Lol not sure anything like this is out there yet, but basically a TBS Discovery with op 8s motors and aggressive props. This is gonna have to wait for next year tho, spent 650 already just for the 5" racer.
Need help buying the correct parts for my first racing drone.
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rtkDarling
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The math is really interesting when it gets to batteries because it's not all about voltage. Plus you have cavitation that's holding you back because propellers utilize fluid dynamics.
Check this guy out doing medium long range on Lithium-ion batteries
That's a really interesting way of powering the drone, I must say. How might I learn the math for drone batteries and basic fluid dynamics?
rtkDarling
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There's more to it than I can explain, there are some guys out there doing fluid dynamics calculations and simulations for quadcopters you can take a look at.
The simple explanation is saturation and cavitation, those are your two max points. Saturation is when an electric motor is at capacity, and you can add more amperage at this point but it will only result in heat because the motor is running at it's capacity. Cavitation (for us) is when a prop is spinning so fast that the air doesn't have time to fill in behind it before it swings through again. Picture a car doing a burn out and it's kind of the same, the prop is spinning so fast that it can't get traction on the air around it.
So to go fast (in theory) you want to deliver as much power to the motors as possible without over saturating, and keep the props spinning as fast as possible without cavitating. That's of course is childishly oversimplified as weight and wind resistance have an exponential effect as speeds increase.
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Huh, this stuff is gonna take some time to learn, but I should be able to figure out how to maximize thrust, flight time, and weight by next year hopefully. Then I can make a TBS Discovery monster lol.
@HighTechPauper @rtkDarling I have another question. So the fc I bought has two gyros, one being the sensitive icm20608 and the other being the standard mpu6000. As I understand, betaflight 4 has dropped support for 32k rate for the gyros, and the manual for my fc suggests going 8k/8k for gyro and pid rates for best experience. That being said, which gyro is better for 8k? Are they the same then since I won't be going above 8k?
rtkDarling
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I've never had an F7, is there an obvious place to choose different rates for the gyros?
I thought the gyros run at the same speed, but they're offset 90 degrees and averaged for a more accurate result.
I thought the gyros run at the same speed, but they're offset 90 degrees and averaged for a more accurate result.
Yeah so according to the hglrc manual, it appears you can only use one at a time, same with the mateks. And from what I read from Oscar Liang, it appears you can select different rates.
@rtkDarling, there is only 1 FC out there trying to do that, all the others are one or the other, good side is that if a gyro goes south you can reconfig and try to use the other one and maybe save replacing the FC.
@1ikhan, you will likely want to use the MPU6000 as the other is much more sensitive to noise and vibration, and the rates they are reffering to are the PID Loop and Gyro Loop times in the Config menu in BF, to use 32KHz filtering is only possible with the ICM20608 but is not longer supported in BF due to iffy results and possible real bad results. Older revisions of 3.5 can use it but... don't even try, it takes a good bit of extra config at the CLI (it isn't just flipping the switch at the top of the Loop timing area) an it won't make a difference you can tell or will like. There is after all a real good reason that BF abandoned it completely, and why you never heard much about it from people other than the few fan boys who of course said it was so great. If it was, all FC's would have gone to the 20608 and everyone would be running it... but they aren't.
IMHO
@1ikhan, you will likely want to use the MPU6000 as the other is much more sensitive to noise and vibration, and the rates they are reffering to are the PID Loop and Gyro Loop times in the Config menu in BF, to use 32KHz filtering is only possible with the ICM20608 but is not longer supported in BF due to iffy results and possible real bad results. Older revisions of 3.5 can use it but... don't even try, it takes a good bit of extra config at the CLI (it isn't just flipping the switch at the top of the Loop timing area) an it won't make a difference you can tell or will like. There is after all a real good reason that BF abandoned it completely, and why you never heard much about it from people other than the few fan boys who of course said it was so great. If it was, all FC's would have gone to the 20608 and everyone would be running it... but they aren't.
IMHO
Thanks, gotcha. Mpu6000 it is. Also one thing I noticed in the betaflight 4.1 rpm filter snippet code is that they use dshot300 by default, stating that it's more robust. Will there be any adverse problems if I change that to dshot1200 since I plan on using that?
I really don't know, can you give me a link to the 4.1 RPM Filtering info where it says that?
Also, most ESC's will not run 1200, many now will, many that will do not do it good, I run DShot600 on most and Multishot on some, the only real way to know is to configure it and give it a test hover and see how it feels. If it twitches or stutters try going down to 600 or 300 and see if it improves. There is not a noticable difference between any of them, when you set it to 1200 you are chasing a difference that you cannot feel or see. Go with what feels best to you, it could be that 1200 is fine, or that it has flight issues that you notice. Also, the Rev 4+ in betaflight has had it's teething pains, almost all of my quads are still running BF 3.5.7 and Dshot600 or Multishot, and I am still a bit leary of BF 4 revs.
Ah I see, so I will keep things at 600 first to get a good sense of stable flight, then push it to 1200 and see if it makes it worse.
The main page:
GitHub - betaflight/betaflight: Open Source Flight Controller Firmware
Open Source Flight Controller Firmware. Contribute to betaflight/betaflight development by creating an account on GitHub.
github.com
Snippet:
bidircfg/BITBANG.cf at master · betaflight/bidircfg
Contribute to betaflight/bidircfg development by creating an account on GitHub.
github.com
The commented out part mentions 300.
Actually, upon further reading, it appears that you dont even need to bother with the cli for configurator version 10.6.
Well I'll be gosh darned, it is back in the latest configurator, might as well give it a try if you want, I would also try 8k/8k and the mpu6000 and see if you can tell a difference, I would also try Multishot over DShot (don't forget to calibrate ESC's for any Analog protocol) and see if you don't like it better, it is after all faster than everything except DShot1200, and most think it is smoother than Digital protocols. It certainly feels smoother to me, but I want Turtle Mode on most of my quads in case I end up upside down on top of another 3 story school building or stuck in a tree... at least that way I have a CHANCE to get down. 
Also, about the robustness of DShot300, I think you can equate that to "over clocking" a CPU in a PC, while it may yield some impressive benchmark numbers for MIP's etc, it can also be unstable on some machines and therefore not worth it since your CPU's (FC and ESC both have them) are flying, and can't afford to flake out or crash mid flight. That being said, I think that most ESC's rated for DShot 600/1200 are getting pretty good and shouldn't cause issues on their own, but who knows with different revs of BF and all the different specific configuration possibilities. Plus, I think it is still pretty much a wash with human response capability, it is like having faster rabbit firmware in your turtle, the turtle will never know the difference and his legs can only go so fast anyway.
Again... IMHO
Again... IMHO
Understood. By the looks of it, rpm filter should allow for some really low latency filtering and the lifting other filters, which should make things smoother overall. Alrighty, 8k/8k, mpu6000, dshot600, and less aggressive lowpass filtering should do. I am now tempted to get the motor soft mounts just to see how smooth and unfiltered I can get things.
I know I know but I saw a few recent-ish videos saying it makes a difference, albeit small. I guess I'll hold off buying them for now lol.
Nah if I crash and break something Imma blame you hahahahIt might be best to go ahead and get them, if you try to fly without them and you crash and break something you will wonder if the motor soft mounts would have made a difference for you, if you have them installed and you still crash then you will know it is all you LOL
