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HelicopterMain Discussion › Understanding Lipo and ESC....
08-29-2017 10:52 PM  22 days agoPost 21
InvertedDude

rrApprentice

USA

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EEngineer

Only different from S1 and S2 was throttle curves and 5F hotter outside.

S1 had hotter ESC and motor...lipo was cool

S2 had cooler ESC and motor but Lipo was hotter

Just hover within a 30 feet circle, boring hover with no excitement.

I live in AZ!

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08-29-2017 10:58 PM  22 days agoPost 22
AirWolfRC

rrProfessor

42½ N, 83½ W

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Something very weird about those test numbers. They're upside down.
Sure, a motor running near full load is typically most efficient but 50% different between 75% and 95% - - no.

Aerodynamically speaking, the lower head speed will need more pitch, be more efficient and require less power - - to a point - - and that point is usually a long way off. (like 1/3 to 1/2 of the speed most helis run)

Something else is going on there.

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08-29-2017 11:02 PM  22 days agoPost 23
InvertedDude

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USA

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AirWolfRC

What can I do to clarify this? Tell me what you would like me to do?

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08-29-2017 11:16 PM  22 days agoPost 24
AirWolfRC

rrProfessor

42½ N, 83½ W

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S1 had hotter ESC and motor...lipo was cool
S2 had cooler ESC and motor but Lipo was hotter
Well, the difference in LiPo temps makes sense - The cooler temp for S1 means lower current draw.

The temp diff on the ESC is up for grabs. Could be the ESC is doing more work PWMing (Pulse Width Modulating) the power to the motor to throttle the motor down to S1.

Double check your charging numbers. How much mah going back in ?

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08-29-2017 11:20 PM  22 days agoPost 25
EEngineer

rrProfessor

TX

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I don't quite understand.....probably just me....

4 tests total...

Test 1 - S1 with 75% flat curve hovering.

Test 2 - S2 with 75% flat curve hovering.

Test 3 - S1 with 95% flat curve hovering.

Test 4 - S2 with 95% flat curve hovering.

All other parameters the same in the above tests.

Looking for any non-obvious difference between S1 and S2
settings in the TX.....besides just the flat curve difference between S1 and S2.

Logo 600SXs, 700XX, 800XX

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08-29-2017 11:34 PM  22 days agoPost 26
Pistol Pete

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Seffner, FL

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The comparison needs to be done under normal 3D flying conditions.
Unfortunately no two flights will be the same althought Im still trying to figure out the normal part.

Original Poster...
Find a happy medium and enjoy the flights.

~~Enjoying the hobby one flight at a time~~

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08-29-2017 11:47 PM  22 days agoPost 27
AirWolfRC

rrProfessor

42½ N, 83½ W

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08-30-2017 12:00 AM  22 days agoPost 28
InvertedDude

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USA

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EEngineer

Repeat the same test in the most possible same parameters to confirm the original numbers.

Now I understand you!

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08-30-2017 12:01 AM  22 days agoPost 29
InvertedDude

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USA

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AirWolfRC

So you want me to run the both test 1 and 2 to confirm the lipo recharge numbers to verify?

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08-30-2017 12:03 AM  22 days agoPost 30
AirWolfRC

rrProfessor

42½ N, 83½ W

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Yep.

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08-30-2017 12:12 AM  22 days agoPost 31
wjvail

rrKey Veteran

Meridian, Mississippi

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Well. I may have missed something but I think we have decided that the original test, and the reason for the OP starting this thread, was somehow flawed. The original question was why is battery consumed (a lot) less per flight at a higher head speed. Why did battery consumption go down by nearly 1,600 mA at 95% ESC as compared to 75% ESC. It seemed counter intuitive.

Further more rigorous testing has shown that there must have been an error in the first test. Battery consumption is indeed lower at 75% throttle. That corresponds to what was expected from the beginning.

Have I got this correct?

Going on: Others have pointed out that ESC are more efficient at closer to 100% output. Certainly true. But the ESC's improved efficiency is almost always offset by the total system being less efficient at higher head speed. The ESC may be more efficient at 100% but the helicopter and head are not.

Maximum efficiency would come from an ESC at 100% paired with a lower KV motor. Gearing would then need to used to achieve desired head speed.

"Well, Nothing bad can happen now."

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08-30-2017 12:13 AM  22 days agoPost 32
InvertedDude

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USA

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AirWolfRC

I will run them in the AM. Too darn hot right now!

Currently 110 F

Not gonna test a thing!

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08-30-2017 12:15 AM  22 days agoPost 33
InvertedDude

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USA

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wjvail

Oh yeah, it wasn't a controlled environment. This is why we have smart people helping out the less smart people such as me! (Joke)

*Winks*

You are absolutely correct, the original flight with the number I posted before running tests was nothing controlled. I was playing with trees and doing massive long climb outs. So yeah! I learned something.

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08-30-2017 01:57 AM  22 days agoPost 34
spaceman spiff

rrKey Veteran

Tucson

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enjoy the flights
Bingo. Testing has relatively low enjoyment per hour efficiency.

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08-30-2017 03:58 AM  22 days agoPost 35
EEngineer

rrProfessor

TX

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"Currently 110 F"

I don't blame you.....it's almost unsafe healthwise to be out in that....

With the heat index, it's almost that hot here.....

When you get around to it.....just curious.

The reason I asked for those specific 4 tests was that I have sometimes thought I just changed 1 thing in the TX....and accidently I changed something I didn't intend to....

And it wasn't obvious.....so when I do that, I perform similar procedures to isolate WTF I did wrong....then it becomes clear....

Logo 600SXs, 700XX, 800XX

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09-04-2017 09:10 PM  16 days agoPost 36
InvertedDude

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USA

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Castle Readings Data

1700 RPMS 78% power

2100 RPMS 100% power

Both about 90 seconds hovering/both with fresh fully charged packs.

Still learning more with electrics, patience please!

If I bump down to 9T pinion and raise the throttle to 85% will that be more efficient? This helicopter is just used for hovering and nose in precision.

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09-04-2017 11:36 PM  16 days agoPost 37
AirWolfRC

rrProfessor

42½ N, 83½ W

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If I bump down to 9T pinion and . . .
You haven't said what you're starting from.

As far as efficiency goes, it's the same old story.

You want control responsiveness - increase head speed.
You want efficiency - decrease head speed - to a point.

It's a trade off. Pick your operating point and go with it.

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09-05-2017 12:09 AM  16 days agoPost 38
InvertedDude

rrApprentice

USA

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AirWolfRC

Current setting 10T and 170 main gear

100amp esc set to 175amp cut off

45c glacier 5000mah

EC5 connectors

Align 600xl 1650kv

6 pole

12khz

0 PW

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09-05-2017 12:18 AM  16 days agoPost 39
AirWolfRC

rrProfessor

42½ N, 83½ W

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You missed noting that your battery is 6S.

1650x6x3.8/17 = 2213 max head speed

How about telling us what rotor diameter you are running ?

Model helis don't push the kind of tip speed speeds you find in full size helis (around Mach .65 - - http://airwolfrc.com/NFB.html about half way down the page). They are considerably lower.

- - and for efficiency you want lower head speeds (lower Mach #) especially since the disk loading is so low.

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09-05-2017 12:53 AM  16 days agoPost 40
InvertedDude

rrApprentice

USA

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AirWolfRC

Yes

6s

rotors 600mm CF

Tail 95mm CF

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HelicopterMain Discussion › Understanding Lipo and ESC....
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