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idle up & normal mode etc... - 6/26/2008 1:52:47 PM   
legine


 

Posts: 205
Joined: 5/28/2007
From: SydneyNSW, AUSTRALIA
Status: offline 		Hey i am awaiting a Belt CP from ebay and before i get it i just wanted to know how the idle up and other throttle modes work....for instance what does idle up exactly mean and what are the other throttle modes/settings and how do they differ from idle up?

Also, when i got my fixed pitch heli, i had to make sure that the swash plate was nice and flat in neutral posiotion (parallel to main rotor gear).....do i have to do this with the collective pitch heli as well (i know i need to set pitch and stuff with a pitch gauge)

Thanks, Daniel
       Post #: 1

RE: idle up & normal mode etc... - 6/26/2008 2:36:23 PM   
BarracudaHockey



Posts: 10815
Joined: 7/13/2003
From: Orange Park, FL, USA
Status: online 		Normal mode increases the throttle as you increase pitch, bring the stick all the way to idle and the motor shuts off (or idles if its a nitro with the clutch dis-engaged)

Idle up usually lets you have 0 degrees pitch at mid stick with full positive pitch at full stick and full negative pitch at low stick. Your throttle curve is set to you have full power at full stick decreasing to mid stick where your throttle has a setting that will maintain your head speed. Then as you go negative the the throttle starts increasing again to full power. You could land and pull the stick back but you would just be getting neg pitch and full throttle holding the heli to the ground. In normal mode the power shuts off and the head can spool down.

If you do a fast descent in normal mode and your head slows down because of a low throttle setting, you may not get your head speed back in time to keep from taking a soil sample. In idle up, it never slows down so you have more instant control of altitude.

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(in reply to legine)
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RE: idle up & normal mode etc... - 6/26/2008 10:18:53 PM   
legine


 

Posts: 205
Joined: 5/28/2007
From: SydneyNSW, AUSTRALIA
Status: offline 		thanks a lot for that!!

One thing, in idle up mode.....is the motor always at the same speed or does it go slower at mid throttle and faster at full or negative throttle???

Thanks, Daniel

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RE: idle up & normal mode etc... - 6/27/2008 1:09:43 AM   
Druss


 

Posts: 4201
Joined: 8/10/2007
From: Edmonton, AB, CANADA
Status: offline 		on the stock transmitter the idle up throttle curve is 100-50-100.

(in reply to legine)
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RE: idle up & normal mode etc... - 6/27/2008 1:18:16 AM   
tadawson


 

Posts: 476
Joined: 9/5/2002
From: Lewisville, TX, USA
Status: offline
quote:

ORIGINAL: legine

thanks a lot for that!!

One thing, in idle up mode.....is the motor always at the same speed or does it go slower at mid throttle and faster at full or negative throttle???

Thanks, Daniel


On any helicopter, the goal is to maintain a constant head speed in a given flight mode, only changing to spool up and spool down. So, in any flight mode (including normal, once past about 1/4 stick), head speed should not change much if at all. Good curves can accomplish this, as can a gov.

- Tim

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RE: idle up & normal mode etc... - 6/27/2008 7:07:25 AM   
legine


 

Posts: 205
Joined: 5/28/2007
From: SydneyNSW, AUSTRALIA
Status: offline 		whats a gov?

and what it throttle hold and does the belt CP have it?

Thanks, Daniel

(in reply to tadawson)
       Post #: 6

RE: idle up & normal mode etc... - 6/27/2008 3:59:24 PM   
kd5boc


 

Posts: 80
Joined: 1/27/2008
From: Abilene, TX, USA
Status: offline 		A gov (governor) is mainly used on Nitro Helis to limit the maximum speed of the engine, and to keep the head speed the same across the board. It uses a magnetic pick up that can tell how fast the head is rotating. You can set it to keep a specific rpm, and if your throttle settings make it go over this amount, the governor reduces power to bring it back down.

Throttle hold is usually a switch that brings a nitro to idle, or turns the electric motor off. Used mainly for Autorotations (landing with no power to the rotorhead - advanced skill) and the stock transmitter doesn't have it.

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RE: idle up & normal mode etc... - 6/27/2008 7:34:42 PM   
tadawson


 

Posts: 476
Joined: 9/5/2002
From: Lewisville, TX, USA
Status: offline
quote:

ORIGINAL: legine

whats a gov?

and what it throttle hold and does the belt CP have it?

Thanks, Daniel


A gov (or governor) is a means by which to regulate rotor head speed. On nitros, it is typically a separate device that uses a sensor magnet on the drivetrain somewhere to determine speed, and which controls the throttle servo to maintain a constant speed - not allowing it to get too low or too high (not to be confused with a limiter, which only controls overspeed . . . ). On electrics, this functionality is often built into the speed controller, although there are external units as well, and while the means of sensing speed differ, the net result is the same.

Throttle hold is a switch funtion on your transmitter which will drop the throttle channel to idle while still allowing all other controls to function normally. It is used to perform autorotations in most cases, and can also be a "safety" in that it will not allow the heli to spool up when engaged. It is also the switch you hit last when you know you are going to crash, since it shuts down the power system, hopefully prior to impact, hopefully minimizing damage.

Since it's a TX function, what model you fly is irrelevant as to whether you have it or not. Considering that most of the small electrics auto very poorly, on that heli, whether you have it or not is probably not that important . . .

- Tim

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RE: idle up & normal mode etc... - 6/28/2008 12:42:18 AM   
legine


 

Posts: 205
Joined: 5/28/2007
From: SydneyNSW, AUSTRALIA
Status: offline 		but if i know im about to crash, what would i do if there is no throttle hold??........Switch to normal mode and pull the thottle back to zero???

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RE: idle up & normal mode etc... - 6/28/2008 12:47:55 AM   
legine


 

Posts: 205
Joined: 5/28/2007
From: SydneyNSW, AUSTRALIA
Status: offline
quote:

ORIGINAL: Druss

on the stock transmitter the idle up throttle curve is 100-50-100.


Sorry, i dont quite understand this just yet......so the throttle will be at 100 at full negative throttle, 50 at midpoint and 100 again at full throttle( is this correct) but what exactly do these numbers mean??

And when setting a pitch curve, should it go like this:

full negative throttle: -10degrees
1/4 throttle: -5 degrees
midpoint: 0 degrees
3/4 throttle: 5 degrees
full throttle: 10 degrees

Thanks for all the help, Daniel

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RE: idle up & normal mode etc... - 6/28/2008 12:57:18 AM   
Cambo



Posts: 1516
Joined: 6/20/2005
From: Phoenix, AZ, USA
Status: offline 		Yes that is correct. That percentage only represents power output not necesarily RPM. By increasing the pitch you are increasing the load thus needing more power to maintain the same RPM. As said before these numbers change between helis. The 5 point curve on my Raven is 100-85-65-85-100 but i am using a computer radio so i can change all of those points.

Gear ration and the desired headspeed along with the pitch range determine what throttle curve you want.

When setting up pitch curves it is easiest to do a perfectly linear V curve. +-10 is only needed in idle up.

Hope this helps
Cameron

< Message edited by Cambo -- 6/28/2008 12:59:49 AM >

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RE: idle up & normal mode etc... - 6/28/2008 4:01:22 AM   
legine


 

Posts: 205
Joined: 5/28/2007
From: SydneyNSW, AUSTRALIA
Status: offline 		I think im going to use my JR RS70 receiver with my JR max66 transmitter.......in regards to setting up the CCPM swashplate mixing, does anyone know the proper mixing values of the Belt CP???

(in reply to Cambo)
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RE: idle up & normal mode etc... - 6/29/2008 1:32:34 AM   
legine


 

Posts: 205
Joined: 5/28/2007
From: SydneyNSW, AUSTRALIA
Status: offline
quote:

ORIGINAL: Cambo

Yes that is correct. That percentage only represents power output not necesarily RPM. By increasing the pitch you are increasing the load thus needing more power to maintain the same RPM. As said before these numbers change between helis. The 5 point curve on my Raven is 100-85-65-85-100 but i am using a computer radio so i can change all of those points.

Gear ration and the desired headspeed along with the pitch range determine what throttle curve you want.

When setting up pitch curves it is easiest to do a perfectly linear V curve. +-10 is only needed in idle up.

Hope this helps
Cameron


How do i know if the headspeed is kept constant....is the only way to do this with a gov and does the Belt CP have a gov?

Thanks, Daniel

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RE: idle up & normal mode etc... - 6/30/2008 7:24:25 AM   
legine


 

Posts: 205
Joined: 5/28/2007
From: SydneyNSW, AUSTRALIA
Status: offline 		anyone???

Would would you setup a throttle curve??...........How can you tell what the head speed is to set the points on the throttle curve???

(in reply to legine)
       Post #: 14

RE: idle up & normal mode etc... - 6/30/2008 1:48:44 PM   
BarracudaHockey



Posts: 10815
Joined: 7/13/2003
From: Orange Park, FL, USA
Status: online 		You can use an optical tach but it probably isn't worth it with that helicopter.

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