Influence of Lightning and Static Electricity as Applied to Helicopter Design

As recently as 1968, there was not a single case on record of lightning striking a helicopter, and it was difficult to obtain funds to support research toward development of lightning protection.

This situation changed in 1969-1970. One helicopter was destroyed by a lightning strike with loss of life; another was hit on the ground with substantial blade damage. So the interest in lightning and static electricity lost somewhat its “academic only” stamp.

This paper reviews three basic domains of static electricity affecting the helicopter, namely:

1. 1.
   Protection of the rotor blade against the effects of lightning strike.
2. 2.
   Cargo hook operation and, connected with it, the problem of active equalization of potential between the cargo and the cargo handler.
3. 3.
   Passive static electricity dischargers as a method to radio interference reduction.

All three domains affect the whole blade design with emphasis on the design of the blade tip.