Originally Posted by Saxguy1000

I use the timer in the DX8, but a lot of times I prefer setting my watch or another timer. Reason is that I know my batteries and I would set them for the appropriate amount of time for each. On the Tx I always just go with the set time because its a pain to keep changing.

Ah, you learned well "Grasshopper." I have always said "all batteries fly different" even if they are the same brand, age, mah, etc. That "extra" minute of flying could put a batt over the 80% threshold.

Listen to Sax Guys. Know your batteries!

Mike.

Originally Posted by BattleDude

There is also an alternate method to accomplish this.

My brain has learned to compensate for this pendulum swing, by applying opposite stick at just the correct "split second" before the swing starts to happen.

It takes pretty good timing and "hand to eye" coordination, but it works if a pilot can learn to do it.

I still say the best place to maiden the 120 is inside a large building such as a gym. That way, if the bird can be brought to a stable "hands off" hover, then we know that what the pilot is experiencing in his flight, is either #1 - the natural tendency of the 120, or #2 - A pilot induced motion.

The outside wind plays funny tricks on pilots minds and their heli's. It is even more so with a pilot who wants to hover. Flying the the machine with lots of forward speed, reduces the effects of the wind pushing it around. Hovering increases it.

hereathome, it does sound like you may have a problem with yours. I am keeping in mind that I am not watching your heli in the video you posted, so I couldn't say for sure. To me, the one in the video looks like it is flying normal, as the pilot is able to bring it to a stable hover at times, for a second or two.

My suggestion would be to try flying it in a large indoor area to eliminate any effect from the breeze. If you can't bring it to a stable hands-off hover you have a problem. At that point with the heli being new, I would makes sure that HH makes it right with you.

+1 BD - your method for preventing unwanted oscillations is preferable but any method may be more difficult at first for a less experienced pilot.

That's why I especially like your suggestion that anyone flying the 120 for the first few times not even try to establish a completely stable hover. Keeping the heli moving in ANY direction should be easier than trying to get it to come to a full stop once it's moving.

And you are dead on when you say that a new pilot should avoid even a hint of a breeze. The 120 can be flown in a slight breeze but it's not much fun even for an old hand.

At any rate it sounds like hereathome may have some mechanical problems that HH will need to address. They've always come through for me.

So I ran a battery through the 120 till I got the low battery warning, then stuck the VOHM on it and got a reading of 3.57v

From what I can find online 2.7 volts is considered "dead" A fully charged 1S is 4.2 volts, so using the 80% rule, you shouldn't go below 3.36 volts. Does that sound right?

Originally Posted by DaveNH

So I ran a battery through the 120 till I got the low battery warning, then stuck the VOHM on it and got a reading of 3.57v

From what I can find online 2.7 volts is considered "dead" A fully charged 1S is 4.2 volts, so using the 80% rule, you shouldn't go below 3.36 volts. Does that sound right?

The one thing I would like to "throw in" here is, that those 80% should be under load as far as I am aware ... however, if you get a 3.57 reading AFTER the flight (ie with NO load), you can be sure you WERE below the 3.3 under load.
(I think most of these LVC warnings are set to 3V which you would get under load and I would claim this is pretty much in line with your 3.57 after the flight ... if I understood the post right ...)

Now if this concerns you is a personal decision - when I was still flying coaxes, I would always fly until the heli comes down by itself ... and in the beginning with the mCPX as well. In the beginning, it seemed not to bother my TNT 300mah batts, now I am not so sure anymore ... ...

Originally Posted by DaveNH

So I ran a battery through the 120 till I got the low battery warning, then stuck the VOHM on it and got a reading of 3.57v

From what I can find online 2.7 volts is considered "dead" A fully charged 1S is 4.2 volts, so using the 80% rule, you shouldn't go below 3.36 volts. Does that sound right?

I'm a little slow today and I didn't follow your calculation. But from my experience, if you want to observe the 80% rule, you wouldn't want to fly it until the voltage is 3.36v. That's way too low. 3.65 volt would be more like it.

The way that I understand it, the 80% refers to 80% of the capacity. For a 500mAh battery, you don't want to deplete more than 400mAh. In other words, if you find yourself putting back 450mAh into the battery, you have gone too far. The 80% is not a direct measurement of voltage. But of course, the two are related.

Originally Posted by Heli Pad

I'm a little slow today and I didn't follow your calculation. But from my experience, if you want to observe the 80% rule, you wouldn't want to fly it until the voltage is 3.36v. That's way too low. 3.65 volt would be more like it.

The way that I understand it, the 80% refers to 80% of the capacity. For a 500mAh battery, you don't want to deplete more than 400mAh. In other words, if you find yourself putting back 450mAh into the battery, you have gone too far. The 80% is not a direct measurement of voltage. But of course, the two are related.

+1 Heli Pad - even though it is an indirect measurement, post-flight voltage should still never be less than 3.7V. Flying repeatedly to LVC has the effect of reducing the battery's available capacity; after relatively few flights to LVC a battery will accept fewer and fewer mAh when recharged until it becomes essentially useless.

I've put a total of more than 500 flights on my eight Hyperion 550's over the past 18 months and have yet to see the LVC light flashing. Plotting mAh "put back" against post-flight voltage for all those flights has revealed the voltage "cliff" at around 3.67V just under the 20% capacity mark. I avoid draining the battery below that point by assiduous use of a countdown timer set at 6:00 minutes. I usually "put back" between 375 and 400 mAh after a six minute flight; post-flight voltages are always between 3.72V and 3.75V.

That's why I said "IF you want to observe the 80% rule". I don't use it as a rule. I use it as a very rough guide line. I don't usually hit LVC, because the fly characteristics start to go downhill before it reaches LVC. But if I hit LVC, I hit it. No big deal. In that sense, I don't really observe the 80% rule.

My Hyperion is also great that way. It has a relatively flat discharge curve. So, even when you've drained 500mAh, more like 90%, the voltage is still above the LVC.

But on a typical easy flying day, when I'm not pushing hard, yeah, my batteries would have 3.75v at the end of the day.

Lately, since I have more and more batteries, I have taken it even easier. I quit flying early, so the final voltage is just around 3.84v. So they are already ready to be stored. Save me time when I get home. I kinda like that.

Originally Posted by hereathome

...

I called Horizon twice and was pretty disappointed. They said I had to either send it to them or buy parts at my expense, even though I had only had run it twice and it was only a day old. Their responses on the phone were pretty curt and they didn't seem very interested in solving the issue. I didn't get an answer to two emails either. I expected good customer service, oh well. I was really surprised by their attitude and lack of customer service. First and last HH product for me I think.
...

Sounds to me like they probaby just think there's nothing wrong with your bird and your described symptoms are pilot induced and that it's not worth (to you or them) sending it in.

Originally Posted by Chap1012

...

Oh Boys...Mikey is getting a new toy tomorrow. My Bud Sonny and I will be picking up his new Carbon Cub tomorrow at the LHS and he is gonna buy me the Super Cub that I've had my eye on.
http://secure.hobbyzone.com/HBZ7380.html

...

Mike, you are reminding me that I still haven't maidened my Super Cub yet and I've owned it for probably a few months now . Never finished my second bushwheel but it looks like I'll be doing my maiden on floats on snow now anyway. Am doing a bunch of scale stuff to it... it'll probably be the most scale looking HZ Super Cub anyone has ever done... but, even to just get it in the air there are some "must do" mods to finish first that everyone recommends before flying it.

Was holding a Carbon Cub in my hands at the LHS last week... it was taunting me... had to keep reminding myself that although there are some modifications to the new improved "V2", there still seems to be the one glaring issue,,,
http://www.rcgroups.com/forums/showt...85631&page=315

Originally Posted by Chap1012

Sax, you surprise me. I thought you might have this website in your faves

I do! It was just that I was writing this at stop lights while driving!!!

Originally Posted by Heli Pad

The way that I understand it, the 80% refers to 80% of the capacity. For a 500mAh battery, you don't want to deplete more than 400mAh. In other words, if you find yourself putting back 450mAh into the battery, you have gone too far. The 80% is not a direct measurement of voltage. But of course, the two are related.

Ahh, ok, the 80% refers to capacity, not voltage. Well, I'll just stick to a 6 minute flight and be done with it for now I guess, until i get a decent charger. We put an awful lot of thought into 8 dollar batteries

Because, batteries = fun!

I tried blade and flybar balancing, polished the linkage balls, used dry graphite lubricant on them too. I would be pickled tink if my 120 flew like the one in post 15877 but it doesn't . It's on its way to horizon hobby for repair.

We picked up a brand new in box never flown 120SR at a yard sale for $50. Flys flawlessly..no problems. It kind of has a few minor differences than my other 120srs. Check were the landing skids go into the frame. Nothing protruding to hit the servo gear!


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Originally Posted by Jake8131

We picked up a brand new in box never flown 120SR at a yard sale for $50. Flys flawlessly..no problems. It kind of has a few minor differences than my other 120srs. Check were the landing skids go into the frame. Nothing protruding to hit the servo gear!

I think they did some redesigning, the one I bought 2 weeks ago looks the same.