FR2594792A1 - Dirigible with lift rotors at the ends of the hull - Google Patents

Abstract

Numerous projects for dirigibles or helicostats comprise lift rotors, or tilting rotors, close to the centre of the hull and placed symmetrically on both sides. Using the longitudinal rigidity of the dirigible, in particular of the dirigible known as "semi-rigid" with a keel, it is possible to place the rotors at the front and at the rear, with great advantages in vertical and pitch manoeuvrability, in drag, in weight and in "versatility" with respect to a basic projects. The front rotor is placed obliquely (lifter-tractor) while two rear rotors may be integrated "in fenestron" in the empennage.

Description

 The object of the present invention is to provide steerable balloons with improved maneuverability in the vertical direction, in particular in slow flight and to access a ground anchoring device such as that described by French Patent 85-02529 by the same author. The handling means concerned are propellers with variable pitch.

 We have known for more than a century the idea of associating a balloon with propellers or rotors with vertical action. The Relicostat of OEHMICEN in the period 1922-1930 demonstrated its validity. Some airships in the period 132-1938 were equipped with tilting thrusters to obtain vertical thrusts and this was repeated on small recent airships. The availability of helicopter rotors has given rise to numerous projects of the "heliostat" type comprising vertically acting rotors mounted on a tapered hull. It should be noted that the rotors are then placed in pairs symmetrically at the ends of transverse beams , with possibly, as in a Goodyear project, a tilting rotor at the rear point allowing corrective actions in pitching. We can criticize this arrangement in pairs of the main lift rotors, because it introduces risks of asymmetries in roll while the airship would naturally be stable in roll; the two rotors must be mechanically synchronized. This solution finally introduces a lot of complexity and weight, as well as a strong drag. The author published in t979 a project comprising a single rotor, coaxial with the load carried, not implying asymmetry.

 The present invention relates to the observation that the rotors with vertical axis can be used not only to lift part of the total load, but also to provide a means of vertical maneuverability in altitude and in incidence (pitching). They can in particular be of a force much lower than the mobile load, the weight of which is lifted for the most part by an aerostatic action with ballast compensation. The device can then be called a partial heliostat.

 The present invention consists in using rotors with vertical action at the two ends of the tapered hull of an airship. We thus use the existing rigidity of the hull in the longitudinal direction, instead of adding transverse beams to it, and we ensure excellent maneuverability in pitching, an essential parameter to master.

 It should be recalled that the hulls of tapered airships correspond to three main types: - flexible hulls where only the internal overpressure of the carrier gas envelope ensures the maintenance of the shape, - the semi-rigid hulls OR the flexible envelope is associated with a longitudinal beam, generally applied under the lower generatrix and called a keel, - rigid hulls, where the shape is maintained by a complete structure.

 The present invention requires significant longitudinal rigidity; to avoid the consequences of partial swelling flanks, it is to be used with rigid or 6e-i-rigidess hulls, preferably the latter within the radius of the fragility often observed from the former.

 The use of vertical rotors according to the invention, at the ends of semi-rigid hulls, poses particular problems which will be explained by the following descriptions, associated with figures: - Figure 1. Profile view of an airship according to the invention, - Figure 2. Variant to the rear rotor.

 The description is applied to a semi-rigid airship comprising a casing 1 iuselée with advanced master-couple and a rig keel: dity 2 carrying at the front a lift rotor 3 and a undercarriage 4 (of the type concerned by Patent 85 -02529) and at the rear an empenna of the 5, the propulsion damper 6 and a lift rotor 7.

 The axis of the rotor 3 is not vertical, oblique (forward at the top) at the same time so that the rotor disc is easier to arrange: between the casing nose and the front tip of the pins so as not to step: blow the rotor directly on the casing when it is operating in the downward direction, and to obtain a certain traction effect providing, under the action of this sedlrotor, an extremely stable flight as demonstrated by the tests on motorized models. This traction effect can be compensated if necessary by a reverse action of the propellants.

 According to a proposal by the author, the envelope of the airship may have an advanced master torque to allow the center of the carried load to be advanced as far as possible and obtain the captive flight stable on a retaining target also used to hoist the charge.

The front rotor 3 then compensates for a much larger part of the load than that taken up by the rear rotor 7 and it must be more powerful.

 The rotor 3, fixed to the keel 3 by means of a gelled sorting frame, is driven either directly by a motor provided with a reduction gear, or by a motor 10 transferred in the keel, by means of a shaft 71 and angle gear 12. A helicopter-type rotor can be used but it does not appear necessary to equip it with a cyelic variation of pitch.

 In Figure 1 the rear rotor 7 is located at the end of a console 15 extending the rear of the keel. It is driven by a motor 16, a shaft 17 and a bevel gear i8. n rotates in the opposite direction to the rotor 3 to partially compensate for the torque, the rest of the compensation being provided by a differential action on the thrusters such as 20, located on either side of the keel.

 This implantation in the far rear has the drawback of lengthening the device and enlarging the area necessary for its development, and also of presenting a certain risk of encountering obstacles.

For a large airship it will be advantageous to use the arrangement of FIG. 2, in which the rotor 7 is replaced by two rotors 30 and 30 'in nozzle in orifices of the two half-wings of the empennage, arrangement known as "in fenestron for tail rotors of helicopters. The tail wings are here in "circumflex" arrangement. The two rotors can be driven by a single motor 31 and their steps can be coupled, unless you want to act differently on these two rotors to obtain roll and transverse force effects.

 The invention thus allows1 without appreciable increase in drag compared to a purely aerostatic airship, to install power lift rotors & choose to obtain any desired result between the only improvement in handling (which makes it possible to do without team at ground at landing) and operation as a handling helicopter controller. This technical continuity for several devices, completely new in this area, is a guarantee of efficiency and economy.

Claims (4)

1. Tapered airship provided with lifting rotors, characterized in that these rotors are placed in the vicinity of the front and rear ends 2. Airship according to claim 19 characterized in that a front rotor is placed on the front end of a stiffness keel attached to the flexible envelope of the airship, with its axis oblique towards the front and up. 3. Airship according to claim t characterized in that a rear rotor is placed at the rear end of a stiffness keel attached to the flexible envelope of the airship, at the end of a console extension. 4. Airship according to claim 1, characterized in that it comprises two rotors at the rear, in nozzle in orifices of the tail.