That's a bold statement ... Worlds Best. But it's even larger than that. Not just Worlds Best, but best for most all applications less than 30 Amps (limit of the tests). That means:
- duration ships that only pull 2 to 8 amps per rotor
- most all 6S and smaller ships (exception of nano-ships)
- any-size FPV racer
- any other ship in between
Why almost any size? Shouldn't a small FPV racer use a smaller and lighter ESC for response? Yes, if it does better on a net-lift response test. In other words, when you penalize the ESC for it's weight, is it still better and faster? What i continue to see is ESC manufacturers downsizing critical components of the ESC at a net loss. They weight savings is lost because of greater thrust loss and response. In other words, this heavier ESC will out accelerate, in the real world, a smaller and lighter ESC.
Why post this? To move technology forward, we need to report to industry what works and what doesn't. For some reason (i don't know why), this ESC works better than all others tested:
- for generating maximum thrust from the motor***
- for net-lift efficiency or the grams of weight it can lift (after it lifts the rotor) per watt
- for response (how fast it can generate targeted lift)
These tests were conducted on multiple days on multiple rotors of highly variant size, always being immediately compared back to another DYS 40A multicopter test to ensure that the baseline wasn't changing.
The ESC that dominated is a DYS 40A OPTO Multicopter using SimonK. The photo is included because there are two others that carry a similar or same name.
- Not the white cover DYS BLHeli 40A
- Not the one that is says "Programmable" versus "Multicopter" in the blue/purple band across the front
Have i tested all ESCs? No, but if you are convinced you know of one that would work better, let me know. I've tested most all of the following and one or more of their variants:
- DYS
- Multistar
- Turnigy
- T-Motor
- Afro
- Motortron
- Quattro
- 3DR
- Spider
- KDE
- ZLW
- Aris
- EMAX
- AutoQuad
- Exceed
- HobbyWing
- Lumenier
To do a test like this, a highly repeatable and finite test stand is needed. It took a while to develop one but what works is one that:
- measures (at a minimum) volts, amps, thrust, motor temp (shoots IR up the aft end of the motor)
- eliminates harmonics between the rotor and load sensor (this proved difficult but achievable)
- is calibrated and proves repeatable within 1.5%
- controlled by a system that can precisely repeat a rotor test (uses a Audurino Mega)
- directly feeds the data into Excel for analysis (uses DATAQ)
- uses a test script that produces repeatable results
- uses a test procedure that minimizes repeatability error (used average of multiple tests)
How much better is this ESC? On average:
- 4.4% higher net lift (after it lifts itself)
- 2.3% more net-lift efficient (usually the larger the better)
- from more than twice the response or the same response as other ESCs (usually the larger the better)
So how to make it better?
Step 1: Strip it naked. See photo below.
... remove the cover
... remove the heat plate (better to locate the ESC under prop wash to run cooler, see below)
Step 2: Right-Size the bullet connectors or wires (see above where heavy wires are replaced by 2mm bullets)
... remove the large bullet connectors or wires
... replace them with ones that are the most net-lift efficient (where heat loss = weight loss)
Step 3: Seal the ESC. Seal it with Electrical Sealant to protect from moisture and conductive dust
... tape or plug connectors and wires
... repeatedly spray each side from different angles
... a mistake i made was not sealing the bullet connectors and solder
- don't tape them off like i did
- insert a male connector into the end of bullets so sealant doesn't get inside them
Step 4: Locate ESCs under Prop Wash. See photos below. The turbulence generated by the prop does not adversely affect lift when the ESC is placed on edge to the prop wash.
... Use something non-conductive like hot glue to bond the ESCs to the motor mast or spar
... Face the FETS (the little square warehouses or Fire Emitting Transistors) to open air
... Protect the ESCs from below from ground contact (not needed here because of clearance)
back-side with hot glue
front-side with FETs completely exposed to open prop wash
Step 5: Tie up wiring. Use dental floss to secure wiring away from the prop.
***Note: The T-motor Air 40 in high-timing mode (an option) generated higher thrust, but at the sacrifice of efficiency and motor temp. Also, the T-Motor Air 40 was 2nd best and close in performance. If you are using an Air40, it probably isn't worth switching.
Replies
if solder, then maybe don't use nylon motor mount bolts? we use nylong motor mount bold to help the motor/prop shear off the bolts and eject during a crash (helps save the motor/prop and the ship is the theory). but that also sort of mandates that you use connectors on the ESC so they can pull free without taking the ESCs with them.
So if solder, maybe use Aluminum bolts that are quite a bit lighter than the steel bolts.
Any experience on this Cala? when you crash, do you motors stay on the motor mounts keeping the soldered ESC protected?
I never hard crash................yet (touch wood we say here).
My bigger crash were one from 10 mts :leg damaged and alum arm crooked.
I try my ships build crash resistant because it's not easy here to buy spare parts and I don't like to break nothing after a crash I cry a week :( Men at the club have impressive airplanes and when they crash they pick up the parts and....nothing happens here :]
My Esc are with standard plugs in case and tie with two little zip tie arround the esc for the moment.
How Can i resist this thread. !!!
The work here in my opinion is unnecessary. For many reason but i speak from personal experience.
I use hobbywing xrotor 40 A ESC. They are always cool to the touch after 20 min of flying. They have NEVER failed me and perform and exceed my expectations. So why would i strip them and coat them ? What do i gain ? Water resistance ?? But why?? Everything else on my quad is not water resistant..Why would i make my ESC water resistant? Even if this material improves thermal dissipation which i dont think it will it has not been proven, they are cool because of the set up and application.. What do we hain from this? NADA !!
I would not compare Darius to Forrest. Forrest puts alot of time and effort which is appreciated in this forum by all members who read his posts.
Darius is wikipedia/google/internet warrior who just trolls. (Nothing positive, ZERO)
"What do we hain from this? NADA !!"
That should read:
"What do **I** hain from this? NADA !!"
Your particular scenarios and applications clearly don't stress your ESCs, and you have no specific need to save weight or to guard against water, so your answer is absolutely correct.. for you.
Personally, I have no particular need to save weight or to dissipate heat (although welcome benefits if available), but I'm very interested in the water proofing aspect as I often fly in adverse conditions and over water (sea mist = death to electronics). Any advance in this direction is very welcome research, I don't see the negativity. If you don't like it, or it's not useful to you, move onto the next discussion! Good discussion, debate and debunking is fundamental to good science, hating for the sake of it isn't.
That said, I'm not convinced about small bullet connectors (very easy to come disconnected in my experience) or about situating the ESCs like that under the props - surely it must have negative effect on thrust.
Absolutely. There is an impact on lift. When there is something below the prop wash that is connected to the ship, it puts a negative load on lift.
So how much? In a previous post here i discussed that. But to satisfy your own curiosity, do what i did. Hold a gram scale under the prop wash with a motor running at 60% throttle. You will be amazed as i was. take that reading and convert it to psi. then do the math by looking at the si of the edge of an ESC.
Umm I'm no aerodynamicist but that sounds like somewhat hokey science to me. Downforce is not just going to be reduced by the equivalent of the area of the top edge of the ESC, there will be all sorts of other aerodynamic interactions, vortices etc with such a large flat area and multiple edges. But the ESC doesn't have to go there of course, certainly none of my ESCs run hot enough to warrant needing to put it directly under the prop wash. I have my ESCs in my CF tubes at the moment and they barely get warm.
The trouble with shrinkwrap (and inside the tubes, to some extent) is that if they do get wet, the water tends to get trapped inside the shrinkwrap and the tubes. A treated component like this, if it worked, would be pretty cool (no pun intended).
Hokey Science--You gotta love it. Skepticism is good. Here in the states, every state is known for a trait. Texas ... well you know that one. Now Missouri, one of our southern states, is so proud of being stubborn and obnoxious that it's called the "Show Me" state. Sometimes i swear that i was born in Missouri. i question everything. ya ... i know, big pain in the ass.
Anyway, Fnoop, from one mule to another :-), this Buds for you ...
Here is the photo of the computer screen measuring rotor output @ 544 grams.
Here is a photo of taking the airflow readings under a prop (i risked my life for Fnoop!).
9 m/s (haulin' #%$).
Here is the ESC on a hot-dog stick under his friend, the prop..
Here is the force of the ESC on a hot dog stick under his friend, the prop, with and without the motor wailing.
So the force in this case was 1ish grams of drag.
So do you need to put the ESC under the prop? Maybe not. Maybe it will do just fine in the airflow from ship movement or stagnant air. Test to find out.
And also keep in mind that by locating the ESC along the mast going to the motor (wires no longer have to traverse that distance), you eliminate 24" (0.6 m) of wire weight on a quad. And that is a lot of weight (12ish grams of wires versus 5ish grams of drag).
P.S. Nice job Fnoop on knowing how to motivate me to "get 'er done" and answer the dang drag question. You weren't the only one that didn't believe it (me included a few years ago).
LOL Thanks for risking your fingers in the name of hokey science ;)
The real question here is not marginal downward force on the ESC, but potential loss of thrust from the prop. Have you measure the actual prop thrust with and without the ESC?
Most of the arguments here about thrust being blocked by the ESC under the prop overlook the fact that thrust is being blocked by the arm anyway. Is the ESC wider than the arm? Not standing on edge. Is the ESC less aerodynamic than the arm? Yes, but is that enough to bother measuring???
Here you go -->
https://drive.google.com/open?id=0BwXIWbT5MUV6ME15MW1Cc09XWTg
Source, page 382 -->
http://www.amazon.com/Tailless-Aircraft-Their-Design-Characteristic...
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