HobbyKing.com New Products Flash Sale
Reply
Thread Tools
Old Jan 08, 2013, 04:48 PM
Is Stateside.......
dav3uk's Avatar
Uk South Wales
Joined Aug 2009
2,188 Posts
Quote:
Originally Posted by jtaylor996 View Post
I'm not a guru, but the lower the IR, the higher C you can charge it. Your problem is that your charger does just barely above 1C on this battery.

Get something with some serious output, like 3.3*3*2 = 20A min, which will parallel charge all 3 of your batteries at the same time at 2C, and you'll be done in 30 minutes. Or get a Powerlab or iCharger that can handle 40A and have them all charged in 15 minutes (@4C).

Note: they say 5C charging is good with most batteries today, but I only charge at 3C, just to be safe. The Nano's say 10C, but I'd like to see it done without a fire/explosion (on a 3.3Ah, that would be 33A input, for a charge in just 6 minutes)!
I am using 4 separate 5amp iMax B6 chargers, I have 4 of them hooked up to a BIG car battery so supply amps is no problem so can charge at 5 amp max rate. The lipos are 2200mah so my thinking was that at 5amp it would be 2c charge with a bit extra for balancing............The problem I get is that the lipos seem to spend a LOT of time trying to balance, they bounce back and for a lot where as on the standard lipos one will climb to to a voltage then the other catch up, only .1v at a time until done. These seem to climb and fall all over the place and at the end may be .3v out between each other, again the standard ones all charge ok. I have checked the voltages manually as well as using the charger and mostly the charger is close enough. To have all six doing the same on all 4 chargers just kinda makes me think there is some incompatability or something.

I usually only charge at 1c or just over so if they respond ok at 2c the times should be back to normal so will be fine, just have always kept the charge c rate down to try and extend the life.........dont know if that is worth doing or not but with the old nicds it was always better when you charged slower........lol

Dave
dav3uk is offline Find More Posts by dav3uk
Reply With Quote
Sign up now
to remove ads between posts
Old Jan 08, 2013, 05:00 PM
Registered Crasher
United States, TX, Coppell
Joined Feb 2011
2,175 Posts
Check your balance leads to see if they have gone flaky. Otherwise, I would post this over in the batteries forum. They'll know a lot more about your specific charger than I do.
jtaylor996 is offline Find More Posts by jtaylor996
Reply With Quote
Old Jan 09, 2013, 01:09 PM
Is Stateside.......
dav3uk's Avatar
Uk South Wales
Joined Aug 2009
2,188 Posts
Right just to keep you all posted re the Turnigy Nano's. I flew today and used 4 packs(2 fights of the B17) When charging I set the charger to 5amp to see if that would make a difference.

Result is hell yes it made a difference. Obviously it took a shorter time but here is what happened.

Set the charger for 5amp balance charge.

Press start and A reading climbs to 4.3a not 5....but it balanced real quick. Before it balanced slow and was up and down by .1v all the time, now it just gets the three cells the same then climbs by .1v and starts again.

Yesterday I had just over 800mah take 2 hrs and it timed out this time it took 14 mins..........result

So it would seem these nanos like a nice high current and balance current to wake them up......

Will see how long they last me before singing their praises too much.

Dave
dav3uk is offline Find More Posts by dav3uk
Reply With Quote
Old Jan 09, 2013, 01:22 PM
Registered User
BlinkguY's Avatar
United States, NJ, Newark
Joined Nov 2005
1,408 Posts
thanks for the info
BlinkguY is offline Find More Posts by BlinkguY
Reply With Quote
Old Jan 09, 2013, 02:54 PM
Registered User
USA, IL, Chicago
Joined Nov 2010
44 Posts
Quote:
Originally Posted by jdm2ner View Post
no not if you keep the pitch at 10 you will ove draw the motor at about 48amp you will have to cut it back to 8 and you will be ok but the speed will be much less about 54 on the pitch speed but if you go with the 9.5x10x4 you will be fine at 10* of pitch at 71 on your pitch speed. i fly the 9.5x10x4 and its good for me
I'm testing my set up with eClac for 870kv with 3s, what should the ratio between Static Thrust, Prop Stall Thrust and Pitch Speed be? Is it good to have bigger Static Thrust or Prop Stall Thrust for this plane. I was going to use 12x8 2 blade from MAS and that's what I'm getting:
Static Thrust: 66oz (in read)
Prop Stall Thrust: 45oz
Pitch Speed: 56mph

When I plug in 9.5x10 4 blade my Prop Stall Thrust drops to 32oz and speed goes up to 71. How is this going to affect flying characteristics of my P-47?

I'm kind of lost here, cannot figure out what's better for her, speed or thrust.

Thanks!
op1900 is offline Find More Posts by op1900
Reply With Quote
Old Jan 09, 2013, 03:31 PM
flying is everything
jdm2ner's Avatar
United States, FL, Hollywood
Joined Oct 2010
244 Posts
well i fly mine with a 9.5x10x4 hobby-lobby prop with a g25 710kv and a 4s 3000mah 40c and it tells me the samething of the prop stall but i have over 20 flights and she flys great with no problems if that helps at all
jdm2ner is offline Find More Posts by jdm2ner
Reply With Quote
Old Jan 09, 2013, 03:38 PM
Registered User
USA, IL, Chicago
Joined Nov 2010
44 Posts
Thanks jdm2ner! I can see that with 4s you have very decent thrust and speed. I do not have that, but I want to stick with 3s, Should I use a different prop? Any advice will be greatly appreciated.
op1900 is offline Find More Posts by op1900
Reply With Quote
Old Jan 09, 2013, 03:42 PM
Registered Crasher
United States, TX, Coppell
Joined Feb 2011
2,175 Posts
For this plane, I think you want about 1:1 thrust to weight, and at least 65mph of pitch speed (likely a good bit more than that).

I don't know that the static or prop stall thrust numbers will mean a whole lot to a plane that moves through the air...
jtaylor996 is offline Find More Posts by jtaylor996
Reply With Quote
Old Jan 09, 2013, 03:48 PM
Registered User
USA, IL, Chicago
Joined Nov 2010
44 Posts
Quote:
Originally Posted by jtaylor996 View Post
For this plane, I think you want about 1:1 thrust to weight, and at least 65mph of pitch speed (likely a good bit more than that).

I don't know that the static or prop stall thrust numbers will mean a whole lot to a plane that moves through the air...
1:1 thrust to weight means that if planes weight is 45oz I need at least 45oz of thrust, correct?
op1900 is offline Find More Posts by op1900
Reply With Quote
Old Jan 09, 2013, 03:52 PM
Registered Crasher
United States, TX, Coppell
Joined Feb 2011
2,175 Posts
Yeah, but you can just plug the weight number into eCalc and it will just display the ratio on the bottom line for you. It displays the pitch speed as well.

Static thrust is not relevant because in normal operation the prop has a big wind in it's face (at about 90% of the pitch speed, fyi, which ~= airspeed). However, it is a number you can double check against if you have a motor test stand with a way to measure the thrust directly.
jtaylor996 is offline Find More Posts by jtaylor996
Reply With Quote
Old Jan 09, 2013, 06:26 PM
Chop it, cut it, bash it
quitcherbitchen's Avatar
United States, CA, La Caņada Flintridge
Joined Jul 2011
4,862 Posts
Quote:
Originally Posted by dav3uk View Post
Right just to keep you all posted re the Turnigy Nano's. I flew today and used 4 packs(2 fights of the B17) When charging I set the charger to 5amp to see if that would make a difference.

Result is hell yes it made a difference. Obviously it took a shorter time but here is what happened.

Set the charger for 5amp balance charge.

Press start and A reading climbs to 4.3a not 5....but it balanced real quick. Before it balanced slow and was up and down by .1v all the time, now it just gets the three cells the same then climbs by .1v and starts again.

Yesterday I had just over 800mah take 2 hrs and it timed out this time it took 14 mins..........result

So it would seem these nanos like a nice high current and balance current to wake them up......

Will see how long they last me before singing their praises too much.

Dave
Thanks again this is good stuff. I know it is in the wrong thread, but it is nice to see once in a while without having to look for it.
quitcherbitchen is online now Find More Posts by quitcherbitchen
Reply With Quote
Old Jan 10, 2013, 02:26 PM
Registered User
Canada, ON, Iroquois
Joined Mar 2012
526 Posts
I just picked up a PZ P-47 yesterday and took it for its maiden flight this morning with no flaps or gear. I am a complete noob at flying planes but have a bit of time in on CP helis, and a ton of time flying both on a sim. I have to say despite what all the naysayers said to me about getting a war bird as a first plane, this one easy bird to fly. Sure my flight was a bit wobbly, but I didn't crash and made a near perfect belly landing on snow first try. The second wasn't as nice, but it wasn't a tumbling crash either.

So being a noob with this bird I was just wondering what sort of flight times people are getting off the stock battery under mild to soft flight? I know that my brushless MCPx gets about 4 minutes of flight time on a hyperion 550 and my Chaos 600 about 7-8 minutes on a 6s 5000mah just hovering and forward flight with plenty of power to spare when I am done. I just want to get an idea of what to set my timer at.

Thanks
George
SG Mason Knives is online now Find More Posts by SG Mason Knives
Reply With Quote
Old Jan 10, 2013, 02:46 PM
Registered User
BlinkguY's Avatar
United States, NJ, Newark
Joined Nov 2005
1,408 Posts
Hey brother... i fly it for 5 min 2200 mah and my. Cells are about 3.85 each... whats your battery mah?
BlinkguY is offline Find More Posts by BlinkguY
Reply With Quote
Old Jan 10, 2013, 02:57 PM
AMA 52726
Edge767's Avatar
United States, TX, Spring
Joined Jun 2005
1,493 Posts
My alarm is set for 6 minutes, so I get a 1 minute warning at 5 at which time I know it's time to set up for a landing and get it on the ground. I typically go 5:30 to 6:15 on mine each time with no issues. I also don't run WOT the whole time, though.
Edge767 is offline Find More Posts by Edge767
Reply With Quote
Old Jan 10, 2013, 02:58 PM
Is Stateside.......
dav3uk's Avatar
Uk South Wales
Joined Aug 2009
2,188 Posts
5-6 mins is about your lot unless you spend all flight at 1/4 throttle...........no, didnt think so........lol

If you set for 5 and then play around at height from 5 - 6 if she cuts glide her in if she is still going at 6 bingo set timer for 5 and then you have that go around because of the dog in the way, kids running about, gusty wind got ya on final etc........lol

Dave
dav3uk is offline Find More Posts by dav3uk
Reply With Quote
Reply


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Discussion World Models p47 1.20 dards Fuel Warbirds 1 Oct 20, 2010 10:55 AM
Discussion E-Flite P47 or Parkzone Corsair?? Gobstopper Electric Warbirds 13 Dec 02, 2009 09:37 PM
Discussion New Parkzone p51 or Greatplanes P47 casedit Electric Warbirds 5 Sep 01, 2009 09:08 AM