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Old Oct 13, 2013, 11:32 AM
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Ken Myers's Avatar
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Did anyone happen to notice the motor on the previous URL is an XYH?
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Old Oct 13, 2013, 12:21 PM
RC Warjet
United States, CA, Jamul
Joined Mar 2013
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Is that good or bad?
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Old Oct 13, 2013, 02:02 PM
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Ken Myers's Avatar
Commerce Township, MI
Joined Aug 2001
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Neither. Just an observation. XYH are an original equipment manufacturer (OEM) in China for many suppliers, including many of the Heads Up Hobby motors. They used to supply the Motors that United Hobby (AKA Hobby City and Hobby King) called HXT and later named Turnigy. They are still marketed worldwide as EMP.
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Old Oct 13, 2013, 02:13 PM
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LVsoaring's Avatar
United States, OK, Moore
Joined Jan 2006
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One question that's been nagging at me.... should be obvious, but it's not, and frankly, I have not done my own research yet to find the answer....yes, sometimes I'm lazy! Anyway, the question is this.... battery packs are different voltages depending on number of cells.... so, does the ESC automatically regulate the voltage to the Rx to 4.8 - 6.0, regardless of the battery pack voltage? Or does the ESC have to be matched to the battery voltage? IOW, if I ran one battery pack and decided I didn't like it, and changed it for one of a different voltage, would I have to change the ESC also?
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Old Oct 13, 2013, 02:41 PM
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Kimber's Avatar
USA
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The esc knows what battery you have and takes care of it.

The esc's are rated for 2 to 4 or more, it is on the esc most
of the time.

If you go above 4s you may need a separate battery for the
rec. As the cell count goes up the esc has to work harded
to bring the voltage down to 5v for the rec.
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Old Oct 13, 2013, 03:02 PM
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scirocco's Avatar
Australia, ACT, Kambah
Joined Feb 2001
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Quote:
Originally Posted by LVsoaring View Post
One question that's been nagging at me.... should be obvious, but it's not, and frankly, I have not done my own research yet to find the answer....yes, sometimes I'm lazy! Anyway, the question is this.... battery packs are different voltages depending on number of cells.... so, does the ESC automatically regulate the voltage to the Rx to 4.8 - 6.0, regardless of the battery pack voltage? Or does the ESC have to be matched to the battery voltage? IOW, if I ran one battery pack and decided I didn't like it, and changed it for one of a different voltage, would I have to change the ESC also?
In the sort of ESC you refer to, there are 2 components - the motor speed control, ie the main ESC bit, and then the battery eliminator circuit, or BEC, which taps off power from the flight pack and regulates it down to the 5-6 V the Rx needs, providing power to the Rx through the throttle port on the Rx. As all the earth and power pins on the Rx are on common buses, the Rx doesn't care which port it gets its power from.

There are 2 types of BEC - linear and switching. Linear BECS are less efficient, usually limited to 3S, sometimes 4S input, and as Kimber said, as flight pack volts go up, BEC servo capacity goes down. Linear BECS are more efficient and are available up to at least 6S input, and servo capacity doesn't depend on input power.

An ESC that will keep you out of trouble for the Skylane is the Turnigy Plush 60 / Hobbywing Pentium 60. 2 to 6S capable, built in switching BEC that will happily cope with 5 standard analog or digital servos, and not expensive.
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Old Oct 13, 2013, 03:03 PM
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United States, ID, Shelley
Joined Dec 2011
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Quote:
Originally Posted by Kimber View Post
The esc knows what battery you have and takes care of it.
Some of the older & smaller ESC's had to be programmed for the # of cells, but most of the ones I've used or seen lately "auto-detect" the voltage each time it's plugged in and provide the appropriate number of beeps to signal the user.

Nice to see the prop data from Hobby People, or whomever the info is coming from. Having some watts, amps & thrust testing data is much better than simply having a recommended prop size.

Still wish each prop manufacturer would provide some type of table to show thrust and speed figures for each prop, based on a RPM. Seems simple, which means it probably isn't.
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Old Oct 13, 2013, 03:28 PM
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Headsup has prop, amp, thrust data for most of their motors. It is just a guide but
helps.
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Old Oct 13, 2013, 06:48 PM
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Thanks again for all the tidbits of info. Sooner or later it will all sink in. I did say something about a steep learning curve..... and it sure is!

In other news, by pure luck, I happened upon a NIB Great Planes Super Sportster 90/120 kit on flea-bay, and I had the winning bid. The wheels are already turning in my head for electrifying this one!
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Old Oct 14, 2013, 04:27 AM
You laugh... But it flies!!!
TEAJR66's Avatar
United States, MO, Rocky Mt
Joined Oct 2013
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LV,

I am new to electric power also. I am using it to get back into RC after about a 25 year break (simply amazed at what is possible now a days with the power systems, construction methods, and construction materials). Started with an AR Drone and a little coaxial helicopter. Took me rite back around to wanting to put an Eagle 2 or a Butterfly back up in the air.

I have decided to play with some scratch built foamies for a while as the power systems are relatively cheap and I can play with combinations to get the feel for the raw data that calculates well on paper and online. Once I have experience and have a few good working set ups, I might look at doing one of the previous models in an electric version.

All that being said, here is something that might help. You can look at most sites that sell power systems and certain motors were made with us old glow pilots in mind (granted we did not do half the calcs for selecting power systems as we do for electric now. most of us bought a model we liked, followed the recommendation for motor sizes i.e .15-.25, then went hot or mild in that size range. Then pops were a matter of the models recommendation also. More experienced fliers tweaked prop and motor combos on the models they liked). Sites like this offer direct conversion motors. For instance on this site

http://www.e-fliterc.com/PowerSystem...Brushless.aspx

you will see that they offer motors based on the size glow engine that you might have selected. Not recommending a manufacturer here, just using an example. There are other companies that do the same thing. Some do not. If you felt so inclined, you could use the specs from one of the motors on this type of site to compare the specs for motors on sites that do not have a direct conversion correlation.

As far as ESC's, they are made by AMP Draw (BEC's aside). Your motor will draw a range of amps (listed in the specs), make sure your ESC can handle those amps. The downside to oversizing the ESC is weight penalty. No power system troubles for a larger ESC just weight. In most cases we are only talking a couple grams and most of us are willing to pay the weight penalty to prevent our motors from drawing too many amps through the ESC and burning the ESC. A lot of guys on these forums recommend about 10% over on the ESC to be safe. I guess much more would be overkill. The BEC powers the receiver by shaving off some power from the flight battery. You can do some research to see if BEC's are important to you. And if BEC is how you want to go, figure out which type suits your needs (not much experience in this area to recommend specifically). Some people, as stated above, use separate power packs for their receivers (weight penalty/flight time correlations there with which I don't have enough experience, again).

The motor will also recommend which battery to use based on its voltage requirements (maybe tolerances would be a better word). That battery range will be related to prop size. Again, not making a recommendation, just using an example.

http://www.hobbyking.com/hobbyking/s...ess_Motor.html

This motor has a battery range and a prop range. The battery/props are in correlation. Bigger prop, lower voltage battery. Smaller prop more voltage. I believe this is because of the nature of these motors. If you feed it, it will eat. These motors are going to try to spin at a certain RPM for every volt you put into them. The bigger prop is harder to turn so the resistance is higher. More resistance in electricity equals more heat. Higher voltage/bigger prop equals more resistance as it tries to reach its RPM for the voltage. The materials that the motors are made form have temperature tolerances, Like any other motor, overheating is a bad thing. Therefore, increase the volts, reduce prop size, get higher RPM's. Still getting all this figured out myself so I am not much help there.

As experienced glow fliers, we know that different props within a motors prop range provide different flight characteristic. Those correlations should apply to flight properties in electric as well.

Ok, sorry for the ramble. There is my two cents worth, from a fellow newbie. Any of you experienced guys feel free point out where my thinking is flawed. I can use any advice also.

Be safe.
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Old Oct 14, 2013, 06:51 AM
You laugh... But it flies!!!
TEAJR66's Avatar
United States, MO, Rocky Mt
Joined Oct 2013
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Kimber,

I saw in another thread that you had a butterfly. Did you go electric? If so, what prop, motor, ESC, battery combo did you use? What are your flight times? I loved this plane when I was a new flyer. I want to do another one in electric. Would love to hear about your trials and tribulations.

Be safe and have fun.
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Old Oct 14, 2013, 08:10 AM
Balsa Flies Better!
Stamford, CT
Joined Oct 2000
6,704 Posts
For all you newbies- the one critical tool in e-flight is a wattmeter. Highly recommended!

Also note- mfgs have got a challenge with batteries- there's a pretty broad range of voltages that lipoly cells can deliver- older packs struggled to hit 3.3V per cell- newer packs seem to be pushing 3.8V per cell under load. Mfgs who were conservative often wound up going out of business so now there's more tendency to be "optimistic" with ratings and performance.

While it's easy to match glow engine and electrics these days- all too often, the glow engine wasn't really well matched to the airframe- like in a Butterfly! A buddy had that airplane- a screaming .15 did not belong on the snoot! Given prop clearance- don't think you can swing more than a 9". Probably needs around 25-300 watts to have a very nice climb.

Sam
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Old Oct 14, 2013, 10:27 AM
You laugh... But it flies!!!
TEAJR66's Avatar
United States, MO, Rocky Mt
Joined Oct 2013
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Megowcoupe,

I understand the need for the wattmeter. I will accumulate all the tools as I go. Jewelers scale being another, just so that I can tell people the AUW as I post builds and get an accurate weight for components as they vary from manufacturers specs. You can tell I am hitting this thing unprepared as I am going electric with a boat load of parts inbound and I don't even own a soldering iron. No worries, it will all get sorted.

As for the Butterfly, I had an O.S. Max .15 on mine and I pulled the wings off on more than one occasion. But it was cool to see the looks on the "old Guys" faces around the GCRCC when I go that thing inverted. And, with an 8 Oz. tank over the recommended 4 Oz., I could fly under power longer than I had receiver pack life. Good times!

Either way, thanks for the input.

Be safe and have fun.
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Old Oct 15, 2013, 03:04 PM
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United States, OR, Salem
Joined Jan 2012
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I've always cheated and gone over to headsuprc and used their tests as a guide. I say guide because I usually need to go up in prop size to get the amps that are in their charts. I've done this for at least 25 planes and have had great success.

One thing to remember when looking at motor size is that different motor mfg use different measurements in the number designation for their motors. Like an Emax GT 4020 (stator size) could be an 5050 (can dimensions) on some sites like HK.
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Old Oct 15, 2013, 03:56 PM
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Kimber's Avatar
USA
Joined Mar 2005
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Quote:
Originally Posted by LawnDartMike View Post
I've always cheated and gone over to headsuprc and used their tests as a guide. I say guide because I usually need to go up in prop size to get the amps that are in their charts. I've done this for at least 25 planes and have had great success.

One thing to remember when looking at motor size is that different motor mfg use different measurements in the number designation for their motors. Like an Emax GT 4020 (stator size) could be an 5050 (can dimensions) on some sites like HK.

As I mentioned earlier, HU is never very far off. Most of the time a bit conservative with the amp numbers. And you can always drop them a Email and get more
info quick.
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