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View Full Version : Throttle Curves - does this make sense?


ttruttmann
08-07-2009, 08:04 AM
I'm trying to avoid any sudden RPM changes when switching from normal to IdleUp1. I noticed that if I was in hover - somewhere between center and 3/4 stick - and switched to IdleUp1, that it would jump.

I'm trying these settings:

Normal 0-50-65-80-95
IdleUp1 95-80-65-80-95

This makes the power curve (line) identical above center stick...is there any reason not to fly this way? IdleUp2 will still be flat. Thanks

jockstrap
08-07-2009, 08:17 AM
the jump may actually be a change in pitch not throttle..

My 450s change HS on idle-up but do not jump in height at all...
There is a little kick in my tail thou on my new 450 pro as the HS chages quite a bit on that one.. but once again, no change in helight..

ttruttmann
08-07-2009, 08:28 AM
hmm...my pitch curves are identical above center stick. It seems to reason that if you're at a given pitch...say 3 degrees at hover...that a sudden jump in headspeed will generate more lift. Maybe it's just more noticeable on my little 250 than on your heavier bird?

I see you have some smaller helis too...can I ask how you have your curves set up for them?

halley
08-07-2009, 08:33 AM
Those throttle curves have an identical center stick. Yes. That does what you want.

But the curves seem really low. 65% throttle on the stock equipment is not enough for a good response. I'd make your common point at least 80%.

Jasmine2501
08-07-2009, 12:06 PM
Forget all that... set throttle to 100% and go balls-out until the battery dies :)

ferret30
08-07-2009, 12:30 PM
You really don't want to have throttle changes past mid stick for normal mode, and also you don't want a v-curve for idle up. Many people on this forum have found that the 250 wags/kicks on throttle changes.

So use flat throttle curves, something like:

N: 0-80-80-80-80
1: 80-80-80-80-80
2: 90-90-90-90-90

Also, for normal mode, having your throttle and pitch changing around the hover point (i.e. 65%) makes the heli especially jumpy. When you move the stick down, the headspeed drops *and* the pitch changes, which makes it drop fast. By keeping headspeed constant and only changing pitch, the heli is more predictable and flyable.

ttruttmann
08-07-2009, 05:05 PM
Thanks! I completely rebuilt the heli profile in my DX7 last weekend and I was suddenly getting a wag...I think we should start a list of things that don't cause a 250 to wag...

Maybe these new throttle curves are the culprit!

Hopefully I'll have a nice weather day this weekend to try it out.

Thanks everyone! :cheers

Jasmine2501
08-07-2009, 06:08 PM
I think we should start a list of things that don't cause a 250 to wag...


That would be a very short list... all I can think of is Tuesday.

ttruttmann
08-07-2009, 07:34 PM
That would be a very short list... all I can think of is Tuesday.

:shock: hehehe!

helidude3
08-08-2009, 05:47 PM
That would be a very short list... all I can think of is Tuesday.
sorry, but what?!?

Jasmine2501
08-08-2009, 10:42 PM
sorry, but what?!?
http://en.wikipedia.org/wiki/Deadpan

It's just my style I guess.

ttruttmann
08-08-2009, 11:13 PM
<grin> as if your sig pic doesn't say it all...my puppy gets that exact same expression occasionally, usually when he's about to clear the room :badair:

jockstrap
08-11-2009, 08:15 AM
@ttruttmann - here are my t-rex250 curves

250 = stock motor, 16 tooth pinion, 410 servos, spartan 760 gyro 3000g tail servo
batt = zippy 20c 800mah, align 800mah 20c
blades = align 205D carbons

Throttle:

norm: 0,40,65,75,85
st1: 100,inh,80,inh,100
st2: flat 100%

pitch:

norm:45,inh,50,inh,100
st1: 0,inh,50,inh,100
st2: 0,inh,50,inh,100

ttruttmann
08-27-2009, 01:14 PM
You really don't want to have throttle changes past mid stick for normal mode, and also you don't want a v-curve for idle up. Many people on this forum have found that the 250 wags/kicks on throttle changes.

So use flat throttle curves, something like:

N: 0-80-80-inh-80
1: 80-inh-80-inh-80
2: 100-inh-100-inh-100

Also, for normal mode, having your throttle and pitch changing around the hover point (i.e. 65%) makes the heli especially jumpy. When you move the stick down, the headspeed drops *and* the pitch changes, which makes it drop fast. By keeping headspeed constant and only changing pitch, the heli is more predictable and flyable.

I've been playing around with these and you're spot on that that higher headspeeds improved stability. I did find that I could hear my headspeed drop off a bit as the rotor pitch bit into the air.

Now I'm trying:

N: 0-40-80-inh-85
1: 85-inh-80-inh-85
2: 100-inh-95-inh-100

TMoore
08-28-2009, 07:16 PM
You really don't want to have throttle changes past mid stick for normal mode, and also you don't want a v-curve for idle up. Many people on this forum have found that the 250 wags/kicks on throttle changes.

So use flat throttle curves, something like:

N: 0-80-80-80-80
1: 80-80-80-80-80
2: 90-90-90-90-90

Also, for normal mode, having your throttle and pitch changing around the hover point (i.e. 65%) makes the heli especially jumpy. When you move the stick down, the headspeed drops *and* the pitch changes, which makes it drop fast. By keeping headspeed constant and only changing pitch, the heli is more predictable and flyable.

I see no reason to use a flat line curve on the throttle as this elimnates the head room that the esc needs to absorb pitch changes. My tail doesn't wag and I'm running 3 different flight modes depending on the batttery I'm running and its power capacity.

TM

watdazit
08-28-2009, 09:38 PM
sorry, but what?!?

It's a sense of humour thing, either you get it or you don't. I like it Jasmine, keep them confused.