A typical power system for foam planes consist of a motor (we will stick to brushless ones, since they offer better power/performance), an electronic-speed-controller (ESC), a right sized prop and an appropriate Lipo battery.  Picking up the right combination of these is vital for success of whatever one is trying to achieve, whether it is slow flight, fast flight, or hovering-with-high-thrust.

What are some of the tricks and rules-of-thumb that people use to determine what combinations work ? 

Should we go for a low KV motor, or a high KV motor ?  How much Amps should the ESC support ? What size prop would a particular combination of Motor/ESC support ?

Hi ,
I normally go essentially by the weight and type of flying to determine the motor .
The Motor's max amp x 1.5 is normally my thumb rule for ESC .
Current Draw of the motor determines the Battery Capacity ( MAH ).
flying Charecteristics of the aircraft determines the Voltage selection .
Motors KV rating largely determines the prop size .
EG
MR MOSS Glider :
Trainer Version : 36 " wing span AUW : 250 gms  , Motor : 2204/14 , 1400 KV  Max amp 6 amp , ESC : 10 Amp , battery : 7.4V 850 MAH
Competition Version : 48 " Wing Span : AUW : 310 gms : Motor 2205 , 1400 KV : Max amp 8 , ESC 10 amp : battery : 11.1V 400 Mah  as competition required excellent climb rate for max duration 1 min hence choise of 11.1V 400 mah.
PROP in both cases GWS 8040 with prop saver

MIG 29 : depron Quick Build : AUW :  400 gms : Motor : 2212/06 KV 2400 , Max amp 22 amps , ESC : 40 amps , Battery : 11.1V 2650 mah  Prop size 6 x 4 APCE .

ONE IMPORANT FACTOR THAT HAS TO BE ALWAYS REMEBERED IS THAT MOTOR SPEED IS INVERSLY PROPORTIONAL TO TORQUE .

HENCE LOWER KV MOTORS SWING A  BIGGER PROP AND VISE VERSA .

One interesting case that could help in better understanding is the CASE of The PILOT Models Seduction  which both myself and Chan fly :
My Motor is a 3520- 6 T , 700 KV  started with  11 x 7 prop on 4 s ( 14.8 V )and used to be very sluggish till I accidently was forced on the field to fit the only prop I had a 15 x 8 APCE with a 3 S 11.1V .
In 1 flight its performance was Transformed .
I was worried about the current draw but to my surprise at full throttle it was only 46 amps .
Hence Proping up and reducing battery weight was just the right thing for this plane .
The same happened with the Pheonix tiger 60 as well on a 15 x 8 APCE .

Chan is on a 2826 Motor ON 4 s ( 14.8 V ) for the same plane am I right Chan ?
Both combinations are amazing on the same plane.

Sai

PS : The Pink Seduction is Chan's and the yellow one Mine

How do you normally measure the max current/amps being pulled at full throttle, or during a climb out ?

You can measure the MAX Current Draw at full throttle with a WATT Meter  which you connect in line between the ESC and the Battery  . It is a Static test on ground not in the air .
EG : Like this one http://cgi.ebay.in/TURNIGY-Multi-F-DC-Watt-Meter-75A-Radio-not-needed_W0QQitemZ110269842696QQihZ001QQcategoryZ2563QQcmdZViewItemQQ_trksidZp1742.m153.l1262

This does not need a radio as it has a potentiometer that simulates variable throttle inputs

sai

Yes uncle,
You are right.  I am flying on a Turborix 2826 with 4s 14.8V 3000 mAh Lipos!!  That works fine on a 10x7 prop for me.  Inspired by you, i tried the 3 cell route on my motor as well.  Put in a 13 x 6.5 prop and used a 2650 mAh 3s 11.1 V Lipo.  Was a big failure.  Took off, but had hardly enough power to keep it airborne.  One circuit and i brought her down.  And i also used a 11x7 on the 4s setup and did not find much of a power difference but batttery was draining faster.  So went back to the original 10x7 setup and am happy with it ..

For Foamies,
I generally look at 500 gms AUW.  I would prefer a 1000kv motor on a 3s which would draw about 13 to 15 amps max.  This should work perfectly on a 10x4.7 prop.

My Nasty which weighs 630 gms has a 175W 1000kv motor (Dualsky).  And it flies on a 10 x 4.7 (slow 3d flying) and a 10 x 5 (fast sport flying) with a 1350 / 1800 3s 11.1 Lipo.

Regards,
Chan

We generally use the following Rule-of-Thumb while powering a EP Model Plane:Power to weight ratio.
50 watts power per pound of model weight for trainer like flying, 100 watts/pound for general Aerobatic flying and 150 or more watts for 3D and extreme wild aerobatics. But here the power is the input power and not the motor's actual output power which depends on the motors efficiency. We all know that brushless motors are more efficient than brushed motors.Also,the actual force which propel the plane is the THRUST generated by the motor and propeller combination. So if we use thrust figures to select the power systems what would be the general rule-of-thumb in terms of thrust to weight ratios for different types of flying?

Friends..was much helpful...thanks..

Sir ,

is  a 30 amp  ESC   suitable  for  a 18 amp prescribed (in the web-site)   Motor ??

and  which one  is good   

Mystery 30A BEC Brushless Speed Controller (Blue Series)
                    OR
TURNIGY Plush 30amp Speed Controller

I have actually built a balsa Delta wing model and it weighs around 460~500 depending upon battery i use 800 or 1000 mAh. suggest me prop and battery voltage to use for good and smooth aerobatics.:

1. volts:11.1V prop:5*5
2. volts:11.1V prop:6*4
3. volts:7.4V prop:8*4

I wud recommend 6x4........its magic prop!!!!!!
Still go for recommended prop for your motor!!!!!

can some one give set of motors,props and battery we should have ready for mid,small plane.maybe self made scratch build or kit.i think one high power esc for all should be ok.may be one smaller for very small planes

Hi  ,

  I plan to use 2 motors on my model (twin-engined).
  I wanted to know that can I use 2 different ESCs (1 from EMAX and 1 from HobbyKing) to drive the 2 motors, or would there be a difference in power output from the 2 motors?

TIA  ,
aX

HI,
I am scratch building a Big beaver with projected AUW to be around 700gm. I have 1100kv motor, 40A esc and a three cell 2300mah battery. I plan to use 10x4 prop. Can you tell me whether its a right combination or not...
thanks

I have made one Base stand for my project and Approx.

Weight of my quadcopter is around 1300 Grams.

Which Motor Should i have to select for it ?

And Which LI-PO Battery i have to select for it ?

Which type of propelors will help me for Proper Motor ?

If I have to Bulid my controlling Board, then How can i Count the Power Consumption for each component and which controller will help me for this whole project ?

Any Suggestions are there please give me it will become helpful for me For my project.
And One Main Thing is about ECS and Which type is Tx. and RX Remote Will help me?
6 channel or 8 channel ? and From where I can Make Order for Components ?

Any indian Company or Anyy indian person is my first priority to make Placeorder for my Component Order.

If anyone has made it theen also share it for this Project. Will Glad to talk about this Project.
Any training proggramme are there then Do Reply on

I thought this was a discussion on foamies, and please use the search box  Judging from your query, you are a beginner so my advice is to first buy a FC for your quad and then try to make one .
From what I have gathered from reading through many forums(especially the multirotor section of RCIndia) for a 1300gm quad(AUW??), for high performance you need to have the following specs(assuming you are on a budget like I am..) :

Atleast 650gm thrust motors : Go for lower kV motors like the dt750 or "FC 28-22 Brushless Outrunner 1200kv" from hobbyking.

ESC : F20(20A) or F30(30A) ESCs work best as they can be reflashed with a suitable firmware for quads.

Props : CW and CCW (counter rotating pairs) props (Size is determined by your choice of motors).

Tx/Rx: Any 4 to 6 channel radio will be enough(I got one from rchobbyaddict)

Battery : 3S lipo with max amp draw that is more than the max amp draw of the motor used x 4. I have purchased a turnigy 20c 3000mAh

Flight controller : kkboard (or HobbyKing Multi-Rotor Control Board V2.1)

Best of luck

Actually  I dont have Any information About KKboard .
What is it ?
cant we bult Our Circuit to make project and control the foour motors and Flip it in Air ?

And About Motor, I was thinking that, let me Take 2200kv motor so if My use will be Definately fulfilled From that. Was i Wrong about it ?

I have make Assumptions About my Project Listed Below.

Approx. Weight -
Dimension = 15'' * 15'' [If possible then will reduce it to 12''*12'']
Battery - 175 gm
base - 325 gm If another mAterial Will use.]
Battery - 75 *4 = 300 gm [Will USE 2200kv Motor So It will aroung 2000 rpm Approx.]
ECS = 15 * 4 = 60 gm [40A Will be suitable for 2200kv Motor Each]
connectors = 50 gm
Controlling Board = 200 gm
Other Peripherels = 200 gm
________________________________________________
Approx Total Weight [[MAX.] = 1310 gm ==>Max. Weight.

Is it okay ? And for that Can you suggest me how can i do work ?

4 batteries of 2200kV Can you please edit your post? It is very difficult for me to understand what you are going on about.. Apologies!
Do not use 2200kV(kV is per volt rpm, so multiply it by the battery voltage to get the no load speed at full throttle). And please go through the thread titled "TUTORIAL - How to build Multirotor from scratch"
HINT: Use the "search" option

For that, Can i build my own Circuit board ? From where can i gt source to built my own Circuit board and How to interface Motor to Controller ? Can you give some more guidance for it then let me start to do work on it.

Dificicult to Control 2200KV ? Really ? how ?
Can you give me a Guidance for to ut GSm Module on my Quadcopter for unlimited range to control Quad Via SMS network. is it possible?

then my Modle will become 1300 gm + 500 gm = 1800gm . Is it Okay or not ?

Quote from: swapnil5775 on August 31, 2012, 11:08:15 PM
Via SMS network. is it possible?

You cannot expect to send a text to your quad reading "Flip mahnnnn!!" and expect it to flip.
If you are really interested and serious about this then you have to first read a lot. Get your basics right and then think about adding exotic control systems. If you just want this to be your college "project" and be done with it, then buy some RTF and modify.

We are hijacking this thread and should stop before we get told off by one of the moderators. If you have specific questions, create a separate thread and post there. I will be happy to help in whichever way I can.

hey!
you have mentioned a motor being "2204/14"
what do those numbers mean?

thanks!
aniket210696

http://www.rcindia.org/electric-power/electric-motor-sizes/ 

guys one thing you can do is use webocalc software.This software suggests motor-esc-battery combination based on input like span,wingarea and most importantly weight of the aircraft.

Hi everyone... just wanted to know what is the method of calculating motor specs

can i use my lipo(11.1v) in an rtf kit in which we were supposed to use 7.4v lipo..