Want to try something out of the norm!

[Dissmantle]

Right so I have got this weird notion in my head that I absolutely must have a 700 class machine but with a catch. I want to run it only on one 6s 5000mah 50c opti pack and have a moderate head speed of ui1 = 1250 and ui2 = 1500 to 1700.

Now From what I can gather a Logo 690SX with a 16 tooth pinion and stock 380kv motor would do the trick but in terms of what ESC I should use is where I get lost. could I get away with using something like a YGE 120LV or do I have to use a high voltage ESC?

chime in at any time and let me know what you guys think.

Also in your opinion should I be looking at any other frames as against just the logo's? Would I be putting a major strain on the pack in this configuration?

[philipjdall]

You probably could get away with running it on 6s but why would you want to? It really depends on your flying style but chances are you will hammer the pack.

if you do run 6s you can get away with an LV esc, but this will give you no option to upgrade to more cells later.

Motor kV might be a bit low too... You'd prob want to be closer to the 500 mark. Even then it will only be setup for low hs flying.

Any 700 system on 6s will strain the system, but the logo is a good choice as they fly well at low head speeds.

[ChrisB]

Many many vids of various 700s flying on 6s so it does happen,the 690SX would be as good an airframe as any,or maybe the E700.

Here is a chunky Logo 700 doing it.

http://youtu.be/7nS1jKi9JQg

[philipjdall]

Sure, it's possible. But it is still going to be hard on packs.

[Dissmantle]

I came across this video of Matt Botos and his Synergy. this has got me thinking that this could work. After some serious thoughts.. I have narrowed the airframe down to the Logo 690SX, Logo 600SE or the Synergy E7SE.

from what I can tell most setups are running a 12s setup and just halving the cell count.
The only reason I'm asking if I could use a low voltage ESC is because I have one Laying about (spare for my Goblin 570).

https://www.youtube.com/watch?v=7bvV...ndex=9&list=WL

[philipjdall]

Cool! Yeah you may as well try it. I wonder if he's running the same pitch and gains (he could quite easily have a different setup on a diff bank)?

Collective does look quite sluggish.

You can always convert it to 12s if you don't like it...

[wadders248]

What LV ESC have you got? Low head speed flying is great, I do this with all my 12s setup, just as Mat shows in the video by adding a 6s pack.

Building a specific low head speed machine can optimise this even more, like you say by using parts you've already got and tuning the setup. You can run a much higher tail gain with longer tail blades and more main blade pitch. The amp draw is really low for this kind of flying and as long as you're not trying to go above 1,200rpm, you won't stress your packs. The other big benefit is much longer flight times.

The only downsides is you loose some of the pop, you have got to be quicker on the collective and you loose some of the stability in windy conditions. Other than that, on a calm evening it's a really enjoyable way to fly!

[Dissmantle]

Waders248, I have a YGE 120 Low voltage ESC on hand.

Thank you for your input. I think the most that I would risk pushing the head speed is about 1300. As I said in my original post, I want to use the optipower 5000 5c packs.
On your low head speed machines, what pitch are you running on them? I would think that this would also play a huge role when it comes to stressing the pack.

[wadders248]

Waders248, I have a YGE 120 Low voltage ESC on hand.

That ESC will be plenty, I even run a 700 Faifa at low head speed on a Jive 80HV.

Going up to 14° of pitch will be just fine, just don't stick-bang! Going higher on the pitch will stop the sinking feeling through transitions.

I also use OptiPower 5000 6s standard 30c packs and they're more than enough.

One of my helis is a stretched 800 Faifa, which I've flown with a 120a ESC and single 5000 pack. Even though it's a huge heli, everything comes down cool and definitely no puffing on the packs, so with a 700 you'll be just fine!

I forgot the other big benefit is the amazing blade noise. It's the opposite of blade bark 'pop', you get great transition noise and slow air whacking!

[wadders248]

Here's Timo, the low head speed master!

[Dissmantle]

That is just what I need to hear. thank you Wadders248.

Now, the only other question that I have is motor? is there any specific KV range I should be looking at? Now I know that the Logo 690SX manual says that you can only use the Scorp HK 4525-380Kv which doesn't leave much room for play. The other frames mentioned earlier however are all open to various motor options. What would you suggest I look into? should I be looking at something simple like the old(er) align 700 motors (520kv) or look at something else?

[wadders248]

The 380kv will be too low, anything around 520kv is what you'll need. The 800 TDR is only running a Pyro 700-52, so an older 700 size motor will be perfect.

[Dissmantle]

Now that is what i'm looking at... I could watch this all day long and never get bored of it.

[Dissmantle]

The 380kv will be too low, anything around 520kv is what you'll need. The 800 TDR is only running a Pyro 700-52, so an older 700 size motor will be perfect.

Thanks again. Will do some searching and see what I come up with.

[trillian]

Just to add to what has already been said. I have two helis setup for low headspeeds on 12s, a Kasama Faifa and a TDR. The TDR has an Align 750mx /450 motor and the Faifa has a Hacker Turnado rewound for 420 KV. For the best KV and gearing on 6s have a look at Mr Mel's headspeed calculator and play around with the various gearing and KV options you have in mind and see what your governed headspeeds come out at.

On my 12s machines the average amp draw is about 30-35 amps so it will be higher on 6s but at 1200/1300 headspeed it will still be relatively low. The power requirement changes much much more in relation to the headspeed, so for example if you double the headspeed it doesn't just use twice the power, it might take three times or more, so that's why dropping the headspeed makes it possible to run on 6s. On my Faifa, as it is geared for low HS on 12s one options it gives me is that I can run a pair of 2650mah packs that I used for the Trex500. You wouldn't think a 700 size heli could fly on such small packs but it does and I can get 6 minutes of gentle aerobatics (I will say though, you have to be gentle with it on such small packs but the lighter weight helps as well).

I find that I need about 14 degrees, give or take a bit, to have the feel I like at those headspeeds. Most of the time you're not using anywhere near that much.