Low cost EDF's, are they any good?

[DWM]

I saw these low cost EDF units on Ali Express and wanted to ask a few questions. Im not currently an EDF flyer but I'm interested in getting into that end of the hobby. I can just see a Versawing with one of these slung under its center in a nacel, or maybe a Kraken with 4 like a b52...😁

1) what are these smaller diameter units used for? From my understanding even the larger 64 and 70mm EDF's are relatively underpowered.

2) is this an EDF thats even worth the time to mess with? Am I better off just buying a more refined unit at a higher cost?

 

[Ryan O.]

always remember shipping may make up the cost of a higher quality fan system in some cases. I have no experience with these, but I haven't heard anything bad from other people. Do you have a link to the fan?

 

[DWM]

Thats one thing that caught my eye, these are shipping for free. Other thing is that they are bundled with the correct ESC for each size. That and of course the price point is attractive too😁

US $22.90 | AEORC Patended Product Ducted Fan System EDF for Jet Plane 27mm/30mm/35mm/40mm/45mm/50mm/55mm/64mm/70mm with brushless Motor
https://a.aliexpress.com/_msfOZpb

 

[Kai-003]

I got some 64mm and 70mm edfs I could sell for cheap. Let me know if you are interested. 64mm and 70mm edfs are not always under powered. They can have plenty of thrust, but the bigger diameter, the more air you can get going through it, so it would be able to more more air, but they also use more power.

 

[Kai-003]

1) what are these smaller diameter units used for? From my understanding even the larger 64 and 70mm EDF's are relatively underpowered.
the smaller edfs are used for small planes, like UMX planes. They are also some times used in vtol planes if needed. Like I said before, not all 64 and 70mm edfs are under powered.

2) is this an EDF thats even worth the time to mess with? Am I better off just buying a more refined unit at a higher cost?
it depends on what you want to build. It probably works fine, but you have to look at the specs. 566g of thrust for a 3s 70mm edf isn't great. I think you are better off getting a 6s 70mm edf that might get 1500g of thrust. It would be more expensive, but way better preformance.

 

[OliverW]

Valuehobby.com sells some really cheap all in one units that put out a lot of thrust. I have their 50mm and 70mm

 

[Kai-003]

If you are going to get 50mm edfs from them, I can sell you some for cheaper. They just dont have the bullet connectors.

 

[DWM]

The EDF is still at a concept phase for me. Im mainly working on DLG'S at this time. Most of the designs im looking at are in to 50-70mm range. Even though Id love to eventually build a big warbird with dual 90mm's. Ive always loved the F15's and would love to fly one.

I was just curious about the smaller ones. Spark of interest kind of thing. I could see an Alpha or Charlie converted to run on one of those 35mm's or dual 30mm's. Just wondering if it would be practical in that power to weigh range. Kind of a small park flyer EDF.

 

[DWM]

I got some 64mm and 70mm edfs I could sell for cheap. Let me know if you are interested. 64mm and 70mm edfs are not always under powered. They can have plenty of thrust, but the bigger diameter, the more air you can get going through it, so it would be able to more more air, but they also use more power.

Maybe after the first of the year, everything but the DLG for my nephew is on hold until them. But I appreciate the offer. No connectors isn't a problem. Electrical engineer here, I've got a stock of spare connections in my kit. No problem on the electronics end of things.

 

[jfaleo1]

The EDF is still at a concept phase for me. Im mainly working on DLG'S at this time. Most of the designs im looking at are in to 50-70mm range. Even though Id love to eventually build a big warbird with dual 90mm's. Ive always loved the F15's and would love to fly one.

I was just curious about the smaller ones. Spark of interest kind of thing. I could see an Alpha or Charlie converted to run on one of those 35mm's or dual 30mm's. Just wondering if it would be practical in that power to weigh range. Kind of a small park flyer EDF.

At least a 50mm the Alpha, probably a decent 4s version. Dual 30mm might do it but it would likely not be a lot of power or fun. The Powerfun EDFs mentioned already are great and, so far, my favorite. Check out the 50 mm L-39 v2 or 50mm F-22 from @Grifflyer both really great designs on that 50mm EDF.

 

[telnar1236]

The changes in performance aren't linear. A cheap edf is often only slightly worse than a much more expensive one. However, you lose out in durability and sound. Cheaper edfs are a lot more likely to break from FOD because of the cheaper plastic and often aren't as well balanced.

I haven't heard anything bad about these, but the shroud looks very cheaply made so I'd be worried about QC and lifespan more than performance.

 

[leaded50]

i also got good feelings on the EDF´s with QX motors. Not the cheapest sometimes, but feels durable. Powerfuns mentioned is great.

 

[DWM]

Good info guys👍 Im asking questions because im not into this end of the hobby yet and I need better info before I put down hard earned dollars on a possible piece of junk.

Does anyone know if you can run a pair of these motors off one ESC? The idea is two 35-40mm EDF's each drawing 10A peak running off a single 25a 4s ESC. Is this even possible or should I just tie two smaller ESC's together on one thottle channel? Its hard to get 10-12A ESC's rated for 4s power. Thanks for any help you can give.

According to the measurements Ive done on the plans a pair of 40mm would fit into an Alpha without any external charges. This would have two relatively straight thrust tubes, each side of the fuselage. A pair of EDF'S would be more efficient than a single large fan right? Im not looking to thrust vector or VTOL with this, just a lightweight, smaller parkflyer with moderate speed.

 

[Kai-003]

Good info guys👍 Im asking questions because im not into this end of the hobby yet and I need better info before I put down hard earned dollars on a possible piece of junk.

Does anyone know if you can run a pair of these motors off one ESC? The idea is two 35-40mm EDF's each drawing 10A peak running off a single 25a 4s ESC. Is this even possible or should I just tie two smaller ESC's together on one thottle channel? Its hard to get 10-12A ESC's rated for 4s power. Thanks for any help you can give.

According to the measurements Ive done on the plans a pair of 40mm would fit into an Alpha without any external charges. A pair of EDF'S would be more efficient than a single large fan right? Im not looking to thrust vector or VTOL with this, just a lightweight, smaller parkflyer with moderate speed.

I believe it is possible to use one esc for both motors. I personally haven't, but I've seen other people try. You would have to get an esc that has enough amps for both motors tho. I personally would just use 2 esc, because you can just use a y-lead to tie them together, or you could use differential thrust. I think getfpv has some 12 amp 4s esc. I found a discussion about using 2 motors and 1 esc that might have helpful info. https://www.rcgroups.com/forums/showthread.php?655876-2-motors-1-esc-any-downside

I'm not sure what you mean by, "A pair of EDF'S would be more efficient than a single large fan right?" but if I understand, using 2 edfs will draw more amps than using just one of the same edf, but you will have double the thrust. (does that make sence?)

 

[leaded50]

Does anyone know if you can run a pair of these motors off one ESC? The idea is two 35-40mm EDF's each drawing 10A peak running off a single 25a 4s ESC. Is this even possible or should I just tie two smaller ESC's together on one thottle channel? Its hard to get 10-12A ESC's rated for 4s power. .

- NO, you cant use one ESC for two EDF´s (or brushless motors)
!0A peak draw is to low for even a 35-40mm EDF. They will draw from approx 20 A (i think is lowest ive seen on a 30mm effective one) and up, each!

 

[quorneng]

The efficiency measured as grams static thrust per Watt is proportional to the diameter of the fan (or a prop for than matter) so for the same electrical power two small will be less efficient then one bigger one.
Further the efficiency of a fan rises as the power is reduced. A bigger fan worked less hard is electrically more efficient than smaller one worked harder to generate the same thrust.
However these relationships will change as the plane speed rises.

 

[telnar1236]

Good info guys👍 Im asking questions because im not into this end of the hobby yet and I need better info before I put down hard earned dollars on a possible piece of junk.

Does anyone know if you can run a pair of these motors off one ESC? The idea is two 35-40mm EDF's each drawing 10A peak running off a single 25a 4s ESC. Is this even possible or should I just tie two smaller ESC's together on one thottle channel? Its hard to get 10-12A ESC's rated for 4s power. Thanks for any help you can give.

According to the measurements Ive done on the plans a pair of 40mm would fit into an Alpha without any external charges. This would have two relatively straight thrust tubes, each side of the fuselage. A pair of EDF'S would be more efficient than a single large fan right? Im not looking to thrust vector or VTOL with this, just a lightweight, smaller parkflyer with moderate speed.

You definitely cannot run two brushless motors off one ESC. BL motors are basically variable speed synchronous motors, so the controller needs to switch at a speed corresponding to the rotation of the motor. If you try, one motor (really both) will be out of sync and not run which will basically short the contacts and burn out the ESC.

If you want to change out the BL motors for brushed motors, you can run as many motors off one ESC as you can supply the current for, if you run them in parallel. If you run them in series you lose a huge amount of power output.

 

[DWM]

- NO, you cant use one ESC for two EDF´s (or brushless motors)
!0A peak draw is to low for even a 35-40mm EDF. They will draw from approx 20 A (i think is lowest ive seen on a 30mm effective one) and up, each!

 

[DWM]

Thanks for the great info guys, I really appreciate it. Yes I was thinking of DC motors when I said multiple off of one ESC. Didn't make my sentence clear enough. Electrical Engineer here. Just about asleep when i posted that question. Really wondering if they would provide equal thrust from both EDF'S off the same thottle signal, or if I would need two thottle channels and need to mix them to make two pull equally.🥱

I was looking at specs sheet for those cheap Chinese duct units and was looking at the smallest 27mm duct when I posted the 10a figures. My mistake, As i said, half asleep. The 40mm takes a 20a and preferably a 25a. 50mm takes a 35a and should have a 40a to handle the wattage and thrust I'm trying to get. Translated the spec sheet from Chinese using Google.🤣

But after looking at thrust ratings and diameter of the units I understand what all of you are talking about. A single large unit produces more thrust than two smaller fans pf the same cross section. I'll probably end up going to HK and just getting higher quality units. The price isn't that much different and the units are much higher thrust for the diameter.

The only reason Im looking at the smaller fans is that I can fit a pair of them into the faux ducts of the FT mini F29/Vector or similar sized bird without too much reworking of the design. A bit of internal former for twin ducts and use the intakes as they are. The idea may not be practical. Just looking at the size of the design and a bit interested in it. Mainly for the much lower torque roll as you hit the throttle compared to a propeller.

The Alpha/Bravo/Charlie are interesting in that the airframe design is already well tested and the configuration is stable. Im looking at these plans now with the idea of mounting the wing permanently and adding two thrust tubes with the largest twin fans I can fit into the airframe. I understand that all I'll be using is the profile of the current design with a completely new internal build design. A removable wing isn't a necessity for me in this size range.

Probably end up hotwire cutting blocks of foam for the fuse like the original Viggen design. This will give twin integrated thrust tubes in a solid foam body. This design/size would require at least a pair of 50mm EDF'S for the required thrust to make it work. The larger plane is more desirable as larger planes tend to be less twitchy to fly than a small micro would be. Has anyone converted one of these (Alpha/Bravo/Charlie) to EDF?

I might end up just using a profile plan of the F15 that I actually want and hotwire and stack blocks. I've got the equipment already and build CF DLG gliders. A hot wired composite bird may be my first edf.

 

[telnar1236]

Thanks for the great info guys, I really appreciate it. Yes I was thinking of DC motors when I said multiple off of one ESC. Didn't make my sentence clear enough. Electrical Engineer here. Just about asleep when i posted that question. Really wondering if they would provide equal thrust from both EDF'S off the same thottle signal, or if I would need two thottle channels and need to mix them to make two pull equally.🥱

I was looking at specs sheet for those cheap Chinese duct units and was looking at the smallest 27mm duct when I posted the 10a figures. My mistake, As i said, half asleep. The 40mm takes a 20a and preferably a 25a. 50mm takes a 35a and should have a 40a to handle the wattage and thrust I'm trying to get. Translated the spec sheet from Chinese using Google.🤣

But after looking at thrust ratings and diameter of the units I understand what all of you are talking about. A single large unit produces more thrust than two smaller fans pf the same cross section. I'll probably end up going to HK and just getting higher quality units. The price isn't that much different and the units are much higher thrust for the diameter.

The only reason Im looking at the smaller fans is that I can fit a pair of them into the faux ducts of the FT mini F29/Vector or similar sized bird without too much reworking of the design. A bit of internal former for twin ducts and use the intakes as they are. The idea may not be practical. Just looking at the size of the design and a bit interested in it. Mainly for the much lower torque roll as you hit the throttle compared to a propeller.

The Alpha/Bravo/Charlie are interesting in that the airframe design is already well tested and the configuration is stable. Im looking at these plans now with the idea of mounting the wing permanently and adding two thrust tubes with the largest twin fans I can fit into the airframe. I understand that all I'll be using is the profile of the current design with a completely new internal build design. A removable wing isn't a necessity for me in this size range.

Probably end up hotwire cutting blocks of foam for the fuse like the original Viggen design. This will give twin integrated thrust tubes in a solid foam body. This design/size would require at least a pair of 50mm EDF'S for the required thrust to make it work. The larger plane is more desirable as larger planes tend to be less twitchy to fly than a small micro would be. Has anyone converted one of these (Alpha/Bravo/Charlie) to EDF?

I might end up just using a profile plan of the F15 that I actually want and hotwire and stack blocks. I've got the equipment already and build CF DLG gliders. A hot wired composite bird may be my first edf.

For such a light airplane, two 40mm EDFs would likely be plenty. And yeah, for brushed motors, the ESC basically just has a PWM output with the switching frequency controlled by the input voltage from the receiver. You only need one port on the receiver (3 pins). Also worth mentioning that for brushless ESCs, you can just connect them to a single port using a Y-connector if the number of pins is your only concern.

I'd love to see a foam and composite F-15.