Terminology and Design of Asymmetrical Gears for Aircraft

Novikov, Alexander S.; Голованов, В. В.; Dorofeyev, D.; Dorofeyev, V.

doi:10.1007/978-3-319-19740-1_18

Cited by 3 publications

(2 citation statements)

References 2 publications

(2 reference statements)

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“…The gears in the reduction gear set consist of a first-stage 0.3 module gear with a gear ratio of 5.71 and a second-stage 0.5-module gear with a ratio of 3.75. The selection of appropriate gear transmission parameters is crucial, and we make these choices based on the references cited in the literature (Wen, 2010; Novikov et al , 2016). Locking arcs were designed on gears to enhance the steering stability of the flapping wings mechanism, as illustrated in Figure 1(b).…”

Section: Prototype Designmentioning

confidence: 99%

Research on insect-like long endurance hovering double-wing FMAV prototype

Zhang,

Cui,

Liu

et al. 2024

AEAT

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Purpose Endurance time is an important factor limiting the progress of flapping-wing aircraft. In this study, this paper developed a prototype of a double-wing flapping-wing micro air vehicle (FMAV) that mimics insect-scale flapping wing for flight. Besides, novel methods for optimal selection of motor, wing length and battery to achieve prolonged endurance are proposed. The purpose of this study is increasing the flight time of double-wing FMAV by optimizing the flapping mechanism, wings, power sources, and energy sources. Design/methodology/approach The 20.4 g FMAV prototype with wingspan of 21.5 cm used an incomplete gear flapping wing mechanism. The motor parameters related to the lift-to-power ratio of the prototype were first identified and analyzed, then theoretical analysis was conducted to analyze the impact of wing length and flapping frequency on the lift-to-power ratio, followed by practical testing to validate the theoretical findings. After that, analysis and testing examined the impact of battery energy density and efficiency on endurance. Finally, the prototype’s endurance duration was calculated and tested. Findings The incomplete gear facilitated 180° symmetric flapping. The motor torque constant showed a positive correlation with the prototype’s lift-to-power ratio. It was also found that the prototype achieved the best lift-to-power ratio when using 100 mm wings. Originality/value A gear-driven flapping mechanism was designed, capable of smoothly achieving 180° symmetric flapping. Besides, factors affecting long-duration flight – motor, wings and battery – were identified and a theoretical flight duration analysis method was developed. The experimental result proves that the FMAV could achieve the longest hovering time of 705 s, outperforming other existing research on double-wing FMAV for improving endurance.

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Section: Prototype Designmentioning

confidence: 99%

Research on insect-like long endurance hovering double-wing FMAV prototype

Zhang,

Cui,

Liu

et al. 2024

AEAT

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“…Conforming gear pairs are used in highly loaded applications, for example, the Novikov gears of the final drive of helicopter gearboxes and some turboprops [1,2]. In such gearing systems, convex-concave teeth pair geometry of a high degree of conformity (with very small radius difference, δR, as shown in Figure 1) is used in order to maximize the contact footprint area and thus the load carrying capacity [3].…”

Section: Introductionmentioning

confidence: 99%

Analytical Elastostatic Contact Mechanics of Highly-Loaded Contacts of Varying Conformity

2020

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In applications requiring high load carrying capacity, conforming contacting pairs with a relatively large contact footprint are used. These include circular arc, Novikov, and Wildhaber gears found, for example, in helicopter rotors. Closely conforming contacts also occur in many natural endo-articular joints, such as hips, or their replacement arthroplasty. The main determining factors in contact fatigue are the sub-surface shear stresses. For highly loaded contacts, classical Hertzian contact mechanics is used for many gears, bearings, and joints. However, the theory is essentially for concentrated counterforming contacts, where the problem is reduced to a rigid ellipsoidal solid penetrating an equivalent semi-infinite elastic half-space. Applicability is limited though, and the theory is often used inappropriately for contacts of varying degrees of conformity. This paper presents a generic contact mechanics approach for the determination of sub-surface stresses, which is applicable to both highly conforming as well as concentrated counterforming contacts. It is shown that sub-surface shear stresses alter in magnitude and disposition according to contact conformity, and lead to the different modes of fatigue failure noted in practice.

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