SCEET5 - Thermoid Aeroduct High-Temperature Silicone Ducting (1.25" ID)

SCEET-5 – Thermoid Aeroduct® High-Temperature Silicone Ducting (1.25" ID)

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The Thermoid Aeroduct® SCEET-5 is a high-performance, double-ply flexible air duct engineered for extreme temperature environments where the transmission of hot or cold air and fumes is required. With a 1.25-inch inner diameter, this ducting is a critical component in aircraft Environmental Control Systems (ECS), avionics cooling loops, and firewall-forward applications such as carburetor heat or cabin heating systems. Its construction provides an exceptional combination of flexibility and thermal stability, far exceeding the capabilities of standard neoprene-based (SCAT) ducting.

Engineered for safety and reliability, SCEET-5 is composed of two plies of silicone-impregnated fiberglass, with a bronze-plated or copper-coated spring-steel wire helix reinforcement bonded between the layers. This integrated wire design provides structural integrity without obstructing the smooth inner bore, resulting in lower air friction losses compared to single-ply ducting. The entire assembly is wrapped in a fiberglass cord, adding to its durability and resistance to abrasion. This component is designed for positive pressure applications and is indispensable for systems operating at temperature extremes.

Key Features

• Extreme Temperature Range: Certified for reliable operation in temperatures ranging from -80°F to +550°F (-62°C to +288°C), making it ideal for both cryogenic and high-heat applications.

• Double-Ply Silicone Construction: Features two plies of high-grade fiberglass fabric, fully impregnated and coated with red silicone rubber, providing exceptional thermal resistance and durability.

• Internal Wire Helix: A bronze-plated spring-steel wire helix is bonded between the two plies, providing crush resistance and flexibility while maintaining a smooth inner surface for minimal friction loss.

• Smooth Inner Bore: The internal construction prevents airflow obstruction, reducing turbulence and the pressure drop ($\Delta P$) across the ducting system.

• Fiberglass Cord Reinforcement: An external fiberglass cord is helically wrapped around the duct, providing an additional layer of abrasion resistance and structural integrity.

• Excellent Flexibility: Easily routed around engine mounts, structural components, and in tight spaces within the airframe or nacelle.

Technical Specifications

• Part Number: SCEET-5

• Component Type: Flexible Air Ducting, High-Temperature

• OEM Manufacturer: Thermoid Inc. (HBD Industries)

• Inside Diameter (ID): 1.25 inches (31.75 mm)

• Material:

  • Inner & Outer Plies: Fiberglass fabric impregnated and coated with silicone rubber.

  • Reinforcement: Bronze-plated spring-steel wire helix (internal).

  • External Wrap: Fiberglass cord.

• Color: Red (indicative of silicone material)

• Operating Temperature Range: -80°F to +550°F (-62°C to +288°C)

• Application: Positive pressure airflow and fume conveyance.

• Note: Not for use with liquids, abrasive materials, or in negative pressure (suction) applications.

Aircraft Compatibility

SCEET-5 is a standard hardware component used on a wide range of certified aircraft, including high-performance piston, turboprop, and light jet airframes. It is specified in any application requiring the flexible transfer of air or fumes within its wide temperature operating range.

Crucial Note: Verification against the specific aircraft's Illustrated Parts Catalog (IPC) or maintenance manual is mandatory to ensure correct part number applicability and diameter.

Applications

• Firewall-Forward Heating Systems: Ducting hot air from a heat muff or cabin heat exchanger.

• Carburetor Alternate Air / Carb Heat: A common and critical application for routing hot air to the engine induction system.

• Avionics Cooling: Supplying cooling air (conditioned or ambient) to instrument panels and remote avionics bays.

• Environmental Control Systems (ECS): Ducting hot bleed air (in bleed-air-equipped aircraft) or cooled, conditioned air for climate control.

• Windscreen Defrosting Systems: Channeling hot air to the windscreen.

Why Choose SCEET-5?

Choosing genuine Thermoid SCEET-5 ducting is a critical decision for safety and reliability in high-temperature applications. Standard neoprene (SCAT) ducting is typically rated to only 350°F and will fail when exposed to the higher temperatures found in many firewall-forward or bleed air systems. The dual-ply silicone construction of SCEET is specifically engineered to resist this extreme heat, preventing ducting collapse, degradation, or a catastrophic burn-through that could create a severe in-flight fire hazard. Its integrated wire helix and smooth bore design ensure efficient airflow, providing the performance and security required for these critical systems.

The exceptional performance of SCEET-5 is rooted in the material science of its silicone elastomer and fiberglass composite. The plies are made from polysiloxane (silicone), a polymer with an inorganic silicon-oxygen backbone ($(-Si-O-)_n$). This chain has significantly higher bond energy ($\sim 445$ kJ/mol) compared to the carbon-carbon backbone ($\sim 347$ kJ/mol) of organic elastomers like neoprene. This inherent thermal stability is what grants the material its ability to resist degradation and maintain its flexibility at continuous temperatures up to 550°F. The fiberglass fabric acts as a substrate, providing the tensile strength and dimensional stability that the soft elastomer lacks. The internal spring-steel helix provides the structure's hoop strength and kink resistance, while its position between the plies (a key feature of SCEET) creates a smooth hydrodynamic internal path, minimizing the Reynolds number of the airflow and preventing the significant pressure drop associated with the turbulent flow created by externally-wrapped or un-lined ducting.

Note: This is a flight-critical component. It must be inspected regularly for cracks, heat degradation, punctures, delamination, and security. Damaged ducting can lead to a loss of heating, defrost, or avionics cooling, and poses a significant fire or carbon monoxide hazard if used in firewall-forward applications. It must be secured at both ends with high-quality, aviation-grade band clamps (e.g., Breeze or T-bolt clamps) as specified in the maintenance manual.

Documentation

• Thermoid Aeroduct® Aviation Ducting & Hose Catalog (General Information)