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Old Jul 19, 2003, 03:30 PM
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Russellton, PA
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Changed Topic To - VentureE Whatt Meter Results With Brushless Motor And TP - LI-PO

Hi guys,

Just wanted to give some more info that I just got on my VentureE with Hackerbrushless motor and Thunder Power LI-PO's. I know itís not a e-rappy but I would think since we are using similar stuff there should be some value to this info...

I just got an Astro in line whatt meter...kewl! And I just conducted some tests. Maybe you guys can add some input to what I see...comments welcomed.

The heli weights 7 lbs 8 ounces. I have (2) 3S4P TP LI-PO packs in series for 6S4P @ 7800 MAH. The motor is a Hacker B50-15XL with 48-3P ESC set in OPTIMUM timing range. The final drive gear ratio is 12.13:1. I am flying 550 mm zigsaw composite mainrotors.

With the Astro meter in line and using ID1, I recorded 25.2 amps and 555 watts, this was in hover. The skytak showed 1720 on the mainrotor blade rpms. I have the meter on the front on the heli so I could hover nose in and walk up to it and see the numbers clearly. I kept the leads very short so the meter cannot mount on the skids like I've seen some do in photos here on the zone.

For ID2 in hover it showed between 28.5 and 30 amps and 610 to 620 watts in hover at 1920 rpms on the mainrotors. I use this setting of power for all out performance and also when the cells reach the 1/2 way point of their capacity I flip to it so it boosts back the rpms near the center T/C stick postion. In both my ID1 and ID2 at the extreme ends of the stick I have it set for full power. I only soften through a manual V-curve the center and ramp to full power. I don't like how the gov feature flies so I don't use it.

Now for the negative load on the ground, which I think should be more than what forward flight would produce since helis fly better with transitional lift so the flying load should be less, I put the heli on the ground and put on ID2 which is my higher throttle curve. I loaded the negative pitch to about negative 8 to 9 degrees from what my transmitter shows on the pitch gauge. The Astro showed 45 to 48 amps at 900 to 935 watts. The skytack showed the rpms on the mainrotors at 1900 to 1910.

SOO, what do you guys think? Is this good or bad? I think good since the heli flies really well.

I'm going to try the 13XL and 6S maybe... It may be too hot a set up. I will definitely try the 5S with the 13XL since I can now check draws with the new meter. The new ESC has not arrived yet and I hate having to un-solder and re-solder for the sake of testing...

I get presently 17 mins with the 7800's in flight with this combo. The 8200's - (2) 3S4P packs are on the way. I'll test these next.

[I redid yesterdays testing this morning to see how consistant the runs were. IMO, very consistant with back to back tests. I've only added some notes to this post as I gathered more info.]

__________
Best regards,

Ron Osinski
aka - GMRO
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Old Jul 19, 2003, 03:40 PM
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Hi Ron,
Very useful information, thanks for posting that! Is 1910 and 8.5 degrees normal for your ID2?
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Old Jul 20, 2003, 10:33 AM
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Russellton, PA
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Scot,

ID2 is set at almost 100% in the center throttle/collective stick position, which gives me 1930 max in hover. I didn't want to squish the skids into the dirt with full negative 10 degrees that I run. So I stopped at 8.5 or so. This is a guess on the pitch. But my pitch gauge and 10X transmitter I would say are pretty close. The heli definitely tried to load up the motor but it kept up very well. The air and stuff blowing up through the disk was tremendous.

ALSO, this was at the 12 min mark on the packs. The 7800's start to drop voltage slightly at this point. This is where I usually flip to ID2 during the flight to get a boost of power back when compared to my ID1 setting. It works well. Sometimes I will fly around in ID2 the whole flight. I get max power with this setting. It just depends on the weather and temps outside.

Without using percentages as power levels for the sake of argument...my thoughts are to have ID1 set at Full Power at the extreme ends for climb outs and say 70% of the available power near center stick for the softer type cruising flights. ID2 uses Full Power at the extreme ends too but the center stick gives 85% of the available power. I use 3-point throttle curves. IMO, it keeps it simple and it works super vs. the gov mode. Both modes are good for aerobatics. ID2 just helps when the packs start to fade as well as gives great power for harder stuff. Normal mode is strictly for run up and basic hovering. I am never in this mode except for run up or if I let someone else try the heli.

Thanks for the interest.

__________
Best regards,

Ron Osinski
aka - GMRO
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Old Jul 20, 2003, 01:33 PM
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South Orange County, CA
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Ron --

Your numbers track pretty consistantly with what I was seeing on my Logo 10. In a hover I would get something close to 450 watts with a weight of about 6 pounds even at similar headspeeds. That works out close to the same watt/weight ratio.

With my Whattmeter strapped to the skids and using a wireless video camera, I could monitor the values in flight. The worst case numbers I would see were from "rocket launches" at full collective from a hover. Current would top-out at about 47-48 amps. Most other hard maneuvers would be in the 35-40 amp range.

My friend's custom eRaptor weighs very close to the same as your VentureE (7 pounds, 7 ounces...). He's using a -9XL, but with the 3.2:1 planetary gearbox. With a 20T pinion and the stock Raptor 30 85T main gear, the final gear reduction is 13.6 to 1.

-- Gary
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Old Jul 20, 2003, 01:35 PM
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Thanks for clearing that up, Ron! I'm still trying to find that magic combination for my Raptor. Hey, how do you like the Zigsaw blades? Helihut sells some 600mm blades that I'm thinking about getting. What do you think?
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Old Jul 20, 2003, 03:40 PM
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Russellton, PA
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Hi Gary,

KEWL!!! Sounds like once you get a heli flying good most numbers are similar. I did see your post with the wireless camera on board. Very ingenious!!! My system is too cumbersome and weights too much. It's good for an IC 60 but it would be a little too much weight for this heli.

Scot,

I've liked the Zigsaws since they came out with the G4's... This is the latest generation. I've used the 550's and 600's and they rock! Clean blades that have the CG out near the tips...so the blades overall weight is low but the autos are great since they hold the energy well with the weight at the tips. I'm going to get a set for my Venture50 IC I'm working on now. Just got the OS50 for it Friday. This week I hope to finish it up and get it into the air. That's another story.

I also have the NHP 550 Razors too. Nice as well but don't shine in the auto as well as the Ziggy's. You won't go wrong with the Zigsaws!

Now if the new ESC would arrive I could do some 13XL testing!

Another thing I've noticed as the temps rise here in PA is that the ambient temp has an effect on the TP packs and the motor/ESC too. I've cut my flights back to 8 or 10 mins respectively when the temps outdoors are above 80 degrees. I see a bit higher temps, packs in the 135 to 140 ranges and the motor in the 145 to 150 ranges. In my discussions with Charlie, since we are only reading the outside temp of the packs we could be getting some lower temps when the TERMINALS on the packs is at a higher temp since it's in the center of the cells. Also the front bank of cells that is exposed where the wires exit the packs are the hottest. So I now monitor this closely. I have a fan on the motor and one on the ESC. The ESC never gets above 100, usually in the 95 to 97 ranges. Prolly since I run my ESC in the higher power ranges for the whole flight. The motor and batteries are my concern. So I just fly for a shorter time period. Basically when I ran the NiMhs and only got 7 mins total flight time I saw the packs in the 118 range and the motor in the 130 range. Of course the shorter flight was more than likely the reason the temps were lower. Now at 17 mins per flight, if I choose to fly that long, the temps rise and from what I've seen itís not a linear climb as well. SOO when you go LI-PO I'd be conservative until you get a good reference of temp before you hurt the batteries or the motor/ESC.

Now I can't wait till the FALL season when the temps outdoors get in the 60's!!! You can see there's just no pleasing me aye?!?!?!

__________
Best regards,

Ron Osinski
aka - GMRO
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Old Jul 20, 2003, 03:49 PM
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Hi Ron,
Thanks, I think I'll try and get a set of the Zigsaws to try out. I'm impatient and want to test more NOW! I really need to get rid of those wood blades...they make me nervous. If I can resolve the motor setup issues and can keep the rpm under control, I wouldn't mind using them again.

You know, the funny thing is governor mode seems to work just fine for me with 6S. When I tried the 7S batteries, and did a quick climb out, the motor sounded funny like the governor couldn't keep up. Strange that it only does that with 7S. Wonder if it's getting out of it's ideal range or something? Maybe it has to do with motor rpm...if the rpm isn't within some optimal (for the controller) range, it doesn't hold as well? Wish one of the guys who designs these things would comment.
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Old Jul 20, 2003, 04:22 PM
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I agree that the Zigsaws or any carbon set of blades will improve your helis performance as well as make it safer.

Since I'm a die-hard IC guy I don't mind setting up throttle curves. It's actually easy and you will get better performance IMO. Just try a 3-point curve. I use full power at the extreme ends of the T/C stick and say 70% in the middle. Try that in ID1 with the gov off. Just make sure you roll up the power in normal mode till all is equalized and the load is constant before you flip to ID1 incase the values are higher. You could also try and just set all 3 points to 80% all the way across and see how the ESC reacts. It wonít damage anything even it you are not in gov mode. Just be sure to run up the power linear in normal mode before flipping into ID1.

I've used 5S and 6S and 16 cells of NiMh's and seen no difference in the same ESC's behavior. But I've not gone to 7S so I can't comment on that. I will say that 16 cells and 5S used very close throttle values. The 6S I did back off the middle setting as the voltage was up and the rpms were up too.

As far as the designers or importers of the ESC's, I've found they may not be true heli guys and don't see or understand the problems we encounter as we try and fly high-powered e-helis. Most tend to listen to problems and try and fix them in the next software upgrade but this takes time.

Good luck with the Zigsaws!

____________
Best regards,

Ron Osinski
aka - GMRO
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Old Jul 20, 2003, 08:00 PM
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Hi Ron,
I certainly have nothing against throttle curves but I'm lazy and the governor was working okay so far. I'm trying to not change anything else while experimenting with cell count and gearing and stuff so as to minimize the variables. I built the Raptor as the instructions say and haven't even changed the pushrod lengths they specify on the rotorhead...not enough negative and the geometry looks a little off the way it is. I'll get around to fixing that one of these days. Anyway, thanks again for posting all your test data and the suggestion on the Zigsaws.
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Old Jul 20, 2003, 09:53 PM
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Hey Ron, Very good numbers and thanks. I do have one question though. Do you have any particular reason for running a V throttle curve?

I used to run one because everybody else was but on reflection I couldn't justify it. Certainly we don't spend much time in the middle except to transition thru going from upright to inverted. Then at the hover points (approximately 1/4 and 3/4 stick) when you suddenly pull max. pitch and throttle, the rotor just won't speed up that fast.

Any more, I just run it 100% (no-gov) and find this to be fine on both my Raptor and VoyagerE. Now when I push the collective I have maximum stored energy in the blade.

Regards,

Hank
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Old Jul 21, 2003, 08:11 AM
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Thanks Hank!

Actually my V-curve is very mild. If you can imagine 100% or full power at both ends of the T/C stick and say 75% in the middle for ID1 and ID2 gives 85% or so in the middle with 100% at either end.

I like the center to be a little softer when I do aerobatics and the load is off the disk. I've found it runs well this way. But to each his own. I've found this also helps eliminate the cavitation I hear coming from the plastic t/r blades. If I leave the rpms high and have no load the t/r will make some funny noises. SO by reducing the power slightly when the load is not there the heli actually flies quieter. At least that is what I find...especially when flying backwards for prolonged periods of time during the flight.

I do the same with my V-E set up too. I find the heli works well with the power being slightly reduced at the center T/C stick as the load is removed too. When I ran 8 cell NiMhs I ran a flat line very close to full power all the time. But now with the added power of the TP LI-POs, the helis power seems like it's in abundance so I can afford to reduce it near center and still have super performance.

Tailoring e-power for everyone's different flying style is easier vs. IC for sure.

__________
Best regards,

Ron Osinski
aka - GMRO
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Old Jul 21, 2003, 02:21 PM
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Ron,

Interesting points. It seems in effect that you are achieving essentially constant speed without the need for gov-mode overhead.

In my case since I'm using only 16 NiMH cells in my eRap (LiPo next), 100% straight line throttle makes more sense to keep the headspeed up high as possible. BTW, I get 6 1/2 minutes out of HRSC2600's, not too shabby.

Hank
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Old Jul 21, 2003, 02:56 PM
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YUP, I think we agree Hank...

When I ran lower voltages, in actually all my e-helis...Hornet, V-E and VentureE, I did run a pretty high manual curve. You could say it was almost a straight line in gov off mode very close to full throttle. The Hornet and V-E ran 8 cell NiMhs and the VentureE was like your heli running 16 NiMh cells. BUT now the extra power you get with LI-PO's I just choose to regulate slightly more. IMO, the heli sounds more natural when it is not screaming its brain/blades off when the load is low. This is why I feel gear ratios are soo important. Geared right you can run the ESC pretty close to open and have great performance. The less we gate the power back the better. I think we are all agreeing on this.

Your heli sounds way kewl too!!! That is not shabby flight times at all.

__________
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Ron Osinski
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Old Jul 22, 2003, 03:28 AM
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Hey Ron,
Well, I went ahead and ordered a set of the Mavrikk Pro blades from Heliproz instead. I needed some other stuff so just went ahead and ordered from them instead of locally. Is anyone running the Pro blades? They look pretty cool and hopefully they work well without being too heavy. I'll try the Zigsaws next.
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Old Jul 22, 2003, 12:50 PM
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Kewl Scot,

Any good quality carbon blade is going to make a nice performance enhancement over woodies for sure!

Let us know how they work!

__________
Best regards,

Ron Osinski
aka - GMRO
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