I'm trying to decide between 2 BnFs:
https://flywoo.net/products/cinerace20-h...-cinewhoop
and
https://flywoo.net/collections/new/produ...long-range

Neither is the right size for me.  I intend to move the components to a 3" frame which would be quieter (well, lower frequency) than the 2" and smaller than the 4".  My flying style is slow and cruisey like Grampa on Sunday morning.

I prefer the CineRace20 to be sacrificed since the FC is an AIO whereas the Explorer has a stack.

Question:  Is the 20A from the CineRace20 adequate to spin 3", 5-bladed props or would I need the Explorer's 40A?
               
I don't even know what the Amp rating refers to with respect to FCs and ESCs.  I plan to use 4S batteries.


Thanks

The amp rating on an esc is how much amperage can be pulled through it without your mosfets melting down and your esc dying.

The amount of amperage that a motor will pull is dependent on a number of factors- the motor itself, its size, its kv rating, the size, pitch, and blade count of the propeller, and the cell count of your battery.

The 1203 motors that come with the cinerace are going to really struggle to spin 3” 5 blade props. You’re likely to burn them out well before you get anywhere near the amp rating on the included esc.

All of the components on the 4” are more suitable to be transferred into a 3”, and the 1404 2750kv motors it comes with will have no problem spinning 3” 5-blade props on 4s.

Thanks for the informative response.

I already have 1404 3500KV motors from another project.

Would the 20A ESC fry itself driving those motors?

If possible, I prefer the 20A AIO since it may fit into more frames than a stack.

Can you tell me the name of those 1404 3500kv motors?

If so, I’ll look up a data sheet and let you know if 20a will be okay.

Just to clarify, if an aio or 4 in 1 esc is rated “20A”, that is per motor output, not 20A total.

You can get a good idea of how much amperage a motor will pull at a given voltage with a given prop by looking at the manufacturer’s motor datasheet.

4PCS HappyModel EX1404 1404 KV4800 3S KV2750 KV3500 4S Brushless Motor 1.5mm for RC FPV Crux35 Micro Long Range LR4 Drones

https://www.aliexpress.us/item/325680161...PL8HurUDbf

EDIT:  If I read that table right, running 4S, with a 3" 2-bladed prop, I'd pull a max of 4.4A, correct?

If so, even with 5 or more blades, I would not come close to 20A?

so much to learn

At full throttle on 4s with 4023 3-blade props (4”), they’re only pulling 9.5A.

3” with 5-blade props will be just fine. We’re adding two more blades, but we’re also going down an inch, so figure your max amperage pull will be around the same as those 4”. Maybe a little lower, maybe a little higher, but regardless, you’ll be well within the 20A rating of that aio.

Thanks again. You're a credit to this site.

(27-Jan-2023, 02:59 AM)Dream Weaver Wrote: EDIT:  If I read that table right, running 4S, with a 3" 2-bladed prop, I'd pull a max of 4.4A, correct?

If so, even with 5 or more blades, I would not come close to 20A?

so much to learn

You’re reading that table correctly, and yes, you won’t come close to 20A.



The reason I chose the 4” tri-blades in my reply above is because we know that if it can handle that and only pull 9.5A, you’ll be fine.

Looking at the 3” bi-blades that only pull 4.4A could be a bit misleading and lead you to think you would be okay with just a 5A aio.

But notice that the bi-blades are 3018. That’s a low pitch, and only two blades. Higher pitch blades are going to pull more amperage, and more blades are going to pull more amperage.

As a shortcut, when you’re looking at a motor datasheet:
Just look at the highest amp draw listed for the kv of the motor you have or are interested in, and just make sure your aio or esc is rated higher.

Or if you have, say a 10A ESC and motors that use 10A at 100% on prop x, you could set motor output limit (in Betaflight) to 90% to create a safety buffer, since at 90%, those motors might be using 9A (checking the datasheet would allow you to extrapolate a rough percentage to amp draw value). I do this on most of my builds and BNFs when using 5A and 12A FC's, even if I only change the output limit from 100% to 95%.

Maybe you already made your purchase, but you might want to consider a 3.5" like the Crux35 as they make for a light, nimble, relatively quiet, great hang time, long flight time cruiser. The Crux frame is a little thin and fragile, so no good if you crash a lot, but otherwise holds up fine for cruising/light acro.
It uses the same 1404 motors you have so you could also build one. 12A ESC is fine, and you can fly 3S/4S. My HD one gives 8+ min of cruising/light acro on a 3S 550HV. My 3.5" get a lot more air time than my 3" or 4" setups, plus it happily carries a light/naked action camera.