UAV propulsion selection
Heavy-lift drone propulsion: motor, ESC and propeller as one set
Motor, ESC and propeller are one decision with three answers. Pick them one at a time and you end up with a controller that cuts out on the first hard climb, or a propeller too big for the frame.
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Why they are one decision
Each part constrains the other two.
The propeller turns shaft power into thrust, and the frame limits its diameter before anything else does. That limit sets the useful KV range for the motor: a low-KV motor on too small a propeller cannot move enough air, and a high-KV motor on a large one overloads. The motor's peak current then sets the ESC, and the battery voltage affects all three.
Change one and the other two have to change. Fit a larger propeller for efficiency and the current rises, so an ESC that had room to spare is now at its limit. Go from a 6S to a 12S battery and the same motor spins twice as fast, so the propeller has to get smaller. That is why a parts list put together from three separate searches often needs replacing after the first flight.
Heavy-lift leaves less margin. A racing quad spends most of its time at part throttle. A cargo or survey aircraft hovers near its design load for the whole flight, so the ESC and wiring have to handle the sustained current, and the peak is the easier part.
Selection process
How the set is chosen.
Start from the all-up weight
Add up the frame, battery, payload, gimbal, mounts and cables. Use the take-off weight for the heaviest mission you plan to fly, and ignore the empty airframe figure.
Set a thrust margin
For a loaded multirotor, the usual rule is total static thrust of about twice the all-up weight, so it hovers near half throttle with power in hand for climbing, wind and a failure. Heavy-lift builds with less still fly, but they have nothing left when they need it.
Fix motor count and arm length
The motor count divides the thrust each motor must give, and the arm length limits propeller diameter. Decide both together: a hexacopter with short arms and a quadcopter with long ones can carry the same payload with very different propulsion.
Decide the battery voltage
Choose the voltage before the KV. A higher voltage moves the same power at lower current, which is easier on the ESC, wiring and connectors, but costs battery weight and may need a different charger.
Read KV against that voltage
A KV figure means nothing without the voltage. The right combination turns the largest propeller the frame allows at a speed inside the motor's efficient range.
Choose the propeller within the frame limit
Diameter gives hover efficiency and pitch gives forward speed. Heavy-lift nearly always wants the largest diameter that fits, with clearance for the blades to flex.
Size the ESC above the peak current
Rate the ESC for the motor's peak current with your propeller and voltage, plus some headroom, and check that its firmware and protocol match your flight controller.
Verify against real data, then bench test
Check the combination against the manufacturer's thrust data for that exact motor, propeller and voltage, then measure it on a thrust stand before you commit the airframe. Published figures are a starting point, and the test is what counts.
What goes into it
The parts, and where each one is listed.
Motors
T-Motor AM-series brushless motors for fixed-wing, multirotor and FPV airframes, from small fixed-wing units up to larger multirotor sizes.
Electronic speed controllers
Individual and 4-in-1 ESCs across a wide current range, in BLHeli-32 and AM32 firmware families, plus the AM-Link configuration tool.
Propellers
Carbon propellers matched to the motor range. Order each rotation direction explicitly; a shipment does not always include both.
Flight controllers and stacks
Flight controllers, stacks and AIO boards, alongside the Holybro autopilot range for larger and mission-critical airframes.
Selection criteria
What decides the answer.
Sustained current first
A heavy-lift aircraft hovers near its design load for the whole flight. Choose the ESC and wiring for what the motor draws in a loaded hover for the full mission, then check that the peak is within the rating too.
Cooling and mounting
An ESC rated in free air behaves differently bolted inside a sealed arm. Airflow, heat path and mounting direction change the current it can handle, so leave margin for how it will be installed.
Redundancy and failure behaviour
Decide early whether the aircraft must stay controllable after losing a motor. That needs more motors and more thrust margin (a hexacopter or octocopter), and cannot be added later in firmware.
Firmware and protocol
Confirm the ESC firmware family and the control protocol against the flight controller before ordering, particularly when mixing 4-in-1 stacks with an external autopilot.
Quantity and spares
Order motors and propellers in matched rotation sets and keep spares of both. Swapping in one motor from a different production batch halfway through a programme often leads to a long hunt for vibration.
Before you enquire
What to have ready.
An enquiry carrying these can usually be answered the same day. One without them takes three emails to get to the same place.
- UAV type: multirotor, fixed-wing, VTOL or hybrid
- Estimated all-up weight at take-off, and the payload within it
- Motor count and the maximum propeller diameter the frame allows
- Battery voltage or cell count, and pack capacity if fixed
- Target flight time, and whether it is hover-dominated or forward flight
- Whether the aircraft must remain controllable after a motor failure
- Quantity, delivery location and when you need it
Questions
Asked often enough to answer here.
Can you recommend a motor, ESC and propeller combination?
Yes. Send the airframe details in the checklist above and we will come back with suitable options from the range, along with pricing and lead time.
Do you publish thrust tables on this site?
No. Thrust figures are the manufacturer's and only apply to a specific motor, propeller and voltage together. We send the relevant manufacturer data with our recommendation.
Can I buy just the motors, or just the ESCs?
Yes. Nothing here is sold only as a set. We describe them together to help you choose parts that suit each other.
Is Vebix an authorised T-Motor distributor?
Yes. Vebix Automation is an authorised Indian distributor for T-Motor, and supplies and supports the range across India.
Why are there no prices on this page?
Contact us to get exact pricing. Each order is quoted individually.
Can you help with the wider airframe as well?
Yes, as an engineering job. See UAV and drone engineering.
Further reading
Guides and calculators on this subject.
Request a quotation
Need a matched motor, ESC and propeller combination?
Send the UAV type, estimated all-up weight, payload, motor count, battery voltage, largest propeller that fits and quantity using the quotation form.
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Or call +91 97028 20020.