6s or 8s power system for my stretched Logo 400

[Bullfrog98]

Good Day All,

I recently purchased a Scorpion HK-4015-1070 (Logo 400SE) motor and a Kontronik Jive 80 HV as a little “from me, to me” birthday gift for my stretched logo 400 (500mm blades). I’m also thinking of replacing my old 3700mah 6s packs with something new as they are on their last legs. My current power system is a Hacker A40-12S with matching 70A Hacker ESC.

I noticed that the HK-4015-1070 is in fact wound for 8s configuration, so my question is: Is it worth running my 400 on a 8s system or should I rather just stick with the tried and tested 3700mah 6s packs that I know and trust? Also if 8s is better then roughly what capacity packs should I be looking for?

I remember someone discussing something similar a few weeks ago on the forum, but for the life of me I just can’t find the thread.

[pgleesonuk]

I have stretched my 400 to run 473mm blades. I use
Hacker A40-10L 1100kv motor
19T Mod 0,5 with 200T main gear
Voltz 6S 3300mah packs
I'm not 3D capable yet, but this setup gives be 8:30mins running at 1900rpm

[stetney]

I guess 8S limitations could be availability and size of packs.
Pack availability:
If you run 6S at 3300mAh then the 8S equivalent would be 2500mAh.
I've never seen a 8S 2500mAh pack so we would have to use 2 x 4S 2500mAh in series.
I've also never seen a 4S 2500mAh, so 2250mAh would have to suffice.
Pack size:
A typical 4S 2250mAh is 35mm x 35mm x 102mm.
I can't image stacking these at the front.
Not sure if you would acheive good CG with them end on end along the length of the chassis either.
Sorry I don't have my 400 in front of me to measure so these are assumptions.

Pgleesnouk
Do you have a photo of yours with the Voltz 6S 3300mAh fitted, I'm curious about spacing and CG.

Steve

[pgleesonuk]

I'll get a picture tonight.

[Bullfrog98]

Thanks guys, all valid points that are leading me towards the standard 6s configuration. My flight times are pretty good with the 3700mah 6s lipos I’m using now as I also have a low head speed setup. Also I didn’t think about the possible CG issues

[pgleesonuk]

Here is the picture of a pack of Voltz 6S 3300mah (500g)

The motor is a Hacker A40-10L 1100kv and weighs 246g

This balances my Logo 400Se perfectly.

Regards, Paul

[stetney]

Thx for the photo Paul
That looks like the 35C version at 136(L) x 44(W) x 38.5(H)
As it just hangs over the front of the battery tray there's a good chance it would sit inside on a standard 400 FBL.

I currently run 6S 2600mAh packs at 400g, they last the typical 5mins max. (sport flying - 2400 hd sp)
The math says a 3300mAh would give 6mins and 20ish seconds. (I've not taken in account the heavier pack)
I like the idea of running 8mins 30 seconds as per your (Paul) SE setup.

I may of just talked myself into converting to an SE

Bullfrog
Sorry for high jacking your thread a little.
I would be gratefull if you could tell me more about your non SE setup (pinion, motor, headspeed) and flight times with the 6S 3700mAh packs. Do these packs sit inside the battery tray?

It doesn't look like 8S is the trend for the SE (especially if look at the packs available, mostly 6S 3300mAh > 3700mAh)

Steve

[Bullfrog98]

Yeh, look like I’m going to go with the tried and tested 6s setup. Thanks for all the input guys.

@ Steve, my Logo 400 is actually a bit of a mongrel. My skids are from the 600 and the bows for the skids and the carbon tail are for the 500 (the field we fly at is very rutted and I had my 400 tip over on me during a landing so I went for the widest longest skids I could find) I also want to try a 500 canopy for better visibility.

Anyway as for the important bits I’m running a logo 10 boom, belt and boom supports; standard mod 0.5 main gear and 15 tooth pinion; the motor is a Hacker A40-12S motor with the matching Hacker X-70 SB Pro.

The batteries I use are Hobby King Rhino 3700mah 25C packs which are a little longer and thinner than the Volts packs. As such the back of the pack sits just in front of where the pinion starts and hangs about an inch and a half off the front of the battery tray. The packs weigh 600g.

I find that the 3700mah packs balance my heli perfectly (probably because of the longer boom, heavier carbon tail and relatively light motor) and because I only “sport fly” (read “not good enough for 3D yet” ) the extra weight in the nose does not affect my flying at all.

I set my timer for 6 min (my hart can’t handle the adrenaline coursing through my veins longer than that ) and come in to land once it starts to beep. There is normally about 35% left in the packs when I charge them.

[stetney]

Bullfrog98
Thx for the detailed reply its most appreciated.
Steve