tip floats are attached at the points on the wing spars where the lift strut tittings occur, and, owing to the fact that the machine is a high-wing monoplane, the struts supporting the wing-tip floats are unusually long. Laterally, the wing-tip float supports are braced by nearly horizontal struts to the main wing bracing struts, and thence by vertical struts back to the wing spars.

A Pratt & Whitney " Wasp " engine is the standard power plant of the H.E.57, but, if desired, a " Hornet " can be substituted to give a better performance. The engine is mounted on struts above the wing, and drives a metal airscrew with blades adjustable for pitch. The airscrew blade tips pass very clese in front of the windscreen, and one would expect the beating of the air on the screen to cause considerable buffeting and noise in the pilot's compartment. Another disadvantage of arranging the engine as a tractor instead of as a pusher is that, when on the water, and manoeuvring up to a buoy or anchorage, the member of the crew who is working from the forward hatch has the airscrew fairly close behind him. It is true that the hatch cover is so designed as to rest at a considerable angle with the deck, and thus to afford some protection, but one cannot help thinking that the Heinkel amphibian, like a good many other machines, would  be improved  in  many  ways  if the engine were turned around and made to drive a pusher airscrew. The main petrol tanks are placed in the wings, one on each side of the hull, and supply to the engine is by engine-driven petrol pumps. In the fairing behind the engine is, in addition to the oil tank, a small reserve petrol tank, separated from the engine by a fireproof bulkhead.

In parenthesis : The first design , later rebuilt with a tailskid

The aircraft was like a lead duck, too heavy and could not take off with the planned load That is why the machine became complete rebuilt. The boat shape was optimized in the water channel of the shipbuilding Research institute in Hamburg. It is  externally changed with a slightly changed rear end with the removal of the tail wheel , which is now replaced by a tail skid behind  the water rudder behind the step of the boat bottom
In principle, it was a completely new one airplane  that in December 1930 went into testing again in the course of which was further tried The engine cowling and mounting of the exhaust system was changed , temporarily a ring cover mounted around the cylinder heads, the Tail assembly was modified several times and provided with small stabilization fins

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Heinkel-Ampfibium H. E. 57.
The Heinkel H. E. 57 aircraft, built as a cabin aircraft for passenger transport, equipped with a 425 hp Wasp engine mounted above the fuselage, is a boat amphibious with lateral support floats. The wings, which are set in a high-wing arrangement, are braced in the outer third, the pull-up landing gear is mounted on the boat in three points each and the tail unit is attached to the end of the fuselage in the usual way.
The entire cell is mainly made of light metal in its vital parts, some highly stressed parts are made of steel. Apart from the
fabric covering of the wing and the tail unit, the only non-metal parts are the wing spars made of wood. The construction is carried out in accordance with the
regulations of the German Aviation Research Institute, Berlin-Adlershof, as well as the approval requirements for commercial aircraft in the U.S. A.
The hull is divided into three compartments by watertight bulkheads.
The middle section is the cabin, which can be reached through a door on the aft deck via a staircase. The cabin contains three pairs
of seats in a row, the two front of which are equipped with controls. A comfortable longitudinal walkway between the chairs allows passage to the bow and stern area. At the back of the cabin, next to the stairs, is the washroom with toilet. There is space for luggage under the stairs.
The bow room is used to store marine equipment and luggage and can be accessed from the outside through a hatch located on the upper deck, and from
the cabin through a watertight bulkhead door.
The stern area is accessed to control the steering and preservation of the boat's interior — from the cabin through a hatch located in the bulkhead.
The boat, which is rectangular in cross-section, is a single-stage boat, keeled at the front and rear. To attach the water rudder, the bottom of the boat behind the step has a V-shaped attachment in the top view. The construction of the boat is carried out by transverse frames, which are connected by four longitudinal members and by the smooth outer skin. The floor is reinforced by a keel profile, which is designed as a rubbing strip.
Particular emphasis is placed on the perfect preservation of all profiles and the internal metal parts.
To drain the interior of the boat, a bilge system with pipes to all three departments is installed. The associated bilge pump with distributor tap is located next to the stairs.
The driver's seats are covered with shatterproof glass panes, which provide good visibility to the front, bottom and side even when landing. For the view to
the rear upwards there is a cellon window in the deck. The windows next to the driver's seats can be opened and are so large that they can be used as an emergency exit. The four rear seats each have an approx. 350X500 mm window made of shatterproof glass on the side of the
boat.
At the bow is the bow fender, the tow shackle and a cleat. The front hatch cover can be folded backwards up to about 135 degrees, so that it offers protection against the running propeller when working on the bow.
The upper deck is accessible from the front to the rear entrance. All fastening befitsGliders for wing, tail, sport, water rudder and engine support frame connection are designed in such a way that they can be practiced/become eight well. Appropriate suspension fittings are provided for the hoisting of the aircraft. There are ascents on the side of the boat near the rear entrance.
The wings have box spars, where the straps are made of spruce and the webs are made of birch plywood. The internal clamping consists of light metal and steel tubes in a diagonal bond. The fabric covering is attached in a special way to the metal ribs by means of wire drawn through eyelets.
The V-shaped strut support after the boat is ordered from teardrop-shaped clad strut tubes with adjustable heads. The V-position of the wings is about ZV2 degrees.
In the wing between the spars is the storage for the fuel tanks, in the nose the accommodation of the toolbox.
The support floats are made of light metal, the struts and fittings are made of steel. The floats are divided into three watertight compartments, which are equipped with a hand hole deck for control and conservation purposes.
The stöbespanned side and height fin consists of two spars with intermediate ribs made of light metal and the diagonal outcrossing. The side fin is screwed onto the fuselage with four bolts, while the elevator fin, which can be adjusted in flight, is inserted halfway up the side fin through it and supported and supported semi-cantilevered by means of a V-strut after the fuselage.
All rudders (rudder, elevator and ailerons) are covered with fabric and consist of the rudder spar (made of light alloy or tubular steel) and the
ribs that are pushed over. Elevator and rudder are not relieved. The ailerons are balanced by their shape.
The steering column, which operates height and transverse control via handwheel, segment and cable, is mounted in the middle of the boat. An arm carrying the handwheel is
swivelled on the control column, so that the handwheel can be operated from both driver's seats.
Side control is provided by adjustable pedals via cables. For the second guide, plug-in foot levers are available if necessary.
All control cables are deflected via ball-bearing rollers. The cables run inside the cabin under the central aisle of the floor, outside the
cabin over the upper deck or in the surfaces. All control cables are easy to control. The height fin adjustment is done by means of a handwheel from the driver's seat via cable and spindle. The rudder cables are coupled to the water rudder mounted at the base of the boat via intermediate springs. The water rudder is designed as a spur.
The chassis is mounted on the boat in three points each and consists of an axle, tension strut, the compression strut with oil shock absorber and brakeable wheels. All
chassis struts are made of steel tubes and are clad in a streamlined manner. The Bendix wheels are braked from the driver's seat by moving the
side control foot levers around the horizontal axis.
The lifting device of the chassis can be hydraulically or mechanically designed on request. In both cases, the operation is carried out from the driver's seat.
The 425 hp Wasp Motor is mounted above the boat on a support frame welded from tubular steel, which is attached to the boat with four bolts. It can be replaced by a 525 hp Hornet engine without any redesign. The metal lag screw moves at the prescribed distance from the guides and the
vital control parts. The engine is controlled by means of linkage using flexible linkages, an easily removable teardrop-shaped
fairing gives the engine good aerodynamic shape. The conical rear part of the fairing is designed as an oil and additional petrol tank, which is separated from the front by a
fire bulkhead. The engine is supplied from the two main fuel tanks mounted in the wing by means of motor-driven pumps.
The cabin with 6 comfortable armchairs is tastefully lined with the best corduroy fabric and covered with dark-colored boucle carpet.
The seat cushions of the armchairs contain the Kapok life jackets. The driver's chairs are adjustable in height. wingspan 16.00 m, length 10.80 m, height 3.55 m, height with chassis 4.23 m, aerodynamic area 39.20 m2, empty weight 1625 kg, payload 825 kg, flying weight 2450 kg; Payload: 6 persons 460 kg, fuel 305 kg, luggage 60 kg, together 825 kg; Max. speed at sea level 180 km/h, landing speed 95 km/h, ascent time at 1000 m 6.9 min., at 2000 m 15.9 min.; Wing load 62.5 kg/m2, power load 6.1 kg/hp.The Heinkel Amphibian (Flight 1931)Dr
. Ernst Heinkel is one of Germany's pioneers, and his name has. almost from the very earliest days, been associated mainly with the twin-float seaplane type of aircraft. In this connection, it is perhaps worth while recalling thai before he formed his own company Dr. Heinkel was associated with the Hansa - Brandenburg lirm. whose machines were not unknown to British pilots during the war. In the main. Dr. Heinkel has remained faithful to his earlier ideals, but this has not prevented him from producing from time to time machines other than float- planes. He has produced some very good landplanes. and at Stockholm he showed an even later type, the H.E.57, which is a boat-type amphibian, designed for passenger-carrying. A model was published in Flight of December 12, 1930. At Stockholm the Heinkel H.E.57 Amphibian arrived from Warnemünde (where the Heinkel factories are situ- ated) piloted by Herr von Gronau. the German pilot who flew from Germany to New York, via Iceland and Greenland, on a Dornier Wal last year. The advantages of the amphibian were demonstrated in a small way at once, in that Herr Gronau was able to alight on the water outside the exhibition and taxi on to the slipway, and then, with wheels lowered, bring the machine right up on the shore just outside the main exhibition hangar.
The Heinkel H.E.57 is a strut-braced high-wing monoplane amphibian flying-boat of mixed construction. The hull is mainly built of Duralumin, while the monoplane
wing is largely of wood construction. Although of the two-stepped type, the hull of the H.E.57 differs in its lines very materially from the majority of British flying-boat hulls, even from those of the well-known SARO boats with which the Heinkel may best be compared, because of its flat-sided hull. It is true that the Heinkel resembles other British boats in that it has two steps (the SARO boats having but one), but the general layout of the machine is more than that found in the boats of Mr. Knowler's design. The forward main step of the Heinkel is very like those found on all British flying-boot hulls, with a fairly pronounced vee. but the rear step is of totally different design, in that it resembles more the heel of a seaplane float, terminating in a vertical stern post which merges into the bottom of the rear. cocked-up portion of the main hull This vertical stern post carries a water rudder bv means of which the machine can be manoeuvred while taxying, and also forms a tail skid when the machine is used as a landplane.
Constructionally. the boat hull is fairly orthodox, the flat sides simplifying the construction of the frames and planking The bottom. from the bows to the rear step. have a pronounced vee, that ahead of the main step being a vee with curved planes while aft of the main step being a vee of the straight-lined type. Two watertight bulkheads divide the bout in three compartments, of which the one in the middle forms the cabin of the machine. In the forward compartment is stowed the marine gear, etc.. and this part is reached either through a hatch in the forward deck through a watertight door in the cabin bulkhead.
The rear part tne hull aft of the rearmost bulkhead. does not contain any load or equipment, but a watertight door in the bulkhead gives access to it for purposes of inspecting controls and the interior of the boat hull. In the middle part of die interior of the hull is arranged the cabin and cockpit equipment, which consists of the usual chair seats with a gangway down the centre. There are seats for four passengers, and the two seats for the crew are placed side by side, and not separated from the
passenger cabin. In the roof there is a celluloid skylight, while in the sides of the cabin are rectangular glass windows. Around the sides and front of the forward part of the cabin are also glass windows of unsplinterable glass, the side windows being arranged to open and serving, in case of accident, as emergency exits for the crew and passengers. The cabin is reached through a hinged hatch in the deck, visible in one of our photographs. The land undercarriage consists of a tripod on each side, axle and radius rod being hinged to the sides of the hull, while the telescopic leg is attached near the top, at the point where the front wing spar fitting is mounted on the hull. The telescopic leg is of the oleo type, and raising the wheels is accomplished hydraulically by means of a hand-operated pump in the cockpit, "next to the pilot's seat.
The monoplane wing is of mixed construction, withwooden spars and duralumin ribs, covered with fabric The wing is braced by a pair of vee struts on each side, the lower end of the vee being attached to the sides of the hull approximately at waterline height. This position might be expected to make the boat slightly " dirty " during take-off. but, as we did not see the machine take off during our stay in Stockholm, we are unable to state from personal observation whether this surmise is correct or not. Wing-tip floats are attached at the points on the wing spars where the lift strut tittings occur, and, owing to the fact that the machine is a high-wing monoplane, the struts supporting the wing-tip floats are unusually long. Laterally, the wing-tip float supports are braced by nearly horizontal struts to the main wing bracing struts, and thence by vertical struts back to the wing spars.
A Pratt & Whitney " Wasp " engine is the standard power plant of the H.E.57, but, if desired, a " Hornet " can be substituted to give a better performance. The engine is mounted on struts above the wing, and drives a metal airscrew with blades adjustable for pitch. The airscrew blade tips pass very clese in front of the windscreen, and one would expect the beating of the air on the screen to cause considerable buffeting and noise in the pilot's compartment. Another disadvantage of arranging the engine as a tractor instead of as a pusher is that, when on the water, and manoeuvring up to a buoy or anchorage, the member of the crew who is working from the forward hatch has the airscrew fairly close behind him. It is true that the hatch cover is so designed as to rest at a considerable angle with the deck, and thus to afford some protection, but one cannot help thinking that the Heinkel amphibian, like a good many other machines, would be improved in many ways if the engine were turned around and made to drive a pusher airscrew. The main petrol tanks are placed in the wings, one on each side of the hull, and supply to the engine is by engine-driven petrol pumps. In the fairing behind the engine is, in addition to the oil tank, a small reserve petrol tank