SE518873C2 - Procedure and apparatus for reducing the take-off distance of water on floated seaplanes - Google Patents

Abstract

The invention refers to a device for reducing the required take-off distance at water surface of float-equipped seaplanes, in which the pitch of the wing is variable in relation to the horizontal longitudinal axis of the seaplane and which comprises a fuselage (1) with pilot and passenger compartment, said fuselage supporting a wing (6) and a drive engine (12) with propeller (13) and said fuselage (1) furthermore through struts (7, 9) and an upright frame structure (5) being carried by a pair of floats (2a, b) and connected with a rudder-equipped tail portion (3a, b, c, 4). The frame structure (5) comprises an upper crossbeam (8) and a lower crossbeam (14). At least one strut (9a, b) with variable length is hingedly connected at its upper end to said upper crossbeam (8) and extends obliquely downardly-rearwardly and is at its lower end hingedly connected to a further crossbeam (10), extending between said pair of floats.

Description

e ø. u of 518 873 ïIšï-gi US-A-6 164 591 discloses a ground power aircraft of the type flying boat with a specially designed hull or fuselage without the usual step and with double, mutually parallel and spaced wings, the rear of which is at a level slightly below the front. Both of these wings are arranged pivotable about a transverse axis at some distance from the leading edge of the wing, namely at 25% of the cord length. Via transmission links, the driver of the craft can influence the wings via levers and change their angle of attack. The object of the construction set forth in this publication is not at all the same as in the present invention but instead to prevent the craft. when traveling in turbulent air currents crashes with before against if it were to be hit by a nose ground surface downwind sweep. Normally, such ground power vehicles or hovercraft travel on. just a few meters above the ground and in any case below the 7-meter level. The time for the pilot to react to such a downwind sweep is usually far too short, but through the proposed arrangement the wing itself reacts automatically to the downward wind village and thereby directly and sharply increases the wing's angle of attack, thereby compensating for the downward effect on the craft.

However, some instructions on how this design solution could be used to shorten others, for example, are provided for purposes, the take-off distance of aircraft is not in this publication.

The present invention now intends to eliminate this problem with the take-off distance by proposing a device for reducing the required take-off distance on water in such floating seaplanes and it is essential for the invention that the frame construction comprises an upper transverse beam and a lower transverse 70463b; 02-03-18 ouvoosu »u ~ v» 51 8 8 7 EP ÉÄÉÉ ~ .Ii ~ beam and that the supports are longitudinally variable and at their upper end articulated to the upper beam and directed obliquely downwards-backwards, while at their lower end are articulated at a transverse beam extending between the floats at a distance behind the frame structure, the floats being pivotally connected to the lower transverse beam of the frame structure via joints and an adjusting mechanism is provided to regulate the length of the struts.

With the invention a significant reduction of the take-off distance is now achieved in a very simple and reliable manner, thus leaving an important for such seaplanes which contribution to flight safety.

The invention is described in more detail below with reference to the accompanying drawing, in which Fig. 1 shows a side view of an aircraft according to the invention in a substantially horizontal position relative to a water surface, Fig. 2 is a top plan view of the same aircraft, Fig. 3 is also a top view but in larger scale of the front of the same aircraft as in Fig. 2, Fig. 4 is a rear view of the aircraft, Fig. 5 is a perspective view obliquely from above-rear of the rear part of the fuselage and the engine arrangement with the propeller and essential parts of the device according to the invention, Fig. 5a 'shows an exposed perspective view of a frame construction behind the cockpit, Fig. 6a shows a side view of the aircraft during an intermediate phase of the take-off and Fig. 6b also shows a side view of the aircraft but in the final phase of the same take-off.

As can be seen in particular from Figures 1-5 of the drawing, the invention is shown applied to a s 1: ultralight aircraft with a fuselage 1 pilot and possibly accommodating passenger space, and this fuselage is supported by two parallel 7046319; 02-03-18. - -. .- 51 ß 873 .iê-ILÉÉ 4 floats 2a, b which at their rear end together support a tail portion in the form of two fins 3a, b with intermediate stabilizer 4. At the rear and substantially vertical wall of the fuselage 1 this is attached in a load-bearing frame construction shown in Fig. 5 and shown exposed in perspective in Fig. 5a. The two floats 2a, 2b are also attached to this frame construction 5. A wing 6 is also attached to the fuselage 1 and the aforementioned frame structure 5.

From the outer ends of the lowest transverse beam in the frame structure 5, usual wing supports 7 extend obliquely outwards-upwards to suitable points on the wing 6.

From one. upper transverse double beam 8 in the frame construction 5 extends obliquely backwards-downwards a pair of preferably parallel and telescopically longitudinally variable supports 9a, b which are hingedly attached to the beam 8 at their upper ends and which at the lower ends 18a, b are hingedly connected to a transverse beam 10 which extends between the two floats 2a, b and is adaptable in its rotational position to changes in length of the supports 9a, b, as will be described in more detail below. In addition, a motor shelf 11 is suitably arranged on these struts 9a, b, which supports an aircraft engine 12 with pushing propellers 13, as will also be described in more detail in the following.

In order to enable the angular adjustment referred to according to the invention between the imaginary horizontal plane in which the floats 2a, 2b are located and the fuselage 1 with associated wing 6, propeller, etc., the frame structure is also limited pivotally mounted at the floats 2a, b at a lower transverse beam 14 in joints 14a, b of known kind, for example in the form of a rubber body attached between outer and inner steel. In addition, according to the embodiments of the invention, the telescopic supports 9a, b are variable in length by means of 70463b; 02-03-18; - »- ~ -. - | - now 518 8 73 Éïï * -.:š - Li i by any suitable known mechanism 15 of electrically, hydraulically or otherwise manoeuvrable type. In the present case, a linear electric motor is shown which, upon actuation by means of a screw mechanism or the like, changes the distance between the attachment of the mechanism 15 to the tube 10 and an overlying transverse strut 16 between the struts 9a, 9b. At maximum reduction of the length of the telescopic supports 9a, b, the fuselage 1 and the wing 6 jointly assume their most reclined position, while at maximum extension of the length of the struts the frame structure 5 assumes its most upright position and thus the fuselage 1 and the wing 6 are substantially horizontal.

A starting procedure with the device according to the invention will now be described in the following. In Fig. 1 of the drawing, the aircraft with the fuselage 1 and the floats 2a, b assume a horizontal resting or starting position. The wing 6 suitably in this position has a small forward-upward angle of attack of 0-2 °.

The procedure begins by causing the aircraft to accelerate as much as possible with respect to the present, minimum air resistance of the aircraft. The floats 2a, b then move in the water surface in a way that can be compared to a motorboat.

When a suitable speed has been reached, the adjusting mechanism for shortening the struts 9a, b and thereby providing a rearward inclination of the fuselage 1 and the wing 6 supported therefrom is started, whereby the angle of attack of the wing is increased by a certain value, for example 9 °, to a total of 11 °. ° towards the horizontal, while the floats 2a, b are still moving forward in the water surface in the same way. The lifting force of the aircraft increases this and when the relief speed is greatly achieved, for example 70 km / h (= 40 miles) the whole aircraft is angled up by another 4 ° so that the total angle of attack is about 15 ° and the plane quickly leaves the water surface. Rather 70463b; 02-03-18 then the angle of attack is readjusted by means of the mechanism 15 so that the fuselage assumes a substantially parallel position with the floats 2a, b, and the air resistance is minimized.

As is particularly clear from Figs. 5 and 5a in the drawing, the motor shelf 11 is advantageously supported by the supports 9a, b and normally assumes an approximately horizontal position. During the take-off process, when the struts 9a, b are shortened and the fuselage 1 is tilted backwards, the shelf 11 will then follow this movement, albeit to a lesser extent, so that the propeller stream will be directed less steeply down towards the water surface. It should also be pointed out that the mechanism 15 described above in the embodiment shown with a linear electric motor may suitably have a conversion distance of 100 mm. The activation of the engine can admittedly be done with some form of automatic, but a cheaper solution is to let the pilot perform this control via a suitable switch.

When landing with an aircraft equipped with a device according to the invention, it is conveniently proceeded in the opposite way, namely so that the wing 6 and the fuselage 1 are angled maximally towards the floats 2a, b before landing on the water surface, which suitably takes place at an angle ( nose up) of about 4 °. vo4s3b; 02-03-18

Claims (1)

1. 0 15 20 25 30 v ~ ø o v n u u ~ n nu s 1 s s 7 3 ššilšï - 7 P a t e n t k r a v Device for 'reduction of' required starting distance. on water in floating and preferably high-winged seaplanes, in which the angle of attack of the wing is adjustable in relation to the horizontal longitudinal axis of the aircraft and which comprise an aircraft body (1) provided with driver and any passenger seats, which carries a wing (6) and a drive motor (12) with propeller (13) and which via a standing frame construction (5) and struts (9) rest on a pair of floats (2a, b) and are connected to a ruddered tail portion (3a, b, c, 4) can be drawn - cartoon water the frame structure (5) comprises an upper transverse beam (8) and a lower transverse beam (14) and that the supports (9a, b) are variable in length and at their upper end articulated connected to the upper beam (8) and directed obliquely downwards-backwards , while at their lower end they are hingedly connected to a transverse beam (10), which extends between the floats (2a, b) at a distance behind the frame structure (5), the floats (2a, b) being limited pivotally connected to the lower cross The end beam (14) in the frame structure (5) via joints (14a, b) and a steel mechanism (15) are arranged to regulate the length of the supports (9a, b). Device according to claim 1, characterized in that the mechanism (15) comprises a drive device or motor, preferably a linear electric motor. Device according to claim 1 or 2, lc a n 11 e - t e c k n a d a v that a shelf (11) is arranged on the support (9a, b) in a substantially horizontal normal position and intended to support the motor (12). '70463b; 02-03-18