FR2660279A1 - Float system with a forward planing point for float planes - Google Patents

Abstract

Float plane float device taking the shape of a notch in the hole situated on the forward first third of the float, thus creating a forward point of planing on the water. The planing point (1) lies in front of the centre of gravity of the float plane, while the step (2) lies aft of the centre of gravity of the float plane. When hydroplaning, the location of the forward planing point (1) allows the float plane to come to be supported on this point acting as a plane on the water, which creates a more forward bearing point. The surface area of the support is defined in proportion to the mass of the float plane and to its hydroplaning speed. This bearing surface area gives rise to a more powerful force than the inertial force of the aircraft in pitching and porpoising. This forward planing is suitable both for single-holes and for twin-holes, and can be used for floats of all aircraft, from the lightest microlite to the heaviest.

Description

The present invention relates to a device for floatplane floats, materialized by a stall in the hull located on the first front third of the float, thus creating a front setting point on the water.

A floatplane float is traditionally fitted, from the step, with a regular planing hull, on its main front part, showing only a single zone of contact with water during hydroplaning during the phases of takeoff and landing. This step delimits the front of the rear of the float and is almost always behind the center of gravity of the seaplane. In this technique, at low speed, the seaplane is supported mainly by the hydrostatic thrust. The shock absorption during landing is collected over the entire length of the float located at the front of the main step, thus causing violent shocks resulting in loss of incidence control of the aircraft. the seaplane must plan its hull to be able to take its necessary speed, that is to say that the hydrodynamic lift on the bottom of the hull replaces the hydrostatic lift. Having only one fulcrum considerably increases the friction surface of the water on the float.

This large "wet" surface brakes the seaplane throughout its speed gain, which causes a longer distance to travel to take off or possibly never reach it if the force of the drag becomes equal to engine traction. From this defect arises the need for larger bodies of water which limits the use of the seaplane. This long distance to be traveled during takeoff leaves the seaplane for a long time in contact with the waves, which tires its structure. In addition, this distance traveled for takeoff represents the phase where the greatest number of seaplane accidents take place. Takeoff and landing are the two critical phases of flying a seaplane.

If the pilot does not accurately measure the angle of incidence where his float has the least drag, the distance will be further increased, and the seaplane may depart in the porpoise phase. This phenomenon can be accentuated until it turns over. The classic bi-hull floatplane float in its classic train amphibious version (center of gravity behind the main train) traditionally has the default of having to have train traps so that water does not rush into the train wells wheels, and therefore brake it, producing discomfort at takeoff.

The device according to the invention overcomes these drawbacks. It indeed comprises, according to a first characteristic, a stall on the first third before the float, revealing a second point of contact with the water during the speed gain phase during takeoff and during the landing of the seaplane. The front stall or calage point is located at the front of the seaplane's center of gravity and the classic step is located at the rear of the seaplane's center of gravity. However, the fact of adding this fulcrum or wedging point on the front of the center of gravity of the aircraft provides better stability during movements on water when the seaplane is gauged. This front setting point due to its damping in the direction of pitching, prevents any departure in porpoise. The shock absorption during the takeoff and landing phases is increased by limiting the surfaces which come into contact with water, the area between the front setting point and the main step being therefore supported on a cushion of air bubbles created by the depression caused by the front setting point.

The front chock point begins to level the waves and materialize a wake creating the passage for the rest of the hull. During the speed-up phase necessary for takeoff, the stall point before the seaplane greatly favors the planing of the aircraft. Behind the front chock point occurs "compressible" vortices and air bubbles in an area that increases with speed until it quickly reaches the main step. The surface of friction of the water on the float is therefore considerably reduced which allows the seaplane to reach its take-off speed over a shorter distance, hence the possibility of using the latter on a plus A large number of bodies of water. Similarly, this reduction in friction on the water can make it possible to take off with a less powerful engine, or with a very loaded seaplane which requires more speed on the water to be able to take off. In addition, the decrease in the drag of the water resulting in a faster take-off tires the structures of the seaplane less, and considerably reduces the risk of accidents during this critical phase. This front setting point makes it possible to stabilize the value of the planing angle at a predetermined value from a certain speed, in order to be in agreement with the optimal setting angle of the wings of the seaplane. In addition, the greater stability of the seaplane obtained by the front fulcrum and the wake it creates, allows it to take off and land in 20% higher wave heights than with traditional floats. .

The two-hull seaplane float in its classic amphibious train version with a front chock point on its main front third, no longer has to have train traps
because we can accommodate the well of the main train in the depression located just behind the front stall point, which by its role of deflector, prevents water from entering the train well as soon as the speed increases. The removal of train traps leads to a reduction in weight, moving parts and greater system reliability.

Depending on the particular modes of use: - The number of setting points on the front part of the float plane float can be increased as soon as the float has at least one main bearing point on its front third.

- On a horizontal plane, the edge which forms the step materializing the setting point can be:
A straight line perpendicular to the plane of symmetry of the device
. In V open towards the front
. In V open towards the rear - This float comprising a recess materializing a setting point on its front third can be used on all aircraft from the lightest (U.LK multi-axis and pendular) to the heaviest as well as on the gyrocopters ..

- In a sophisticated version and mainly for very heavy seaplanes taking off in several phases, you can equip the front chock point with movable flaps or "flaps" controlled in incidence by a mechanical or hydraulic system, as and when taken speed of the seaplane, to obtain the best performance from its hull at all speeds.

- This float must be manufactured with suitable materials and be of sufficient strength for its use.

- This setting point on the front third of a float can be used both on two-hull floats and on a monohull float.

- This front setting point is adaptable to all forms of hulls, whether V-shaped, flat or concave.

The attached drawings illustrate the invention:
Figure l shows the device according to the invention seen in profile.

Figure 2 shows the device according to the invention seen from below.

With reference to these drawings, the device comprises a front main part (A) and a rear main part (B). Part C represents the front third of the float. In FIG. 1, the dotted line D represents the reference line of the surface of the water after the float has been taken off.

The front main part (A) includes the setting point (1) located in front of the center of gravity of the aircraft and in the front third of the float (C>, and the main step (2) located at the rear the center of gravity of the aircraft (2). The setting point (1) and the step (2) constitute the two points of contact with the water during takeoff and landing.

FIG. 3 represents the device according to the invention used on a hull for conventional amphibious train seen in profile, making it possible to place the main train (3: train extended, 4: train retracted) in its well (5) behind the recess of the shell materializing the front setting point by its role of deflector.

FIG. 4 represents the device according to the invention used on a hull for conventional amphibious train seen from below.

FIG. 5 shows the device according to the invention in its sophisticated version, seen in profile, the front setting point (1) being fitted with movable flaps or "flaps" (6: retracted position, 7: extended position).

Figure 6 shows the device according to the invention in its sophisticated version, seen from below.

Claims (5)

 l) Device for floatplane floats, characterized in that it includes a stall (1) in the hull located on the first front third (C) of the float, thus materializing a setting point on the water. 2) Device according to claim 1 characterized in that the setting point (l) is located in front of the center of gravity of the aircraft, while the step (2) is located behind the center of gravity of the aircraft . 3) Device according to claim 1 and claim 2 characterized in that in hydroplaning, the situation of the front setting point (l) allows the seaplane to come to rest on this point acting as a wedge on the water , which creates a more forward stop. The surface of the front support is determined in proportion to the weight of the seaplane and its speed of hydroplaning.  in V open towards the rear 8) Device according to any one of the preceding claims, characterized in that this float comprising a recess materializing a setting point on its front third CC> can be used on all aircraft of the lightest CU .LX) to the heaviest.  in V open towards the front 7) Device according to any one of the preceding claims, characterized in that, on the horizontal plane, the edge which forms the step materializing the setting point (l) can be  a straight line perpendicular to the plane of symmetry of the apparatus 6) Device according to any one of the preceding claims, characterized in that, on the horizontal plane, the edge which forms the recess materializing the setting point (1) can be  4) Device according to claim 1 or claim 2 characterized by the number of setting point on the front third of the float (C) which must be at least one in number ( 5) Device according to any one of the preceding claims, characterized in that, on a horizontal plane, the edge which forms the step materializing the setting point (1) can be  9) Device according to any one of the preceding claims, characterized in that in its classic amphibious train version, the setting point Cl> makes it possible to accommodate in the depression it creates just behind it the well of the main train, it plays a deflector rail and prevents water from entering the train well as soon as the speed increases, which eliminates the use of train doors.