What a Thrust Table Actually Shows (and What It Hides)
Every brushless motor you consider buying comes with a thrust table — a grid of numbers that looks authoritative but can quietly lead you to the wrong motor. A thrust table is not a promise of how your quad will perform. It is a snapshot of one motor, on one test rig, with one specific propeller, at one specific voltage. Change any of those, and every number on the page moves.
The most common mistake builders make is scanning a table for the single highest thrust number and calling it a day. But peak thrust is almost always measured at full throttle, on a bench, with a fixed prop and voltage — conditions your aircraft rarely sustains, and a data point that says almost nothing about efficiency, heat, or flight time. To read a thrust table properly, you need to understand the three variables that frame every number on it: voltage, propeller, and current.
The Three Numbers That Actually Matter
Thrust Per Amp — the Efficiency Number
The single most useful figure on any thrust table is not thrust at all — it is thrust per amp, often written as grams of thrust per amp of current (g/A). This is your motor’s efficiency under that specific load. A motor that produces 1,000 g of thrust at 20 A is producing 50 g/A; a competitor that hits 1,000 g at 25 A is only producing 40 g/A. Both “push” the same, but the second drains your battery 25% faster and runs hotter doing it.
Why this matters more than peak thrust: your battery has a fixed amount of energy, and your ESC and motor have a thermal limit. Higher thrust-per-amp means longer flight time, cooler components, and more headroom before something overheats. For almost every use case — from aerial photography to long-range FPV — efficiency beats peak thrust as a purchasing criterion.
Continuous vs Peak (Burst) Thrust
Most thrust tables quote the maximum thrust the motor produces at full throttle. That number is a burst figure — sustainable for seconds, not minutes. What the table rarely shows clearly is continuous thrust: what the motor can hold without overheating.
The gap between burst and continuous is where motors get over-sold. A motor may claim 2,000 g of peak thrust but only be able to sustain 900 g continuously before its windings cook. If you are building a heavy-lift or long-endurance platform, the continuous number is the one that decides whether your build survives a full flight. When a vendor only shows you peak, ask for the continuous figure — or estimate it yourself from the current draw at that thrust level.
Voltage and Prop Pairing — the Hidden Context
Every thrust table is measured at a specific battery voltage and with a specific propeller. The same motor tested at 4S versus 6S, or with a 5″ versus a 5.5″ prop, produces completely different numbers. This is the context most people skip.
Higher voltage spins the motor faster for a given KV, which usually raises thrust — but also raises current and heat, and stresses the bearings. A larger or steeper-pitched propeller moves more air per revolution but loads the motor harder, drawing more current. When you compare two motors, make sure the thrust tables you are reading were measured at the same voltage and prop size as the setup you actually plan to fly. Comparing a motor’s 6S numbers against a rival’s 4S numbers tells you nothing.
How to Read a Real 5-Inch FPV Thrust Table
Let us walk through a typical 5-inch FPV thrust table so the columns stop looking like noise. A standard table lists, for a given voltage and prop, a row per throttle setting — or a single row per prop size:
| Prop | Voltage | Throttle | Current (A) | Thrust (g) | g/A |
|---|---|---|---|---|---|
| 5.0″ tri-blade | 6S | 50% | 12.4 | 610 | 49.2 |
| 5.0″ tri-blade | 6S | 75% | 28.1 | 1,140 | 40.6 |
| 5.0″ tri-blade | 6S | 100% | 47.8 | 1,560 | 32.6 |
Read it row by row. At 50% throttle the motor is efficient — 49 g/A — because it is barely loaded. By full throttle the efficiency has collapsed to 32 g/A: you are spending a lot of current for diminishing thrust. This is the shape of every motor’s curve, and it tells you two things. First, efficiency falls as load rises, so a motor that cruises at low throttle flies far longer than one running near its limit. Second, if your flight style keeps you pinned near full throttle, you are choosing the wrong motor or prop for that style — a lower-KV motor swinging a bigger prop would hold efficiency better.
The takeaway is not to memorize numbers but to look for the g/A column and how it decays. That decay curve — not the peak — is the real story of the motor.
KV vs Thrust — What Changes When You Swap Motors
KV is how many RPM the motor spins per volt. A higher-KV motor spins faster at the same voltage, and lower KV spins slower but with more torque per amp. This directly reshapes the thrust table, even with the same prop and battery.
Here is what changes in practice:
- Higher KV + same prop → more RPM, more peak thrust, but more current and more heat, and often lower thrust-per-amp at the top end.
- Lower KV + same prop → less peak thrust, but the same thrust at lower current, so better efficiency and cooler running at cruise.
- Lower KV + bigger prop → the real efficiency move. A slower motor turning a larger prop moves air more efficiently, which is why long-endurance builds go low-KV, big-prop, high-voltage.
So when you compare two motors, KV is not “better or worse” on its own — it only means something in the context of the prop and voltage you will actually use. Two motors with the same peak thrust can behave entirely differently in the air if their KV forces you into different prop choices.
Thrust vs Real-World Flight (Why Lab Numbers Lie a Little)
Bench thrust tables are measured in static conditions — the motor is bolted to a rig, pulling air from still surroundings. In flight, the motor is moving through air that is already flowing, which changes the effective angle of attack on the propeller and reduces the thrust you actually get at a given throttle. This is why your real-world top speed and climb rate never quite match the bench numbers.
Other real-world factors also eat into the gap:
- Battery sag. Under load, voltage drops below nominal, so the motor never sees the voltage the table assumed.
- Heat. As the motor warms, its copper resistance rises, cutting efficiency further during a long flight.
- ESC and wiring losses. The current measured on the bench is at the motor; your ESC and battery leads add their own losses.
None of this means vendor tables are dishonest — it means they are idealized. Treat them as a relative comparison tool between motors measured the same way, not as an absolute prediction of your build’s performance.
A Quick Comparison Framework (Decision Table)
When you are down to two or three motors and the thrust tables blur together, step back and match the motor to the job:
| Use case | What to prioritize | Look for |
|---|---|---|
| Aerial photography / long hover | Efficiency, low vibration | High g/A at cruise throttle, balanced bell |
| FPV freestyle / racing | Peak thrust, punch | High peak thrust, fast response, but watch heat |
| Long-range / endurance | Efficiency above all | Low KV, big prop, high g/A over the whole curve |
| Heavy-lift / industrial | Continuous thrust | High continuous (not just peak) thrust, thermal headroom |
Hold two motors side by side and ask three questions: At my cruise throttle, which produces more thrust per amp? Which sustains the thrust I need without overheating? And am I comparing them at the same voltage and prop? Answer those three, and the right motor usually becomes obvious.
FAQ
What does “thrust per amp” mean and why does it matter?
Thrust per amp (g/A) is grams of thrust produced per amp of current drawn — your motor’s efficiency at a given load. It matters more than peak thrust because a fixed battery only holds so much energy: higher g/A means longer flight time, cooler components, and more thermal headroom. Two motors can push the same peak thrust but drain your battery very differently.
Is a higher thrust number always better?
No. Peak thrust is a burst figure measured at full throttle on a bench. A higher number often comes with much higher current draw and heat, and may not be sustainable. For most builds, efficiency at cruise throttle and continuous-thrust capability matter more than the headline peak.
How do I compare two motors with different KV?
Only compare them at the same voltage and prop size, then look at thrust-per-amp rather than raw thrust. KV is not “better or worse” on its own — it determines what prop and voltage work best. A lower-KV motor with a bigger prop usually wins on efficiency; a higher-KV motor wins on raw RPM and punch.
Why is my real-world thrust lower than the spec sheet?
Because spec sheets are measured statically on a bench. In flight, airflow changes the propeller’s effective angle of attack, battery sag lowers voltage, and heat raises copper resistance — all of which reduce real thrust. Use the table as a relative comparison between motors, not an absolute prediction.
Should I trust vendor thrust tables?
Use them as a guide, not gospel. The best vendors publish the full test conditions — voltage, prop, throttle, current, and often g/A. If a table shows only peak thrust with no current or prop details, treat the number with skepticism and ask for the full test data before buying.
Conclusion
A thrust table is only as useful as your ability to read the parts that matter: the voltage, the propeller, the current — and the thrust-per-amp number that ties them together. Peak thrust is a burst figure that flatters every motor; efficiency at your actual cruise throttle, and continuous-thrust capability, are what decide flight time, heat, and whether your build holds up. Compare motors at the same voltage and prop, watch how the g/A decays as load rises, and match the motor to the job — and the right choice will stop feeling like a gamble.
If you are tired of guessing between near-identical spec sheets, a properly matched motor makes the decision easy. X-TEAM builds FPV and UAV brushless motors wound in-house, with custom KV options and OEM service, and we publish real test data so you can spec with confidence. Tell us your frame, prop, and voltage, and we will help you pick a motor — and read the table — like a pro.