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Beginners New to e-power flying? Get the low down in here from experienced e-power RC pilots!

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Old 07-20-2010, 04:19 AM   #1
DanWard
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Question 300 size, 370 size, 400 size, 450 size = what does it mean?

The new guy is shopping and I'm struggling because I do not understand what is meant when I see "300 size brushlss motors" or "450 series motors", or "400 size motors".

Search is not being my freind. Google has let me down.

So just exactly what are these vendors trying to tell me when they tell me it is of some particular size? 300 what? 400 what? 450 what?

Glow engine I knew what a 35 was. It was motor displacement. But in this electric stuff I don't have a clue.

And while I'm asking, are the vendors consitent in there definitions? Is one manufactores 300 motor the same as someone elses 300? Here again I'll refer to glow, a 35 was a 35 no matter if it was McCoy, Fox, etc. Yes there were differences among 35s, bearing type, sleeve, etc. But I knew what someone was saying when they said they had a 35.

Help?
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Old 07-20-2010, 04:53 AM   #2
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There is little consistency and the whole arena of electrics is confusing as hell. It takes months of reading to sort it out.
Dan, you are a man that seems to like information and details. I think you really need to read this:

EVERYTHING YOU WANTED TO KNOW
ABOUT ELECTRIC POWERED FLIGHT


You need to read the WHOLE thing.

To 'too briefly' answer your question this is referring to small brushed electric motors and trying to compare them to brushless. Even THOSE do not have consistent nomenclature (ie one manf. 370 is the same as another 400). Best to ignore all the drivel and useless information and concentrate on the watts you need to fly your particular plane. Watts is power, don't matter if brushed or brushless.
In the end the comparison is essentially futile and mostly confusing. It's about as good as using 'hands' to measure horses and elephants and then compare their work output.

fly
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Old 07-20-2010, 10:13 AM   #3
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Yes, in the good old days there were a few common sizes of brushed can-motors.
I believe the numbers originally referred to the length of the motor housing. If you had a car with a 400-motor, you could be reasonably sure that another 400-motor would be a good fit as well.

When they started making brushless motors, people were so used to the old motor-names, that they often declared a motor to be equivalent in power to an old 300, or 370, or 400 etc motor, even though the size could be different.

All in all it's just a throwback to 10-20 years ago. When you choose a brushless motor now, the two main stats are weight and KV.

The weight tells you about how much power the motor can use (watts), and the KV tells you the 'virtual gearing', i.e. how big a prop it can turn.

When comparing motors, if the weight and KV matches, they'll turn the same size props at about the same amp-draw.

To rein in my train of thought, instead of saying you have a 30 size glow engine, you might say that you have a 100gram, 2500KV motor, or an 800 watt motor turning a 6x5 prop running on 4S batteries, just as an example.

The first way would make it easier for people to find an equivalent motor, the second way says more about what it feels like to fly.
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Old 07-20-2010, 10:51 AM   #4
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You say you knew what a glow 35 means. Well to us old electric fliers it's the same thing. I know what a 400 or 540 motor means...it means roughly equivalent to the old 400/540 size brushed motors that we used for many years. But if you don't have that background it tells you very little, sorry.

As the others say it's best to ignore all motor names and descriptions like that and concentrate on the real specifications.

Steve
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Old 07-20-2010, 02:58 PM   #5
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Now I understand the 400, 370, etc size terminology is a legancy terminology with roots back in the "pre-Dan" history of electric flight and cars. That is something I can grasp and understand.

Yes I like to learn and know the details. Right now I'm in the very steep part of the learning curve with this hobby but as my knowledge grows my questions will taper off.

I work in the industrial automation field. In my experience few take the time to read, learn, and ask questions, "ahh Dan we just always did it this way" or "Dan the sales man said it would do ..." I've proved to myself that if I learn the details then I hold the power to make the right equipment selections and avoid the pitfalls.

Thanks for the link to the document. I'm old, you can bet it has been printed to paper and my highlighter is active as I read.

And on a final note Mesh wrote:

"The weight tells you about how much power the motor can use (watts), and the KV tells you the 'virtual gearing', i.e. how big a prop it can turn.

When comparing motors, if the weight and KV matches, they'll turn the same size props at about the same amp-draw."

I understand watts is power and efficiency determines what percentage of watts goes up in heat and what percentage turns the prop. But I had only begun to develop the notion in my own mind that there was a relationship between weight and watts. Mesh has now confirmed this for me and for that I am very appreciative.

Thanks for allowing me to participate in this group and learn from you all!
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Old 07-20-2010, 04:43 PM   #6
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Here is another way to look at it and why the 400 and others get confusing. Hobby partz lists several 400 size motors each has different kv's and winds. So now you have a 400 that puts out 148 watts, but with a different kv and winds it might put out more. They also list 400 size for heli's which is a much higher kv.
Flydiver gave you a great link to go and read. Here is a link to the different size motors not to confuse you ,but to give a visual and you can look at the different specs and what the motor produces for watts, and kv's. Hope this helps you out some everyone that posted gave great advive and insight I learned some history myself on motor size then and now.
http://www.hobbypartz.com/40simo.html
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Old 07-20-2010, 09:14 PM   #7
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Some rules of thumb from Lucien Miller-tech guru at Innovative Designs (Scorpion Motors)

Sizing The Components:
• Rough rule of thumb #1: 4-7 watts per ounce of aircraft weight will fly a trainer adequately. 10-15 watts per ounce will fly a 3D aerobatic plane, sport plane or scale warbird. 15-20 watts per ounce will fly a fast prop jet or flying wing. Speed/power freaks will naturally want more. Both low-speed thrust and high top speed require power. All else being equal, increasing speed requires more power than increasing thrust.
• Rough rule of thumb #2: a brushless motor can handle 80-100 watts per ounce of motor weight. High quality motors are at the high end and cheap motors are at the low end. Low speed, high-torque motors (700-950 Kv) are best suited to high-thrust low-speed or high-drag planes such as trainers, 3D aerobatic types and biplanes. High speed motors (1500-5000 Kv) are for ducted fans, prop jets, flying wings and similar types. Intermediate speed motors (950-1500 Kv) are for general sport planes, scale WWII fighters and the like. High speed motors and higher pitch props will draw more current than low speed motors and low pitch props.
• For most planes with brushless motors, the sweet spot in voltage is 8-12 volts. This is a 7-10 cell NiMH or a 3s LiPo battery. For small planes with moderate performance or if weight and cost are critical, a 2s LiPo or 6-cell NiMH is often enough. For bigger planes – larger than about 2-3 lbs - or very fast planes, more volts are called for.
• Brushed motors in general can’t handle as much power per ounce of motor weight. Not sure of their limit – maybe 50-70 watts/ounce?

I thought you might be someone that would actually read that. Good for you, too many don't even try to bother.

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Old 07-21-2010, 12:01 AM   #8
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Hi Dan and Welcome to Wattflyers There is no need to Struggle To make things a little easier when starting out with E Power, Look at Heads Up Rc page, Jeff has some motors for sale, and he gives some stats on his motors with prop selection, battery selection and ESC selection, he has taken the Guess work out of trying to set up a combo for a given plane, his specs are right on, and they wont exceed the motors limits, on amps and watts so you dont burn things up in a puff of smoke here are a few examples. Tell Jeff that Chellie sent you a lot of people here on Wattflyers buy from Jeff, he has been very very helpful, and I learned a lot from Jeffs motor specs when setting up my own planes, Hope that helps, Chellie

http://www.headsuprc.com/servlet/StoreFront


Power Up 400 Sport Outrunner Brushless Motor




The Power Up 400 Sport is a 1.8 ounce, 1050KV, 400 class outrunner brushless motor that works well on many small to medium size parkflyers. It will produce up to 30 ounces of thrust when using a 3 cell Lipo battery and the GWS 9050 prop. This motor includes an X mount and prop saver!

The Power Up400 is a good choice for models such as the GWS P-38, P-40, Me-109, 190, T-6, Spitfire, Corsair, Mustang, Zero, Formosa and Estarter. You might also consider this motor for planes like the popular Super Cub, Mini Super Sportster, Seawind, Sig Rascal, and many, many others. You can choose to have moderate performance and very light weight using a GWS EP8040prop and the Power Up 11.1v 1000 20C Lipo battery. If you're looking for high speed, try the GWS HD8060 prop and the Power Up 11.1v 1300 20C Lipo battery. And if you're after maximum thrust and a long flight time, the GWS EP9050 prop and Power Up 11.1v 1650 20C Lipo battery will give you excellent results.
I recommend using the Power Up 20 Amp ESC with the Power Up400 motor. All Power Up Electronic Speed Controls come with 3.5mm female connectors installed, and male connectors are included for your motor.
MOUNTING OPTIONS: The Power Up400 includes an X mount that makes it easy to mount the motor in front of a firewall. It also can be mounted on the front of a GWS Plastic Outrunner Mount, making it a drop-in fit for many planes with 10mm sticks. The picture below is for reference only. THE STICK MOUNT MUST BE PURCHASED SEPARATELY.

A 3.17mm Prop Saver is included for mounting props. A 3.17mm Prop Adapter is available in our store.
Propeller test data when using a 3-cell Lipo battery:
GWS EP9050:30 ounces of thrust at 15 amps.
GWS EP8040:24 ounces of thrust at 10 amps.
GWS 8040 3-blade:25 ounces of thrust at 12 amps.
TP 8 x 4E: 25 oz thrust at 12 amps.
GWS HD8060:23 ounces of thrust at 14 amps.
GWS EP7035:13 ounces of thrust at 5 amps.
TP 7 x 6E: 18 oz thrust at 10 amps.
The above data is a result of our own testing using a fully charged 3-cell 1800 20C Lipo battery. Thrust and amp draw may be less with the use of batteries rated at lower amp output, and slightly more using batteries rated for higher amp output.
Propeller test data when using a 2-cell Lipo battery:
GWS EP1060:21 ounces of thrust at 11 amps.
GWS EP9050:17 ounces of thrust at 8 amps.
The above data is a result of our own testing using a fully charged 2-cell 1800mah 20C Lipo battery. Thrust and amp draw may be less with the use of batteries rated at lower amp output, and slightly more using batteries rated for higher amp output.
Power Up 400 Sport Specifications:
Weight = 1.8 ounces (52 grams)
Diameter = 1.1 inch (28 mm)
Motor length = 1.1 inch (28 mm)
Shaft = 1/8 inch x 0.4 inch (3.17mm x 10 mm)
Voltage = 7.2 - 13.0
Current = maximum of 15 amps for 30 seconds
KV = 1050
Mounting holes are spaced 16mm and 19mm on center and are tapped for 3mm screws.
Please visit theHeads Up RC Brushless Motor Guidefor help in deciding whether this is the best motor for your plane.
************************************************** ****


3530-11 Outrunner Brushless Electric Motor



The 3530-11 is a 2.6 ounce, 480 class, 260 watt, 1100kv direct drive outrunner brushless motor capable of producing 40 oz of thrust from a 3-cell Lipo battery. It's an excellent choice for medium to large parkflyers and mid-size 3D planes and provides it's best performance with 10 inch props. I've been using the 3530-11 on two planes: the E-Flite Mini Edge, and a Simple Stik with a reinforced wing.
I use the GWS 1060 prop and the Power Up 11.1v 1500 30C Lipo battery on the Edge, and this combination provides unlimited vertical with plenty of speed, making the Mini Edge one of my favorite planes to fly. The 3530-11 gives the Edge 'over the top' performance!
For the Simple Stik, I use the TP 10x5E prop and the Power Up 11.1v 1800 20C Lipo battery. The Stik easily climbs straight up, and the speed is fast enough to provide for a nice roll rate and some fun aerobatics.
The popular E-Flite Mini Ultra Stick is very similar in size and weight to my Simple Stik, so the 3530-11 should be a perfect match for this model if you're looking for some really hot performance.
If you're interested in something unique, here is a link to a build thread on the Wattflyer RC Forum where the 3530-11 was used to power a very special model: STAR WARS Tie-Fighter Interceptor Build After reading, just hit the 'back' button on your browser to return the store.
The 3530-11weighs less than a 400 speed brushed/geared motor, and it can be used in many applications calling for a 400 to 600 brushed motor. Keep in mind that the 3530-11 is a 35mm (1.4") diameter motor, so you'll want to be sure you have room to mount it on your model. Should you need to use a 28mm diameter motor, take a look at the 2836-11 and see if that will do the trick for you. And if you need a brushless motor that is the same size and weight as the 3530-11, but uses smaller propellers and provides higher speeds, please check out the 3530-14.
I recommend using the Power Up 32A or 40A ESC with the 3530-11 motor.
The 3530-11 comes with 3.5mm male connectors installed, and female connectors and shrink tube are included.
MOUNTING OPTIONS: The 3530-11 can be mounted in front of a firewall using the 3500 series 'X' mount and the 3500 series rotor end prop adapter, which are included with the motor. You can also mount it behind a firewall, and a 4mm prop adapter can be purchased to mount a prop on the motor shaft. The picture below shows the motor without the 'X' mount and rotor end prop adapter attached.

Propeller test data for the 3530-11 using 3-cell Lipo batteries:

It's a good idea to balance all propellers with a Propeller Balancer before using them on this motor. TP propellers are available in our store, and are nearly identical in performance to APC props. Rotating propellers are dangerous. Please stay clear of prop and wear eye protection.
TP 10 x 5E: 39 oz thrust @ 23 amps
GWS DD1060: 40 oz thrust @ 22 amps
Power Up 10 x 6 folding: 35 oz thrust @ 18 amps

GWS 9050: 36 oz thrust @ 18 amps

GWS 9050x3 3-blade: 38 oz thrust @ 21 amps

TP 9 x 6E:
36 oz thrust @ 21 amps
APC 9 x 6E: 36 oz thrust @ 21 amps
GWS 9075: 32 oz thrust @ 25 amps

The above data is a result of my own testing using a fully charged 3-cell 2250mah 20C (45 amp) Lipo battery. Thrust and amp draw may be less with the use of batteries rated at lower amp output, and slightly more using batteries rated for higher amp output.
3530-11 Specifications:
Weight = 2.6 ounces (74 grams)
Diameter = 1.4 inch (35 mm)
Motor length = 1.2 inch (30 mm)
Shaft = 4 mm x 0.7 inch (18 mm)
Voltage = 7.2 - 13.0
Current = 25 amps or 260 watts maximum for 30 seconds.
KV = 1100
Mounting holes are spaced 19mm and 25mm on center and are tapped for 3mm screws

I may be getting Older, But I Refuse to grow Up I am Having to much Fun to Grow Up LOL
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Old 08-04-2010, 02:19 AM   #9
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As mentioned in the e-book link that was provided, the best way to compare electric motors is watts.

The best way to size electric motors to your airplane is watts/pound

Then you combine, battery voltage, motor kV and prop sizes to take those watts adn tune them to your airplane and the kind of performance you want.


This is very similar to my days of working on cars. We would talk about pouns/horse power. We would talk about tall rear gears vs short rear gears. We had close ratio vs. wide ratio gear boxes. We had high lift cams and valve overlap.

Every hobby/sport has its terms. And every power sport has its various ways of getting that power to do useful work.

You can make 4 cylinders be economical, or very high torque or very fast. It all depends on how you tune it and how you gear it.


And so it is with electric motors. Watts/pound is your starting point. Set that target, then you tune the rest.

Read the e-book and you will understand.

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