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Old Apr 30, 2005, 07:12 PM
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Logo 20 Performance - NiMHs vs LiPos

Well, the weather here is lousy so I'm sittin' here watchin' TV as I cycle my two new TP6000-4s3p packs. So, since I can't fly, I'm trying to imagine the difference in performance between 24 HR2600 NiMHs and these LiPos.

What should I expect? Will it be a bit more powerful or will I be blown away? The motor is a Tango 45-08 and I've switched to an 11T pinion with the 140T gear.

Rob
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Old Apr 30, 2005, 07:35 PM
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more power and lighter weight will make significant improvement in responses. you will love it...
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Old Apr 30, 2005, 07:39 PM
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Please let us know what you think!! That will be my next move with the Logo . I think you'll be blown away. I already have a 4S3P, just need to get one more.

But the true 3D setup would be a 10S2P.

Chachin..
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Old Apr 30, 2005, 08:42 PM
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Hey Chachin.

I was hoping you would say it would be exactly like a Fury Ion.

Hehehe.

Rob
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Old Apr 30, 2005, 09:00 PM
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Hey Rob, today at the Bithlo FUNFLY we had plenty of Fury Ion's These are definitely top notch machines... I don't know if the L20 could get to be a smooth as the Ion, but it should get pretty darn close . The reason I want to upgrade the batteries is because I rarely fly my other helis now.

Hopefully for the next event (St. Petersburg, FL) I should have my L20 LiPolized I can't wait to hear your report!

Chachin..
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Old May 01, 2005, 06:25 AM
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Quote:
Originally Posted by Chachin
The reason I want to upgrade the batteries is because I rarely fly my other helis now.
Yup. LiPos spoil ya. I "lipoized" a Logo 10 and was pretty impressed. I prefer the flight characteristics of the 20 though. The Logo 10 3D at 2krpm is fun but seems a bit unsteady and unpredictable in comparison. Maybe the new LLS head is better.

Anywho, I'm hoping the 20 will now significantly exceed the 10 in performance.

Rob
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Old May 08, 2005, 06:28 PM
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I flew the "LiPoized" Logo 20 for the first time today. I spent the first hour-and-a-half just trimming it (I changed to the new head, changed the gearing and changed some tail rotor parts). On the second charge, I flew it around but tried to be gentle. I flew it for 13 minutes and there was about 1500mAh useable capacity left.

I haven't flown this heli since last year so the difference between the LiPos and the round cells wasn't all that obvioius. It did tach it at about 100 more RPM on the head (close to 1850) which was expected. The head speed seemed very low to me. I think this is because I've been flying the Logo 10 at over 2krpm and this spoils you. I didn't notice the lighter weight that much but it does seem to hold RPM better with collective changes. Even with HR-2600s hot off the charger I seem to recall the RPM would drop a lot more under load than it does now.

I also thought that with the longer flybar, longer linkages and KSJ paddles the cyclic response would be quicker than it was. This heli sure flies smooth though. The Logo 10 is almost frantic in comparison. Mind you it also has faster digital servos...

Anywho, it is an improvement for sure but so far not a "night-and-day" difference. Perhaps I am being unfair - the batteries aren't broken in and I haven't tried any flippy things. I wish I could have tried before and after without six months inbetween! I suppose I could also go up a tooth on the pinion to get more head speed but more flying skill is probably most needed.

Rob
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Old May 09, 2005, 02:33 AM
ehx
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Interesting... When I switched over about a year ago Lipos made the helicopter seem like a whole new machine. My setup is the same as yours except the head and gearing are the old version and my headspeed is about 100 rpm more.

So you are going back and forth between Lipos and round cells and don't see a huge difference? For me, with round cells everything happens in slow motion with the lower headspeed and extra weight. That's only a good thing when it's windy. The heli is definitely more agile with the Lipos and I get ~15 minutes of fairly consistent power instead of ~4 "good" minutes and ~2 "losing power" minutes.
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Old May 09, 2005, 05:55 AM
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Quote:
Originally Posted by ehx
So you are going back and forth between Lipos and round cells and don't see a huge difference? For me, with round cells everything happens in slow motion with the lower headspeed and extra weight. That's only a good thing when it's windy. The heli is definitely more agile with the Lipos and I get ~15 minutes of fairly consistent power instead of ~4 "good" minutes and ~2 "losing power" minutes.
I hear ya! But no. I'm not going back and forth. As I mentioned, I haven't flown the heli at all for six months between the round cells and the LiPos. It's the darn weather thing up here! So my comparison to the round cells from both the scientific and subjective perspectives is very poor. All I can say for sure is that it didn't seem as good relative to the Logo 10 as I was expecting.

The Logo 10 has head speed up the wazoo and I've gotten used to it. It must be the relatively low head speed in the 20 that makes it seem sluggish. Maybe I should try a 12T pinion so the max speed is closer to 2000 RPM. It should be good for it - KC's Spreadsheet predicts it still won't bog as nearly as much as it did on the round cells...

Rob
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Old May 09, 2005, 09:34 AM
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I can't even imagine having to haul around 24 cell NiHM, man what a boat anchor.
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Old May 09, 2005, 10:11 AM
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Yes 24-cells makes it feel like a tank! But it will still fly around nicely with a fresh pack, it's been posted before but here's a video of my 24-cell NiMH setup:
http://rcwerks.devnul.org/modules.ph...view_photo.php

Hey Rob, sorry to hear that. I hoped it would be a night-and-day difference. I was also thinking about the 8S setup and thought that you pretty much have the same voltage.... your only true advantage to a 24-cell setup right now is less weight but with a little more power.

But still, I saw Gary Wright fly his Logo20 on 7S LiPos and it sure could move. I could hear the cool and futuristic buzzing sound of the blades everytime it flipped over (like the Ion). Climb out was also pretty impressive. Too bad I didn't grab my video camera. But then again it was Gary flying it and maybe he made it look too good.

How much lighter is your new setup?

Chachin..
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Old May 09, 2005, 11:33 AM
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I had your exact same setup. went from 24 hrsc-2600mah, to 8s3p gen 2's. The hrsc2600's are great, run hot off the charger for the first minute, but get weaker very quickly. They only allow for very marginal aerobatics of any kind, but forward flight is still good. THe lipo's make the heli lighter, and have a slighter higher voltage, that really allows the logo to punch into the air.

Rhett
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Old May 09, 2005, 11:54 AM
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Hey Rob, another thing you have to consider is that your packs are still new. How many times did you cycle it?? I think Gary G. said you need to cycle them around 10 times before you start noticing the real juice. It's so true, in my T-Rex I am flying two back to back 4S packs, one brand new and one with around 10 cycles. The 10cycle pack definitely gives more punch!!

Rhett, I will be joining your switch to 8S soon . Darn LiPos, I couldn't help it and purchased my second 4S3P Gen2 pack from Lasllc. Hopefully I will receive it sometime by the end of this week and hook it up with my other pack for 8S3P in the Logo20. Both packs are well broken in at around 20-30 flights each so hopefully I'll notice the improvement right away.

Chachin..
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Old May 09, 2005, 04:27 PM
ehx
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Get some back-to-back tests in and then see what you think. My guess is that you will probably want a little more headspeed. The difference between 1850 and 1950 for me is huge. Whether or not upping the pinion will create too much bogging for you depends on your flying style.

With the old gears and a 8T pinion mine bogs a little, but it's not bad. I knew I would have to spend the money on batteries and, if need be, upgrade the head/gears, but so far they've held up so it has been a relatively cheap upgrade.

The new head should handle 2000+ rpm, but at that point you might be looking at a new power system for the best match... Hopefully some direct comparisons will show more benefits than you originally thought or a simple pinion change will do it.
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Old May 09, 2005, 06:13 PM
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Quote:
Originally Posted by HoverDown3K
I can't even imagine having to haul around 24 cell NiHM, man what a boat anchor.
LOL. I got this heli before LiPos. That's the only way we could fly these helis back in the old days.

Chachin. You fly the Logo very well on round cells! The way I fly, I need all the help I can get from more performance. A higher roll rate gives me less time to screw up.

The more I think of it, the more I think I was expecting too much considering my setup resulted in only a modest increase in head speed. I think I'll appreciate the performance increase more as the cells break in and I do more with the heli. I checked the voltage of the parallel groups through the taps and they are dead even. So far, so good! Now where the heck is that balancer thingy?

The Logo 10 is really at fault. When you have just flown a heli screaming at you at 2100RPM and go to fly one that is at 1800 it is a bit of a letdown.

I have cycled the batteries a few times but until Sunday it was discharged at only the very low currents the Orbit is capable of at that voltage.

ehx. I can't really do meaningful back-to-back tests because the gearing is set for the LiPos now and I don't have any other pinions for the new gearing. The head speed will be unfairly low with the round cells. I do have the new head now, so I don't have to worry about bending the blade bolts anymore.

I'm definitely going to order a 12T pinion and give that a try. I'm also going to need a new main gear for the 10 pretty soon. The XL Hacker is kinda hard on it.

Rob
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