New E7SE on it's way...

[Ding0]

I'm new to electric and would love some help with figuring out what would work best for the style of flying I plan on doing - no serious 3D just inverted on occasion. I use a JR X9503 but will upgrade to the new XG14. I already have 3 JR DS8717 servos that I bought for the project. I know there's a lot of different products out there and have been religously reading about all of them online. I've come up with a couple of items that I think I want to use, and have no idea about the other parts.

Don't I need to know what motor I'm going to use, with the servos and receiver and FBL controller so that I can calculate a maximum current draw, before thinking about what I need as far as battery mAh size, C rating, etc?

Then once I know what the bird will draw under full load I can figure out these items:
1- what SEC or BEC or both to use (or is this also part of my max current draw equation?)
2- what battery to use for a given flight time I want to achieve (at least 10 minutes)
3- what power supply and charger I would need to charge the LiPo's at a reasonable rate from home (I'm first on line to purchase a 24V 1800W system with iCharger 4010Duo or PRC 48V 2000W 4010Duo in a case)

Is there anything I'm missing from this equation? or how should I approach this build?

Help is greatly appreciated!

-EDIT-
Am I overthinking this whole thing...? also I should add that I would like to use a KDE X700XF-535-G3 motor and a Spirit FBL system

[flyalan]

By your flying style description you have many options.  Most of which will yield flight times from 5-7 minutes. 10 minutes will be hard to achieve. Yes you are over thinking just a bit 

No you do not need to calculate anything really other than KV and gearing versus your desired head speed. I suggest a target of 1900-2000.

Suggestions on motor:  a 4035 of same brand.  I use Xnova 4035. Also have used Scorpion 4025.  The KDE 700XF is also  good choice.  KV can be 480-530 with pinion selection of 13t for a 480 and 12t for 1 520(or 530)

ESC:  If I we building a new E7 SE I would go with the Castle Talon 120.  I currently run one on my E7 SE with an Xnova 4530-480.  I get spikes around 140amps and the Talon handles it well.  The reason I suggest the Talon is the build in BEC is flawless. 

Batteries:  I have run 3850's to 5000's in my E7 SE.  I find that 4400 or so is the best trade off for weight versus flight time.  I currently get 4-1/2 minutes of moderate 3-d using the 4530 motor.  The 4035 motors would give you somewhere around 5-6 minutes depending on your head speed. If you go to 5000mah then 7 minutes would be attainable. 

If you have not looked at this I would suggest trying MrMel's head speed calculator.

http://heli.dacsa.net/calcv3/Default.aspx

It is a very useful tool for calculating gearing and head speed.

Either of the charger choices you listed will be fine.  It really depends on how fast you want to charge.  If at home I would assume you have plenty of time?  A 1000W system would actually do.

Cheers
Alan

[Danny Dugger]

That KDE motor will be perfect! The stock 12T pinion will do just fine with it. As for batteries, go for 5000s if you're looking for longer flight time. 10 minutes might be a little steep but if your flying is tame you can probably get 6-7 minutes out of 5000s no problem at around 1850 RPM. Make sure you spring for some decent packs with a good reputation. Pulse, OptiPower, Gens Ace, or Thunder Power are all popular choices. Since your servos are meant for a max of 6V you will need to use either an ESC with a good built in BEC or use a quality external BEC. I like Kontronik ESCs for their top notch governor and heavy duty internal BEC but they are very expensive. I've also heard good things about the Talon's integrated BEC. An ESC rated for anywhere from 120A-160A will do just fine for you. If you want to use an external BEC I like the Western Robotics Hercules Super Mini BEC - they're small, stout and reliable with selectable output voltage. Other popular choices are Gryphon and the Castle BEC Pro. Hopefully this helps.

[Ding0]

Thank you guys! I have some clarity now, along with more confusion (about batteries) 

Here's the definite gear:

Spirit FBL system
KDE X700XF-535-G3 motor
JR RG831BP receiver w/telemetry
JR DS8717 cyclic servos
MKS HBL980 tail servo

Here's the questions:
1- Kontronik JIVE Pro 120+HV OR Castle Creations Talon 120HV (does the K really warrant an extra $370?)

2- Glacier LiPo's - how does this work and how many? (can I use 2 6S 6000mAh in parallel to equal 1200mAh?)

last but not least, how does that MrMel headspeed calc work? I'm guessing the RPM result is not the same as Headspeed? I'm getting 1250 to 1111 beginning to end of flight - doesn't sound like the 1850 RPM to 2000 you guys are mentioning... 

Thanks again for all the help!

[dpelletier]

For your batteries, you probably meant two 6S lipos 6000mah in series to give you 12S 6000mah.
Its the voltage that you want up for the power system you are planning on using.
Others will know better than I if 6000mah packs are a good choice or if they are to big (heavy) for your setup.

[Ding0]

I think I understand now... the batteries I use will be directly correlated to the Voltage Range of the motor I choose. The KDE's range is 10S-14S. Let's assume I choose 10S for this example. I would need two 5S in series to make a 10S, correct? And if those two 5S are 6000 mAh, then that will dictate my flight time based on the draw (how much I work-out) the equipment.

So to get a 10 minute flight time, I would need (just guessing) to fly scale style (no work-out), have 8000+ mAh and 10S-14S LiPo's - do I have that right?

I'm guessing that doesn't exist... 

[Rodney Kirstine]

The motor's kv rating is how many RPM it will spin per volt applied.

Based on what I've seen from people's posted setups I think most people run 4400mah or 5000mah 12S packs (2 6S in series).  The most popular motors are in the 450kv - 520kv range. Head speeds most people run are usually right around the 2000rpm range +/- a few hundred RPM.

If you wanted to get 10 minutes of flight time your best bet would be to set it up for around 2000rpm on 12S and then run it on 6S at really low head speeds.

https://youtu.be/249VykGgeDY

[Ding0]

Thanks Rodney, but that KV rating just confuses me... how does that math work out?

and does that mean I would need to choose a new motor?

[Rodney Kirstine]

No, you wouldn't.  The most simple way to think about it is that the motor will spin 1/2 the RPM running on 6S than it will on 12S.  For now, don't worry about the slow head speed thing, I didn't mean to muddy the waters.

The setups that Alan and Daniel mentioned are really what you want to shoot for.

[Danny Dugger]

1- Kontronik JIVE Pro 120+HV OR Castle Creations Talon 120HV (does the K really warrant an extra $370?)

You will need a Kosmik for a 700 class machine. The Jive Pro is really intended for 500-600 class applications. Overcurrent protection is too sensitive and last I heard it very frequently shut down on 700s. The older Helijive 120 is a different story though, and could handle very high current spikes but your only hope there is to find one used.
   Is it worth the premium? If you're not pushing the helicopter... probably not honestly. The Kosmik has an unbelievable governor that is super easy to set up and a very stout BEC which is made to work with a buffer pack for redundant receiver power. It shines in high power applications and where the governor is being worked hard like in hard 3d. For scale like flying there's really no need to spend so much on a monster ESC when just about any of them would suit your needs and you probably wouldn't notice a difference. The really smooth slow spool up on the Kosmik is probably the only feature you would miss. Power redundancy can be achieved with any unit using an Optipower Ultraguard.
   
  Your choice of motor is perfect, you don't need to change kv. You need to run two 6 cell batteries in series. I think you could probably fit two 5300mah packs in the frame but I know 5000s are a sure thing. The batteries get wired in series so the capacity remains at 5000mah and the pack voltages add together. Essentially with this setup you will have about 45V running the motor. If your motor is 535kv this means the motor will turn 535rpm per volt. 535x45=24,075 max motor rpm. You'll be using a 12t pinion and 121t main gear - so the main drive gear ratio is 121/12=10.08 (10.08 motor revs:1 rev at the head). Motor rpm/gear ratio=headspeed, so you're looking at about 2388 max theoretical headspeed. <-- You'll not actually hit this number in the real world. Your low numbers from the calculator were probably a result of either not enough lipo cells or wrong gear tooth counts. Use 12 cells, and choose the governor from the ESC of your choice after checking the gov box at the bottom.

[Ding0]

OK Danny, I think you're saying the CC Talon 120HV will probably be OK because of the type of flying I'll be doing, but the Phoenix Edge HV 160 will be better suited for if/when I decide to do some flips, rolls or inverted without issue. Do I have that right? 

Thank you for the great explanation on calculating headspeed!!!    I get it now!

is 2 of these a viable option http://www.buddyrc.com/glacier-30c-8000mah-6s-22-2v-lipo-battery.html ?

[Josh Moen]

A 160 amp high voltage ESC such as the Castle you are talking about will definitely give you overhead and room to grow(this is the ESC Matt uses in his E7). I would steer you in the direction of buy it right and buy it once. You could get by with a 120 and sport flying but when you're learning and you suddenly jab that collective, or grab a lot of cyclic, a shutdown is much more prone to happen without a 160.

On the battery question, the E7 only has an inner frame width of 62mm and those batteries are 64x48x165 so they probably won't fit real great unless you lay them on their side, you would never want to get them puffed! Also keep in mind the weight of the packs, you could get into an instance where the extra capacity doesn't add to the benefit of  flight time, but this would be trial and error testing, although if you're learning the weight may not be a subject of concern.

These would fit much better and give you more clearance.
http://www.buddyrc.com/glacier-30c-6000mah-6s-22-2v-lipo-battery.html

or these:http://www.buddyrc.com/glacier-45c-5800mah-6s-22-2v-lipo-battery.html

When selecting your batteries keep in mind the inner frame width, it can come back and bite ya!  Good Luck!

[Danny Dugger]

Keep in mind if you choose the Edge 160  that you will need to buy an external BEC, as it does not have one built in. My personal favorite: http://www.amain.com/rc-helicopters/western-robotics-hercules-super-mini-bec-g2-5.3-6-7.3-8.2v-wrl-hbecm2/p226647?gclid=CjwKEAjwmZWvBRCCqrDK_8atgBUSJACnib3lgzgeiJEKDeWQbhdrdCWeDzLBPsEa4Z93HUUpdlklihoCaLLw_wcB

[Dan Roysdon]

I've heard great things about the WR. I've been using a cc BEC pro on half my 12s packs for years without issues too.


Sent from my iPhone using Tapatalk

[Ding0]

Ok guys a 160 it is... the question now comes down to:

Kontronik Kosmik 160HV for $750 OR CC Phoenix Edge HVF 160 w/Fan for $271   with: WR Hercules Super Mini BEC for $89   or   WR Hercules Super BEC PRO for $119 $750 compared to $400 +/-  a $350 difference goes a long way - like half the cost of a new JR XG14 w/receiver+telemetry Why would I spend the extra money for the Kosmik? Would I really use all its features? I think I have a better handle on the battery scenario also - the only way to get more flight time is fly with a Low Head Speed. I'll leave that for another discussion! WoW - this all started out with just wanting to get a used 700 FBL size on the cheap (all in about $800 I was planning) - to see how much different it would be from flying the Sceadu (which is a lot of work I think) - I'm up to my eyeballs now in info and tech! Upgrades across the board! Thank you all for your help!