Ok, before you guys tell me to go look through the forums and find the answers to my questions, I already have basically, I am just trying to make sure that how I am understanding everything is correct.

First off, I am looking for a brushless motor for my slow stick I have, I am not going to ask what motor you guys suggest for it, I am going to try and find a motor myself so I dont rely on others for everything and I can be more knowledgeable in this area of the hobby.
I get that the numbers like 2206 (fictional number , not from anywhere) is the size of the can or the size of the stator or shaft?

Secondly, the K/V rating is rpms per volt, and as I think I understand this, the lower the kv the more torque but slower the motor bigger prop is needed. which is better for a slow flyer. The higher the kv, the faster the motor but less torque so a smaller prop is needed but the motor will be better suited for a faster application.

Thirdly, Right now i have a 25a brushless speed control that I have had when I bought a helicopter a while ago and would like to use that esc to save a little money, its an align programable one. So my question is do I look for an esc that will match the max constain amp draw or the max burst draw of the motor or do I calculate what power I am using with what prop I will be applying to the airplane I choose to fly.

I am sorry for the begginer questions and I am sorry if this annoys anybody due to the frequency of this topic but try not to be to mean as I did do a lot of research but not everything I read is understandable from my standpoint and I could just use a little guidance. Thanks for reading.<br type="_moz" />

There is not set standard. Some company measure the can, others measure the stator. You need to look at the amperage, weight and wattage.

Sorta but not really. The lower Kv will not a bigger battery (more cells) to turn a higher RPM. You can have a 700 kv and 1400 kv motors turn the same rpm with a 6 cell and 3 cell battery. Your prop and battery size will determine the Kv you need.

Go 20% above the MAX Amp your motor will pull. It (ESC) will run cooler if its not being taxed out all the time.

Click link below..........

http://www.headsuprc.com/servlet/the...tor-%26/Detail

If you read through all of the posts, you probably saw this. But, I'll add to give you some additional information to work through.

This is a cut and paste from a previous post in this forum:

Read through the following and work it out.

Once done, you will know what wattage you are working with and what motor and esc to buy. Always go to the higher level when figuring out what motor and esc to buy.. if it works out to 17 amp ESC, go to a 20 amp ESC. Match the motor to the esc. If it doesn't match up with what you picked out, move to a motor/esc combination that does, get the weight (should not be that much difference) and work it out again and get the right one.

You should be fine.

Here are some guidelines:

1. Power can be measured in watts. For example: 1 horsepower = 746 watts

2. You determine watts by multiplying ‘volts’ times ‘amps’. Example: 10 volts x 10 amps = 100 watts

Volts x Amps = Watts

Therefore,

Amps = Watts / Volts ( / = divided by ). Simple elementary math.


3. You can determine the power requirements of a model based on the ‘Input Watts Per Pound’ guidelines found below, using the flying weight of the model (with battery):

50-70 watts per pound; Minimum level of power for decent performance, good for lightly loaded slow flyer and park flyer models
70-90 watts per pound; Trainer and slow flying scale models
90-110 watts per pound; Sport aerobatic and fast flying scale models
110-130 watts per pound; Advanced aerobatic and high-speed models
130-150 watts per pound; Lightly loaded 3D models and ducted fans
150-200+ watts per pound; Unlimited performance 3D and aerobatic models

4. Determine the Input Watts Per Pound required to achieve the desired level of performance:

Example:

Model: E-flite Brio 10 ARF
Estimated Flying Weight w/Battery: 2.1 lbs
Desired Level of Performance: 150-200+ watts per pound; Unlimited performance 3D and aerobatics
2.1 lbs x 150 watts per pound = 315 Input Watts of total power (minimum) required to achieve the desired performance

5. Determine a suitable motor based on the model’s power requirements. In this case, you will need a motor/esc/battery combination for 30 amps continuous... 3 cell LiPo at 11.1 volts (nominal) is 315/11.1=28.xxx amps, round out to the higher 30 amps.

So, get your paper and pencil out and work out the details. Let us know if we can help.

Ok, that was very helpful cgr and scooter and by the way happy Independence day to you guys and thanks for the help. Ill pos again if I run into anymore problems while looking for a motor. Oh and one last thing, wont putting a bigger esc on a motor make it work harder or does the motor work the esc. As you guys were saying put 20% bigger esc than what the motor is rated, wouldnt that work the motor 20% harder or am I getting this wrong?

Make life easy for your esc, they can be easily fried if kept working at max Amps.
It's all about temperature; hence, ventilate each component as much as possible.

The load that your prop and plane impose to the shaft of the motor determines how much Amps or current of electrons will go through the system, and how much temperature will rise up.

You may have read this:

http://www.rcuniverse.com/magazine/a...rticle_id=1344

"Hardware Amperage Limits - 10 amps, 25 amps, 35 ampsÂ…
Unfortunately, amperage limitations are not always black and white. Here's a list of considerations that determine the current an ESC can handle successfully:

There is a current above which the silicon inside the FETs or the metal legs or connections on the FET break down and fail. Damage from excessive amp draw takes place in an instant. Think of a fast acting fuse, except and ESC is not usually considered to be expendable. It is very hard to anticipate high currents and shut the controller down in time to prevent the current spike from damaging the controller.
Partial throttle operation generates more heat as does high PWM rates.
The amperage capability of an ESC is limited by the ability of the device to dissipate the heat generated by the resistance of the FETs and circuit boards. If a controller is making more heat than it can dissipate, a "runaway" condition occurs which can lead to thermal destruction of the controller - the solder holding the components to the boards literally melts and the parts are free to float away.
A great way to rate a controller is to determine its "steady state amperage." That is the maximum current it can carry at its rated voltage without experiencing further temperature rise. This can vary a bit as the temperature rise is dependent on the ambient air temperature and the amount of cooling airflow over the ESC. A dangerous way to rate a controller is to state its "surge" or "burst" capabilities. These are an indication that the controller may be able to handle higher currents for short periods, but these periods are sometimes shorter than the pilot would hope. This is another area where manufacturers can rate their products' based upon their own, often ridiculous, definition of a controller's duty cycle. Always read the fine print."

From what I understand, The ESC is rated to withstand a maximum current (amps). If the motor and servos draws a current of, lets say, 20 amps, than you'd be best to get an esc rated 25 or 30 amps. This way, you have a buffer, just in case there is any unforeseen spike in current draw.

Hypothetically, a 100 amp ESC is capable of running a electric setup that draws 1 amp up to 100 amps.

Please correct me if I am wrong folks!

~Noah
***Edit*** Words in bold replaced words to better suit what I was saying

see if I can help a little and I'll probably explain this wrong but, as you probably have already read, the C in ESC stands for control, you can look at electricity the same as the flow of water, the esc acts as a control valve, it just controls the flow of electricity, the motor doesn't pull electricity, it uses whats made available, as long as the esc allows enough electricity to flow to meet what the motor needs your ok, it's when the motor needs more than it can handle, the esc will limit or shut off the flow so no damage can occur

now if you understand that, then lets say your motor needs 20 amps to run and you have a 20 amp esc, where you'll run into problems is should the motor get an amp spike, meaning for some reason it needs more amps very quickly, which will usually be caused by the prop, and lets say it needs 2 more amps, your esc will probably burn up, but with the little extra amp rating on the esc you shouldn't have any problems and won't hurt anything. in other words, your motor makes your esc work not the esc makes the motor work

To add to what the others have said:
Typically when working with electrical or electronic circuits it is standard practice for engineers to size the components 25% larger than the power requirements.

As an example, you want a system that will produce a continuous output power of say 400 watts you want all of your components to be able to handle 500watts peak.
This will allow for some overpower spikes without damage to your system.

Ok, guys. Note the term "Beginners" in Beginners Forum. Let's keep the engineering out of this and keep things to the point where a "beginner" can understand.

CGr.

I am sorry if you feel the words "engineering practice" takes this out of context for a "beginner". But I have found that one of the least understood rules for sizing an electrical system is proper sizing of the components. If you want a system that is reliable and fairly resilient, sizing the components for nominal power requirements is a recipe for failure.
As he stated he is a "beginner" looking to " Understanding Electronics Better" I wanted to let him know one of the most fundamental rules of sizing electrical systems components that all beginners should know.

Its fine my father and grandfather were both engineers so the terms arent bothering me. But now you guys have me confused. If you guys said&lt;meta charset="utf-8"/><span style="font-family: Verdana, Arial; font-size: 13px; -webkit-border-horizontal-spacing: 1px; -webkit-border-vertical-spacing: 1px; ">you can look at electricity the same as the flow of water, the esc acts as a control valve, it just controls the flow of electricity, the motor doesn't pull electricity, it uses whats made available, </span><div><font size="2" face="Verdana, Arial"><span style="-webkit-border-horizontal-spacing: 1px; -webkit-border-vertical-spacing: 1px;">how can the motor draw more than what is available, I would assume that the motor just wouldnt work up to maximum performance and that the esc would just give all its got and the motor would just have to do. </span></font></div>

No. The motor WILL pull whats it needs. If it goes over what the ESC can handle, the ESC will burn up. You prop your motor to pull less amps than the motor and ESC can output.

So if you have a 50 amp motor and 60 amp ESC (20% over motor rating), you will want to prop the motor to pull LESS than 50 amp wide open with a fresh battery. I like to prop a motor at least 10% UNDER the motor rating.

Exactly what scooterinvegas says! That is the perfect way to set up a robust system you know isn't going to be prone to failure.

How it works is this: the prop is the load for the motor, the motor is a load to the ESC, the esc the load to the battery, which is your power source.


One other thing to watch out for are these two terms... Continuous and Burst or Peak ratings...
Always base you setup on the continuous ratings of the particular component is the safest way to size you components. While the peak or burst ratings is useful information for what type of short term abuse the system can tolerate, it not something you want to run any electrical setup at for more than a few seconds or risk letting the smoke out.

Ahh Iron Eagle that make sense. Thanks and I am sorry for the these somewhat stupid questions<div>
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No problem the only stupid question is the one not asked....

With electrical systems everything is about the load as far as power systems, once you understand that you see how it all fits together.

CGretired tables are perfect for how to size your system as far as the weight of the aircraft, and the math examples he showed are how you figure out what type of power level you are dealing with.

It is actually fairly simple. Many sellers have "max amps", Recommended prop size, and max battery size. IE 1, 2, 3, cells referring to lipo.
You have a 25 amp esc. You look for a 20 amp motor swinging a 9 or 10 inch slowfly prop and you will be perfect. If you figure for a 3 cell motor. as long as your esc can handle three cell you will fly for a long time and never have heat issues. especially if you throttle back.

Kv rating is rpms per volt.

if the motor gives max watts then watts/voltage(battery used 3 cell 11.1)=amps.

The hobby king website is really good about that so can you can make sound decisions on decent information. Plus you can get a pretty good price too.

To put what he said into perspective...

A twenty amp motor propped to draw twenty amps with a three cell li-pol (11.4 volt) battery is a 228 watt system. Using the above table that will power a one to two pound airplane depending on the level of performance you are looking for.
Keep in mind the weight you want to use is the figure your power requirements is that of both the airframe and power system (this includes the battery, ESC, motor and wiring).
(It all is kinda a vicious circle when you get into it.) To go back to the load concept the plane is the load for the prop and so on...

The Castle Creations website has a great power calculator application online that is a good resource as well.
Be advised: the phrase "Max Amps" typically refers to burst or peak power not the continuous rating; and this is were a lot of people get into problems with things cooking.

Right. And there wasn't one engineering term in his post. My point is that no one needs to know about the engineering factors involved in electric powered aircraft. It is interesting but not significantly applicable to trying to learn the basics of setting up an electric powered plane. Many don't have a clue as to what you are saying, and probably don't care.

But, I guess mkruse made my point for me in his post after yours.

Don't get me wrong on this.. we've gone through this several times in the past. Many beginners just don't want to hear all the engineering stuff. All they want the basic answer. And, as I said, if they want to know the more involved information, they will surel ask.

CGr.

CGR, what if I wanted to know the engineering factors involved in electric powered aircraft. [8D]

Well, simply asking for that information would suffice. I know that someone, including me, would provide that to you. The point here is to try to keep things simple. We do get a lot of youngsters that don't have a clue about such things, and it just goes to make something that could be somewhat complicated, almost impossible to comprehend.

I don't object to being technical when technical is called for. In your case, you asked a simple question about understanding electronics, but what I read from your request is what do I do on an electric powered plane to get what I need to fly it, which is a frequently asked question that normally calls to start with a simple answer with information that you can easily use, ie. weight the plane with everything taken into consideration, apply the "rules" then go out and buy what you need.

The sample I gave early in this thread was the Brio 10 electric pattern plane. But, suppose you have a plane like a Sig Little Something Extra, which was designed to be a glow powered plane but want to fly it with electric power.

Well, that would involve getting the weight of the plane, decide how you want to fly it (trainer, pattern, 3D, and so on), see what wattage you need, let's say you want to use a 3 cell LiPo.. that's 11.1 volts (nominal) so that part of the watts determination ( Watts = Volts X Amps) is a no-brainer.

Next, you would take the watts you need for, say Sport flying, mild aerobatics. That's 90 to 110 watts. So, at 110 watts, 11.1. volts, you will need an ESC that can supply 10 amps of current ( I would go higher, say to 12 amps) per pound of aircraft. If it weighs in at 2.2 pounds (everything considered) you would need a 25 amp ESC (going slightly higher than the numbers actually show for a little safety margin). Because you don't know what motor you will use to get the weight, well, you have to do a little research on the internet to see what motors will work with the wattage you are going to consume and go with that weight. Add everything.. servos, ESC, airframe, candidate ESC and motor, and the battery pack.

No where in that was there anything technical, unless you would consider Watts = Volts X Amps technical.

That does not mean that we can't get technical, because we certainly can. But it simply means that the simple answer to your original question was simple. If you want more, then it is definitely available.

As I said, I've seen many posts that come in with information that is just plain mind boggling when It does not have to be, and this is what can push someone away from the hobby. That's all I"m saying.

Again, if you want technical......

CGr.

Being an engineer sometimes it's hard to describe things in a non-technical way, you tend to forget that what to you is basic to others is magic...

Well, I'm a EE. But, I was also an instructor at a technical school for Electronics. So, teaching basics comes easy to me .

CGr.

See CG that helped me understand things a ton better when I see formulas and other mathematical figures to find out what I need, that is what I can understand. Thanks for trying to keep things simple but I am capable of understanding these mind boggling magical numbers and calculations to get  what size motor I need. Thanks

This question comes up so often that I've copied and pasted it into a word document so I can copy and paste to the replies. Some fine folks have suggested I make it a "sticky". But we try to minimize cluttering up the forums with stickys.

The general "formula" or method of determining the "BASIC" motor and ESC combination is just that.. basic. Of course, there are improvements that can be made with handling characteristics by changing some of the components. Always try to make them lighter, though, is a general rule of thumb that always applies to electric power. It also applies to glow power, but is not quite as critical.

Generally, glow power is much easier to work out than electric power.

CGr.