3,4,6s and 350's question.

[epc2]

Hi Guys,

I have a Mini P on the way with strecht kit and 350's, so from what I've read 3s is a no go with the bigger blades, are you guys seeing a big difference between 4 and 6s?? It looks like there're more 4s batts available.

Trying to decide between 4 or 6s?

Thanks,

epc2.

[Freeskiken]

I went 6s. I had no problem getting batteries. Runs great.

[JustPlaneChris]

Biggest difference between 4S and 6S is the motor temperature. Everything runs cooler on the 6S setup. Power on either will be very good.

[Aleusius]

I run the 350mm blades on the mini for 100 flights now and have no probs at all. Enough power and much less weigth then 4 or 6S. I head never temprature problems not with the motor, not with the EBC not with the Lipos. The 3s has a big weight advantage.... as long, as you dont go for 3D Competion.

[spykez]

Sorry, this last bit I don't get. A 3S pack is about 200G and a 6S pack is also about 200G (unless you get pairs of small 3S's).

Ok, the 4S packs are a bit heavier at about 250G but How is the 3S significantly lighter than the 6S when they stretched?

[Aleusius]

Hello,

here is a 6S pack just as an exemple;

Capacity: 1300mAh
Voltage: 6S1P / 6 Cell / 22.2V
Discharge: 25C Constant / 50C Burst
Weight: 206g (including wire, plug & case)

and here is a 3S pack, that is compareable:
Capacity: 1600mAh
Voltage: 3S1P / 3 Cell / 11.1V
Discharge: 25C Constant / 50C Burst
Weight: 143g (including wire, plug & case)

it has 69% of the weight, or 63 gramm less. You need much less head speed for the same "power".
As I said before, It may make a difference in Compettion but not in sport flying...

Caren

[rossk]

According to physics, P=VI => Power = Volts x Impedance, impedance is halved when volts are doubled for the same power.
So 1300 6S pack is == 2600 3S pack in terms of flight times at the same power.

Head speed is head speed, the same amount of power is required either way.

[Aleusius]

hi,

According to physics, you can not double bouth Volt and Capacity. If you have double the Voltage, the Capacity stays the same.

Would be great if it would be different

Caren

[epc2]

I'm just going to order 1300 3s x 2 run and them in parallel with the stock 3s motor , if I don't like it I'll just order the 6s motor and wire them in series, that way If I decide to go 6s I won't have a useless 3s pack.

epc2.

[spykez]

Originally Posted by Aleusius

Hello,

here is a 6S pack just as an exemple;

Capacity: 1300mAh
Voltage: 6S1P / 6 Cell / 22.2V
Discharge: 25C Constant / 50C Burst
Weight: 206g (including wire, plug & case)

and here is a 3S pack, that is compareable:
Capacity: 1600mAh
Voltage: 3S1P / 3 Cell / 11.1V
Discharge: 25C Constant / 50C Burst
Weight: 143g (including wire, plug & case)

it has 69% of the weight, or 63 gramm less. You need much less head speed for the same "power".
As I said before, It may make a difference in Compettion but not in sport flying...

Caren

Ahhh. I get you. You are using much smaller 3S's. I use 2000-2200 mAh 3S's. Weigh just around 200g. You must get about 3 mins on those? How's your cog?

[spykez]

Originally Posted by Aleusius

hi,

According to physics, you can not double bouth Volt and Capacity. If you have double the Voltage, the Capacity stays the same.

Would be great if it would be different

Caren

I don't know what you mean. The energy content of the lipo as you can see can vary. You use 1600mAh I use 2200mAh. Different energy content. Same voltage. I have 4000 mAh 6S's. There are larger I am sure. Energy content depends on the lipo design and not voltage of the pack although I am sure at some point there is a practical limit on how large a lipo cell can be.

[spykez]

Originally Posted by rossk

According to physics, P=VI => Power = Volts x Impedance, impedance is halved when volts are doubled for the same power.
So 1300 6S pack is == 2600 3S pack in terms of flight times at the same power.

Head speed is head speed, the same amount of power is required either way.

My physics is really rusty but I think you probably mean current instead of impedance - but I get you all the same ; )

I was thinking the CoG would be really off with a pack that weighs but 140-150g stretched....

But I have to admit, I like Aleusius's idea and I never actually did think they made packs at 1600mAh at 3S. If it balances nicely unstretched, it might prove to be interesting...

[Aleusius]

Hi spykez,

me too. I really got inspired by the idea to use very small Lipos.
So I found a 3S nano tech 1300mah with 119g of weight inbetwen my spares.
I hat to ad an other 30g in the front of the Canopy to be in balance...... and, what shall I tell you incredible performance with unknowen agility. I had 1750 rpm on the head of the streched bird (350mm helitec Blades). I was flying for 6 minutes, using ca. 1000mah.
Only the battery place looks very emptey....

Why dont you try it??

Caren

[th0rg0d]

Aleusius,

You're running a stretched 350 on 3s 1300mah? And you're getting 6 min flights at 1750 HS?

Are you using the stock dampers? What pinion?

That seems incredible. I have to admit I'm a tad skeptical, but that's just because I'm ignorant of running a setup outside of the norm.


Sent from my Tapatalk using iPhone.

[macem]

... hi caren,

hard to believe you get "incredible performance at 1750 rpm headspeed"
even with the 350-blades,... mine would be wobbeling all around the place ...

i feel good with 3000 rpm - perhaps you have to double your measurement results? 3500 would be the right figure for "incredible preformance"....

macem

[th0rg0d]

Originally Posted by macem

... hi caren,

hard to believe you get "incredible performance at 1750 rpm headspeed"
even with the 350-blades,... mine would be wobbeling all around the place ...

i feel good with 3000 rpm - perhaps you have to double your measurement results? 3500 would be the right figure for "incredible preformance"....

macem

That was my first thought. 1750 has got to be too low for flight. TC would also be <60% with 14t.

I'd like to see a vid if you got one.




Sent from my Tapatalk using iPhone.

[SidewaysLS4]

MiniProtos flys pretty good at low speeds...here's some 1400...

[ame]http://www.youtube.com/watch?v=Ockgs-o1qa0[/ame]

[spykez]

Originally Posted by Aleusius

Hi spykez,

me too. I really got inspired by the idea to use very small Lipos.
So I found a 3S nano tech 1300mah with 119g of weight inbetwen my spares.
I hat to ad an other 30g in the front of the Canopy to be in balance...... and, what shall I tell you incredible performance with unknowen agility. I had 1750 rpm on the head of the streched bird (350mm helitec Blades). I was flying for 6 minutes, using ca. 1000mah.
Only the battery place looks very emptey....

Why dont you try it??

Caren

I was thinking more of a 3S unstretched with a slightly smaller Lipo - but I was wondering how adversely affected the CoG or flight time would be.

I think I'll wait a bit. Buying a 130X and that's taking up my budget. I'm not all that handy with mods and I'd hate to buy a Lipo I'd have to do drastic things to balance.

[Aleusius]

Originally Posted by macem

... hi caren,

hard to believe you get "incredible performance at 1750 rpm headspeed"
even with the 350-blades,... mine would be wobbeling all around the place ...

i feel good with 3000 rpm - perhaps you have to double your measurement results? 3500 would be the right figure for "incredible preformance"....

macem

Hi,

as I said no 3D but all kinds of sport flying.

You have to consider the very light weight. I just went through 3 packs, 7min of flying with 1750 rpm and 5:30 with 2000 on the head.
I head my fun and I cant believe what a big range the MiniProtos has.

I have the turnigy 1860KV motor with a Kontronik Jazz40LV and 48% for the low and 60% at the high RPM curve. I have the 13t pinion.

All with the stock dumpers of the low profile head.

I will try to make a vid on the next weekend. (will be my first....)

Caren

[desertstalker]

I have flown mine on 2200 RPM, 4S stretch and a lot heavier due to 2500mah packs. It flies fine, no bad behaviours (bobbing or such) and is fine for circuits and slow aerobatics (im sure a better pilot could do more). The YGE Gov didnt like it at all though, bogged really bad if you gave it much pitch (anything more than a slow climb) and a very slow recovery, I think to do Low HS stuff I would need to use the 6S wound motor (1300Kv) and a larger pinion, since the 14t is unreliable.

Heli is much more fun at 3000RPM though, but then you get 5mins instead of 12... I usually fly at 2700 and get ~7:30 from 4S 2500mah

A quick look at Mr Mels calc shows that on 4S at least the 1300Kv and 17-18T pinions would be quite suited to a low HS setup. Similar results could be achieved with 3S and the 2010Kv motor.