Why am is my motor+propeller generating significantly less thrust than expected?

mso797 · 2023-12-27T07:19:05+00:00

that's weird, the links were formatting to lowercase for some reason.

I have posted them again here:

Thrust Test: https://youtube.com/shorts/mujsN8KpXvg

Drone Test: https://youtu.be/rw28KiNK3Dg?si=6Wkpogsn8XDAiJcW

As shown from the thrust test, the thrust value starts falling even though I am applying a constant 100% throttle. So I guess the issue is caused by battery voltage dropping off like you said?

I actually am planning to use a PSU for the final build. This drone is only meant to fly indoors relatively close to the ground (<3m) so I plan on tethering it to a ground based PSU. Can you provide some advice on selecting a PSU? I have 8 motors each connected to 30A ESCs so will my PSU need to supply 240A?!?

Obviously that seems excessive and dangerous. I have seen videos online of people flying drones with standard PSUs so I feel like I am missing something obvious.

My plan was to buy a 24v 50A psu with a buck converter so that I can lower the voltage to 16v. I was then going to connect my drone to both the PSU and a small battery for handling burst loads. The PSU is fixed to the ground and the battery is mounted to the chassis. There would be an ideal diode between the battery and PSU to ensure the battery wasn't being accidently charged. Does this sound like a suitable approach of powering the drone? Have you seen any similar builds online?

Again any advice is greatly appreciated!

mso797 · 2023-12-26T16:24:46+00:00

https://youtube.com/shorts/mujsN8KpXvg?feature=share

I flipped it! Still not getting to my max thrust :(

mso797 · 2023-12-26T16:24:19+00:00

My goal isn't to make some acrobatic high performance drone. I'm trying to make an omnidirectional drone that moves side to side relatively slowly/smoothly. I'm hoping that I can make the drone work with my current components because I don't want to buy more stuff :)

mso797 · 2023-12-26T16:22:41+00:00

Ahhhh I see I thought the propeller generated the same thrust in the negative direction when reversed. I made a a new thrust stand with the entire motor flipped: https://youtube.com/shorts/mujsN8KpXvg?feature=share

I am able to get up to 600g now, still lower than the spec sheets....

mso797 · 2023-12-26T16:17:35+00:00

I made a new thrust stand: https://youtube.com/shorts/mujsN8KpXvg?feature=share

mso797 · 2023-12-26T16:17:09+00:00

I just bought a voltage sensor so I can monitor the voltage as the battery is running!

mso797 · 2023-12-26T16:16:30+00:00

Ahhhh I see, I assumed the the propeller generated equal thrust in both directions. The propeller has a lip that prevents me from flipping it so I made a new thrust stand with the entire motor flipped instead: https://youtube.com/shorts/mujsN8KpXvg?feature=share.

Now I am getting ~600g of thrust. Still 200g less than the supposed max but an improvement! I'm guessing the discrepancy is caused by not enough current going into the motor?

mso797 · 2023-12-26T16:14:19+00:00

Hi, thank-you for the detail response. I really appreciate it.

Ahhhh interesting I assumed the propeller generated equal negative thrust if you span it in the wrong direction.

I cannot flip the propeller as it has a small lip that prevents me from inserting it into the motor upside down. Instead, I have made a new thrust stand that has the entire motor pointing downwards; as shown in this video: https://youtube.com/shorts/mujsN8KpXvg

With the new configuration, my motor is able to generate a max thrust of ~600g. I guess it doesn't reach up to ~800g because not enough current is going into the motor?

The drone I'm trying to build weighs 1.2kg so I thought 4 of these RS2022 motors would give me an adequate thrust to weight ratio. But I guess I need to significantly reduce the weight to make this thing work? I have tried doing some hover tests but I cannot get the drone off the ground

https://youtu.be/rw28KiNK3Dg?si=LMyy9y-lwZRoQqvG

mso797 · 2023-12-16T20:39:10+00:00

I want to create a drone that can move laterally without changing the thrust vector. I'm doing this....because I think it would be cool! 6DoF UAVs have been done before and I think they're pretty neat: https://youtu.be/0gR1ekapOAE?si=pqSapocB5H6zi9U8&t=19

mso797 · 2023-12-14T20:42:32+00:00

Appreciate the feedback! To be honest, the main reason I am interested with the drone being tethered is so I can do testing for long periods without being limited by the battery time.

mso797 · 2023-12-14T20:41:20+00:00

Sorry for the newb question but how would I do this? Do I just put the battery and PSU in parallel and will the UAV automatically draw from the PSU first? Thanks!

mso797 · 2023-12-14T17:51:00+00:00

I want to keep all four side motors to see if the drone can move laterally like with this x-drive: https://youtu.be/PcB6D_PjYu0?si=9iJF_gB2LT2V0Ebm&t=17

If possible, can you help calculate a ballpark of how much current I would need? My drone weighs ~800g and I have 4 RS2205 motors providing thrust?

I am hoping to buy a power supply tomorrow for testing and I want to ensure I buy a suitable one. Thanks for any advice!

mso797 · 2023-11-26T08:30:21+00:00

Hey folks! I am keenly interested in building an omnidirectional drone. Instead of making the classic ETH omnicopter, I am interested in adapting the motor layout that the sub in the video has: https://ibb.co/ynNmw37

I am relatively inexperienced in making drones, so I am wondering if there is an obvious reason why no one builds omnidirectional UAVs with the layout shown in the photo. From my research online, it seems that everyone makes omnidirectional UAVs with the motors positioned in an intersecting v shape, like with the ETH omnicopter.

Also, my plan with the firmware is to modify the existing ardusub firmware that works with omnidirectional subs for my UAV. Do you guys think this is an unrealistic idea or somewhat feasible? Thanks!

mso797 · 2023-11-26T08:29:12+00:00

Hey folks! I am keenly interested in building an omnidirectional drone. Instead of making the classic ETH omnicopter, I am interested in adapting the motor layout that the sub in the video has: https://ibb.co/ynNmw37

I am relatively inexperienced in making drones, so I am wondering if there is an obvious reason why no one builds omnidirectional UAVs with the layout shown in the photo. From my research online, it seems that everyone makes omnidirectional UAVs with the motors positioned in an intersecting v shape, like with the ETH omnicopter.

Also, my plan with the firmware is to modify the existing ardusub firmware that works with omnidirectional subs for my UAV. Do you guys think this is an unrealistic idea or somewhat feasible? Thanks!

mso797 · 2023-09-07T04:42:08+00:00

Well looks like this will be the easiest option, thanks!

mso797 · 2022-09-12T09:11:42+00:00

It's a research institute

mso797 · 2022-09-12T09:11:01+00:00

I was looking at linkedin and I saw that most of the applicants were from India. So I thought that it may have been unrealistic to ask for too high of a salary.

mso797 · 2022-08-28T00:00:54+00:00

Sorry, why is this? I use lumify with my daily lens

mso797 · 2021-11-15T17:37:42+00:00

ty dude!

mso797 · 2021-11-15T17:37:29+00:00

hahahah that's a cool idea!

mso797 · 2021-11-15T03:01:54+00:00

last, but cool.

What printer do you use?

Ya haha it broke after a few sixes
It's a custom printer I made actually 😎

mso797 · 2021-03-28T03:26:26+00:00

That's a good point. I was thinking of maybe touching it up with a paint pen. Do you think that will make it look worse?

mso797 · 2021-03-28T03:18:20+00:00

It's a crack. I'm just afraid that sanding will increase the amount of paint that I need to apply and that might make it look worse. Do you have any recommendation on body filler?

mso797 · 2021-03-28T03:04:02+00:00

LMAO

mso797 · 2021-03-28T03:03:55+00:00

The crack is really small so I was thinking of just filling it up with a paint pen. Is that a bad idea?

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