Line-of-sight (LOS) establishment is a significant part of the neighbor discovery process for an ad-hoc network with highly directional antennas/transceivers. And, this problem of establishing LOS between neighbor nodes become even more challenging when they have no a priori information about each other’s location. In this work, we present a heuristic for LOS neighbor discovery between two drones capable of scanning the 3D space around them using highly directional transceivers. The drones can mechanically steer their respective transceivers with randomly chosen angular speeds on arbitrary circular paths and perform a simple three-way handshake to discover each other. They change the circular scanning paths and angular speeds if the discovery is not successful within an optimal time interval. Through extensive simulations, we demonstrate that using such mechanically steerable highly directional transceivers, two neighbor drones can discover each other successfully even without prior location information about each other and without any omnidirectional out-of-band channel to exchange information with each other.