Single pack - Low Head Speed

[craigjell]

So - I'm quite interested in trying some low head speed stuff because I'm starting to prefer the smooth 3D stuff now. I also like the idea of single pack convenience with possibly extended flight times.


I currently have

• Torsion 690mm blades
• Align 700MX 530KV
• Stock 20T pinion
• YEP 120A.
• Batteries are Turnigy blue 4500mAh 40C packs but I also have a couple of puffy 5000mAh 30C packs to try.

My question is this: Would I be able to achieve a descent low head-speed setup on a single 6S 4500mAh/ 5000mAh pack (1200RPM - 1400RPM)?
I've had a quick look and the biggest available 23T pinion/ gov store puts me in the 95%:1347RPM range but do I ideally need a lower KV motor/ smaller pinion?


What is the best way to get a single pack setup on a Protos Max V2?


cheers Craig

[Guest]

I would just make a jumper, put one pack in set 100% on the Esc and see how you get on. Bigger pinion, less torque and trying to govern might be a bit too much on the Esc. Stick your pack as far forward as you can get it and go enjoy.

MJ

[craigjell]

Sounds simple enough to try, perhaps I'm overthinking things - I'll see how I get on.

[craigjell]

Will the cyclic/ tail gains generally need increasing or decreasing?

[Guest]

Your biggest decrease in performance will be your tail. It will def need the gains upping and depending on the size of the tail blades you could put larger ones on or speed up the tail if you have that option. For starters up your tail gains in the hover and don’t get too demanding on it. Head gains and agility tune to your liking. Do what you usually do but higher until you get used to the timing differences with the collective.

MJ

[trillian]

Will the cyclic/ tail gains generally need increasing or decreasing?

Generally speaking the cyclic gains can usually stay the same. As it's a 'rate demand' control loop it will just apply as much pitch as it needs to try to give you the rate of motion you're asking of it. Sometimes, you may get a little nodding in a hover with high gains, so in my experience I have sometimes dialed down the cyclic gain a bit, but not all helis will have that issue.

I'm running my 700s on 12s setups where the target headspeed is quite low (around 1300-1400) and at those headspeeds the watts of power needed are very low, even for aerobatic, smooth 3D, type flying and crazy low for hovering at like 1000. But I have not tried them on a single 6s pack. I've seen plenty of videos of various 700s on a single pack where they had their 12s setup geared for 2000 headspeed governed so they're flying at a bit more than half that and just running at max throttle.

I have converted my 600s from 12s to 6s in order to share packs with the bigger helis and this has worked really well. I'm running my Kasama Dune at about 1700 on a single 6s 4000-5000mah pack and it is just brilliant, at that speed the tail is still good without changing anything - I literally just changed the motor and put a jumper on the ESC Y harness. Now I have fitted a Jive 100LV for a little more headroom and to free up the 80HV for something else.

Basically, I think the answer to the question about what you can do on a 700 on 6s is that you're looking at around 1200 headspeed. Much more and you're asking a lot of only 6 cells. Obviously you drop 600-700 grams straight away so the heli is very light. The ideal situation with motor Kv and gearing is to have the highest Kv motor and smallest pinion - this way the amp draw is more even, less potential spikes.

I'll just add - because I have mine geared for low headspeeds on 12s I can't really fly them on just 6s. But... I have flown them on really small packs. I was actually a bit amazed to find that I could fly for 5-6 minutes on a pair of 2600mah Turnigy blues - so roughly the power of a single 5200mah pack. (the helis are: Minicopter Triabolo, Kasama Faifa and TDR1 - the Faifa and the TDR are pretty light, but the Triabolo is not at all light, it's a big heavy thing)

[atomiccomp]

I used to fly my compass 6HV on one 6s battery and 100% on my esc I would guess 1100-1200 rpm. It flew quite nicely and would do most maneuvers with ease.

I found the tail was very twitchy and the cyclic and collective quite soft. Plenty of tail holding power as long as you were careful with the pitch.

I would chuck a battery in and have a go. It's good practice.

[craigjell]

I see - thanks for the replies guys. I guess my main concern now is, will the tail hold well enough! I can work with slower pitch responses etc but - if the tail blows out mid-maneuver I could be in trouble!!

I'm going to give it a go with one of the 4500mAh, governor off, gyro gain up a few points to start and flat 100%. I'll make the jumper tomorrow and give it a whirl.

cheers

[trillian]

Sometimes bigger tail blades may be needed but you just have to try it and see. On the Faifa I originally had Radix 105s on the tail and sometimes it didn't quite have enough power for some moves but with Rail 106s, they're just that little bit wider chord and it holds really well.

I see - thanks for the replies guys. I guess my main concern now is, will the tail hold well enough! I can work with slower pitch responses etc but - if the tail blows out mid-maneuver I could be in trouble!!

I'm going to give it a go with one of the 4500mAh, governor off, gyro gain up a few points to start and flat 100%. I'll make the jumper tomorrow and give it a whirl.

cheers

[trillian]

Hi Craig, just curious how you got on trying a single pack flight?

[craigjell]

Hi Trillian - well that one was a 'no go' in the end. I got as far as making up the jumper cable but that was it. I way was too worried about the tail blowing out since I've had the tail let go on my 450s (mid maneuver) and that's scary enough so I didn't want to risk it on the big one.

As a quick test I turned the gov off and lowered my throttle curve to around 60% or so I think, and the tail was so sloppy - the most I dared try was FF and a few stall turns! I considered speeding up the tail but there was no stock anywhere at the time for the smaller tail pulley.

Its something I may look at again in the future but I've been getting into planes recently so haven't really been bothered flying it for months now.


cheers for the help anyway, Craig

[trillian]

Yeah some helis lend themselves to low headspeeds better than others. When I first built the JR E8 I tried to go for low ish headspeeds on a single 6s pack as it has a three blade head, but the tail ratio is just too low, even with longer blades. And then the available collective pitch range just wasn't quite enough either. So It just wouldn't 'gel' until it was around 1700. So I converted it to 12s where it has plenty of power and it's very happy now, just no long flight times but so it goes.

Hi Trillian - well that one was a 'no go' in the end. I got as far as making up the jumper cable but that was it. I way was too worried about the tail blowing out since I've had the tail let go on my 450s (mid maneuver) and that's scary enough so I didn't want to risk it on the big one.

As a quick test I turned the gov off and lowered my throttle curve to around 60% or so I think, and the tail was so sloppy - the most I dared try was FF and a few stall turns! I considered speeding up the tail but there was no stock anywhere at the time for the smaller tail pulley.

Its something I may look at again in the future but I've been getting into planes recently so haven't really been bothered flying it for months now.


cheers for the help anyway, Craig

[RichardV]

I've been flying mine on 6s quite a lot lately, very relaxing.