  This paper uses Coanda Effect to reduce motors, the source of noise, and
finds low noise materials with sufficient lift force so that it can achieve
acoustical stealth UAVs.According to NASA research [1], the noise of UAVs is
better heard to people. But there must be some moments when we need to operate
the drones quietly, so how can we reduce the noise? In previous research, there
have also been steady attempts to produce UAVs using Coanda Effect, but have
never tried to achieve Acoustic Stealth through Coanda UAVs. But Coanda Effect
uses only one motor and is structurally quiet. So we tried to find quiet
methods (materials, structures) while at the same time having sufficient
stimulus through the Coanda Effect. Verification went through experiments. The
control group used the most common type of Quadrone, and determine if the
hypothesis is correct by testing various structures and materials under the
same conditions, and measuring noise. UAVs using Coanda Effect are not of any
shape or structure that is not changeable, and internal space is also empty.
That's why the Coanda Effect UAV we present can be improved through follow-up
research. That's why the Coanda Effect UAV could open up a new frontier for the
Stealth UAVs.
