Tail Cone Ram Air Turbine Eliminates Mechanical Governor

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Solution Overview

Problem

Conventional ram air turbines (RATs) used for emergency power in aircraft are complex, expensive, and add mass to the system due to their mechanical governors, which complicate the emergency power generation process.

Innovation Solution

A tail cone integrated ram air turbine system that deploys RAT blades from a rotatable segment of the aircraft's tail cone, using a power transfer shaft to drive an auxiliary power unit (APU) generator and a controller to manage power output, eliminating the need for mechanical governors and leveraging existing structural and power systems.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If conventional RATs utilize a mechanical governor to vary blade pitch, then the power output of the turbine can be controlled, but the system becomes expensive, complex, and increases system level mass

Engineering Contradiction:

Improvepower output controlVSAvoidsystem complexity

Core Design Contradiction:

PowerVSDevice complexity

Solution Approach 1:

The patent extracts and removes the mechanical governor from the RAT system entirely. Instead of using a mechanical governor to control blade pitch, the invention uses a simpler system where the RAT blades are directly connected to the APU generator, allowing the generator's electromagnetic characteristics to naturally regulate power output without complex mechanical control devices.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the mechanical governor system with an electromagnetic control mechanism. The APU generator's electromagnetic field and electrical load characteristics serve as the control mechanism, substituting complex mechanical blade pitch regulation with simpler electromagnetic interactions that achieve the same power control function.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Power

If conventional RATs utilize a mechanical governor, then power control is achieved, but system cost increases

Engineering Contradiction:

Improvepower control capabilityVSAvoidsystem cost

Core Design Contradiction:

PowerVSEase of manufacture

Solution Approach 1:

The patent extracts and eliminates the expensive mechanical governor component from the system. By removing this costly mechanical control device, the overall system cost is reduced while maintaining power control capability through the APU generator's inherent electromagnetic regulation.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent employs simpler, less expensive components in place of the expensive mechanical governor. The system uses readily available APU generator components and basic mechanical linkages that are more cost-effective than precision mechanical governors, achieving the same functional outcome at lower cost.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

3Speed

If conventional RATs utilize a mechanical governor, then turbine speed control is achieved, but system mass increases

Engineering Contradiction:

Improveturbine operating speedVSAvoidsystem mass

Core Design Contradiction:

SpeedVSWeight of moving object

Solution Approach 1:

The patent extracts and removes the heavy mechanical governor assembly from the RAT system. By eliminating this mass-intensive mechanical control device, the overall system mass is reduced while turbine speed control is maintained through the APU generator's electromagnetic characteristics and electrical load management.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the heavy mechanical governor system with a lighter electromagnetic control approach. The APU generator's electromagnetic field and electrical system serve as the control mechanism, substituting mass-intensive mechanical components with lighter electrical and electromagnetic elements that achieve the same speed regulation function.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This solution reduces system complexity, cost, and mass while providing reliable emergency power by integrating RAT blades into the aircraft's tail cone, streamlining power generation and control without the need for mechanical governors.

Implementation Method 1

air rushing past the aircraft due to the aircraft's forward speed causes the turbine blades to spin

Methodology Applied

Scientific EffectAerodynamic force: Aerofoil

Implementation Method 2

transferring power from the rotatable segment to an auxiliary power unit (APU) generator

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentUS9284063B2Tail cone driven emergency power generating system

Publication Date: 2016.03.15 HAMILTON SUNDSTRAND CORP

AI summary

A tail cone integrated ram air turbine (RAT) includes a rotatable segment of an aircraft tail cone configured to deploy a set of RAT blades. The tail cone integrated RAT also includes a power transfer shaft connected between the rotatable segment and configured to transfer power to from the rotatable segment to an auxiliary power unit (APU). The tail cone integrated RAT further includes a controller connected to the APU and configured to control power output from the APU. When emergency power for an aircraft is needed, the set of RAT blades is deployed from the rotatable segment of an aircraft tail cone. Mechanical power from the rotatable segment is transferred to an APU generator to produce emergency electrical power.