RC India

RC Equipments => Electric Power => Topic started by: rohan123 on September 11, 2014, 10:11:30 PM



Title: which prop to use???
Post by: rohan123 on September 11, 2014, 10:11:30 PM
hello everyone, i need to choose a prop for my dys 1400kv brushless motors(specs are below) ,i have a 10X4.5 can i use it??
specs of the motor:
KV: 1400
Configuration: NP
Stator Diameter: 22mm
Stator Length: 8mm
Shaft Diameter: 3.17mm
Motor Dimensions(Dia.*Len): Φ28×26mm
Weight: 44g
No.of Cells(Lipo): 2-4S
Max Continuous current: 26A
Max Continuous Power: 384W
Internal resistance: 0.106Ω


Title: Re: which prop to use???
Post by: sanjayrai55 on September 12, 2014, 05:57:49 AM
You would be stretching that motor too far on that prop. Go for a 7*4.5, 8*5, or maximum 9*47 SF - the last will draw nearly 30 A


Title: Re: which prop to use???
Post by: madaquif on September 12, 2014, 06:07:03 AM
hey rohan.....which battery do you plan to use?

2 3 or a 4 cell ???


Title: Re: which prop to use???
Post by: rohan123 on September 12, 2014, 04:12:45 PM
im using a 2200 mah 3s 25C 11.1v lipo...


Title: Re: which prop to use???
Post by: sanjayrai55 on September 12, 2014, 04:38:03 PM
That motor is the same as this:

http://www.hobbyking.com/hobbyking/store/__12920__D2826_10_1400kv_Brushless_Motor.html (http://www.hobbyking.com/hobbyking/store/__12920__D2826_10_1400kv_Brushless_Motor.html)

See the prop indicated; same as I told you


Title: Re: which prop to use???
Post by: K K Iyer on September 12, 2014, 05:05:44 PM
@rohan123,
DYS site does not show any 2826 motor of 1400kv, of 44gms and 384 watts.
http://www.dys.hk/ProductShow.asp?ID=30 (http://www.dys.hk/ProductShow.asp?ID=30)
Their 2826-10, 1400kv (as well as the motor mentioned by Rai saheb) are rated for 205 watts
The pamphlet that came with the Turnigy 2826-10/1400 specifies 7x4 for 3s and 9x4.7 for 2s

Perhaps you may need to verify the motor specs again.
Maybe it is not DYS or Turnigy at all, or maybe it is a different size!


Title: Re: which prop to use???
Post by: sanjayrai55 on September 12, 2014, 05:24:00 PM
Iyer sir, it's obviously at 4S. 384 watts, @ 26 Amps => 14.8 V


Title: Re:
Post by: docnayeem on September 12, 2014, 05:30:24 PM
384 watts!  Rai sir aren't we expecting too much from this motor...?


Title: Re:
Post by: docnayeem on September 12, 2014, 05:39:39 PM
If we go by numbers... 
A 10*4 prop with a voltage of 14.8 (4 cell)  and spinning at 1400 kv would require a motor of 1300 odd watts...


Title: Re: which prop to use???
Post by: sanjayrai55 on September 12, 2014, 05:42:20 PM
384 watts!  Rai sir aren't we expecting too much from this motor...?

Those are not my figures Doc!

IMHO this motor is good for 200 W. Period.

Unless it's a Hacker, Scorpion, AXI; this is just a case of some Chinese manufacturer showing off his size :D


Title: Re: which prop to use???
Post by: sanjayrai55 on September 12, 2014, 05:43:02 PM
If we go by numbers... 
A 10*4 prop with a voltage of 14.8 (4 cell)  and spinning at 1400 kv would require a motor of 1300 odd watts...

How?


Title: Re: which prop to use???
Post by: K K Iyer on September 12, 2014, 05:52:18 PM
Iyer sir, it's obviously at 4S. 384 watts, @ 26 Amps => 14.8 V
@sanjayrai55 sir,
Oops, i missed that!
Surely one would expect DYS and/or Turnigy to publicise 384 watts instead of 205.

@rohan123
Could you post pics of the motor and the spec sheet please?


Title: Re:
Post by: docnayeem on September 12, 2014, 06:28:07 PM
Sanjay sir... I use a webcalc routinely
http://adamone.rchomepage.com/calc_thrust.htm
Please have a look


Title: Re: which prop to use???
Post by: sanjayrai55 on September 12, 2014, 06:32:46 PM
I don't agree with it. Reality is something else.

As you know, I do my own testing. I have run a 2826-1400 with a 10*4.5 at 3S, goes to about 24 A.

At 4S will go to about 30 A.

What actually happens is as the motor capacity is reached, the RPM drops. So V drops, the wattage peaks out. If you continue running, it burns out  >:D


Title: Re: which prop to use???
Post by: rohan123 on September 12, 2014, 06:55:06 PM
Photos of my motor... It says BE2208-1400Kv on it


Title: Re: which prop to use???
Post by: sanjayrai55 on September 12, 2014, 07:02:35 PM
Item No.   NO LOAD   ON LOAD   LOAD TYPE
BE2208-13
(1400KV)   VOLTAGE   CURRENT   SPEED   CURRENT   Pull   Power   Battery/prop
V   A   rpm   A   g   W
7.4   0.4   7970   3.4   170   25.2    LiPoх2/6x5E
9.6   340   71.0    LiPoх2/7x5E
10.3   430   76.2    LiPoх2/8x4E
12.1   530   89.5    LiPoх2/9x6E
11.1   0.5   11930   6.3   380   69.9    LiPoх3/6x5E
16.1   580   178.7    LiPoх3/7x5E
17.1   730   189.8    LiPoх3/8x4E
19   835   210.9    LiPoх3/9x6E
14.8   0.5   15880   9.8   640   145.0    LiPoх4/6x5E
22.1   780   327.1    LiPoх4/7x5E
23.5   960   347.8    LiPoх4/8x4E
26   1060   384.8    LiPoх4/9x6E


Title: Re: which prop to use???
Post by: sanjayrai55 on September 12, 2014, 07:03:40 PM
I think this clears up all. The manufacturers propchart, which should have been posted in the very first place


Title: Re: which prop to use???
Post by: rohan123 on September 12, 2014, 07:07:13 PM
Sorry sir, i was unable to find this data and the seller suggested 10x4.5 props so i bought them,and now im worried i can damage the motors so help me pleasenn


Title: Re: which prop to use???
Post by: sanjayrai55 on September 12, 2014, 07:08:49 PM
What do you want to use it on? Give details


Title: Re:
Post by: docnayeem on September 12, 2014, 07:09:47 PM
Can't get that table right :( it's all smudged up


Title: Re: which prop to use???
Post by: sanjayrai55 on September 12, 2014, 07:11:54 PM
Search DYS 2208 1400 KV on google


Title: Re: Re: Re: which prop to use???
Post by: docnayeem on September 12, 2014, 07:12:25 PM
I don't agree with it. Reality is something else.

As you know, I do my own testing. I have run a 2826-1400 with a 10*4.5 at 3S, goes to about 24 A.

At 4S will go to about 30 A.

What actually happens is as the motor capacity is reached, the RPM drops. So V drops, the wattage peaks out. If you continue running, it burns out  >:D
Sir actually when you shift from 3 cell to 4 cell the current drawn drops and does not increase...  If motor and prop setup is the same....


Title: Re: which prop to use???
Post by: sanjayrai55 on September 12, 2014, 07:13:52 PM
Rohan- the props will work on a 2S with no problem. On a 3S they should be OK, but you should check with a wattmeter


Title: Re: which prop to use???
Post by: sanjayrai55 on September 12, 2014, 07:14:34 PM
Doc Nayeem: Have you tried this with measurement?


Title: Re: Re: Re: which prop to use???
Post by: docnayeem on September 12, 2014, 07:17:33 PM
Doc Nayeem: Have you tried this with measurement?
Sir logically
I (current) * V(voltage) = W(Power)
So when power consumed is the same (w)  is constant in both the cases... If V increases.. 'I' has to decrease..


Title: Re: which prop to use???
Post by: sanjayrai55 on September 12, 2014, 07:21:58 PM
Who says W is the same? With higher V, W will increase! Don't just talk, do it and see

I'm not interested in hijacking someone else's thread. So, this stops on this thread.


Title: Re: which prop to use???
Post by: rohan123 on September 12, 2014, 07:51:29 PM
sanjay sir,i want to use it on my quadcopter,so which props do you suggest???


Title: Re:
Post by: docnayeem on September 12, 2014, 08:01:32 PM
Take my words back... 
Sorry Sanjay sir...


Title: Re: which prop to use???
Post by: sanjayrai55 on September 12, 2014, 08:02:32 PM
If you want maximum lift, you can try the 10X4.5. If you are using a 3S battery, as said before, verify once the maximum Ampere draw, which should be within the manufacturers limit


Title: Re: which prop to use???
Post by: rohan123 on September 12, 2014, 08:50:41 PM
sir, max current is 26amps


Title: Re: which prop to use???
Post by: sanjayrai55 on September 12, 2014, 09:07:34 PM
Yes, I saw


Title: Re: which prop to use???
Post by: rohan123 on September 12, 2014, 09:19:18 PM
So should i use 10x4.5 props sir??


Title: Re: which prop to use???
Post by: K K Iyer on September 12, 2014, 09:21:11 PM
If you want maximum lift, you can try the 10X4.5. If you are using a 3S battery, as said before, verify once the maximum Ampere draw, which should be within the manufacturers limit

26 amps at 14.8v?
Probably won't draw over 20amps on 3s if you stick to the (smaller) props suggested by Rai saheb.
Take care: More than 16-17amps (200w) may kill the motor.


Title: Re: which prop to use???
Post by: rohan123 on September 12, 2014, 09:31:52 PM
I am still confused will the smaller prop give 500-700g of thrust???and will the bigger prop damage the motor?? And what should i do to get a thrust of 500-700g without damaging my motors???and thanx to everyone for the help it has helped me alot, Especially sanjay sir... Now i need a final verdict coz i need to show the quad working to my school in a few days,i certainly dont want any damage as this my first project, the budget is an issue...


Title: Re: which prop to use???
Post by: sanjayrai55 on September 12, 2014, 09:39:58 PM
Use the bigger prop for maximum thrust. It SHOULD work OK, but use of a wattmeter is better. If you don't have one use Lifeline - phone a friend :D

Exact thrust cannot be determined unless tested


Title: Re: which prop to use???
Post by: rohan123 on September 12, 2014, 11:47:08 PM
thank you sir :) :)


Title: Re: which prop to use???
Post by: K K Iyer on September 13, 2014, 12:16:55 AM
@rohan123,
Your motor is different from what we were taking about.
Prop recommendation by DYS attached.

Hope this helps.
Over and out. Bye.


Title: Re: which prop to use???
Post by: maahinberi on September 13, 2014, 09:04:20 AM
Since you hardly ever go full throttle on a quad, the bigger prop should work fine.

On quads, people prefer to go with lower kv motors. 1000kv max if using 3S batteries. The 1400kv might be too inefficient. Might not get very long flight times from these motors.
Also, do you know how to fly quads?


Title: Re: which prop to use???
Post by: rcrcnitesh on September 13, 2014, 11:20:45 AM
For how much did you buy the motor for. If you want you could sell it and get a better motor.


Title: Re: which prop to use???
Post by: rohan123 on September 13, 2014, 03:13:51 PM
@maahinberi im new to rc stuff,its my first project and i dont know how to fly quads but will shortly learn using a simulator...
@rcrcnitesh i bought a combo of the motor and the ESC for 1500 rs. and i asked the seller for a lower kv motor but he told me they are out of stock and dont know when they will be in stock...


Title: Re: which prop to use???
Post by: rcrcnitesh on September 13, 2014, 03:15:02 PM
from where did you buy it.


Title: Re: which prop to use???
Post by: rohan123 on September 13, 2014, 03:29:33 PM
i bought it from a seller in delhi


Title: Re: which prop to use???
Post by: rcrcnitesh on September 13, 2014, 03:38:39 PM
well use it with an 8*4.7 prop.


Title: Re: which prop to use???
Post by: rohan123 on September 13, 2014, 03:58:30 PM
ok thanx sir


Title: Re: which prop to use???
Post by: rcrcnitesh on September 13, 2014, 04:03:00 PM
no sir please.


Title: Re: which prop to use???
Post by: maahinberi on September 13, 2014, 08:27:01 PM
Yes, please practice on the sim, and then when you build the quad, practice a lot on that in an empty ground where you can't hurt anyone. Do not fly in front of people till you don't have total control of the quad. They can cause a lot of damage if out of control.

How are you planning on building the quad? What size quad are you building? Do you have an estimated weight?

Actually 10" props will give you more flight time, because the quad will hover at a lower throttle than the 8" props.
Also, 10" props will be more stable. Easier for a beginner to control.


Title: Re: which prop to use???
Post by: sanjayrai55 on September 13, 2014, 08:28:21 PM
+1 Maahin!  {:)}


Title: Re: which prop to use???
Post by: rcrcnitesh on September 13, 2014, 08:47:17 PM
but these motors pull 18amps on 9*6 props on 10" props they will burn.


Title: Re: which prop to use???
Post by: maahinberi on September 13, 2014, 11:18:03 PM
As I said before, that is only the max amp rating at full throttle. I have been flying quads for quite some time and personally, I have never gone full throttle even once. I know people do go full throttle on quads, but only for doing flips and rolls, or flying extremely fast in forward flight.
Being a beginner he is a very long way from getting into acro flight. Also, these motors will not have enough thrust with 8" props for acro flight.
So if he is not going to be going full throttle at all, then why waste battery on every flight for just hovering.

Let's assume he builds a 450 size quad (which normally weighs around 1000g). With 8" props on those motors, it will hover at about 60-65% throttle. With a 2200mah 3S battery, this would give him a flight time of about 3 minutes.

With 10" props however, it should hover at half throttle and should give a flight time of 5-6 minutes.


Title: Re: which prop to use???
Post by: rohan123 on September 14, 2014, 12:30:04 AM
i agree with maahin sir as i wont need full throttle ...and sir i will take every precaution as possible so that nobody gets hurt.and i will be making a 450quad with max. weight 1kg .i am planning to make the frame for testing the motors and will either buy or use aluminum square rods for the final product.i will be using a flysky ct6b(which im feeling hard to find in budget) and for the flight controller i am using an arduino UNO r3 with 6DOF(whose code im working on) gyro but for the testing i'll be using the hobbyking multi rotor flight-controller v3...thats the plan by now