Naval aircraft launching with steam ingestion affecting the engines.

Engine Stall During Catapult Launch: Can We Predict and Prevent It?

Rhea Morgan in Tech & Innovation September 2025 • 4 min read.

"New research dives into how steam ingestion affects transonic rotor fans, potentially leading to safer and more reliable naval aircraft launches."

Imagine a naval aircraft poised on a carrier deck, ready for launch. The steam catapult hisses, building pressure, then releases in a burst of power, rocketing the plane skyward. But what happens when that steam gets sucked into the jet engines? This isn't just water vapor; it's a superheated mix that can drastically alter engine performance, sometimes leading to compressor stall and even afterburner blowout.

While twin-engine aircraft have traditionally been more resilient, single-engine planes with serpentine intakes are particularly vulnerable to these disruptions. This is where cutting-edge research comes in, aiming to understand and predict the effects of steam ingestion to prevent dangerous engine failures.

This article explores a detailed investigation into how steam affects transonic compressor rotors – the critical fans within jet engines. By combining experimental data, thermodynamic analysis, and numerical modeling, researchers are uncovering ways to mitigate stall and ensure safer, more reliable aircraft launches.

Understanding Steam Ingestion: Why It's More Than Just a Little Moisture

Naval aircraft launching with steam ingestion affecting the engines.

You might think a little steam is no big deal, but hot steam ingestion is vastly different from the normal moisture found in the air. The key difference lies in temperature. The higher the temperature, the greater the moisture fraction in the mixture. This, in turn, causes significant changes in the gas properties within the engine, throwing off the delicate balance required for optimal performance.

Think of it like this: jet engines are designed to work with a specific blend of gases, primarily air. When hot steam is introduced, it alters the gas constant (R) and the specific heat ratio (γ), two critical factors that determine how the engine operates. This isn't just a minor adjustment; it's like changing the rules of the game mid-play.

Here’s a breakdown of the key factors:

Gas Constant (R): A measure of how much a gas expands or contracts with changes in pressure and temperature.
Specific Heat Ratio (γ): The ratio of the heat required to raise the temperature of a gas at constant pressure versus constant volume.
Sonic Velocity: The speed at which sound waves travel through the gas mixture, directly affected by R and γ.

These altered properties don't just shift the engine's operating point; they actually change the shape of its performance map. Compressors are designed for a specific gas mixture (usually air), and introducing steam requires additional measures to prevent adverse effects.

The Future of Safer Launches: Predicting and Preventing Stall

By combining experimental data with advanced modeling techniques, researchers are developing tools to predict and mitigate the risk of steam-induced stall. This means designing engines that are more tolerant to steam ingestion or developing operational procedures that minimize the amount of steam entering the engine during launch. The ultimate goal is to ensure that naval aircraft can launch safely and reliably, even under challenging conditions.

About this Article -

This article was crafted using a human-AI hybrid and collaborative approach. AI assisted our team with initial drafting, research insights, identifying key questions, and image generation. Our human editors guided topic selection, defined the angle, structured the content, ensured factual accuracy and relevance, refined the tone, and conducted thorough editing to deliver helpful, high-quality information.See our About page for more information.

This article is based on research published under:

DOI-LINK: 10.1115/1.4028318, Alternate LINK

Title: Investigation And Prediction Of Steam-Induced Stall-Margin Reduction In Two Transonic Rotor Fans

Subject: Mechanical Engineering

Journal: Journal of Fluids Engineering

Publisher: ASME International

Authors: Anthony J. Gannon, Garth V. Hobson, Collin R. Hedges, Gregory L. Descovich

Published: 2014-09-04

Everything You Need To Know

What is the main problem addressed by the research on steam ingestion in jet engines?

The primary concern is engine stall, specifically the compressor stall, which can occur during catapult launches of naval aircraft. Steam, particularly hot steam, can be ingested into the jet engines, disrupting the engine's optimal performance and potentially leading to engine failure or afterburner blowout. The research aims to understand, predict, and ultimately prevent these failures, improving aircraft safety and reliability.

How does steam ingestion affect jet engine performance, and why is it a significant issue?

Steam ingestion alters the gas properties within the engine, specifically the gas constant (R) and the specific heat ratio (γ). These factors determine the engine's operational characteristics. The introduction of steam shifts the engine's operating point and can change the shape of its performance map. This disruption is critical because jet engines are designed to function with a specific blend of gases (primarily air). When steam enters, it throws off the delicate balance, increasing the risk of compressor stall and other performance issues, particularly in single-engine aircraft with serpentine intakes.

What are the key differences between normal moisture and hot steam ingestion, and why does temperature matter?

The key difference lies in the temperature and the resulting moisture fraction. Hot steam has a much higher temperature and a higher moisture content compared to the normal moisture found in air. This is critical because temperature significantly influences the impact on the engine. The higher the temperature, the greater the moisture fraction, leading to more significant changes in the gas properties within the engine. These changes to the gas constant (R) and specific heat ratio (γ) have substantial effects on engine performance and can cause compressor stall.

How are researchers working to predict and prevent steam-induced stall in jet engines?

Researchers are using a combination of experimental data, thermodynamic analysis, and numerical modeling to investigate the effects of steam ingestion on transonic compressor rotors. They are developing tools and techniques to predict the risk of steam-induced stall. The goal is to design engines that are more tolerant to steam ingestion or to create operational procedures that minimize steam entry during launch. This approach aims to ensure safer and more reliable launches for naval aircraft, even under challenging conditions.

Why are single-engine aircraft with serpentine intakes particularly vulnerable to steam ingestion issues during catapult launches?

Single-engine aircraft with serpentine intakes are more susceptible to steam ingestion problems due to their intake design. Serpentine intakes have a curved path, which can increase the likelihood of steam entering the engine during launch. This design, combined with the effects of steam on the engine's gas properties (R and γ), increases the risk of compressor stall or afterburner blowout. Twin-engine aircraft, on the other hand, are often more resilient to these disruptions, making single-engine planes with these intake designs a focus of the research on steam ingestion.