Helicopter Duration

33.1 Scope

Helicopter Duration comprises eleven events open to any single-stage model rocket that uses autorotation as the sole means of recovery. The purpose of this competition is to achieve the longest flight duration using an auto-rotating recovery system.

33.2 Autorotation

Each entry must be decelerated during descent by its auto-rotating recovery device. The resulting autorotation must be around the vertical axis. An entry that descends nose first, or flips over during descent is permitted.

33.3 Recovery

Recovery devices employing flexible (e.g., plastic film or cloth) surfaces are prohibited. Entries using a recovery system that is designed to act (or that actually acts) in a manner similar to a parachute, a rigid inverted bowl, or similar techniques are specifically excluded from this competition.

33.4 Qualification

The entry must make a minimum of one complete rotation around its vertical axis during the recovery portion of the flight to be considered qualified.

33.5 Classes

This event is divided into classes based on the permissible total impulse of the motor(s). The following classes of Helicopter Duration are established:

Motor Class	Multi-Round Maximum (sec)	NRC Maximum (sec)
1/8A	20
1/4A	30	90
1/2A	60	180
A	120	360
FAI A	180
B	180	540
C	240
D	300
E	300
F	300
G	300