# How Boeing Shortens Engine Exhaust Fairings to Save Weight

> A design for aircraft engine exhaust systems that allows the protective fairing behind the engine to be shorter, reducing weight and drag.

- **Patent:** US 11827373
- **Original title:** Aircraft engine exhaust systems enabling reduced length aft strut fairings
- **Owner:** Boeing Co
- **Granted:** 2023
- **Status:** Active
- **Times cited:** 0
- **Field:** aerospace, mechanical

## What it does

This patent describes a way to shorten the aft strut fairing—the aerodynamic cover that sits behind the jet engine on an aircraft wing. By precisely aligning the heat shield so it ends exactly where the engine's exhaust nozzle ends, the design eliminates the need for extra shielding further back. It uses specific pressure regions (1.3 Pbar vs 0.85-1.2 Pbar) at the nozzle outlet to create an aerodynamic barrier, preventing hot engine exhaust from flowing into the gap between the engine and the fairing. This allows the fairing to be physically shorter without risking heat damage to the aircraft structure.

## What it does NOT cover

- Does not cover exhaust systems where the heat shield extends downstream past the nozzle trailing edge.
- Does not cover fairings that include heat shielding on the surface located downstream from the nozzle outlet.
- Does not cover engine designs that do not utilize the specific pressure differential described to prevent exhaust flow into the fairing gap.

## The clever bit

Instead of using more physical material to shield the fairing from heat, the design uses the engine's own exhaust pressure profile to create an invisible aerodynamic wall that keeps hot gas away from the structure.

## Real-world examples

1. Modern Boeing commercial aircraft engine pylon assemblies
2. High-bypass turbofan engine exhaust configurations

## Why it matters

In commercial aviation, every pound of weight reduction translates directly into fuel savings and increased payload capacity. By shortening the aft strut fairing, Boeing can reduce the overall drag and weight of the engine pylon assembly, which is critical for the efficiency of modern high-bypass turbofan engines.

## Frequently asked questions

### What does How Boeing Shortens Engine Exhaust Fairings to Save Weight cover?

A design for aircraft engine exhaust systems that allows the protective fairing behind the engine to be shorter, reducing weight and drag.

### Who owns patent US 11827373?

Boeing Co owns this patent, granted in 2023.

### When does this patent expire?

This patent is expected to expire on November 28, 2043, when the invention enters the public domain.

### What problem does this patent solve?

In commercial aviation, every pound of weight reduction translates directly into fuel savings and increased payload capacity. By shortening the aft strut fairing, Boeing can reduce the overall drag and weight of the engine pylon assembly, which is critical for the efficiency of modern high-bypass turbofan engines.

### What does this patent NOT cover?

Does not cover exhaust systems where the heat shield extends downstream past the nozzle trailing edge.

**Full plain-English explainer:** https://patentbrief.org/patent/us/11827373/starship-tanker-variant

**Original patent:** https://patents.google.com/patent/US11827373

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_Source: PatentBrief — https://patentbrief.org. Patent facts are from public records; the plain-English explanation is PatentBrief's._