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Edge 540 motor ?

Chuppster

Active member
#21
I am back in tot he hobby after being gone 30 years. My logical mind wants as much fun with as few parts as possible, so C Pack swappables is where I started. Storch and Mustang first. Next is Guinea Pig (this will be my favorite, and the reason why I came back) and ________. I am torn between Bloody Baron and Goblin. Remember, C Pack. Not sure if a Goblin could take a C Pack. Research for later...
Trainer. Warbird. Large high wing. Something small and fast.


I am not a 3D guy at all. Scale is the way for me. Indef vertical would be nice, but I can't see well enough past 300' so what's the point. Landings are an important part of my day at the field. Landing with power and rudder is a hard thing to master.


I standardized on 3s so far. 2200 size seems like the sweet spot, but I have 1300, 1600, 2100, and 2500. I think paralleling 2 batt for the Guinea may be needed, but I hear it may be more dangerous when batts are not at the same voltage.


I am not. I was hoping to standardize on 30a, but given my desires, a step or two up may be warranted.


I have no desire to have the Cadillac of everything, I like the 40-60" size in the 1-2lb weight class. But I do not know where this journey will take me.... I do live in an area where wind is always present, therefore the smaller planes aren't as desirable.
Thank you for the answers! Welcome back to the hobby, we are very glad you're here! I haven't built the Bloody Baron, Guinea, or Goblin (yet), but I DO have an NTM 28-26 and I can say that they work really well in my airplanes. They should power everything you're looking at just fine on 3s and you can get some extra zoom on 4s (provided your ESC will handle it). I think the 2826 motor is a good place to start for you. I had two on my Sea Duck and on 4s I could do vertical.

On the Goblin you could run this motor and it would likely do fine, but I plan to build it someday with a little quad motor on the back. The reason for this is that it'll be able to push the Goblin to higher speeds due to the high KV and tiny prop. But you probably already know that.

So, it sounds like for what you're looking to do you'll be just fine with the 2826. However, for a few bucks more you can go up to the PropDrive 2830 and get a few more watts of power on the same ESC. I like the 1200KV motors because they let you run an 8"-9" prop which is a good size range for these airplanes.

Do you have any more questions?
 
#22
Do you have any more questions?
Probably have a million more questions, but you have been very helpful. Thank you.

1200kv letting you run a 8-9" prop. Is there a general correlation between kv and prop diameter??

The only real challenge I have now is finding a programming card for the EMAX 30A ESC that comes with the C Pack. I hear that changing one setting to 8 degrees can have a real positive effect.
 

PsyBorg

Fly Angry
Mentor
#23
I have my edge ready to maiden on the FT C pack. I did the taxi tests and learned trying to take a tail dragger off that sits nearly level doesnt work. I now have a nice angle of attack on it after rebending my gear.

The C pack moves it on the ground nicely on 3s. Here is my taci test to show the power and how NOT to make a plane sit nearly level that has Zero angle of incedence. Anyway should have plenty of power to fly jusy not extreme 3d.

 

DamoRC

Well-known member
Mentor
#24
1200kv letting you run a 8-9" prop. Is there a general correlation between kv and prop diameter??
.
Not quite. Although the two are connected to the performance of your plane in a round about fashion, there are no "rules of thumb" that let you link Kv and prop size. You can have a small, low power motor at 1200kv or a large high power motor at 1200kv and they both wear very different prop sizes. Here is a thread that gives some nice info on how to think about motor and prop combinations. Take this as a starting point only as you will come across lots of opinions and debates around the topics covered.

DamoRC
 

Chuppster

Active member
#25
Probably have a million more questions, but you have been very helpful. Thank you.

1200kv letting you run a 8-9" prop. Is there a general correlation between kv and prop diameter??

The only real challenge I have now is finding a programming card for the EMAX 30A ESC that comes with the C Pack. I hear that changing one setting to 8 degrees can have a real positive effect.
I use a tool that lets me get an idea of what prop might work on the motors I'd like to buy. You can find it here: https://rcplanes.online/calc_motor.htm

Yes, there are 100 fields to fill out, but the most important ones are your cell count, motor KV, motor Rm (resistance), and your max current. Then you can pick a prop from the drop-down list that is closest to what you are thinking of running. It'll calculate a fairly accurate "maximum current" for the power setup you're looking at using. It'll also give you max thrust and static prop pitch speed. I have found these values to be surprisingly accurate, within 20% most of the time. If you give it your wing area down at the bottom you can also get a rough top speed estimate.
 
#27
You can change the timing setting using the transmitter. Attached is the manual for this ESC family.

DamoRC
I am aware, but I can't get the correct beeping patterns following the instructions. Maybe when my throttle stick is up, the correspond PWM value isn't correct, so the ESC thinks I am less than 100% therefore it won't give me the programming mode. Honestly I came up with this theory this week, so I haven't had time to test my theory.
 

DamoRC

Well-known member
Mentor
#28
I am aware, but I can't get the correct beeping patterns following the instructions. Maybe when my throttle stick is up, the correspond PWM value isn't correct, so the ESC thinks I am less than 100% therefore it won't give me the programming mode. Honestly I came up with this theory this week, so I haven't had time to test my theory.
If your throttle at 100% does not allow you to enter programming mode then maybe you just need to calibrate it (which is kind of the same as programming the esc).

(1) Transmitter off, ESC not powered but connected to a motor (no prop for safety)
(2) Transmitter on, set throttle to 100%
(3) Apply power to the ESC. You should hear startup tones, a brief pause, then two beeps (confirming that the ESC now knows what 100% throttle is) at which point pull the throttle to zero.
(4) Remove power from the ESC

Once you have done this calibration if you repeat steps 1 - 3 and, after the two beeps, wait for a second or two, you should enter programming mode.

DamoRC
 

DamoRC

Well-known member
Mentor
#30
Apologies to @Photon Phil (the OP) and @james90755.

The information I posted earlier on the static thrust values for the NTM 2826 1200kV were incorrect. Instead I posted data from the 1000kV version of the same motor. I have one single unit of the 1000kV and a bunch of 1200kV units and the data presented earlier were from tests performed in order to build a quad. I mistakenly tested the 1000kV during the thrust tests, and worse, built the quad with this motor and three 1200kV units. If flew fine but it took me forever to understand why one of the motors seemed to be always working harder than the others - it was only when I checked the RPM at each arm that I realized my mistake - and then promptly forgot that the data I had was from the slower motor.

So this weekend I repeated the static thrust tests using the 1200kV motor, various ESC timings, and different props, all on 3S. The results were:

Static Thrust Data.jpg
Given the all up weight of the model and the thrust being generated in the static tests, its clear that a lot of this thrust is being lost when the motor is installed in the plane. I am going to try to extend the motor mount to move the prop away from the nose to see if it makes any difference.

I flew the plane using both the 9x4.7 and 10x4.7 on the weekend (ESC low timing) and the 10 inch prop was a lot closer to hanging the plane in the air and almost hovering, but not quite (I should also point out that my flying skills are not up to the task yet).

DamoRC
 

DamoRC

Well-known member
Mentor
#31
Quick update. From this years edition of the "DamoRC Almanac of Clever but Stupid" I wanted to see what the in-plane static thrust was. So I did this... IMG_3755.JPG

Static thrust was 1000g with a 2850mAh 3cell onboard. So its down 150 grams (5 oz) from the bench testing results. Then I added standoffs to the motor mount, pulling the motor forward by about 1 inch.

IMG_3756.JPG

In-plane testing produced another result of 1000 grams. So the proximity of the prop to the nose (at least from stock to 1 inch forward) doesn't make any difference.

Apart from my lack of 3D skills my build clearly does not have enough power to hover easily. So why can't I get a good hover with a thrust to weight of about 1.4? I think that this is related to battery drain. Sure, on the bench when I test these motor prop combinations, I can get plenty of thrust. But to remove battery charge and voltage from the list of variables I paralleled 3 x 2200mAh batteries for the tests and even the in-plane tests were performed with a fresh battery. As the battery loses charge you won't see those thrust numbers. This is, of course, all pretty obvious but how much thrust do you lose? Well I ran another static test on the bench with a single, 1600mAh 3S (the lightest battery I fly) when it was approx 40% charge (~3.75 - 3.8 volts per cell) using a 9 x 4.7 prop and at full throttle the voltage sagged and the thrust was 660 grams drawing 11 amps , this is down about 350 grams (~ 12 oz) from the original test.

Anyway - gonna play with this a little more - profiling the drop in thrust over flight time and checking out some 4S options on this motor.

DamoRC
 
#32
Thanks DamoRC for sharing so much detail... as this would take a long time for us to repeat individually.

I like the ladder tester idea, but let me pose a question. When in the air a plane has little to no obstruction of the air in front of the propeller as it comes to travel thru the propeller. In your test rig, the air isn't coming from in front of the prop so much as entering from the sides. I would imagine this could have effects on thrust and the motor would be working harder to get each unit of thrust. So the question is what possible effects could the wall in front of the propeller have??
 
#33
Some additional detail on C Pack motors and 4s... I stumbled across the Mig3 build video. At 2:08 it is mentioned that Josh's favorite battery is a 4s/1600 and it runs great in the Mig3. He then advises to not got above 9x4.5 prop to protect the 30A ESC and motor. He says this combo draws 27Amps.

This makes me think about thrust differences between 3s/9x6 or 3s/10x4.7SF and 4s/9x4.5... does the 4s really pay dividends here??
 
#35
Quick update. From this years edition of the "DamoRC Almanac of Clever but Stupid" I wanted to see what the in-plane static thrust was. So I did this... View attachment 115015

Static thrust was 1000g with a 2850mAh 3cell onboard. So its down 150 grams (5 oz) from the bench testing results. Then I added standoffs to the motor mount, pulling the motor forward by about 1 inch.

View attachment 115016

In-plane testing produced another result of 1000 grams. So the proximity of the prop to the nose (at least from stock to 1 inch forward) doesn't make any difference.

Apart from my lack of 3D skills my build clearly does not have enough power to hover easily. So why can't I get a good hover with a thrust to weight of about 1.4? I think that this is related to battery drain. Sure, on the bench when I test these motor prop combinations, I can get plenty of thrust. But to remove battery charge and voltage from the list of variables I paralleled 3 x 2200mAh batteries for the tests and even the in-plane tests were performed with a fresh battery. As the battery loses charge you won't see those thrust numbers. This is, of course, all pretty obvious but how much thrust do you lose? Well I ran another static test on the bench with a single, 1600mAh 3S (the lightest battery I fly) when it was approx 40% charge (~3.75 - 3.8 volts per cell) using a 9 x 4.7 prop and at full throttle the voltage sagged and the thrust was 660 grams drawing 11 amps , this is down about 350 grams (~ 12 oz) from the original test.

Anyway - gonna play with this a little more - profiling the drop in thrust over flight time and checking out some 4S options on this motor.

DamoRC
Did you... put an arrow through your edge?!?!?!
 

DamoRC

Well-known member
Mentor
#36
Some additional detail on C Pack motors and 4s... I stumbled across the Mig3 build video. At 2:08 it is mentioned that Josh's favorite battery is a 4s/1600 and it runs great in the Mig3. He then advises to not got above 9x4.5 prop to protect the 30A ESC and motor. He says this combo draws 27Amps.

This makes me think about thrust differences between 3s/9x6 or 3s/10x4.7SF and 4s/9x4.5... does the 4s really pay dividends here??
The 4S will make a big difference because that extra 3.7 volts is converted to an additional thoretical 4300 RPM, that is, the Kv by the voltage. Note, you wont actually get the full RPM based on Kv by voltage so it could be an additional 3500-4000 RPM. The flip side is that if you don't reduce the diameter of the prop, the current draw will increase significantly (perhaps to the point where you damage a motor or an ESC). I'll be doing the 4S tests soon so I'll post the results.

Thanks DamoRC for sharing so much detail... as this would take a long time for us to repeat individually.

I like the ladder tester idea, but let me pose a question. When in the air a plane has little to no obstruction of the air in front of the propeller as it comes to travel thru the propeller. In your test rig, the air isn't coming from in front of the prop so much as entering from the sides. I would imagine this could have effects on thrust and the motor would be working harder to get each unit of thrust. So the question is what possible effects could the wall in front of the propeller have??
Yep - the test rig is not 100% ideal (I could go higher on the ladder :)) but even if there was restrictions on the air flow on the test rig compared to in air (so I could get the ~150 grams of thrust back) this just makes the question of why it doesn't hover easily harder to answer.

use the gt 2215/09 on a 4s with a 40amp esc and a 10x5 prop
Wow! I need to get me some C-pack motors - that's a lot of prop. What current are you actually drawing and has your plane caught fire yet? ;)

DamoRC
 
#38
The 4S will make a big difference because that extra 3.7 volts is converted to an additional thoretical 4300 RPM, that is, the Kv by the voltage. Note, you wont actually get the full RPM based on Kv by voltage so it could be an additional 3500-4000 RPM. The flip side is that if you don't reduce the diameter of the prop, the current draw will increase significantly (perhaps to the point where you damage a motor or an ESC). I'll be doing the 4S tests soon so I'll post the results.



Yep - the test rig is not 100% ideal (I could go higher on the ladder :)) but even if there was restrictions on the air flow on the test rig compared to in air (so I could get the ~150 grams of thrust back) this just makes the question of why it doesn't hover easily harder to answer.



Wow! I need to get me some C-pack motors - that's a lot of prop. What current are you actually drawing and has your plane caught fire yet? ;)

DamoRC

Plane has not caught fire lol! The 4s is not recommended but I have been using a 4s for months now with no damage at all. I get about 3.5 lbs of thrust in total and the 40 amp esc is for safety. I don't know exactly how many amps it draws.
 
#39
Plane has not caught fire lol! The 4s is not recommended but I have been using a 4s for months now with no damage at all. I get about 3.5 lbs of thrust in total and the 40 amp esc is for safety. I don't know exactly how many amps it draws.
Damn, 3.5lbs. FT is backordered on 2215/09 but you can get them in the C pack. Wish their ESC was 40Amp. What ESC are you using?? (I don't think Emax has a 40).