M.S. Aerospace Engineering thesis / 2026
KTMS
Phase Control.
A dual motor synchronization system that makes relative blade phase a commanded, repeatable variable for close-proximity counter rotating propeller experiments.
01 / The experimental problem
Same RPM does not
ensure blade alignment.
Two independently controlled motors can share the same nominal speed while their relative blade position drifts continuously. For close propeller experiments, that drift damages repeatability and can create an unintended blade encounter.
KTMS, the Kanan Thummar Motor Synchronization System, controls the relationship between two motor drives rather than replacing their low-level control. This makes phase a repeatable experimental input while geometry, spacing, offset, and encounter condition are varied.
02 / System architecture
Motor control manages each rotor.
KTMS controls their relationship.
Each motor controller reads its associated MA702 magnetic encoder and regulates its assigned motor. The Teensy receives position and velocity estimates from both motor controllers over CAN, calculates phase error at a common effective time, applies an outer synchronization correction, and updates both motor-controller velocity commands.
03 / Phase control
Control the
relative relationship.
For counter rotating motors, KTMS defines measured relative phase from the sum of their angular positions.
A natural reference phase is established, a commanded phase offset is applied, and the wrapped phase error is corrected through a staged control chain. Common-time extrapolation reduces apparent phase error caused by unequal encoder-message ages.
04 / Validation requirement
Not perfect.
Explicitly verified.
99%
Of selected median-21 deglitched phase-error samples must remain within ±5 mechanical degrees of the commanded relationship.
The earlier ±1° goal was aspirational. The final requirement reflects the practical encoder estimate and communication architecture. Validation distinguishes raw measurement behavior, phase bias, dispersion, RMS error, and compliance with the selected phase band.
05 / Measurement hardware
Measure each rotor
on its own terms.
Two Tyto Robotics Flight Stand 15 Pro systems measure thrust and torque independently, one for each motor and propeller assembly.
Each motor mounts to its force hardware through a custom CNC machined 6061-T6 adapter plate that I designed. Both powertrains are acquired through a single Tyto Sync Hub, creating one force-test dataset while KTMS logs synchronization data separately.
06 / Aerodynamic campaign
Geometry becomes
the question.
With relative blade phase controlled, the experiment isolates how close-proximity geometry changes the aerodynamic loading of each counter rotating propeller.
Spacing
Coplanar non-overlap, nominal disk-edge, and projected-overlap cases.
Offset
Out-of-plane side-by-side configurations used as an intentional safety progression.
Encounter
Repeatable non-encounter, 0°, and 45° blade-encounter geometries.
Baseline
Single-propeller controls establish the isolated reference condition.
The study does not assume that a particular encounter geometry is optimal. It builds a controlled response map from accepted runs, separating phase validity from aerodynamic outcome.
07 / Controlled overlap
Three inches of overlap.
Zero blade contact.
At 3000 RPM, a commanded 90° phase offset keeps the counter rotating propellers clear even in a deliberately high-overlap condition.
08 / Exploratory axial inflow
Change the inflow.
Keep the control.
A limited VortexField Apparatus subset evaluates KTMS and aerodynamic response under approximately axial, ascent-like inflow.
The VFa is a spatially nonuniform controlled inflow source, not a conventional wind tunnel. This secondary test family examines whether altered aerodynamic loading changes synchronization behavior or selected thrust and torque responses.
09 / Thesis contribution
Build the capability.
Then ask the question.
The thesis first develops and validates a reusable phase-controlled dual-propeller experimental system. It then uses only accepted phase-controlled data to investigate how spacing, offset, and prescribed blade encounter geometry affect individual rotor thrust and torque.
A synchronized experiment with no measured aerodynamic difference is still a valid result. The point is to make the comparison controlled enough to trust.