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yellowpecora
10-18-2010, 09:21 AM
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...:)

dk31
10-18-2010, 10:05 AM
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

Steve Joblin
10-18-2010, 10:31 AM
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.

Tomy.
10-18-2010, 11:18 AM
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 :YeaBaby:.

Starcruiser
10-18-2010, 03:49 PM
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.

yellowpecora
10-18-2010, 03:58 PM
Thanks to all, guys. Always good to learn something new! ;)

craig303uk
10-18-2010, 04:22 PM
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 :)

Starcruiser
10-19-2010, 08:42 AM
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

Tomy.
10-19-2010, 11:01 AM
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.


TC
N = 0-45-45-45-45


Are you sure this is not 0-85-85-85-85 or similar?

Starcruiser
10-19-2010, 11:57 AM
nope I am using the fixed RPM mode (Governor) and a 45% TC activates the first RPM setting.

Tomy.
10-19-2010, 05:42 PM
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?

dze
10-19-2010, 06:24 PM
you all sure do make it complicated:YeaBaby: 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 ..

Tomy.
10-19-2010, 06:39 PM
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 :).

Starcruiser
10-19-2010, 09:29 PM
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.

Tomy.
10-19-2010, 10:26 PM
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).

Starcruiser
10-20-2010, 08:18 AM
:thumbup:

silversmurfer
10-23-2010, 10:39 AM
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