RunRyder RC
 4  Topic Subscribe
WATCH  2 pages [ <<    <    ( 1 )     2     NEXT    >> ] 348 views POST REPLY
ProModeler Scorpion Power
Dingo07

Senior Heliman

Newport Coast, CA - USA

My Posts: All  Forum  Topic

Well folks, I can use all the help I can get and appreciate any input from here on out!

I'm at the point where I need to purchase flight batteries and I'm not sure which ones to purchase. I also have a couple questions... Here's the scenario: I don't plan on doing much 3D with this bird, it'll eventually get shoved into an Airwolf fuselage that I'm building and think I've settled on an 8S battery for a head speed between 1256@80% to 1571@100%. The other Head Speed calc with a 10S battery results in 1571@80% to 1963@100%. It's a low head-speed setup because I want to hear the wallop of the blades when I'm flying Airwolf.
Question - Which am I more likely to fly with, a head speed at 80% throttle or 100% ?

I think I want to get Pulse batteries, after reading good things about their use for some time. Because I won't be doing 3D, will a pair of 8000's be too heavy? I'm trying to push the limits of flight time and definitely want more than a 5000. How do I calculate how much time I'll get from those two battery options based on flying scale?

I'm using a JR XG14 radio, Kontronik JivePRO 120+ with its internal BEC, Spirit FBL, KDE X700XF-535-G3, JR DS8717 for cyclic and MKS HBL980 for tail. I also have an iCharger 4010DUO that I need to purchase a power supply for, in order to charge the batteries I get.
Thanks and hope every had a safe and wonderful Holiday!

12-25-2016 08:23 AM
PM  EMAIL  GALLERY  Attn:RR
Dr.Ben

rrMaster

Richmond, VA, USA

My Posts: All  Forum  Topic

The easiest way to get long flight time without carrying a ton of battery weight is with high voltage. Go with 12s in something in the 5500-6000 mah range. With that speed control you gear for highest headspeed at 80%, not 100. Depending on your all up weight, a conservatively geared set up running 1500 rpm (plenty for scale) will give you the better part of 10 minutes of runtime. You can play with 8s and use larger packs, but you will find pack selection less diverse and pricing less competitive. Predicting exact runtime is really hard until you can log and see your consumption/min via a Tellme or Jlog or similar interface.

NOW, this all said, if you're set on a lower cell count set up, I can help you with that, but you still need to gear for 80%. A friend of mine has a SS E5 on 12s 5000's. He can fly for the better part of 10 minutes of sport aerobatics at about 1600-1800 depending on what he's doing. I have the same model on 7s 5000's. It's good for 7:30 min @ 1450. My other SS uses 6S 5000's. Its runtime is about 6:45. So you can see the effect of less voltage. On my models I have to drop headspeed and runtime to still not get the flightime of the HV set up. Plus the models are light. If I added capacity to match his flightime, the packs would end up making the model weigh the same or more and cost more too.

I do see your motor kv, and I wish you weren't obligated to that kv since its kv is so high for gearing for the absolute most efficiently running model at the desired headspeed and runtime. It's also way more power than you need and at a fairly stiff weight penalty as well. All this model needs is a basic 450 kv Scorpion 4035, Kontronik Pyro 700 or similar modest and comparatively lightweight motor.

Ben Minor

Team Synergy Team Futaba Team Kontronik USA
Progressive RC

12-25-2016 02:01 PM
PM  EMAIL  GALLERY  Attn:RR
Dingo07

Senior Heliman

Newport Coast, CA - USA

My Posts: All  Forum  Topic

Thank you DrBen for the insight! From what I gather the motor I have is more for heavy 3D work instead of light flying and in order to use all the efficiency of it I'll need to gear the pinion with a 10 tooth running on a 12S. Those head speed numbers are 1594.23@80% Is that correct?
Then I'll be able to use 2x6S batteries in series to make a 12S, and with a 6000mah I hopefully might get more than 8 minutes flight time (pure speculation on the facts)
IF that's the case, here's the rub... where do I get a 10 tooth pinion for my heli?
If what you mean by: "With that speed control you gear for highest headspeed at 80%" - is electronically set in the Kontronic, all I need to get going is the batteries, yes?

If you haven't noticed electric helis are all new to me, thanks again!

12-25-2016 05:27 PM
PM  EMAIL  GALLERY  Attn:RR
Dr.Ben

rrMaster

Richmond, VA, USA

My Posts: All  Forum  Topic

You can't get a 10t for the Synergy E7 or E5. 12 is the smallest which is why I said what I did about your motor kv. 80% refers to your throttle curve. At that percentage you want to have your max desired head speed. The extra 20% is your governor headroom. A few percent higher would be ok since this is a scale model. It's going to be tough to make the numbers pretty on 12s with 535 kv. The used market is pretty rich with good used motors for steals. I would try to find a 450 kv one. Doesn't need to be fancy.

FINALLY..... because of its active freewheeling design, you can run the Jive at a much lower throttle percentage to get your desired headspeed. The downside is that the esc will run hotter and less efficiently. Runtime won't change a whole lot since you won't be mashing on the collective, but it's not ideal technique and as nice to the esc as using the correct motor kv for the available gearing and voltage.

Ben Minor

Team Synergy Team Futaba Team Kontronik USA
Progressive RC

12-25-2016 06:34 PM
PM  EMAIL  GALLERY  Attn:RR
Dingo07

Senior Heliman

Newport Coast, CA - USA

My Posts: All  Forum  Topic

Got it! Why don't they make gearing for a low head speed!!! Life would be so much easier! Botos can easily sell "Low Headspeed" Kits for every existing unit they've sold!

So my Best option is to get a 450KV motor to bring the head speed down with the stock gearing. Worst option is to run 8S with the stock gearing and existing 535KV motor, or would that 1256@80% head speed be too slow? Would 10S 1885@80% be better with an adjustment in the Jive?

Which batteries should I now be looking at? Either 4S or 5S to make 8S or 10S flight packs? Recommendations?

And should I use a separate battery for the receiver, FBL, servos, etc? Size if yes?

12-25-2016 09:36 PM
PM  EMAIL  GALLERY  Attn:RR
Chuck Bole

Elite Veteran

Tulsa Ok. U.S.A.

My Posts: All  Forum  Topic

Don't think you can go too much smaller tooth count and still run a motor with a 6mm shaft.

Get ya a 40 series 450 KV motor as Ben suggested. 12s 5000 will be easier to balance the model as far as CG. I run 8s stick packs on my E7 with a 4530 500KV motor. Kinda over kill for what i'm doing but needed the nose weight to balance the heli and it's what was laying around..

Chuck

Team Synergy Field Representative / Thunder Power

12-25-2016 09:58 PM
PM  EMAIL  HOMEPAGE  GALLERY  Attn:RR
Dr.Ben

rrMaster

Richmond, VA, USA

My Posts: All  Forum  Topic

BEC: Use the Jive's set to the voltage that suits your servos. It is an utterly bomb-proof BEC. Use a small buffer pack for redundancy with the same voltage range you are using from the BEC. You can read about how to wire buffer pack in the instructions for the original Jive HV speed controls. Let me know if you have questions about this point. Premade stick packs are convenient, but if one cell in one pack goes bad, disassembly and repair becomes more ttoublesome. It is for this reason that a lot of guys just use separate packs and shrink wrap them together themselves to form a stick. 10s with the throttle curve turned down a bit would not be too bad if you stay will tbat motor, but you'll need 6000's at least ($$). 1200 rpm is pretty low for a model that heavy on 700mm blades. I'd stay in the 1400-1500 rpm range.

Ben Minor

Team Synergy Team Futaba Team Kontronik USA
Progressive RC

12-25-2016 10:03 PM
PM  EMAIL  GALLERY  Attn:RR
Dingo07

Senior Heliman

Newport Coast, CA - USA

My Posts: All  Forum  Topic

Excellent! I think I'll keep the motor I have for the time being, get it all completed (stock E7SE) and in the air and then figure out if I should change it with the information provided and after I shove it into Airwolf.

Any suggestion on 5S sticks? I was only able to find a Hobby People 6500mah 30C stick, keeping clear of 5000mah sticks.

also found a Zippy 5S 30C 8000mah - any good?

12-25-2016 10:44 PM
PM  EMAIL  GALLERY  Attn:RR
Dr.Ben

rrMaster

Richmond, VA, USA

My Posts: All  Forum  Topic

See what Thunderpower and Pulse have to offer. As I noted earlier, the selection of these larger capacity packs is more narrow and pricey. You may find that life will be a lot easier and overall less costly if you start simple with a 450 kv motor and 12s 5000-5300 packs. And remember for 10 or 12s 25 or 30c packs are all you need. Higher C packs are a waste.

Ben Minor

Team Synergy Team Futaba Team Kontronik USA
Progressive RC

12-25-2016 11:00 PM
PM  EMAIL  GALLERY  Attn:RR
Dingo07

Senior Heliman

Newport Coast, CA - USA

My Posts: All  Forum  Topic

The average price I'm seeing for a Thunder Power 5S 25C 6000mah or greater is $180. 55C or greater jumps into the $220 range and higher... Times 2 to make a flight pack - wOw

Pulse only makes one 5S LiPo at 4500mah

I guess there's no way get over this LiPo hump. I'll have to weigh the different motor swap/LiPo S change before I commit! And just when I thought it was all figured out...

Thank you again for your help Dr.Ben

12-25-2016 11:27 PM
PM  EMAIL  GALLERY  Attn:RR
Dr.Ben

rrMaster

Richmond, VA, USA

My Posts: All  Forum  Topic

With TP you need to wait for one of their 40-50% off sales. I got my last two 7S 5000's from them for about $130 each. Motor change is the best option. Don't pigeon hole yourself with costly boutique packs.
Remember what I said about C rating too.

Let me know what you decide to do.

Ben Minor

Team Synergy Team Futaba Team Kontronik USA
Progressive RC

12-26-2016 12:18 AM
PM  EMAIL  GALLERY  Attn:RR
Dingo07

Senior Heliman

Newport Coast, CA - USA

My Posts: All  Forum  Topic

Well, I'm about to box up the KDE 700XF-535-G3 to send back to AMAIN for an RMA refund (!AwesomE!) What's odd is AMAIN said the KDE 700XF-455-G3 is discontinued... I'll reach out to KDE and find out, perhaps there's a new model coming we're not aware of...

12-28-2016 01:42 AM
PM  EMAIL  GALLERY  Attn:RR
Dr.Ben

rrMaster

Richmond, VA, USA

My Posts: All  Forum  Topic

Patrick might not want to use that kv. It's a bit low for the gearing used on most modern 3D models with 2200 or so target headspeed. But then not everyone flies that way.....

Ben Minor

Team Synergy Team Futaba Team Kontronik USA
Progressive RC

12-28-2016 03:03 AM
PM  EMAIL  GALLERY  Attn:RR
Dingo07

Senior Heliman

Newport Coast, CA - USA

My Posts: All  Forum  Topic

OK, I'm thoroughly confused now... I was just reading through the Kontronik Jive Pro 120+ manual and I came across page 20 where it shows an example Heli setup using the Flight Mode switch:
Start / motor off: 0%
Hover (IdleUp 1): 45%
Scenic flight (IdleUp 2): 60%
3D-flight: 80%

Once I plug in the numbers relating to the KDE 700XF-535-G3 motor (that I was just about to return for a refund) I started to wonder...

45% = 535KV(motor) * 37V(10S LiPo) / 10.08(Gear Ratio) = 883.71 Head Speed
60% = 1178.27 Head Speed
80% = 1571.03 Head Speed

First, are my calculations correct? Is this Real World numbers?
Is that how I will eventually set up my radio to fly the bird?
Based on my abilities I'd end up going between IU1 and IU2 and would never fly at 80%.

If all this is true, I have a hard time believing it will fly once I put it into the Airwolf fuselage, unless I'm pushing the envelope of blade pitch perhaps?

Should I be concerned about putting in a 455KV motor?
The numbers with a 455KV @12SLiPo are roughly the same as above

It goes without saying I expect to pay roughly $280 for a LiPo flight pack either way... Help!

12-29-2016 07:37 AM
PM  EMAIL  GALLERY  Attn:RR
Dingo07

Senior Heliman

Newport Coast, CA - USA

My Posts: All  Forum  Topic

Head Speed calculations

Please correct me if my math is wrong!!!

Just like my previous post's calculation except I was missing an efficiency factor, here's the complete formula using a 455KV (93% efficiency) motor and 10S LiPo with a Gear Ratio of 10.08:

((455 x 37) x .93) / 10.08 = Max Theoretical Head Speed 1553
Head Speed @ 60% = 932
Head Speed @ 80% = 1242

Same as above with a 12S LiPo:

Max Head Speed 1864
Head Speed @ 60% = 1118
Head Speed @ 80% = 1491

Here's my question: Will the actual head speed during flying be between 60% and 80% based on the numbers above?

01-04-2017 05:26 AM
PM  EMAIL  GALLERY  Attn:RR
Dingo07

Senior Heliman

Newport Coast, CA - USA

My Posts: All  Forum  Topic

Thanks for the help, I got it all sorted out now. KDE 455KV motor is being sourced and will be run on 12S.

01-08-2017 07:08 AM
PM  EMAIL  GALLERY  Attn:RR
Dingo07

Senior Heliman

Newport Coast, CA - USA

My Posts: All  Forum  Topic

I have to Thank AMAIN Hobbies

Well... I sent amain my motor back under RMA after a year of having it - Thank You amain Hobbies!!! But they went one step further. The KDE 700XF-455-G3 was Discontinued on their website so they got one Just For Me! It's on it's way to me now - HUGE Thank You to Graham @ amain Hobbies for making life great! Lifetime amain customer for that

01-17-2017 04:24 AM
PM  EMAIL  GALLERY  Attn:RR
gwright

Veteran

Champaign Il

My Posts: All  Forum  Topic

Listen to Ben and Chuck. Lots of good advice from them. I'd like to offer another perspective however. Currently running an E5 stretched to 700, like Ben's. I've been using a 400KV motor (Hacker) on 12S, with the 12 tooth pinion. My style is more old-school smooth 3D, and I have flight modes setup for 1250,1500, and 1750, all using lots of pitch (16/16). plenty of performance for anything I want to do, (yes, piro aerobatics and slow motion tic tocs are fine). I average anywhere from 12 to 14 minutes, using various rpms at different times in a flight. I'm only using 4350mah packs. My point (yes I do have one ) is that I think you need to go even lower on the KV. I'm only using an HV80 ESC (I'm a bit too fanatical on weight), and rarely see peaks that come anywhere close to pushing it. Since I don't really need the 1750 flight mode, don't use it a lot, it's getting an even lower KV motor installed now. I have another hacker that's been wound for 350kv instead of 400. I should be able to do 1000/1250/1500 if my numbers are correct, with a bit more efficiency than the 400 setup.

Another comment, this time regarding weight. I initially had 5500mah packs in this machine (I use flightpower, the 6s/5500's are 27 ounces ea and provided 12 to 15 minutes of flight). I came to realize over the years that 10 minutes is a good flight time where I don't get bored. I figured I could reduce weight and maybe retain 10 minutes with some smaller batteries. I looked at all the flightpower packs in the appropriate range for this heli and the 4350 cells stood out as having the highest energy density. 6s/4350 is 20 ounces compared to the 27 of the 5500's. this means a savings of 14 ounces total on the heli,.. which is substantial. I tried a pack of them, and the strange thing is, although everything got better from the weight reduction, I didn't lose any flight time. With the lower KV motor I may be able to go down even further in battery weight.

Gary Wright
Futaba
Flightpower
Prod manager at Hobbico

01-17-2017 02:15 PM
PM  EMAIL  GALLERY  Attn:RR
gwright

Veteran

Champaign Il

My Posts: All  Forum  Topic

Forgot to mention,.. I disagree with this "efficiency factor" that folks commonly use when configuring power systems. I realize I'm in the minority with those thoughts, but actual data recorded over the years indicates it is correct. KV times voltage (3.7 times cellcount) divided by gear ratio, gives you a good number. Minimal overhead is a key to high efficiency setups. the more overhead you have, the higher the peaks will be, and of course the related heat that's generated. My current setup, 400kv times 44.4v, times 12 pinion divided by 121 maingear equals 1761. My highest rpm, governed, is 1750, and it governs well. Without governer, at full throttle, it will spin much higher than the calculated 1761. This is probably due to current batteries maintaining higher than 3.7/cell, but that's obviously enough for the needed headroom.
My biggest dissagreement with this "efficiency factor number " that people use is that it is completely irrelevant to rpms. Efficiency is a characteristic of how much energy is consumed to produce the output, not a characteristic of rpms (which is the KV). Say you have two motors that are both 1000KV although one is 90% efficient and the other is 80% efficient. If you apply 10 volts to both of them, they will both turn 10,000 rpms. The lower efficiency motor will draw 8.8% more current from the battery to turn those rpms, but it will still turn the same rpms. Efficiency is very important (or I wouldn't be changing motors in my 700 to get rid of wastefull headroom) however, it has nothing to do with the unloaded rpms for our headspeed calculations.

Just My $0.02, consume with exactly one grain of salt

Gary Wright
Futaba
Flightpower
Prod manager at Hobbico

01-17-2017 02:30 PM
PM  EMAIL  GALLERY  Attn:RR
Chuck Bole

Elite Veteran

Tulsa Ok. U.S.A.

My Posts: All  Forum  Topic

exactly one grain of salt

Gary you've been doing this for a long time, i'm speaking to your experience. The next motor i install in my E7 will be in the 400Kv range.
I put the 4530 500 in mine to balance the 8s stick pack i've been running for the last 2-3 years. Time for new batteries so i'm going to change my
setup to get even more of a "Wright" setup..

chuck

Team Synergy Field Representative / Thunder Power

01-18-2017 01:43 AM
PM  EMAIL  HOMEPAGE  GALLERY  Attn:RR
WATCH  2 pages [ <<    <    ( 1 )     2     NEXT    >> ] 348 views POST REPLY
ProModeler Scorpion Power
 Print TOPIC Advertisers 

 4  Topic Subscribe

Monday, January 23 - 12:38 pm - Copyright © 2000-2017 RunRyder   EMAILEnable Cookies