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Scorpion Power GLOBAL 3D
HelicopterMain Discussion › throttle setting recommendation
04-19-2017 04:01 PM  67 days agoPost 1
joshreynolds777

Senior Heliman

Willis, Tx

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was trying to set up the governor in my Goblin 570 with Castle Creations 80 Edge HV, and the RPM I was trying to enter were telling me too high for the set up or whatever.

So Im fine just messing with the Governor modes on my helis later. The level Im at, throttle setting in the radio will work just fine.

I read that Goblin doesn't recommend more than a 2600 RPM on this model for "safety" reasons, so Id want to stay under that?

I have the following...
21T Pinion, 206 tooth main gear
Scorpion 4025 550KV
Castle Creations Edge HV 80
12S Thor 3300's

Normally I'll do something like linear at neutral mode.
Stunt one is usually a "V' curve at 75-80% and stunt 2 at 85 or so %

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04-19-2017 04:05 PM  67 days agoPost 2
joshreynolds777

Senior Heliman

Willis, Tx

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while you guys are at it.
You could tell me if you think those throttle setting are ok with the other two goblins as well.

I have a 380 running 2200 mah 6S, dont remember the kv off hand. Pretty sure its a goblin addition quantum

and a G770 12S with the 500KV Quantum

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04-20-2017 01:52 AM  66 days agoPost 3
HeliNutAndy

Key Veteran

worcester, MA USA

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while you guys are at it.
Can you rub my feet too wifey? LMAO

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04-20-2017 05:27 AM  66 days agoPost 4
joshreynolds777

Senior Heliman

Willis, Tx

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No body yet lol ? I'm shocked.
I can't believe no one hasn't told me to go to hell or something by now.

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04-20-2017 05:49 AM  66 days agoPost 5
Pistol_Pete

rrProfessor

Seffner, FL

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Options

RPM = Motor KV x Batt V (3.7 per cell) x Motor Efficiency (ie:80%=.8)
Gear Ratio = RPM / Head Speed
Pinion = Main Gear Teeth (MGT) / Gear Ratio (GR)

Plus a head tach and a buddy to help you out.

Or

SET GOVernor in ESC (versus later)

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

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04-20-2017 06:27 AM  66 days agoPost 6
joshreynolds777

Senior Heliman

Willis, Tx

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The esc was telling me 1900 rpm was high tho. Confused

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04-20-2017 01:18 PM  66 days agoPost 7
dkshema

rrMaster

Cedar Rapids, IA

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The Castle ESC has a couple of governor modes.

Assuming you have performed the TX throttle to ESC calibration sequence first in fixed throttle mode, and have entered the correct motor info (number of poles, I believe), you then select either high or low governor mode. If you choose the wrong mode, your settings won't make the ESC happy. Choose the other mode and see if that makes it happy.

To determine the pole-count of your motor, if you can't find it in a manual or online, count the number of magnets in the motor.

Number of poles = number of magnets.

-----
Dave

* Making the World Better -- One Helicopter at a time! *

Team Heliproz

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04-20-2017 04:48 PM  66 days agoPost 8
FNFAL

Heliman

Dayton OH

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I like the third gov mode, "set RPM" the best. I don't see why you can't set 2100 RPM in the box.

I'm in the Castle link demo right now and it's allowing me to go up to 2128 rpm with proper governing.

That works out to:

Max Gov RPM = 0.85 x kv x #cells x 3.7 x pinion / main

You motor is 10 pole.

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04-20-2017 06:00 PM  66 days agoPost 9
Ladymagic

Key Veteran

South Korea

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Stunt one is usually a "V' curve at 75-80% and stunt 2 at 85 or so %
You could tell me if you think those throttle setting are ok with the other two goblins as well.
Assuming I'm understanding you correctly; yes. Those settings are fairly generic for initial setup on practically any e model of any size. It's smart to leave a bit of head room for spikes and those curves are just about right. I'm actually running happy at around 75% on my Forza700 in stunt 2. That puts my HS around 1950.

Some will say just go 100 because the esc actually might run cooler since the FETs stay open the whole time. But, I wouldn't recommend it to anyone. I'm not saying anyone is wrong here it's just a personal preference.

Oh, setting a HS at or above 2600rpm on any heli is kinda reckless and unnecessary IMHO. (Unless the heli/head is designed specifically with high HS in mind.) At that point any performance gains are negligible and your heli just becomes a hazard. Too much HS is hard on the head and forces you to service it more often. A lot of pilots don't ever service their heads and then you hear about close calls because of parts and blades shooting off. I rarely run heads speeds above 2000rpm but that's me.

Mellisa

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04-20-2017 09:56 PM  65 days agoPost 10
EEngineer

Elite Veteran

TX

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"the esc actually might run cooler since the FETs stay open the whole time."

The FETs don't stay open "the whole time".....they have to conduct current for there to be a magnetic field within the armature of the motor(for a particular coil at the right instant).

Logo 600SXs, 700XX, 800XX

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04-21-2017 01:04 AM  65 days agoPost 11
FNFAL

Heliman

Dayton OH

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The FETs don't stay open "the whole time".....they have to conduct current for there to be a magnetic field within the armature of the motor(for a particular coil at the right instant

Isn't the young lady trying to say that under partial loads the PWM cycles the MOSFETS more creating heat in those ESC's that do not have free-wheeling construction?

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04-21-2017 01:21 AM  65 days agoPost 12
joshreynolds777

Senior Heliman

Willis, Tx

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Fnfal. Thatbks for plugging that in for me. I'll try 2100
Rpm sir !
And as far as max Rpm. Totally depends on the model am I right. And the size. !?
In the sim my little goblin 380 runs at 3000rpm. Seems right for such a Small bird. Smaller heli higher Rpm right ?

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04-21-2017 01:26 AM  65 days agoPost 13
joshreynolds777

Senior Heliman

Willis, Tx

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This is pretty unrelated. But I just ran my trex550 at an rpm decrease safe setting for low voltage cut off at 3.4v. That was a mistake. Under a load in stunt 1.
An soon as I flipped it upside down and bavk over it hit. And lost all my
Head speed. Putting that back to the standard cut off in a hurry. Wasn't even a minute In to the pack yet. The cells were used. Might have 1000 cycles on them for all I know.

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04-21-2017 01:41 AM  65 days agoPost 14
EEngineer

Elite Veteran

TX

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"Isn't the young lady trying to say that under partial loads the PWM cycles the MOSFETS more creating heat in those ESC's that do not have free-wheeling construction?"

Perhaps...but that's a confusing way to put it....

If what was meant was.....that in passive freewheeling ESCs(like the CCs) and the duty cycle of the PWM is half on/half off during partial loads(1/2 throttle)....would be correct.

MOSFETs don't like to be partially biased on....they work best full on or full off.

Passive freewheeling ESCs use a diode to "snub" the back EMF, whereas an active freewheeling ESCs use another MOSFET to do this, by turning them on at the right instant.

And the "on" resistance of a MOSFET is in units of milliohms resulting in the dissipation of less power(heat) than that of a diode.....

Logo 600SXs, 700XX, 800XX

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04-21-2017 02:26 AM  65 days agoPost 15
AirWolfRC

rrProfessor

42½ N, 83½ W

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diode to "snub" the back EMF
? ? ? In the old days, "snubbing" the back EMF was to save the contacts of the relay controlling the inductive load. In switching buck regulators, diodes are used to capture the inductor's colapsing field energy and provide power to the load. Since diodes have a forward break-down voltage (about 1/2V for Schottky and 1V for silicon) higher priced FET's are used instead to improve efficiency (much less forward conduction loss).

2600 rpm is not going to happen with 12S, that gear set and a 550KV motor.
As FNFAL pointed out, 12 x 3.8 x 550 x 21 / 206 = 2557 max (maybe)

A head speed of 2600 on 570 blades is conservative (aerodynamically) but pushing it structurally. Even though the tip speed is well below full size (only Mach 0.51 vs Mach .66) model hardware is not built that strong. Besides, with a disk loading of only about 1/2 lb/ft², you don't need that much speed.

A head speed of about 2000 (75% of calculated max) sounds like a comfortable number for the electronics (and structurally for the blades).

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04-21-2017 02:33 AM  65 days agoPost 16
joshreynolds777

Senior Heliman

Willis, Tx

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75%
Got it !
Sounds good

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04-21-2017 03:31 AM  65 days agoPost 17
EEngineer

Elite Veteran

TX

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"In the old days, "snubbing" the back EMF was to save the contacts of the relay controlling the inductive load."

I failed to mention a FET can also be used as a diode.

Don't know about the "old days"....

The inductive voltage spike due to the collapsing magnetic field of an energized coil(back EMF) can be destructive to the transistor/FET that is used to energize the coil.....depending upon the circumstances(high voltage/high current conditions).

FETs can handle high voltage(source/drain) in one direction, but not in the other....the diode used to "snub" is to protect the FET.

Still used today for that purpose.

Diodes are used for a variety of purposes, so what's the "beef"?...

I agree with what you posted....in addition to saving the contacts of the relay.....I responded about diode "snubbing".

Logo 600SXs, 700XX, 800XX

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04-21-2017 02:07 PM  65 days agoPost 18
Richardmid1

rrProfessor

Leeds, England

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Just use set rpm mode and put 2000 in normal, 2100 in IU1 and 2200 in IU2 (ignore the governor warnings it'll govern fine at 2200!). Remember to set your throttle curves to 0-30-30-30-30, 70-70-70-70-70 and 100-100-100-100-100 and go fly.
And as far as max Rpm. Totally depends on the model am I right. And the size. !?
In the sim my little goblin 380 runs at 3000rpm. Seems right for such a Small bird. Smaller heli higher Rpms right ?
Yes it depends on the model and blade size. 3000rpm for a 380 is about right for most of us doing 3D but can go higher if your names Tareq!

2700rpm for 425mm blades but again can go higher depending on the model.

2500rpm for 550mm but can go higher see above.

2250rpm for 600mm ^^^

2000rpm for 700mm ^^^

1800rpm for 800mm ^^^

These are electric 3D head speeds.

60% of the time, it works every time!

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04-21-2017 02:49 PM  65 days agoPost 19
Pistol_Pete

rrProfessor

Seffner, FL

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ignore the governor warnings
Are you recommending to ignore the max settings set by a team of engineers that designed the product?

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

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04-21-2017 02:54 PM  65 days agoPost 20
AirWolfRC

rrProfessor

42½ N, 83½ W

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The inductive voltage spike due to the collapsing magnetic field of an energized coil(back EMF) can be destructive to the transistor/FET that is used to energize the coil.....depending upon the circumstances(high voltage/high current conditions).
FETs can handle high voltage(source/drain) in one direction, but not in the other....the diode used to "snub" is to protect the FET.
In these applications the devices are used in the forward direction and instantaneous surges can easily be accommodated when sized properly.

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ProModeler Scorpion Power
HelicopterMain Discussion › throttle setting recommendation
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