ramboman

Most of my a123 packs are now assembled as 6s2p like this...
One exception is my Super Reaper that will have
* either 12s nanotech 5Ah @ 1984gr (5+5+2)
* or 14s2p a123 4.6Ah @ 1960gr + connectors (6+6+2)
She gets Jeti telemetry to return pack usage and generate an alarm at 85%... time to land.

PS: another is a ring around the brushless to push CoG full forward.
Not to say: not removable...

JetPlaneFlyer

No flaming from me, I agree totally. I've not been very impressed by the durability of Nano's. They performed great when new but about 50 cycles later started to puff and are pretty much done now with less than 100 cycles. Even at the same price point i think there are better batteries out there, Gens-Ace being my current favorite. If price is no object the yes, Thunder Power must take the crown for 'the best LiPo'.

Steve

JetPlaneFlyer

I don't know enough about A123 fakes to argue this point, but i do know that lots of stuff gets 'ripped off' in China ever day and it can be all but impossible to spot fakes. You said 'I' was wrong but the statement was not mine, it came from the Hobbyking web site, I just quoted it. If you know the statement to be untrue take it up with Hobbyking.

Bottom line, at the end of the day, it is only toy planes and these are only batteries that make them go.. We are all free to use whatever we please.

Steve

mred

Well, to tell you the truth, I haven't used them enough to know how long they will last. I just bought the NanoTech batteries and have about 15 flights on them now and they are working fine. Can't say yet how they will do in the long run yet. May puff up, I don't know. I have Zippy batteries that have a lot of use on and they are still working fine. I have a couple other brands of batteries from China and they are all running good so far. A few of them, about 4 have been used for a long time and have over 500 flights on 2 of them. They were my first batteries and I kind of baby them. They are starting to look old and a little fatter then new, but not much and I am watching them for signs of going. Right now they are all charging good and the discharge is fine on all of them, so I guess they are still working right. I don't work my batteries very hard, so they should last longer. The rest of my batteries have less then 200 flights on them. The old ones are 2200MAh 3S 20c and they are working so far. I was really surprised they lasted this long to tell you the truth, but they just keep chugging away.

Ed

ramboman

Thanks for the info... I thought nanotech was a potential alternative to a123... but with a life expectancy of 50 cycles... 10 days of flying... forget them.
Life expectancy of a123 is 1000 cycles !

ramboman

Sorry for hurting you, Steve, that was not my intention...
Just sharing experience !

danauti1

I have spent hours reading here and my brain is hurting from all the knowledge lol...I have some ideas but, would like some opinions since this is new ground for me. I am switching a stick built Great Planes F14 to electric. I flew it with a Super Tigre 75...

Plain and simple...What motor and esc should I use to power this...It is 6-8 lbs but I am trying to lighten it best I can...

Thanks for any advice/tips/help in advance!!

mred

Well now, that is going to depend on what kind of flying and what price range you are looking at. A Scorpion motor is great and has sort of a high KV rating and can spin a smaller prop faster then most normal 60 type motors. A normal 60 type motor will run about the 300KV range and that means a bigger prop. The Scorpion motors run higher in price then most motors, but I have never heard anyone say anything bad about them. Your going to need around a 6 cell battery too, so that is a little higher in cost, but the ESC is pretty cheap if you get something like a Turnigy. Get a Castle ESC and you are talking quite a bit more money, but a very good ESC and worth it to a lot of people. I guess you need to tell us the budget you have for this and then maybe we can tell you about a good setup for that price range. Not everyone can afford to spend $300.00 for a setup like this and some can, but we don't know unless you give us a range for the budget.

Ed

kyleservicetech

What's the wingspan, wing area, and weight without motor/ESC/battery?

One of those programs such as www.motocalc.com will be of considerable assistance in your power selection.

Running about 8 pounds, a good performing model will work well at 150 watts per pound of airplane, so that would be around 1200 watts or so. A very large number of electric motors of that power range are available. Some good, some bad, some just crap. (The Scorpion motors have a good record)

IMHO, when power levels of 1000 watts or higher are involved, it's wise to use quality name brand motors and ESC's. I'm known for liking the Hacker motors, and a Hacker A50-16S motor with a 6S LiPo of around 4000-5000 Mah will work well. The Castle Creations ICE series of ESC's are also good, they also have the switching power supply uBEC's (Battery Elimination Circuit) The ICE ESC's also have the ability to record voltage/current/watts/RPM/temperature and a few other things during flight. You need the CC programmer to download this information.

I've got three A50 motors. One is the A50-16S motor which is installed in a Showtime 50, with a 7S2P A123 battery pack, and a 16X12 APC-E prop. That combination hauls the 8 pound model straight up, out of sight. (The 7S2P A123 pack is similar in power performance to a 6S 4200 Mah LiPo battery)

Other options would be a Hacker A50-12S motor running on a 5000 Mah 5 cell LiPo. This A50-12S setup will turn a 14X10 APC-E prop at about 8000 RPM, pulling 65 Amps and 1100 Watts out of a good quality 5 cell LiPo battery. (I've got two of these A50-12S motors. Flawless over 5 years of flying with them.)

Take a look:
Thread on 70 size glow engine conversion to electric
http://www.wattflyer.com/forums/showthread.php?t=45222

Hacker 6S2P A123 powered Models
http://www.wattflyer.com/forums/showthread.php?t=44686

The bottom line, a good quality electric power system, properly matched to the propeller size, and LiPo battery can easily match the model performance using a similar size glow engine. The glow engine can fly longer on a tank though. A good electric setup will fly about 6 minutes on a battery charge, with a few minutes reserve power.

ramboman

Different simulators, including motocalc, give very different results...
I have very good experience with Castle in various configurations:
* Torque 4014 with 6s2p a123 and 15*8 for .60
* Scorpion 5525/225 with 12s2p a123 and 18*12 for .160
* Hacker A60-6XS with 7s2p a123 and 19*10 for .110
I needed a smaller pack fo my TaylorCraft 20cc...

danauti1

Thanks for the quick responses...I have the specs here...

SPECIFICATIONS
Stock Number: GPMA0435
Wingspan: 58.25 in (1480 mm)
Fuselage Length: 51 in (1295 mm)
Wing Loading: 26-28 oz/ft² (79-85 g/dm²)
Wing Area: 628 in² (41 dm²)
Weight: 7-7.5 lb (3180-3400 g)
Requires: 2-stroke .60-.75 (10-12.5 cc) engine

It is on the heavier side but, I am trying to lighten it of course...

I plan on flying this fast so I would love to have all of or more power than needed to make it fly well...

I can spend $300.00 on the setup if needed but of course a less expensive setup is preferred...

I guess what I mean is I will spend the money necessary to have this thing powered well without worries...

AEAJR

Probalby worth posting this link again.

EVERYTHING YOU WANTED TO KNOW ABOUT ELECTRIC POWERED FLIGHT
A Free e-book on Wattflyer
http://www.wattflyer.com/forums/showthread.php?t=31368

mred

If you are after speed, then I would go for a Scorpion which is a higher KV motor. That would spin a prop faster and using the right prop I think you would get more speed. It will suffer in the climb a little but still give you a pretty good climb. A slower KV motor will turn a bigger prop slower, but give you a lot of thrust for climbing, but not quite the speed in level flight.

I would guess if you want a really good system, you are talking around the $300.00 to $400.00 range, but it will be a great system and will last. A cheaper motor like the ones from China may fly your plane OK, but no with the same speed and you are really taking a chance on those motors. Some go out on the first flight and some last, but they are throwaway items because of the cost.

A Thunder Power is probably the beast battery on the market, but they are costly. I have never heard of a customer that was not given top notch support and never heard anything bad about them and they really deliver the current.

Zippy batteries are probably the cheapest one you can buy and they are decent for the price, but cannot match TP batteries in terms of service and life. Cost is much less however.

I guess it is up to you to pick out what you can afford, but I would plan on at least $300.00 and up for a good system. Just remember the old saying, you get what you pay for.

Ed

danauti1

this seems to be what I have come up with.

.61

50-55-650

GPMG4745

SS-80

Not Needed

Large

8

11 x 8E

11,970

66.0

5 cell (2x3200

or

91

50-65-450

GPMG4770

SS-80

Not Needed

Large

8

16 x 6E

8160

43.0

5 cell (3200)

my only question is can I swing a smaller prop than the recommended if I go for the larger motor?? the plane can onlly handle about an 11 to 12 inch prop...

kyleservicetech

You've really got to watch the prop size with these electric motor power systems. These motors are pretty much constant RPM power plants, as compared to a glow engines constant torque type power plants.

So, taking an electric motor setup designed for say, 14X8 prop, and putting a 10X8 on it will REALLY kill power output.

Take the hacker A50-12S motor as an example, running on a 6S LiPo.

Motocalc suggests this motor running with a 10X8 prop will turn over at about 10,500 RPM, pulling about 22 Amps and 500 watts, with 60 ounces of thrust.

Upgrading to a more reasonable 14X8 Prop, that motor/battery will turn over about 9600 RPM, pulling about 66 Amps and 1400 watts, with about 180 ounces of thrust. What with what appears to be a reasonable propeller size change can have a very drastic change in power output, and along with that current input to your motor.

This is why so many wattflyers indicate that it is mandatory to pick up one of those wattmeters to measure what current/voltage/watts your power system is running, so as to not burn anything up. These motors are DUMB. They will happily turn over far to big of a propeller. Until the magic smoke comes out.

mred

Electric motors are normally rated for a range of current. Say it is 60A top. The rating will normally read something like 50 to 60 amps constant. 70A peak. When you put a smaller prop on it, then the current will drop down a lot and so will the power as in thrust. If a motor is rated for 600rpm per volt, then it will try to turn that no matter what kind of prop you put on. That's why the current changes with a prop change. It is trying to get to that 600rpm per volt. You notice I said trying. With a prop on it, it can't reach that rpm and the harder it tries the more current it draws. What you aim for is that area around 50 to 60 amps and that is the area the motor gives the best performance. Drop the prop size and sure the current goes down, but so does performance. When you drop down in diameter, you increase pitch to make up for it. You never go from a 14X6 to a 12X6 and expect it to fly good. You may need to go to a 12X12 or something. What you gain in forward speed you loose in vertical climb, but there are always tread-offs no matter what you do.

If you don't have a watt meter, get one. They are NOT something just nice to have. If you try changing props blind or changing anything really, you don't know what you are getting into and can either make a poor choice in operation and get a bad flying plane, or burn something up. The ESC and motor are rated for a given max voltage and current. If you are changing things blind, you don't know if you are safe or not without a watt meter. That is a must have item for anyone using electric power sources and I would say get one that will go to at least 100 amps if you are going to play with the big stuff. The currents may go as high as 100 amps on some motors and they can take it "IF" they are rated for that.

An ESC is rated for current and also voltage. Just because it says it can take 60 amps does not mean you can use it if you are using a 5S or 6S battery. It may only be rated for 4S, so make sure you get the right one. It will start popping like pop corn if you put a 4S ESC on a 6S battery. Needless to say it won't work very long. Also don't use a 100A ESC at 50 amps. You are not in the proper working range of the ESC and it will over heat cutting down on the life of it. Get a 60A instead. A little over size is fine, just don't go overboard. Also make sure you have good air flow through the inside of the plane so the motor, ESC, and battery get cooling air. With these higher amp ratings especially, they need that air flow to cool things off.

Ed

kyleservicetech

That says it all!

For those that need to measure very high currents, check out the Sears Craftman #82369 AC and DC clamp on ammeter. Not cheap at about $60, but it will measure up to 400 Amps DC. Should be enough to cover most models. To use one of these meters, just clamp its jaws around one of the battery leads. Doesn't need adaptors or anything.

Note that most clamp on ammeters are AC only, not useful for our models.

mred

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

You can go here and check out the watt meters. The go up to about $50.00 and depending on how fast you want one you can order from them if you are not in a hurry. It can take up to two weeks to get an order from them since they are in China.
http://www.hobbyking.com/hobbyking/s...Analyzer_.html
This one looks pretty good and I have been thinking of getting one. I have the Watts Up now, but it only goes to 60 amps. If you do order from these people, they are good to order from, but never put an item in your cart that is not in stock. Otherwise they whole order will sit there and wait until it comes in. I've been ordering from them for about 5 years and never got burned, but I guess there is always a first time. If you are looking for service out of them, you can pretty much forget it. I sent them three e-mails once and I'm still waiting for an answer. If you expect good service, order from a company in the states. Almost everyone has great service and you get the order faster and far less back orders.

Ed

danauti1

MrEd, you answered about the next 3 questions I had also clued me into not buying the 100a esc for the 60a motor I want to get lol...You also dumbed it down for someone who is totally new to electric...I appreciate all the feedback and have decided on a castle creation phoenix 70a esc and an eflite 60 brushless outrunner...still playing with the batteries...

mred

Great choice on the ESC, but I will never buy an eflight motor again, but that is personal with me. Nothing to do with the quality of the motor. There are a lot of good batteries out there and I think the best are Thunder Power, but again, that is personal. I am sure they have quality batteries just as good elsewhere. They are pricy though, but they are also good and they have great service. Good luck on your project and let us know how it all works out.

Ed

AEAJR

70 sould be plenty of headroom. Be sure to check all your battery/prop combinations to be surre you don't get too close to the 60 amp rating of the motor.

AEAJR

It has been some time since we updated this tread.

Components change, products change and the prices change. But I believe the principals that were the start of this discussion still apply.

Power to weight ratio
Understanding the relationship of battery, ESC, motor and prop

Whether it is a single engine electric plane, an electric launched glider or a quad copter, the principles do not change.


Would you agree?

ramboman

There are other factors like :
* life expectancy
* ease of use
* charge speed
* discharge capacity
* cost
* size
* form factor

For the same "6s" brushless, I may use :
* "common" LiPo
* MultiStar LiPo
* Graphene LiPo
* 7s2p a123
* 7s4p LiIo

There are "+" and "-" for each...

AEAJR

Good points, especially about the different LiPos. I only use the "common" type.

rixonm

Hi all , anyone with recommendation on what are the better brands - performance wise - of motors ??
Scorpion - Hyperion - Hacker - have not used them , but heard that they are at the upper end of quality / performance .
I am talking 2kW motors and up . Perhaps someone has had the time and money to go through several brands and have advice . Thanks !