What is the culprit for flameout at high altitude? Prevention of creepage in aircraft model spark plugs

1. The nature and harm of creepage

Creep (flashover): The high-voltage current does not discharge normally through the spark plug electrode gap, but forms a conductive path along the surface of the insulator, breaking through the insulation layer between the ceramic body and the metal shell.

Consequences: Ignition energy leakage, resulting in single-cylinder or multi-cylinder fire; the air is thin in the high-altitude environment, the insulation performance is reduced, the creepage risk is doubled, and it is easy to cause flameout in the air.

Typical fault manifestations——

Engine shaking, weak acceleration, and increased fuel consumption;

Sudden power interruption during high-altitude flight (oxygen-deficient environment exacerbates arc formation);

Black tree-like patterns appear on the surface of the insulator (can be erased with sandpaper, which is obviously different from cracks).

2. The relationship between high-altitude flameout and creepage

Low air pressure and low temperature: the insulation strength of air decreases, the breakdown voltage decreases, and the probability of creepage increases;

Temperature change: the spark plug cycles between -50°C and +1500°C, and the thermal stress of the ceramic body is prone to microcracks, providing a path for creepage.

3. Prevention and maintenance: key measures to block creepage

Zero contact principle: wear gloves to operate, and do not touch the ceramic body with your hands;

Insulation enhancement: apply high-voltage insulating silicone grease between the ceramic body and the metal shell to fill the microscopic gap.

Regularly replace product parts and check compatibility.

4. Four causes and factors of creepage