DE29512397U1 - Torsion arm for folding engine - Google Patents

Description

Description:

The KlOE design minimizes the installation width B for minimal weakening of the hull with maximum torsional rigidity of the drive unit.

Compared to conventional designs, the number of components is reduced in the TORSION ARM design.

The KlOE system works with 1 pendulum support and 1 torsion arm.

This design provides a maximum stiffness ratio Qs = Mt/B

(Torsional moment Mt / installation width B).

This design is statically determined and can be cut free at any point in the system.

In the following, an approximate comparison of the installation widths of both systems is carried out (Figure 2).

System 1: 4 support brackets for all forces (Image 2; right half) System 2: 1 pendulum support, 1 torsion arm (Image 2; left half)

Torsion angle Phi, = Phi ₂ = const, (axial twisting of the torsion arm

or the retaining bracket) torsional moment Mt _λ = Mt ₂ = const.

The following approximately applies for small angles Phi:

4x ( π /32xD, ⁴ ) = Ix ( π /32D ₂ ⁴ ) 4 support bracket 1 torsion bar

thus _{1.4HxD1 -D2} I; ; if D ₂ <D _Engine The following applies: 2xD, > _D2 ; if D ₂ >D _Engine +D The following also applies: _B1 = 2xD,+D _{Mc B2} = lxDp+D _{Mt B2} = _lxD2

It follows: B ₁ > B _;

Necessary and sufficient conditions: »B _f <«Di,.since Di-as-pendulum-seat.does not absorb any torques!

Possible uses: Optimization of retractable engine systems with &Egr; engine in Model gliders;

specifically: optimization of parallelogram construction (Figures 1-4)

Retractable engines of gliders are propulsion units that are completely housed in the glider’s fuselage.

They are extended mechanically, unfold the propeller and take the aircraft to a freely selectable altitude. This altitude is limited by the energy on board, depending on the efficiency of the drive unit and the aircraft.

Problem:

In order to use a folding engine, a fuselage cutout is required. In the designs described here, the length L and the width B of the fuselage cutout are decisive for the weakening of the fuselage. The length L results from the length of the propellers and the required folding height H (Fig.I).

This length L should remain unchanged.
The width B must be minimized.

The forces are essentially caused by the axial drive force of the propeller, the engine torque, dynamic forces and moments during start-up, as well as precession forces caused by propeller and rotor rotation.

State of the art:

The parallelogram constructions on the market work with 4 holding brackets, which absorb the resulting tensile and compressive forces, as well as the torques. These designs are statically overdetermined. Two holding brackets arranged next to each other require a width of the fuselage cutout, which must be minimized.

·

Solution:

The four retaining brackets are replaced by a torsion arm and a pendulum support. The torsion arm is the component to be protected, as defined in the protection claim.

Further design:

For reasons of symmetry (possibly optical flaw), two pendulum supports can also be used. The stiffness quotient Qs is only slightly reduced by this measure.

Ze declaration of identity 1 - - Parallelogram construction 2 - ■ Folding propeller in operating position 3 - - Electric motor 4 - ■ Torsion arm 5 - ■ Pendulum support S - ■ Folding propeller in rest position 7 - ■ Pendulum support 8th - Torsion arm 9 - Retaining bracket 10 - Electric motor 11 - drive shaft 12 - ■ Hull contour 13 - Torsion arm 14 - Pendulum support 15 - Pivot points 16 - Mounting frame 17 - Retaining bracket L- Installation length B - Installation width H - Folding height Bl - Installation width for system 1 B2 - Installation width for system 2 (KlOE) Dl- Diameter of a bracket D2 - Diameter of the torsion arm Dp- Diameter of the pendulum support Dn- Diameter of the electric motor

Claims (1)

Claim for protection: The component to be protected in the retractable engine as a parallelogram construction is the TORSION ARM. It is the main support of the structure. The torsion arm connects the fuselage support with the engine mount and is mounted at both ends so that it can rotate around the transverse axis (here: z-axis) to realize the swivel movement. The torsion arm transmits tensile and compressive forces as well as all torques generated at both mounts.