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Old Sep 01, 2011, 05:03 AM
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Originally Posted by RuthlessINXS View Post
it sounds as though the only way to determine the the actual amp draw of a particular power system is to physically use all of those components and take measurements or find someone who already has; is this the case?
Many better motor MFG will provide test data that tells you what the motor will draw based on voltage and prop combos.

www.maxxprod.com is one example. They provide excellent documentation.

for more depth on the topic:

EVERYTHING YOU WANTED TO KNOW ABOUT ELECTRIC FLIGHT
http://www.wattflyer.com/forums/showthread.php?t=31071
http://www.rcuniverse.com/forum/m_7100376/tm.htm
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Old Sep 01, 2011, 08:11 AM
Obsessive Information Sponge
Joined Apr 2011
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Originally Posted by aeajr View Post
Many better motor MFG will provide test data that tells you what the motor will draw based on voltage and prop combos.

www.maxxprod.com is one example. They provide excellent documentation.

for more depth on the topic:

EVERYTHING YOU WANTED TO KNOW ABOUT ELECTRIC FLIGHT
http://www.wattflyer.com/forums/showthread.php?t=31071
http://www.rcuniverse.com/forum/m_7100376/tm.htm
I tried contacting Extreme Flight a week ago about getting the information for the 4016T-500 to plug into MotoCalc (no-load current, resistance). The response I was given was as follows:

"Honestly we do not have that information.
We do know the motor is a 1250 or more watt motor and pulls our 60" airframes around with plenty of power to spare."

That statement seems awry to me but nothing to be done about it. So I'm left with buying the power system and taking my own measurements.
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Old Sep 03, 2011, 09:27 AM
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Here is a question, it may have been covered in some of the 200+ pages sorry if I missed it.

Why dont servo specs indicate their current draw?

Yes I understand they vary wildly and constantly but some basic info would be helpful for guestimating.

Typically mfgrs. will indicate the servo speed / torque at a certain voltage(s). However current draw is not indicated.

Similar to real life electric motors the following info would be usefull.

Locked rotor current - (current drawn if the servo was 'locked' into position) worst case.

Running current draw - (even if it is an 'unloaded' servo it gives a rough idea)

Idle current - (probably negligable but still usefull info.)

With those tidbits of data an educated guess as to the servos demands could be made.
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Old Sep 16, 2011, 05:46 PM
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My son just got a project to design, build & fly a RC Airplane with a max 20AMP motor. Doesn't appear to be any other limitations. How would affect a plane if you added a prop reduction to it? A bigger prop, more pitch sounds good but we have vast knowledge with gas & glow engines but are "electric virgins" so we need some help. Any motor manufacturer that I really look at (or stay away from)? Last question for now in-runner or out-runner: or does it really matter?
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Old Oct 02, 2011, 09:38 PM
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Originally Posted by Tomcat_104 View Post
My son just got a project to design, build & fly a RC Airplane with a max 20AMP motor. Doesn't appear to be any other limitations. How would affect a plane if you added a prop reduction to it? A bigger prop, more pitch sounds good but we have vast knowledge with gas & glow engines but are "electric virgins" so we need some help. Any motor manufacturer that I really look at (or stay away from)? Last question for now in-runner or out-runner: or does it really matter?
Not sure if this will help but its a cheap, easy to build plane that might fit the bill...it flies great too. I built one and have over 150 flights on it.
http://www.rcgroups.com/forums/showthread.php?t=354237

I pesonaly use this setup:
Motor
http://www.hobbyking.com/hobbyking/s...or_1500kv.html
ESC
http://www.hobbyking.com/hobbyking/s...idProduct=2161
Battery
http://www.hobbyking.com/hobbyking/s...idProduct=7305
Prop
http://www.hobbyking.com/hobbyking/s...dProduct=10054
Speed Prop
http://www.hobbyking.com/hobbyking/s...dProduct=10059
I tried a APC10x10 prop and tore the wings clean off it way too fast!
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Old Oct 23, 2011, 10:04 PM
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I am a 60 something that flew a lot of R/C back in the days of glow engines.
I'm finding the conversion to electric extremely difficult. Is there somewhere I can go to find a real basic overview of "power systems" without a flood of acromyms, that would include something about motor ratings that don't go into Ohm's Law? Wonderful would be a chart that showed what electric system is comparable to the old glow motors, if such a thing exists.
I am totally lost!
Thanks!
Dave
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Old Jan 19, 2012, 06:58 PM
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Quote:
Originally Posted by delta2ul View Post
I am a 60 something that flew a lot of R/C back in the days of glow engines.
I'm finding the conversion to electric extremely difficult. Is there somewhere I can go to find a real basic overview of "power systems" without a flood of acromyms, that would include something about motor ratings that don't go into Ohm's Law? Wonderful would be a chart that showed what electric system is comparable to the old glow motors, if such a thing exists.
I am totally lost!
Thanks!
Dave
I started into electrics about 10 months ago after flying RC for 40 years and I can relate to what you are saying. It IS a whole new spectrum of terminology.

In the past 10 months, I've spent countless hours learning the fine minutia of SOME of this stuff (but not all). Needless to say, you can learn all of it.

Wading thru the swamp of info can drown someone!

Just as a quick starting place, look here at the G series of motors. These are quite "middle of the road" for performance and represent reasonable "value" (people confuse quality and value often).
http://www.hobbyking.com/hobbyking/s...EasyMatch.html

Assume that a G-32 replaces a .32 glow motor, etcetera.

You'll notice that each G-32 has 2 or 3 sub-sizes based upon a number called Kv. For now, ignore that number and pick a number in the middle of the Kv's offered.

There are other factors to consider but just start somewhere.
Contact me thru the PM or email settings and I'll do what I can to answer as much as possible.
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Old Mar 16, 2012, 10:34 PM
China, Guangdong, Shenzhen
Joined Nov 2010
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Reasons for flying RC airplanes. Answer = many.
However, some answers seem to be poorly represented here. There seems to be a pervasive attitude of the more power the better. Maybe this is why the selection of NiMH batteries for RC has declined as of late - everybody is going to LiPo. Some people don't fly RC airplanes because they have a lot of extra money and want to spend it on something. There is a place for the less expensive, albeit lower performance, power systems.
A related subject: What is flying? A model with > 250 watts / kg doesn't have to fly in the same sense that a Cessna 150 has to fly. The pilot of a Cessna 150 must be acutely aware that they are flying the WING or they are going to cease being a pilot, and become a smoking hole in the ground. If an RC pilot really wants to learn how to fly they should NOT start with a plane for which the drag bucket is a fiction as long as the throttle works. I have seen videos of model planes flying around at a ridiculous AoA and the pilot is congratulating themselves on their plane and piloting skills - the wing isn't functioning as anything but a place to hang control surfaces!
To each their own, but I submit that if you really want to learn how to fly, then choose a plane that is not able to maintain an angle of climb (not AoA) of much more than 10 degrees. Maybe you will save some money too )
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Old Mar 16, 2012, 11:38 PM
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Huh?
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Old Mar 17, 2012, 12:52 AM
Fly it low.. and fly it fast!
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Originally Posted by Turner2 View Post
Huh?
I think the main point he's making is.... A lot of people throw together an airplane and electronics "package" that makes the plane overpowered and thus you rely on the "motor" to get you out of an "ooops", rather than having a plane that is much more like a "scale" aircraft, where you MUST rely on the actual flight characteristics of the plane itself to get out of an "oops".

I see his point, and pretty much agree with what he's saying. Because honestly, we all have to admit, it's a lot easier to put together a power package on a piper cub for example, that gives it enough power to hover if you wanted to, even though that's considered way overpowered when you think about it in a "scale power" manor. I know i'm guilty of doing that on more than a few of my models, BUT, I also build many of my models quite scale in performance. So you HAVE to use the aerodynamics of the plane to fly it, and not just rely on the power that the motor has, to get you out of a jam if you screw up or the wind gets one over on you, etc, etc.

It definitely helps you to become a better pilot by flying the plane, and not the motor. A person flying a plane just above stalling speed, and maintaining good flight characteristics, has more skill than a pilot who can only fly at full throttle most of the time and just zip around the flying field. (granted, that last comment leaves a lot to argue over)

But with that said, I still like to build the majority of my planes with a happy medium of power AND scale habits in mind. It's always nice to have a little "nitrous under the hood" when you want to play, yet fly respectfully and scale-like as well. Doing that, still gives you the best of both worlds. And you're still learning to not always rely on the motor to get you out of a bad situation. I actually make it a habit to try to maneuver out of "mistake" rather than muscle out of it with full throttle. I try to use full throttle only for the sake of "top speed". I find it has made me a better pilot for flying this way.

But everyone has there own style......
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Old Mar 17, 2012, 01:09 AM
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Thanks Hit N Run! Excellent clarification )
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Old Mar 17, 2012, 07:39 AM
drjazzneedstofly
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Joined Oct 2010
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Hello Chris,many thanks for putting together in one place many answers we noobies need to learn.I realise its almost impossible to include everything ones needs top know when starting from scratch(my head)setting out to fly electric power.I have no one localy i can get advice from so I'm learning from RC Groups,which is a mine of free info and many interesting articles etc.I used to fly basic RCmodels like DBs Tyro with IC motors.Now I'm back and have nearly finished building an elarged to 36" Vic Smeeds lovely 'Coquette'from the 50s Aeromodeller.I found a nice 2300kv outrunner at a garage sale last year,and I've bought 2 x 1500mh 25c 7.4 lipos off the web.and an 30a esc.and a new IMAX B6 Balance/charger.I will be using 3x 9g servos,rudder-elevator-motor.with mnh receiver battery pack.A couple questions spring to mind if anyone will help me?will this setup be suitable,or is the motor too powerful?And as non of the wires have any connectors which is the best to go for...Deane or gold bullett?and best size.3.5 4 or 5?I can cope with the soldering them on ok.Obviously on this plane/setup I'm not looking for fantastic speed or aerobatics.just poodling around the park/field and getting my two 12 to learn..theyre certainly keen to get going.Many thanks guys.I'l keep in touch.Derek.Somerset.UK.
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Old Mar 17, 2012, 07:41 AM
drjazzneedstofly
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My two 12 year old grandsons want to learn.....continued from 1st post about going electric...
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Old Mar 17, 2012, 09:04 AM
Fly it low.. and fly it fast!
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United States, MA, Westport
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Quote:
Originally Posted by Mitchell Covell View Post
Thanks Hit N Run! Excellent clarification )
Hey, no problem!
I'm always happy to help whenever I can.
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Old Apr 26, 2012, 06:21 PM
I don't do Normal
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Little Wright up I did as a nitro to electric comparison with other info
http://www.rcgroups.com/forums/showthread.php?t=1640938
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