Thoughts on running 4s?

fiveoboy01 · 11-23-2007, 01:02 AM

I'm thinking about switching to a 4s setup on my trex.

I'd end up ditching the JGF motor and going with something like one of the scorpion motors at the 4500ish kv.

Questions:

How bad is the weight penalty? Does it cause any major CG issues?

What esc would be recommended(amperage)? It has to be a CC esc, because I'm spoiled by the Castle Link. I'm running a Phoenix 35 right now, would a 45 cut the mustard? Or would I want larger than that for a safety margain?

I'm assuming the woodies aren't safe at real high headspeeds. I've been running 2800 on mine for many flights now with no issues, but I'm unaware of their maximum rated rpm. Will v-blades be safe up to(or exceeding) 3300?

DominicD · 11-23-2007, 01:41 AM

4500KV is the wrong type of motor for 4S. A cc p35 is overkill, remember higher voltage will mean a lower current.

Essie · 11-23-2007, 05:28 AM

HFG how does a higher voltage give you a lower current? Is it not I=V/R (ohm's law), so if you increase the volts (r stays the same) you will increase the Amps?

kgfly · 11-23-2007, 06:09 AM

The brushless motor will always try to spin at its nominal speed for the applied volts. What varies is the power required for it to attain that speed. The power required to spin the blades at a given RPM and pitch is almost constant (other than parasitic I^2R losses). Thus at a higher voltage, for any given headspeed, less current will be drawn to provide the necessary power.

Going to 4s you want a lower KV motor since you have 33% higher voltage. Even if you want a higher headspeed, that will be achieved with a combination of voltage, KV and pinion.

3300rpm is really much higher than needed, even for wild 3D. Around 3000rpm is all you really need. The woodies are only rated to 2400rpm but many people fly them at 3000rpm with very rarely reported problems. It is a safety issue and good quality CF blades are certainly recommended. Metal blade grips are a must have item at those headspeeds.

So a reasonable 4s setup is probably something around 3000KV with an 11t pinion. However if you do a search you will find many recommendations for 4s setups with specific motor/pinion combinations.

As for weight, a 4s 1800 weighs about the same as a 3s 2200 with about 9% more energy so will give longer flights at the same headspeed.

aussiemick · 11-23-2007, 07:08 AM

Jazz 40 6 18
Thunder Power 4S2100 Prolites (180g) or Flight power 2100 EVOLITE (210 grams)

Go check out Trextuning 4S supertest.
Most of the winning motors are still the ones to get, maybe another Neu has slipped in as well. Just watch the weight of the motor ,this is where some good setups come unstuck (the weight issue).

I can thoroughly recommend the Medusa 28 32 2800, with an 11 tooth pinion 3200HS at full noise for the full flight of 7 minutes, 2900 HS for 9 minutes or 2600 for 11 minutes.

Mick

Mick

aaron07 · 11-23-2007, 07:43 AM

I have Jazz 40 6 18 / Medusa 28 40 2500 100g / 12 tooth and run 30sec to a 1 minute less than Aussiemicks set-up but with 4S TP2070 217g / 4S Hyperion Litestorm 195g / 4SFP 2100 Evolites 210g.

They say there is no turning back on a 4S set-up and I agree.

fiveoboy01 · 11-23-2007, 11:10 AM

Ok thanks for the replies guys...

So do you think I'd be ok keeping my JGF motor? It's a 500TH(3550kv). I'm running a 13t pinion and seeing 2820 rpm right now... I can always step it down a couple teeth. Working backwards with a headspeed calculator and my current setup, if I bump up one cell and reduce the pinion to 11t, I'd see roughly 3200 rpm.

I do have metal grips already, wouldn't think of running plastic ones at high rpms. Definitely would switch to some carbon blades.

Will the 35 esc be ok here, or no? Sorry for the questions but I'm still sucky at electric stuff especially doing all the calculations.

Funky · 11-23-2007, 11:28 AM

The JGF500 on 4s is a great motor. Run it with an 11 tooth pinion for high headspeeds and lots of fun. I flew a Mini Titan with this setup and it was a rocket. Temps and times were both very reasonable.

I am flying the Scorpion 2221-8 w/11 tooth on 4s with EVOLite 2100s. I am running the CC35 too. I tached it yesterday at 75% flat idle it was ~3050. At 80% it was ~3125 and ~3200 at 85%. 80% flat idle seems to be a good compromise that gave me 5 min flights using less than 1400mah with very low temps. All headspeeds were measured in a hover with a skytach within the 1st minute of a freshly charged lipo.

aussiemick · 11-23-2007, 03:57 PM

Quote:

Originally Posted by Funky

I am flying on 4s with EVOLite 2100s.

Hey Funky

Have you ever weighed your FP EVOlites? If so, how heavy are they?

Mick

Funky · 11-23-2007, 04:27 PM

Yes... and I am kind of dissapointed. The weight is supposed to be about the same as my old 2170s, but instead they weighed 202 with deans connector. Weight isn't up too much from my 3s setup. I was running the Align ESC and FP EVO25s for a little under 810 grams. The new setup has a CC35 with a Medusa BEC for 836 grams with the 2100s.

They still fly good though so I won't pass judgement until I see how many cycles I get from these lipos. I am picking up 2 more 4s lipos next week but I am trying to decide on 2 more EVOlites, 2 Prolites or 2 Align 16C 4 cell lipos.

fiveoboy01 · 11-23-2007, 04:58 PM

Funky, are you then using the governor mode with the CC 35? Or just running a curve that tops at 80% on each end of the V-curve?

Funky · 11-23-2007, 05:03 PM

I am running a flat curve so far (80,80,80,80,80), (90,90,90,90,90), etc. I am not running gov mode yet, but that is what I am testing these curves for. CC wants you to match the gov mode headspeed to the headspeed reached between 75% and 85% in fixed endpoint mode to get the best performance from the CC govener which is the reason for these low curves I am testing.

I have always been "against" gov mode on 3s. I always flew high, flat curves. 95% always worked best for me with my old Align ESC and 3s setup. I am very anxious to see how gov mode works out with the CC. It was VERY dissapointing when I tried testing the Align gov mode

aussiemick · 11-23-2007, 05:05 PM

You got light ones!!
I haven't flown with my FP's yet , hopefully they deliver good power when the time comes.

For some reason it is getting hard to track down 4STP2100Prolites.

I can get the CG to work well with both types, The FP's must slide back about 20mm compared to the TP. If I really wanted to lose some weight from the heli I could ditch the EagleTree logger. But the 4S setup more than compensates for any increase in the weight. This thing pulls harder than a 14 year old school boy.

Mick

Funky · 11-23-2007, 05:13 PM

How much do the heavy EVOLites weigh? I am really tempted to just go for Prolites or Aligns for my next 2 batteries. I know the 22c lipos are junk but my Align 16c lipos have over 200 logged cycles and are still flying and balancing great. I have tried MANY lipos, but none of them have lasted as long as these 2 lipos.... and they actually weigh what they are supposed to weigh

aussiemick · 11-23-2007, 05:20 PM

I got 4 FP's during the week.

the average weight is 209 grams, the worst was 210 the best 208 with deans connectors.

MIck

Funky · 11-23-2007, 05:23 PM

How much do your TPs weigh?

I may have slightly lighter ones.... but we are both a far cry from the 185g advertised wieght

I can't really feel a difference in overall weight from my old setup... although it is a LOT more powerfull so I can't compare it fairly. On my old 3s setup, I could feel a weight difference in the air between running 185g 2170s and my 145g Align packs. The power of the EVO packs definately helped make up for the difference and made me prefer them.... but not by as much as I would have guessed.

aussiemick · 11-23-2007, 05:34 PM

I just weighed them
I have 6 TP's and they all weigh 188 grams with deans.

I too have my original Align 3S2100 16C lipo. It hasnt been used for 3 months since I crashed and decided not to rebuild my Aplus400. If I had of seen this ad http://www.grandrc.com/inc/sdetail/39546 I may have got 4. the price is fantastic.

Mick

Funky · 11-23-2007, 05:38 PM

Exactly the ad I was looking at

My only concern is how old these lipos could be. Not many people fly 4s so these lipos may have been sitting there for a year... or more. I know lipos hold their charges well, but I have already been burned with old lipos which held about 20% less than their specified capacity. They were "new" although they had been on a shelf for a little over a year. If I knew these 4s aligns were new lipos (from the past 3 months or so) I wouldn't have to think twice about ordering them.

Thanks for the info Mick

aussiemick · 11-23-2007, 05:39 PM

And they have 16 in stock!!!
MIck

aussiemick · 11-23-2007, 05:49 PM

Get 1, if it is ok then order a few more.
If you order now you would have a test fly by Wednesday or so. Then capacity check them. If they are up to scratch by a few more.

For $70 it is a fairly safe experiment. For me the shipping costs kill little experiments.

Mick

11-23-2007, 01:02 AM	#1
fiveoboy01 Registered Users My HF Map location Join Date: Sep 2007 Location: Waunakee, WI	Thoughts on running 4s? I'm thinking about switching to a 4s setup on my trex. I'd end up ditching the JGF motor and going with something like one of the scorpion motors at the 4500ish kv. Questions: How bad is the weight penalty? Does it cause any major CG issues? What esc would be recommended(amperage)? It has to be a CC esc, because I'm spoiled by the Castle Link. I'm running a Phoenix 35 right now, would a 45 cut the mustard? Or would I want larger than that for a safety margain? I'm assuming the woodies aren't safe at real high headspeeds. I've been running 2800 on mine for many flights now with no issues, but I'm unaware of their maximum rated rpm. Will v-blades be safe up to(or exceeding) 3300? __________________ Bill - RWMAA #1009, AMA #805853

11-23-2007, 01:41 AM	#2
DominicD The Capi - HF Support My HF Map location Join Date: Oct 2006 Location: Toronto	4500KV is the wrong type of motor for 4S. A cc p35 is overkill, remember higher voltage will mean a lower current. __________________ SAB Heli Canada / RotorQuest/Compass Team KBDD Spreading capibara awareness since 2006 To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.

11-23-2007, 05:28 AM	#3
Essie Registered Users Join Date: Sep 2006 Location: Welkom, Freestate-South Africa	HFG how does a higher voltage give you a lower current? Is it not I=V/R (ohm's law), so if you increase the volts (r stays the same) you will increase the Amps? __________________ To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.

11-23-2007, 06:09 AM	#4
kgfly HF Support My HF Map location Join Date: Jun 2006 Location: Melbourne, Australia	The brushless motor will always try to spin at its nominal speed for the applied volts. What varies is the power required for it to attain that speed. The power required to spin the blades at a given RPM and pitch is almost constant (other than parasitic I^2R losses). Thus at a higher voltage, for any given headspeed, less current will be drawn to provide the necessary power. Going to 4s you want a lower KV motor since you have 33% higher voltage. Even if you want a higher headspeed, that will be achieved with a combination of voltage, KV and pinion. 3300rpm is really much higher than needed, even for wild 3D. Around 3000rpm is all you really need. The woodies are only rated to 2400rpm but many people fly them at 3000rpm with very rarely reported problems. It is a safety issue and good quality CF blades are certainly recommended. Metal blade grips are a must have item at those headspeeds. So a reasonable 4s setup is probably something around 3000KV with an 11t pinion. However if you do a search you will find many recommendations for 4s setups with specific motor/pinion combinations. As for weight, a 4s 1800 weighs about the same as a 3s 2200 with about 9% more energy so will give longer flights at the same headspeed. __________________ Kenneth * MSH Protos Stock motor/15t/Align75/Align DS510/GL730+DS520/7s A123 2300 * TRex450CF/430L/12t/CC45/HS65mg/L2100T/KP 3s 2200 25C or 4S LiFe Previous rides: HX242, W5-4, TRex450(HDE), TRex450(SE), QJ-EP8v2, BCX2 ,Logo10, Hurricane550 SIM: Phoenix (previously also Reflex/XTR, ClearView, RF, FMS)

11-23-2007, 07:08 AM	#5
aussiemick Registered Users My HF Map location Join Date: Jul 2006 Location: Brisbane Australia	Jazz 40 6 18 Thunder Power 4S2100 Prolites (180g) or Flight power 2100 EVOLITE (210 grams) Go check out Trextuning 4S supertest. Most of the winning motors are still the ones to get, maybe another Neu has slipped in as well. Just watch the weight of the motor ,this is where some good setups come unstuck (the weight issue). I can thoroughly recommend the Medusa 28 32 2800, with an 11 tooth pinion 3200HS at full noise for the full flight of 7 minutes, 2900 HS for 9 minutes or 2600 for 11 minutes. Mick Mick __________________ To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.

11-23-2007, 07:43 AM	#6
aaron07 Registered Users My HF Map location Join Date: Feb 2007 Location: Sydney City, Australia	I have Jazz 40 6 18 / Medusa 28 40 2500 100g / 12 tooth and run 30sec to a 1 minute less than Aussiemicks set-up but with 4S TP2070 217g / 4S Hyperion Litestorm 195g / 4SFP 2100 Evolites 210g. They say there is no turning back on a 4S set-up and I agree. __________________ 8S Trex 500 3026-1000KV, Jazz 55 10 32, Sportbec, 3 9650mg's, Vistabi V Bar V4 / JR8900. 8S Trex 600esp 4025-890KV, Jazz 55 10 32 with heatsink, Herc HC/HV bec, 3 JR8915's, Vistabi V Bar V4 / JR8900.

11-23-2007, 11:10 AM	#7
fiveoboy01 Registered Users Thread Starter My HF Map location Join Date: Sep 2007 Location: Waunakee, WI	Ok thanks for the replies guys... So do you think I'd be ok keeping my JGF motor? It's a 500TH(3550kv). I'm running a 13t pinion and seeing 2820 rpm right now... I can always step it down a couple teeth. Working backwards with a headspeed calculator and my current setup, if I bump up one cell and reduce the pinion to 11t, I'd see roughly 3200 rpm. I do have metal grips already, wouldn't think of running plastic ones at high rpms. Definitely would switch to some carbon blades. Will the 35 esc be ok here, or no? Sorry for the questions but I'm still sucky at electric stuff especially doing all the calculations. __________________ Bill - RWMAA #1009, AMA #805853

11-23-2007, 11:28 AM	#8
Funky Registered Users My HF Map location Join Date: May 2006 Location: Westerville, OH - USA	The JGF500 on 4s is a great motor. Run it with an 11 tooth pinion for high headspeeds and lots of fun. I flew a Mini Titan with this setup and it was a rocket. Temps and times were both very reasonable. I am flying the Scorpion 2221-8 w/11 tooth on 4s with EVOLite 2100s. I am running the CC35 too. I tached it yesterday at 75% flat idle it was ~3050. At 80% it was ~3125 and ~3200 at 85%. 80% flat idle seems to be a good compromise that gave me 5 min flights using less than 1400mah with very low temps. All headspeeds were measured in a hover with a skytach within the 1st minute of a freshly charged lipo. __________________ More helis than brains

11-23-2007, 04:27 PM	#10
Funky Registered Users My HF Map location Join Date: May 2006 Location: Westerville, OH - USA	Yes... and I am kind of dissapointed. The weight is supposed to be about the same as my old 2170s, but instead they weighed 202 with deans connector. Weight isn't up too much from my 3s setup. I was running the Align ESC and FP EVO25s for a little under 810 grams. The new setup has a CC35 with a Medusa BEC for 836 grams with the 2100s. They still fly good though so I won't pass judgement until I see how many cycles I get from these lipos. I am picking up 2 more 4s lipos next week but I am trying to decide on 2 more EVOlites, 2 Prolites or 2 Align 16C 4 cell lipos. Attached Thumbnails __________________ More helis than brains

11-23-2007, 04:58 PM	#11
fiveoboy01 Registered Users Thread Starter My HF Map location Join Date: Sep 2007 Location: Waunakee, WI	Funky, are you then using the governor mode with the CC 35? Or just running a curve that tops at 80% on each end of the V-curve? __________________ Bill - RWMAA #1009, AMA #805853

11-23-2007, 05:03 PM	#12
Funky Registered Users My HF Map location Join Date: May 2006 Location: Westerville, OH - USA	I am running a flat curve so far (80,80,80,80,80), (90,90,90,90,90), etc. I am not running gov mode yet, but that is what I am testing these curves for. CC wants you to match the gov mode headspeed to the headspeed reached between 75% and 85% in fixed endpoint mode to get the best performance from the CC govener which is the reason for these low curves I am testing. I have always been "against" gov mode on 3s. I always flew high, flat curves. 95% always worked best for me with my old Align ESC and 3s setup. I am very anxious to see how gov mode works out with the CC. It was VERY dissapointing when I tried testing the Align gov mode __________________ More helis than brains

11-23-2007, 05:05 PM	#13
aussiemick Registered Users My HF Map location Join Date: Jul 2006 Location: Brisbane Australia	You got light ones!! I haven't flown with my FP's yet , hopefully they deliver good power when the time comes. For some reason it is getting hard to track down 4STP2100Prolites. I can get the CG to work well with both types, The FP's must slide back about 20mm compared to the TP. If I really wanted to lose some weight from the heli I could ditch the EagleTree logger. But the 4S setup more than compensates for any increase in the weight. This thing pulls harder than a 14 year old school boy. Mick __________________ To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.

11-23-2007, 05:13 PM	#14
Funky Registered Users My HF Map location Join Date: May 2006 Location: Westerville, OH - USA	How much do the heavy EVOLites weigh? I am really tempted to just go for Prolites or Aligns for my next 2 batteries. I know the 22c lipos are junk but my Align 16c lipos have over 200 logged cycles and are still flying and balancing great. I have tried MANY lipos, but none of them have lasted as long as these 2 lipos.... and they actually weigh what they are supposed to weigh Attached Thumbnails __________________ More helis than brains

11-23-2007, 05:20 PM	#15
aussiemick Registered Users My HF Map location Join Date: Jul 2006 Location: Brisbane Australia	I got 4 FP's during the week. the average weight is 209 grams, the worst was 210 the best 208 with deans connectors. MIck Attached Thumbnails __________________ To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.

11-23-2007, 05:23 PM	#16
Funky Registered Users My HF Map location Join Date: May 2006 Location: Westerville, OH - USA	How much do your TPs weigh? I may have slightly lighter ones.... but we are both a far cry from the 185g advertised wieght I can't really feel a difference in overall weight from my old setup... although it is a LOT more powerfull so I can't compare it fairly. On my old 3s setup, I could feel a weight difference in the air between running 185g 2170s and my 145g Align packs. The power of the EVO packs definately helped make up for the difference and made me prefer them.... but not by as much as I would have guessed. __________________ More helis than brains

11-23-2007, 05:34 PM	#17
aussiemick Registered Users My HF Map location Join Date: Jul 2006 Location: Brisbane Australia	I just weighed them I have 6 TP's and they all weigh 188 grams with deans. I too have my original Align 3S2100 16C lipo. It hasnt been used for 3 months since I crashed and decided not to rebuild my Aplus400. If I had of seen this ad http://www.grandrc.com/inc/sdetail/39546 I may have got 4. the price is fantastic. Mick __________________ To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.

11-23-2007, 05:38 PM	#18
Funky Registered Users My HF Map location Join Date: May 2006 Location: Westerville, OH - USA	Exactly the ad I was looking at My only concern is how old these lipos could be. Not many people fly 4s so these lipos may have been sitting there for a year... or more. I know lipos hold their charges well, but I have already been burned with old lipos which held about 20% less than their specified capacity. They were "new" although they had been on a shelf for a little over a year. If I knew these 4s aligns were new lipos (from the past 3 months or so) I wouldn't have to think twice about ordering them. Thanks for the info Mick __________________ More helis than brains

11-23-2007, 05:39 PM	#19
aussiemick Registered Users My HF Map location Join Date: Jul 2006 Location: Brisbane Australia	And they have 16 in stock!!! MIck __________________ To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.

11-23-2007, 05:49 PM	#20
aussiemick Registered Users My HF Map location Join Date: Jul 2006 Location: Brisbane Australia	Get 1, if it is ok then order a few more. If you order now you would have a test fly by Wednesday or so. Then capacity check them. If they are up to scratch by a few more. For $70 it is a fairly safe experiment. For me the shipping costs kill little experiments. Mick __________________ To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.

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