Fun, Learning, Friendship and Mutual Respect
START  HERE


Unregistered
Go Back   HeliFreak > R/C Helicopter Support > 250 Class Electric Helicopters


250 Class Electric Helicopters 250 Class Electric Helicopters manufactured by Align, Tarot, SYMA, Airhog, Chaos, HK and similar.


Reply
 
Thread Tools Display Modes
Old 10-18-2010, 09:21 AM   #1
yellowpecora
Registered Users
 
Posts: 142
 

Join Date: Sep 2010
Location: Rome, Italy
Default Newbie pitch question

Hi all,

finally got my 250SE in the air yesterday. An overall OK flight, with just a little tail wag that needs some working on, but nothing to worry about.

Now it's time to fine tune my tx's settings.
I've been reading lots of threads on the ideal throttle/pitch curve settings and that helped a lot. One question buggers me though: Why would I want a Norm pitch range of -2/+11?

OK for the positive part, but why start with a (slight) negative pitch?

I read it's because it would facilitate landings. But wouldn't an all-positive range curve be better for this? Say like 0 pitch at 0 throttle, 2 degrees at 25%, 6/7 around 50% for hovering, and so on?

Sorry for the silly question, but I'm still going through RADD and John Salt's guides and the training I got on the Walkeras just doesn't help...
__________________
Align TRex 250SE - AR6100
Align TRex 250SE MD500E semi-scale - AR8000
E-Flite Blade 450X - AR7200BX - all with Spektrum DX8
Walkera CB100 - 4G6S - WK2801Pro
yellowpecora is offline        Reply With Quote
Old 10-18-2010, 10:05 AM   #2
dk31
Registered Users
 
Posts: 382
 
My HF Map location
Join Date: Nov 2009
Location: Greece, Athens
Default

When there's wind, you ll find it is hard to bring down the heli even with -2 degrees pitch - especially when you go too high. As soon as you re comfort with throttle hold, increase your negative (eg -4) or go directly to idle up
dk31 is offline        Reply With Quote
Old 10-18-2010, 10:31 AM   #3
Steve Joblin
Registered Users
 
Posts: 4,144
 
My HF Map location
Join Date: Aug 2008
Location: Blue Bell, PA USA
Default

As dk31 said, it is to help bring the heli down if there is wind... As a newbie, if you will be flying indoors or only flying outdoors on very calm days, then starting with a slight positive pitch will help you bring the heli down gently.
Steve Joblin is offline        Reply With Quote
Old 10-18-2010, 11:18 AM   #4
Tomy.
Registered Users
 
Posts: 1,792
 

Join Date: Aug 2010
Location: Redmond, WA
Default

You also want to take into account how your throttle curve is set. I'd recommend you go to a flat curve as soon as you can (you can start with something like 0-60-70-80-85 but move up to 0-100-100-100-100 as soon as you can). The 250 needs the high head speed for stability, you'll learn to fly with the high speed that'll help you transition to idle mode and you'll find keeping the heli in level will be much easier because the headspeed will not need to change as you move the collective!

So as in normal mode I'm running 0-100-100-100-100 throttle, I can afford the 40-40-50-75-100 for the pitch, the 40 at 25% stick gives about 2 degrees negative, but with the 100% headspeed at that point I never had problem bringing the 250 down even in considerable wind. But I found it's very stable to land this way because the head is 100% all the way until the bird is on the ground. I can literally land on a napkin .
__________________
I am a HeliCoholic! RCHN #207
MD 600 TRex 500 180 CFX G 380
120SR custom built Coastguard AW109 see my avatar
DX9 RF6.5
Tomy. is offline        Reply With Quote
Old 10-18-2010, 03:49 PM   #5
Starcruiser
Registered Users
 
Posts: 3,810
 
My HF Map location
Join Date: Sep 2009
Location: Rockford, Illinois
Default

I use a governor on mine for a set HS of 3800 in normal mode with a PC of -4 to +11 and linear curves +/- 11 in idle up and 4000 HS.

As mentioned you will need the negative to get the heli down on a windy day, otherwise it will float away like a FP heli in a breeze.
__________________
Carl
Trex 550E FS Vbar Pro 5.2- EXI-450T Mini Vbar Pro 5.2 - EXI 450T BeastX - Trex 250SE - mCPx v1 Hp05 & HP06 w/HP03t tails - AMA #952544
Starcruiser is offline        Reply With Quote
Old 10-18-2010, 03:58 PM   #6
yellowpecora
Registered Users
 
Posts: 142
Thread Starter Thread Starter
 

Join Date: Sep 2010
Location: Rome, Italy
Default

Thanks to all, guys. Always good to learn something new!
__________________
Align TRex 250SE - AR6100
Align TRex 250SE MD500E semi-scale - AR8000
E-Flite Blade 450X - AR7200BX - all with Spektrum DX8
Walkera CB100 - 4G6S - WK2801Pro
yellowpecora is offline        Reply With Quote
Old 10-18-2010, 04:22 PM   #7
craig303uk
Registered Users
 

Join Date: Oct 2007
Location: Scotland
Default

Quote:
Originally Posted by Starcruiser View Post
As mentioned you will need the negative to get the heli down on a windy day, otherwise it will float away like a FP heli in a breeze.
when i 1st started flying heli's i used to hate trying to bring it down it would just kind of float there, i'd have to drop the throttle that much that the heli was about to fall out of the sky which felt kind of dodgy lol till i learned that i had to used more neg, now it comes down when i tell it too
craig303uk is offline        Reply With Quote
Old 10-19-2010, 08:42 AM   #8
Starcruiser
Registered Users
 
Posts: 3,810
 
My HF Map location
Join Date: Sep 2009
Location: Rockford, Illinois
Default

yeah same here. I now fly in Idle up for the most part except when I am testing the heli. My TC in normal is pretty much a flat curve now, use like 80% in normal (with 0 at low stick) and 85% in Idle up (non-governed) otherwise I use a fixed RPM setting in the ESC, I like that better.

my 250 has;

PC
N = 40-45-50-75-100
IU - 0-25-50-75-100

TC
N = 0-45-45-45-45
IU = 95-95-95-95-95
IU2 = 100-100-100-100-100

I run similar curves on my 450's and 550E
__________________
Carl
Trex 550E FS Vbar Pro 5.2- EXI-450T Mini Vbar Pro 5.2 - EXI 450T BeastX - Trex 250SE - mCPx v1 Hp05 & HP06 w/HP03t tails - AMA #952544
Starcruiser is offline        Reply With Quote
Old 10-19-2010, 11:01 AM   #9
Tomy.
Registered Users
 
Posts: 1,792
 

Join Date: Aug 2010
Location: Redmond, WA
Default

Quote:
Originally Posted by craig303uk View Post
i'd have to drop the throttle that much that the heli was about to fall out of the sky
Yep, and it's important that you set up the throttle curve to keep the headspeed constant (or close to constant) until the heli is on the ground.

Quote:
Originally Posted by Starcruiser View Post
TC
N = 0-45-45-45-45
Are you sure this is not 0-85-85-85-85 or similar?
__________________
I am a HeliCoholic! RCHN #207
MD 600 TRex 500 180 CFX G 380
120SR custom built Coastguard AW109 see my avatar
DX9 RF6.5
Tomy. is offline        Reply With Quote
Old 10-19-2010, 11:57 AM   #10
Starcruiser
Registered Users
 
Posts: 3,810
 
My HF Map location
Join Date: Sep 2009
Location: Rockford, Illinois
Default

nope I am using the fixed RPM mode (Governor) and a 45% TC activates the first RPM setting.
__________________
Carl
Trex 550E FS Vbar Pro 5.2- EXI-450T Mini Vbar Pro 5.2 - EXI 450T BeastX - Trex 250SE - mCPx v1 Hp05 & HP06 w/HP03t tails - AMA #952544
Starcruiser is offline        Reply With Quote
Old 10-19-2010, 05:42 PM   #11
Tomy.
Registered Users
 
Posts: 1,792
 

Join Date: Aug 2010
Location: Redmond, WA
Default

Hmm. I can't even take off under 65-70% with the stock motor (though very unstable and I would not really do it), but of course if you run the Scorpion, that governde 45% can be higher than my 70%.
So when you switch from normal to idle1 and you're on 45 and jumping to 95, isn't that just too much throttle difference?
__________________
I am a HeliCoholic! RCHN #207
MD 600 TRex 500 180 CFX G 380
120SR custom built Coastguard AW109 see my avatar
DX9 RF6.5
Tomy. is offline        Reply With Quote
Old 10-19-2010, 06:24 PM   #12
dze
Registered Users
 

Join Date: Mar 2008
Location: florida
Default

you all sure do make it complicated i put it at 100% throttle, dont worry about normal, dont screw around with gov, flip to idleup before i touch off and just go ... i land in idleup, pop it to norm and cut ..
dze is offline        Reply With Quote
Old 10-19-2010, 06:39 PM   #13
Tomy.
Registered Users
 
Posts: 1,792
 

Join Date: Aug 2010
Location: Redmond, WA
Default

I run 0-100...100 in normal and 100...100 in idle. Starcruisers settings grabbed my attention. But hey if it works! Now I'm off to fly. Maybe one of the last sunny days in the Seattle area for this year .
__________________
I am a HeliCoholic! RCHN #207
MD 600 TRex 500 180 CFX G 380
120SR custom built Coastguard AW109 see my avatar
DX9 RF6.5
Tomy. is offline        Reply With Quote
Old 10-19-2010, 09:29 PM   #14
Starcruiser
Registered Users
 
Posts: 3,810
 
My HF Map location
Join Date: Sep 2009
Location: Rockford, Illinois
Default

Tomy,

What you need to understand is that in a Phoenix ICE 50 (Castle Creations ESC) has a governor and I am operating in that mode, when running Fixed RPM mode (Governor) there are 3 RPM ranges to operate in, when the Tx throttle curve is below 50% I get RPM range 1, if it is between 50% and 99% it is range 2, and 100% gets me range 3.

I have Range 1 set to 2600 RPM, range 2 is 2800 and range 3 is 3000, so when my TC is 45% my head speed is 2600 rpm, when I move to IU 1 it goes to 95% and that tells the ESC to get me 2800RPM and IU 2 gets me 3000 RPM because it is set to 100%.

To use this mode I must run a flat TC at less than 50% to get the ESC to provide a motor RPM that provides a head speed of 2600RPM (Range 1) etc..

This is a function of the ESC so my Tx Throttle output tells the ESC which RPM range to govern to. Do not let the TC settings I mentioned in my previous post make you think I am running a normal ESC mode because I am not.
__________________
Carl
Trex 550E FS Vbar Pro 5.2- EXI-450T Mini Vbar Pro 5.2 - EXI 450T BeastX - Trex 250SE - mCPx v1 Hp05 & HP06 w/HP03t tails - AMA #952544
Starcruiser is offline        Reply With Quote
Old 10-19-2010, 10:26 PM   #15
Tomy.
Registered Users
 
Posts: 1,792
 

Join Date: Aug 2010
Location: Redmond, WA
Default

Carl, I got that, I'm just saying I looked at the 45% numbers and were surprised, but I understand that the <50% number means for the ESC governor set 1 which has nothing to do with the actual 45% (you could have set 30% for that matter).
__________________
I am a HeliCoholic! RCHN #207
MD 600 TRex 500 180 CFX G 380
120SR custom built Coastguard AW109 see my avatar
DX9 RF6.5
Tomy. is offline        Reply With Quote
Old 10-20-2010, 08:18 AM   #16
Starcruiser
Registered Users
 
Posts: 3,810
 
My HF Map location
Join Date: Sep 2009
Location: Rockford, Illinois
Default

__________________
Carl
Trex 550E FS Vbar Pro 5.2- EXI-450T Mini Vbar Pro 5.2 - EXI 450T BeastX - Trex 250SE - mCPx v1 Hp05 & HP06 w/HP03t tails - AMA #952544
Starcruiser is offline        Reply With Quote
Old 10-23-2010, 10:39 AM   #17
silversmurfer
Registered Users
 
My HF Map location
Join Date: Aug 2010
Location: London
Default

Just finished my stock Trex 250 se with a 6110e bound to a DX8 - very docile settings at the moment until I get used to it! - if you like I can send you my settings file for your DX8 - Smurfer
silversmurfer is offline        Reply With Quote
Reply




Unregistered
Go Back   HeliFreak > R/C Helicopter Support > 250 Class Electric Helicopters


250 Class Electric Helicopters 250 Class Electric Helicopters manufactured by Align, Tarot, SYMA, Airhog, Chaos, HK and similar.

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


Copyright © 2004-2015 by RCGroups.com, LLC except where otherwise indicated. The HeliFreak.com logo is a trademark of RCGroups.com, LLC.