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PostPosted: Mon Jan 03, 2011 8:24 am 
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I thought I would pass this on for anyone looking for batteries:

http://hicountryhobbies.com/index.php?m ... Path=53_58

These are 50C batteries sold by a us vendor with quality control, warranty, and crash protection program at very good prices. According to testing done by Charles on rcgroups they hold up as well as the thunder power packs without the cost.

Right now they have an extra 10% off until the 8th which makes a 3s2250 battery $29.

So if your looking for a budget electric power system for a 40 size airplane you could go this route:

Battery (4s4300) $75
http://hicountryhobbies.com/index.php?m ... cts_id=120

Motor (Hobby People motor) $40
http://www.hobbypeople.net/index.php/en ... dware.html

Speed control (Castle creations ice 75) $115

That will do around 900 watts and will weigh around 29oz and cost $230.

That puts it at $50 more than an OS 46ax, and servo, and a gallon of fuel. Weight wise it's 2.5oz heavier than the glow setup.

Basically, the electric will perform just as well if not better than glow, but it still costs more and is a little heavier, assuming you have a charger and your not going to go through 3 gallons of fuel.

schu


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PostPosted: Mon Jan 03, 2011 11:55 pm 
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...but does it come with that cool putt-putt or ying-ding sound??? What about the great smell of nitro and castor oil?? and don't forget about the free "lube" on all the control surfaces down wind from the exhaust pipe :wink:


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PostPosted: Tue Jan 04, 2011 7:30 am 
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Schu, I picked up that same motor with a 40amp ESC and 4cell 25c.....

I am looking to power the 98" reaper from nitro planes....

Question..
To much for the plane?

To little?

Not a big enough ESC?

Let me know thanks..
Britt

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PostPosted: Tue Jan 04, 2011 8:42 am 
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Britt,

No that ESC is nowhere close to big enough. In order to make the same power as a 46 engine you need 900 watts. If you take 900 / 14.8v = 61 amps. I would get at least a 75 amp esc.

Also, keep in mind you need a fairly large battery. The one I put in the link is 4300mah. If you run that at 15c you get 64.5 amps (4.3 x 15.)

Flight times will probably be around 8-9 minutes.

I have the motor on a trainer with a 75amp esc and a 14x7 prop and it's right at 900watts and runs the trainer around every bit as well as the glow engine did.


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PostPosted: Tue Jan 04, 2011 8:58 am 
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Gary,

I do miss the putt putt sound, but I don't miss the mess or the tuning. Now I get perfect idle and transition every time regardless of how the motor and battery are mounted :)


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PostPosted: Tue Jan 04, 2011 9:06 am 
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I forgot about the RX battery. The electric doesn't need one, you can swap in a new flight back every 10 minutes and fly all day long without thinking about the RX battery.

This also means that the $50 cost difference is cut down by whatever you spend on a RX pack and the electric is now lighter since any decent battery will be well over 3oz.

All that said, 40 size glow isn't for everyone, the batteries are expensive and dangerous, but if someone wants to try the electrics out, here is a good deal to get started:

http://www.adchobbystore.com/in-stockspecials.htm

For $175 you get the airplane with a hacker motor and esc. The servos are cheap at $20 each, and the batteries should be under $20.

This setup has pretty modest charger requirements so you wouldn't need to spend more than $60 on a charger.

schu


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PostPosted: Tue Jan 04, 2011 11:00 am 
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schu wrote:
I forgot about the RX battery. The electric doesn't need one, you can swap in a new flight back every 10 minutes and fly all day long without thinking about the RX battery.

This also means that the $50 cost difference is cut down by whatever you spend on a RX pack and the electric is now lighter since any decent battery will be well over 3oz....


Wait a minute Schu ... truth is you will be thinking about the (RX and motor) battery constantly to make sure you don't over discharge and damage it and your not going to fly "all day long" on this setup with only one battery. Won't you need to add at least one or two more (+$75 to $150) so that you can safely charge as you fly?


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PostPosted: Tue Jan 04, 2011 11:28 am 
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Gary23 wrote:
Wait a minute Schu ... truth is you will be thinking about the (RX and motor) battery constantly to make sure you don't over discharge and damage it and your not going to fly "all day long" on this setup with only one battery. Won't you need to add at least one or two more (+$75 to $150) so that you can safely charge as you fly?


Yes, your going to be thinking about the battery, but your probably not going to loose a model to running the RX battery dead because the radio is the last thing to go out. My point was that you only need to think about the main battery, that is it.

Your absolutely right about not over discharging the main battery. That is one of the things you really need to pay attention to. I use a timer and so far haven't had any problems. Really, people should use a timer anyway.

As far as continuous flying goes, the batteries I linked to are 5C charge batteries. This means you can charge them in 12 minutes if you have a strong enough charger. Given the requirement to periodically charge the rx battery in a glow airplane and the cost of fuel, I would say you could fly this airplane every bit as much as glow even with one battery. If you had two batteries you could literally fly it every 3-4 minutes.

One of the great things about electric is that the biggest cost of the airplane (the battery) can be moved to different models and shared between them.

Lets say I bought the motor and speed control listed above 4 times for 4 different airplanes. I could then purchase 2 batteries and a strong charger and fly all 4 aircraft back to back to back until my TX battery dies.

Yes, electrics are dangerous, yes they can be more expensive, yes you have to pay attention to batteries and chargers, but they are also quite convenient.

I pulled this out:
Attachment:
glow.jpg
glow.jpg [ 87.9 KiB | Viewed 4554 times ]


And put this in:
Attachment:
electric.jpg
electric.jpg [ 79.48 KiB | Viewed 4554 times ]


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PostPosted: Tue Jan 04, 2011 12:02 pm 
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Location: Wasilla Ak
OK - I've got to chime in here. HobbyKing Flightmax batteries. 2200ma 3s 20c packs for 7.49 each. This is the only way I can afford electric flight. You need at least 3 or 4 battery packs for a days flying, because it takes about 40 minutes or more to charge each pack. For sport flying these packs are great. I've never had one fail. Yes, there is the shipping cost from Hong Kong, but if you package your order with another buddy it's not bad. Check out HobbyKing for all your electric flight goodies. Don't forget you're going to need Dean's connecters, soldering iron, wattmeter, a good charger etc. I like my electric planes, but I'm thinking gas is the way to go. I have a new DLE 20cc in my hands - we'll see how that works. I'm all for buying made in the USA, but let's get real - most of this stuff is not made here anyway. Also on HobbyKing - just for comparison.

Nano Tech 4000mah 4s 90c 59.99 (Yes 90c)
Flightmax 4000mah 4s 40c 35.10
Turnigy Plush 80amp esc 39.99 w/ubec (Programming card 7.99)


Mike (cheap retired guy)

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PostPosted: Tue Jan 04, 2011 12:22 pm 
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Yup,

HK is a good alternative, but can be a bit of a gamble. Many people have gotten damaged or poorly matched cells from them and was unable to get them to resolve it. Many have resolved to expect a problem once and a while and let it go due to the cost.

For me personally, I would rather spend $75 on a 4s4300 90C battery pack that is double checked and supported by a US vendor with free 3 day shipping then spend $60 on a HK 4s4000 90C pack that basically has no support or warranty then pay shipping on top of that.

That was the original point of the thread, the availability of a good and affordable battery inside the US for basically the same cost.

As far the the ESC goes, yea, the smaller plush ESC's are good, but the larger ones tend to have trouble timing larger motors and have poor low end throttle response. Also, the BEC circuit is only rated for 3A vs the 5A switching regulator on the castle, and the castle has a data logger, and can handle 8 cells. Bottom line, be careful using the BEC on that speed controller for any reasonable sized model.

I agree that gas might be the way to go. I would love to have a gas airplane. Cheap fuel, no mess, and real engine noise sounds great. Let me know when you get it running. I'm very interested in the DLE-20 and DLE-30 engines.

schu


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PostPosted: Tue Jan 04, 2011 1:08 pm 
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I probably won't get the DLE 20 going until I get back from warmer climes in Feb. I'm interested to see how it runs. I have returned an esc to HobbyKing after I fried it due to user error. They sent me a new one no questions asked. I think the Flightmax 4000mah 4s pack is a closer comparison to the pack you omentioned and it is half the price! I have heard some bad things about the larger Turnigy esc's also, but my experience with the 40 and 60 amp models have been excellent. As long as you don't dunk them in the lake like I did they are fine! My goal eventually will be to go all gas or electric - I'm tired of the mess and the fuel prices.

Mike

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PostPosted: Tue Jan 04, 2011 2:10 pm 
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Here is the thread on the hicountry batteries posted above:

http://www.rcgroups.com/forums/showthread.php?t=1244249

Here is the thread on the turnigy nano packs:

http://www.rcgroups.com/forums/showthread.php?t=1302258


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PostPosted: Tue Jan 04, 2011 3:21 pm 
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Just was testing my TP ProPower 30c battery and was able to charge it up from 15% in 12 minutes and it didn't even get warm, unfortunately that is only at 10amps (4c) because that is the limits to my charger. My new charger will be here later this week which will allow me to move up to 12amps on this battery and 15amps on my 4s batteries.

I hope the weather is up in the mid twenties or even thirties this weekend. If so, I'll probably come out and fly.

schu


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PostPosted: Tue Jan 04, 2011 5:03 pm 
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WOW.. I started a discussion..lol

So that elec motor I need to get a better ESC...

So power wise.. if its equivalent to a .46.... then it should have plenty of power for the 6 pound 98" wing span Reaper fron Nitro Planes.
I think my batt is a 3XXX Mah

But if I only run it at half throttle or less... it should last semi decent.

Schu.... whats a cheap ESC 75AMP and what is a good good ESC for the motor?

Thanks for all the help..

Im a GAS GAS guy..lol

Go MIKE 20cc!!!

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PostPosted: Tue Jan 04, 2011 5:24 pm 
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Britt,

That motor will do 800-900 watts according to my own testing so on a 4s battery you need 60-65 amps. I would get a castle esc if it where me, especially if I didn't have a watt meter, since it has a data logger built in, and I trust the BEC to power my RX without brownouts.

The battery really needs to be a little bigger at these power levels. If you have a 3300 battery then 65 amps is 20C. I think a 4000 would be much better because you are running it at 16C and it will give you more flight time.

As far as performance, it should be fine. 150 watts per pound will fly well, but then again I shoot for 225 watts per pound because I like LOTS of power.

Please be sure you get a watt meter before flying this. Electrics are reasonably safe if you stick to known limits, but if you over prop the motor you could burn up stuff or even cause a fire.

schu


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