Solving the BIG PROBLEM I have with DIY Drones!
video description
The lower the number of blades also has an impact on efficiency, ideally a single blade with a weight is optimal, but it's not a huge performance difference from just two blades, but going from two to three blades makes a large difference
Date: 2022-05-08
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Comments and reviews: 9
Asu
Personally, I think your approach of starting with the motor first isn't really a good idea. The proper way is to determine your needs first and then go from the most restrictive specs to the least. This is important, especially with trial-and-error approach as changing the most restrictive specs will be challenging and oftentimes means starting all over again.
When coming up with a quadcopter, I'd start with the payload first. What kind of load I'll be strapping on? What is the size and weight? You'll need bigger quadcopter with more load obviously, and the quadcopter size comes in either motor-to-motor wheelbase (450mm) or propeller diameter (9. Generally, a quadcopter with 7 prop should handle up to 200g. I'd push up to 500g for a 9 quadcopter. There isn't any absolute guideline on this because every system performs differently, but it should give you a good approximation of what frame you should settle with.
With the suitable wheelbase picked, then comes the propulsion system. Just go with the recommended setup for that particular size and you should be good to go. For example, the 450mm frame I mentioned is optimized for a 9 to 10 propeller. Typical 9 propeller requires motor ranging in size of 2208 to 2312 to spin. For the KV, it comes down to what electrical specification you want to go with. For a 4S system, the setup requires motor in the range of 920 KV. For a 6S system, the setup requires motor in the range of 610 KV. Basically, pick the frame and propeller size. Motor size has to be enough to spin the propeller, and the KV has to be enough to give the speed for thrust generation, while not being overloaded by the propeller.
The battery can be a bit tricky, but it's very forgiving. Unless you're looking for absolute efficiency or a mission that requires the battery to last down to 10% of the charge. There's no need to calculate the most optimum battery size and you can trial-and-error it if you want to. Then, the electronics are the least restrictive here. Determine the ESC capacity by the maximum theorized current and voltage. For the previous setup, a 25 and up 6S ESC will do the job. Pick your favorite flight controller that will do the things you'll throw at, probably like GPS support or autonomous missions. The rest are pretty much up to you.
Just because you started your project since 2016 doesn't mean you have to be stuck with the technology coming from back then. The industry in quadcopter has come a long way since then, and more and more hardwares are released that are cheaper, more capable, and way easier to work with. Some of the performance motor classes have improved that it might worth forking over, while general usage motors are pretty much the same. The electronics have improved a lot in the recent years. ESCs that won't randomly kamikaze mid-flight and come with 32-bit MCU, hardware PWM, and dedicated driver that runs silent and more efficient. Flight controllers with capability to fly a quadcopter with 4 different propellers and motors easily, or even be configurable from a smartphone with standalone app. Open-source control transmission with LoRa modulation that can do 30 KM on a legal power level and 2. 4 GHz frequency. HD video transmission system that can broadcast 720p image with less than a tenth of second latency and 10's KM of range.
And talking about your approach on testing the motors, there are a lot of things to consider. With the given input power and propeller combination, the two favors the smaller motor despite it won't be optimized for your purpose later. The larger motor requires larger prop to drive and will beat the smaller motor in terms of efficiency and low-speed thrust generation with optimized setup, the two you'd be looking at for the class you're the most suitable for. It's good for educational purpose, but I won't make any conclusion out of it.
Will be updating this guide later.
reply
Personally, I think your approach of starting with the motor first isn't really a good idea. The proper way is to determine your needs first and then go from the most restrictive specs to the least. This is important, especially with trial-and-error approach as changing the most restrictive specs will be challenging and oftentimes means starting all over again.
When coming up with a quadcopter, I'd start with the payload first. What kind of load I'll be strapping on? What is the size and weight? You'll need bigger quadcopter with more load obviously, and the quadcopter size comes in either motor-to-motor wheelbase (450mm) or propeller diameter (9. Generally, a quadcopter with 7 prop should handle up to 200g. I'd push up to 500g for a 9 quadcopter. There isn't any absolute guideline on this because every system performs differently, but it should give you a good approximation of what frame you should settle with.
With the suitable wheelbase picked, then comes the propulsion system. Just go with the recommended setup for that particular size and you should be good to go. For example, the 450mm frame I mentioned is optimized for a 9 to 10 propeller. Typical 9 propeller requires motor ranging in size of 2208 to 2312 to spin. For the KV, it comes down to what electrical specification you want to go with. For a 4S system, the setup requires motor in the range of 920 KV. For a 6S system, the setup requires motor in the range of 610 KV. Basically, pick the frame and propeller size. Motor size has to be enough to spin the propeller, and the KV has to be enough to give the speed for thrust generation, while not being overloaded by the propeller.
The battery can be a bit tricky, but it's very forgiving. Unless you're looking for absolute efficiency or a mission that requires the battery to last down to 10% of the charge. There's no need to calculate the most optimum battery size and you can trial-and-error it if you want to. Then, the electronics are the least restrictive here. Determine the ESC capacity by the maximum theorized current and voltage. For the previous setup, a 25 and up 6S ESC will do the job. Pick your favorite flight controller that will do the things you'll throw at, probably like GPS support or autonomous missions. The rest are pretty much up to you.
Just because you started your project since 2016 doesn't mean you have to be stuck with the technology coming from back then. The industry in quadcopter has come a long way since then, and more and more hardwares are released that are cheaper, more capable, and way easier to work with. Some of the performance motor classes have improved that it might worth forking over, while general usage motors are pretty much the same. The electronics have improved a lot in the recent years. ESCs that won't randomly kamikaze mid-flight and come with 32-bit MCU, hardware PWM, and dedicated driver that runs silent and more efficient. Flight controllers with capability to fly a quadcopter with 4 different propellers and motors easily, or even be configurable from a smartphone with standalone app. Open-source control transmission with LoRa modulation that can do 30 KM on a legal power level and 2. 4 GHz frequency. HD video transmission system that can broadcast 720p image with less than a tenth of second latency and 10's KM of range.
And talking about your approach on testing the motors, there are a lot of things to consider. With the given input power and propeller combination, the two favors the smaller motor despite it won't be optimized for your purpose later. The larger motor requires larger prop to drive and will beat the smaller motor in terms of efficiency and low-speed thrust generation with optimized setup, the two you'd be looking at for the class you're the most suitable for. It's good for educational purpose, but I won't make any conclusion out of it.
Will be updating this guide later.
reply
Kiet
Hi Scott! FPV pilot here: some suggestions I would have are to use a motor from a more reliable brand (Lumenier, T-motor, RCinpower, EMAX, and some others, I'd suggest propellers that are perfectly balanced as it can interfere with your onboard gyro from all the vibrations, making more filtering needed, and more phase delay. Some brands of propellers I suggest for big quads are from HQProp, their 10x5x3s are good, they also have 9x5x3 and 8x5x2s. Master Airscrew also makes great propellers for the 8-13 diameter range. I'd also suggest using a flight controller firmware like iNAV for it's autonomy features and a lot of community support (although I'm extremely biased on that. Using a newer firmware with a newer ESC (like a 4-in-1 ESC) would give you the ability to use an ESC communication protocol like DSHOT. Some newer flight controller firmwares like iNAV, Betaflight, and emuflight are capable of bidirectional dSHOT, which allows your ESC to report back RPM and more data to the flight controller, allowing you to use RPM filtering. RPM filtering allows the FC to smartly target the specific noise frequencies the motors are generating.
I'm however, a FPV pilot and I build fast racing quads, and occasionally big 10 racing quads. I understand some of these might now apply to you because it seems like you want a more efficient slow flying build. But hey, anything helps!
reply
Hi Scott! FPV pilot here: some suggestions I would have are to use a motor from a more reliable brand (Lumenier, T-motor, RCinpower, EMAX, and some others, I'd suggest propellers that are perfectly balanced as it can interfere with your onboard gyro from all the vibrations, making more filtering needed, and more phase delay. Some brands of propellers I suggest for big quads are from HQProp, their 10x5x3s are good, they also have 9x5x3 and 8x5x2s. Master Airscrew also makes great propellers for the 8-13 diameter range. I'd also suggest using a flight controller firmware like iNAV for it's autonomy features and a lot of community support (although I'm extremely biased on that. Using a newer firmware with a newer ESC (like a 4-in-1 ESC) would give you the ability to use an ESC communication protocol like DSHOT. Some newer flight controller firmwares like iNAV, Betaflight, and emuflight are capable of bidirectional dSHOT, which allows your ESC to report back RPM and more data to the flight controller, allowing you to use RPM filtering. RPM filtering allows the FC to smartly target the specific noise frequencies the motors are generating.
I'm however, a FPV pilot and I build fast racing quads, and occasionally big 10 racing quads. I understand some of these might now apply to you because it seems like you want a more efficient slow flying build. But hey, anything helps!
reply
Hippo
Why 3S instead of 4S? I was also not very active in the drone building and racing game in the last 2 years (did it since 2012, but your hardware looks a bit outdated to be honest. Many people even go 5-6S these days: )
Not surprised that the RS2205 motors won though, it was a very solid choice. Just consider replacing this SimonK ESC with a Blheli_S or even Blheli32 and using DShot, this is a digital protocol and can run faster loop frequencies (lower latency. In my experience it makes it much easier to tune and generally fly smoother.
The DIY teststand is very interesting, could be easily extended with a voltage+current sensor and automatic calculation in the code. On the PC could Serial Plotter etc. draw some graphs, then it should be almost as good as the buy solution and is probably still only a fraction of the cost: )
reply
Why 3S instead of 4S? I was also not very active in the drone building and racing game in the last 2 years (did it since 2012, but your hardware looks a bit outdated to be honest. Many people even go 5-6S these days: )
Not surprised that the RS2205 motors won though, it was a very solid choice. Just consider replacing this SimonK ESC with a Blheli_S or even Blheli32 and using DShot, this is a digital protocol and can run faster loop frequencies (lower latency. In my experience it makes it much easier to tune and generally fly smoother.
The DIY teststand is very interesting, could be easily extended with a voltage+current sensor and automatic calculation in the code. On the PC could Serial Plotter etc. draw some graphs, then it should be almost as good as the buy solution and is probably still only a fraction of the cost: )
reply
Shubham
I have another method to check the thurst.
1. Hard fix your motor and fan facing up such that it the thurst should be downwards
2. Place your smartphone under your fan parallel to the floor using a tripod. Also use the weight for the tripod, it should not move due to fan's thurst
2. Use you smartphone's gyro or gravity or accelerometer sensor readings (whatever you think works best for you) to measure the readings.
I bet there will be a difference in the readings between thursts.
However not so accurate but it will work.
Note: you can also fix your phone to a flat metal rod attached to a tripod so it will move down due to thurst.
If any other ideas then please reply
reply
I have another method to check the thurst.
1. Hard fix your motor and fan facing up such that it the thurst should be downwards
2. Place your smartphone under your fan parallel to the floor using a tripod. Also use the weight for the tripod, it should not move due to fan's thurst
2. Use you smartphone's gyro or gravity or accelerometer sensor readings (whatever you think works best for you) to measure the readings.
I bet there will be a difference in the readings between thursts.
However not so accurate but it will work.
Note: you can also fix your phone to a flat metal rod attached to a tripod so it will move down due to thurst.
If any other ideas then please reply
reply
Mike
I feel that a super easy (I don't need 3d printers, or speciality load sensors) DIY solution to test would be simply to attach a motor (with blade of course) to a mass that is too heavy for it to lift, put it on a scale, use some sort of shield with a small hole in the center to allow the motor to pass (this to make sure the downward air doesn't affect the scale) and simply measure what the mass difference is to figure out lift at various voltages. You wouldn't even need a particular high resolution scale either as I doubt you'd need to know the difference down to even the hundredth of a gram
reply
I feel that a super easy (I don't need 3d printers, or speciality load sensors) DIY solution to test would be simply to attach a motor (with blade of course) to a mass that is too heavy for it to lift, put it on a scale, use some sort of shield with a small hole in the center to allow the motor to pass (this to make sure the downward air doesn't affect the scale) and simply measure what the mass difference is to figure out lift at various voltages. You wouldn't even need a particular high resolution scale either as I doubt you'd need to know the difference down to even the hundredth of a gram
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MC's
Dude, today we have 4in1 escs. One board where you solder all the motors. About efficiency, look for long range quadcopters. Dave_C has some fantastic designs!
Freestyle quads, on the other hand, fly for about 5 minutes at most, because it's all about the acrobatics, so it needs a lot of power.
Racers, in the other hand, are all about the lightest and more powerful possible. And there are races in Germany, so look for one of those events!
Anyway, I'm definitely looking forward to see what you're going to end up building!
Stay safe and creative there!
reply
Dude, today we have 4in1 escs. One board where you solder all the motors. About efficiency, look for long range quadcopters. Dave_C has some fantastic designs!
Freestyle quads, on the other hand, fly for about 5 minutes at most, because it's all about the acrobatics, so it needs a lot of power.
Racers, in the other hand, are all about the lightest and more powerful possible. And there are races in Germany, so look for one of those events!
Anyway, I'm definitely looking forward to see what you're going to end up building!
Stay safe and creative there!
reply
Minecraft
Great I have a doubt, My rocket which has a 1400kv A2212 bldc motor, a 30 amp esc(like the yellow one), a 12v 3s battery. I have a doubt, do we need the 3s battery or we can go 2s because I'm trying to reduce the load to carry. Btw should I go 2 or 4 motors for my rocket? Bcs you said the thrust is 400g but you have a 2200kv motor so your kv motor makes more thrust but will not enough for me, what can I do in a budget?
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Great I have a doubt, My rocket which has a 1400kv A2212 bldc motor, a 30 amp esc(like the yellow one), a 12v 3s battery. I have a doubt, do we need the 3s battery or we can go 2s because I'm trying to reduce the load to carry. Btw should I go 2 or 4 motors for my rocket? Bcs you said the thrust is 400g but you have a 2200kv motor so your kv motor makes more thrust but will not enough for me, what can I do in a budget?
reply
Andy
Don't worry so much, it either flys or it doesn't, as long as it does, it's all good: ) the motor specs define how many volts you need, use an ESC with 10a more than you need then just swap props until you get the performance you want, depending on what you are doing, weight isn't that important as they have a high lift capability. I just slapped one together and it flew, quite well too. The yellow motor mount is too big.
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Don't worry so much, it either flys or it doesn't, as long as it does, it's all good: ) the motor specs define how many volts you need, use an ESC with 10a more than you need then just swap props until you get the performance you want, depending on what you are doing, weight isn't that important as they have a high lift capability. I just slapped one together and it flew, quite well too. The yellow motor mount is too big.
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Xenro66
I'm not surprised both DIY & Buy won this. While it might be nice getting all the extra features from an expensive bit of kit, often most people don't need that kind of precision. Then again, if you're proficient enough to build a DIY setup like this, then the data you could get out of it (with a bit of fiddling) will be just as good as the commercial product.
Can't wait to see you flying a custom build quad
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I'm not surprised both DIY & Buy won this. While it might be nice getting all the extra features from an expensive bit of kit, often most people don't need that kind of precision. Then again, if you're proficient enough to build a DIY setup like this, then the data you could get out of it (with a bit of fiddling) will be just as good as the commercial product.
Can't wait to see you flying a custom build quad
reply
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