  At present, new approaches for the use of Multirotor Unmanned Aerial Vehicle
or multirotor drones in high precision optical applications are rising.
However, the optical turbulence effects generated by multirotor drones are not
entirely understood. These optical effects can reduce the performance of the
optical instruments that they transport. This paper presents measurements of
the wavefront deformation generated by the temperature fluctuations and the
airflow of a drone's propulsion system. To do so, we used a single arm of a DJI
S800 EVO Hexacopter (professional drone) and measured its operating temperature
with a commercial infrared camera. The resulting temperature variation, between
a switched-off propulsion system at room temperature and one running at its
maximum performance, was 34.2{\deg} C. Later, we performed two different
interferometric tests, Takeda's method, and the phase-shifting technique, using
a ZYGO interferometer. These tests show that the total deformation over an
incident wavefront to the propeller airflow is lower than 0.074 \lambda PV and
0.007 \lambda RMS (HeNe laser, \lambda=633nm). We conclude that the optical
turbulence produced by a drone propulsion system is negligible.
