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Old Jun 27, 2007, 09:13 AM
ProBro #1889
DsWright's Avatar
United States, OH, Amelia
Joined Aug 2004
603 Posts
Help!
Thinking of going 4Cell Help me figure out what i need!

After puffing and killing all my 3S1P lipos, i figure now is as good a time as any to go to 4S....

I know i need an external BEC, no prob.

My current setup.

Trex-Se V2
430 XL
CC 35
(Will add park BEC)
HS 65's
Fut 3110 (Getting 9650)
401


Im not sure about a couple things.

#1 will the 430XL need to be replaced? Like a JGF 500th or something?

#2 What Mah 4S1P packs do i need? Can i use the flightpower 1500mah and not be pushing them to hard? (25C x 15 = 37.5 Amps). I know my amp draw should decrease when i go 4S. otherwise my CC35 is suspect as well....
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Old Jun 27, 2007, 10:01 AM
Registered User
United States, GA, Roswell
Joined Mar 2007
1,237 Posts
Actually, you could decrease your amp draw by going to 4s. You will get a lot more headspeed for the same amount of current with 4s, so you could either get the smallest pinion possible, or a much more efficient motor. Steve Neu reccomends the 1107/2y, which was one of the most efficient motors tested by trextuning.com . You could push 2900 rpm, even with 10T on that motor, and would be pulling less current than with a 3s + higher tooth pinion setup.

In other words, your CC35 should be fine, an external BEC is a great idea, and 4s 1500's would be fine, amp-wise... duration is another story.
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Old Jun 27, 2007, 10:07 AM
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Christchurch, New Zealand
Joined Jun 2006
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430XL is 3700 KV... that's too high for 4s. You'll need to find another motor.
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Old Jun 27, 2007, 10:08 AM
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HeliSmith's Avatar
United States, CA, Chico
Joined Feb 2007
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I would just stick with 3S. You are puffing packs for a known problem with the 430XL because it is just a hungry monster. The fix is a couple Flightpower 2170 3S Evo 25 V-Power packs and a nice little Blinky balancer.
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Old Jun 27, 2007, 10:22 AM
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Christchurch, New Zealand
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And if you don't already have one, a lipo alarm so you don't run off the bottom of the charge.
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Old Jun 27, 2007, 10:35 AM
ProBro #1889
DsWright's Avatar
United States, OH, Amelia
Joined Aug 2004
603 Posts
Quote:
Originally Posted by HeliSmith
I would just stick with 3S. You are puffing packs for a known problem with the 430XL because it is just a hungry monster. The fix is a couple Flightpower 2170 3S Evo 25 V-Power packs and a nice little Blinky balancer.
Im trying to wiegh the options right now... since i have to buy all new packs anyway

I want 3000+ Headspeed and great performance.
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Old Jun 27, 2007, 10:38 AM
TEAM SCHC
Joined Jul 2006
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430XL motor will give you 3200 headspeed, 13 tooth pinion with 2170 flight power packs. Good power and wont puff packs. Less weight as well...i really dont see the point in going 4S at all for a 450 sized heli. UNLESS you want to fly around for like 15 minutes. I fly for 4 minutes and i get bored already.
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Old Jun 27, 2007, 11:07 AM
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Money, LOTS of it............
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Old Jun 27, 2007, 11:14 AM
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Christchurch, New Zealand
Joined Jun 2006
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I do not understand this obsession with huge headspeeds. Does anyone care to explain what it is possible to do with a T-Rex at, say, 3100 that can't be done at 2400 *if* there's enough power there? I've seen some pretty impressive stuff done with a T-Rex that was running 5S and 900W peak power, but only 2400 headspeed.
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Old Jun 27, 2007, 11:36 AM
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well if you ever tried to roll or do any mild 3d with a heli running @ 2400 vs 3000... You would know why people like to run @ 3000.

Dont get me wrong... Some of the pro's could do hot 3d on 2400 but why??? Its makes the job 3x harder
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Old Jun 27, 2007, 11:39 AM
ProBro #1889
DsWright's Avatar
United States, OH, Amelia
Joined Aug 2004
603 Posts
Quote:
Originally Posted by blade strike
well if you ever tried to roll or do any mild 3d with a heli running @ 2400 vs 3000... You would know why people like to run @ 3000.

Dont get me wrong... Some of the pro's could do hot 3d on 2400 but why??? Its makes the job 3x harder
Exactly.. at low headspeeds the response is mush....
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Old Jun 27, 2007, 01:15 PM
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HeliSmith's Avatar
United States, CA, Chico
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But the question is should you get a 4S since you have to replace your batteries. No you should get quality 3S batteries. That 430XL will give you the headspeed you need. I am going to swap it out for the JGF500th soon and I will give a review on how that goes.
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Old Jun 27, 2007, 09:03 PM
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Christchurch, New Zealand
Joined Jun 2006
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Hmm. I still reckon that 5s monster was 3ding just fine at a very low headspeed... but he did have 900W available. I think it's down to peak power, rather than headspeed, and the reason really high headspeeds work is that there's a whole lot more energy in the rotor so it doesn't matter as much if the motor can't keep up.

But what do I know, I can't fly any of that stuff myself.

Anyhow, if you have a 430XL you don't need or want 4S packs, because the right pinion is impossible.
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Old Jun 27, 2007, 09:40 PM
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Orlando, FL
Joined Nov 2006
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I'm using the 500TH in one of my Mini Titans. Amp draw is quite a bit less than a 430XL on the same pinion. Its 3380kv but the HS feels similar to the 3700kv XL. On 13t the 500TH has identical amp draw to my 430XL on 11t. But the HS is higher than the XL on 11t so its a good trade. 500TH runs cool and my 2200's are around 10deg cooler at 105-115deg after a 3D flight of 6min.(Almost 9min on my Kong Power 2200's) Remember a Mini Titan is a pig and a V2 will have much better numbers all the way around!
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Old Jun 27, 2007, 10:51 PM
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HeliSmith's Avatar
United States, CA, Chico
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I am getting 3200rpm on 10tooth from the calculator but yeah that's turning really fast.

3700 x 150t main x 10t pinion

http://www.readyheli.com/category_s/81.htm
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