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HelicopterMain Discussion › pitch curve question
03-09-2015 03:54 PM  3 years agoPost 1
emederos

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Miami, Fl Dade

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I have -3 and +10 mechanically set up but im curious to know how adjusting pitch curve settings on the radio affect pitch. I.e. if my negative pitch max is neg 3 if i put the last point on my radio to 70% does this mean i will not get full negative pitch?

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03-09-2015 05:19 PM  3 years agoPost 2
tonyd12

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hamlin,PA

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info
Well the easisest way to test , is to put a pitch gauge on the blades and see what happens when you change the curve. Very easy to do and easy to change if you mess things up.

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03-09-2015 07:33 PM  3 years agoPost 3
GREYEAGLE

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Flat Land's

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1st tip : STUDY and READ ALL you can get your hand's on .

!st: TCP is ( = ) Total Collective Pitch

You mention you Have : { -3 } plus ( +10 ) = a Total of 13 TCP

or a Total of 13 Degrees' " Mechanically of Pitch Available "

It seem's short : Maybe a Total of 16 to 20 TCP " Maybe available "

What do the Written Instructions / Print's or Info on your Bird Indicate ? Only 13???

Mechanically - Find out - Gota use a Pitch Gauge - PRIME

Long Prior to Even start thinking about the Radio and Curves

greyeagle

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03-09-2015 08:49 PM  3 years agoPost 4
Hamo

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Ireland

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If the mechanical setup gives -3 to +10 degrees, adjusting the radio can only limit these to smaller values.

You should aim to set mechanically from -12 to +12 and then use the radio pitch curve settings to limit these to whatever you want, depending on the desired flight modes you want to use.

Using the radio pitch curves:
For example, you would limit throttle hold to -4 to +12.
For inverted flying, you would set the pitch to -9 to +9

In short, adjust mechanically for maximum possible pitch and limit using radio pitch curves.

Hamo

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03-09-2015 09:18 PM  3 years agoPost 5
Jerry K

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Houston Area

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Hamo look we do have something in common

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03-09-2015 11:34 PM  3 years agoPost 6
emederos

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Miami, Fl Dade

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Im just scale flying no 3d here , seems like everyone mentions neg 3 for autos amd pos 10 degrees is good for scale flying,

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03-10-2015 12:19 AM  3 years agoPost 7
dgoss999

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UK - Lancashire

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Those end points don't seem unreasonable for scale..

What is your centre stick pitch??

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04-07-2015 03:30 AM  3 years agoPost 8
emederos

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Miami, Fl Dade

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I'm sorry I had it all wrong I'm set mechanically at neg 10 and pos 10 zero at center, now I set my pitch curve in the radio to give me neg 3 low and pos 10 high just trying to figure out a good throttle to match the pitch curve for scale flight low headspeed.

PC - 30,62.5,75,87.5, 100

For TC is this ok I want to run 80% throttle

TC- 0,60,80,80,80.

Motor is scorpion 3226 1400kv

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04-07-2015 03:49 AM  3 years agoPost 9
rcflyerheli

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Granbury, TX USA

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The easiest way that I can think of is to make sure at 0 stick, you have -10, 50% you have 0, and at 100% you have +10 degrees.

Set your stick to 50% (mid stick) and insure you have 0 pitch, set your pitch scale up and zero it out at mid stick, then move your collective stick to low, and adjust your low stick pitch curve value to give you -3 degrees on your scale. Your high stick reading should already be +10 degrees.

Now simply look at the pitch curve value you set at low stick and adjust the remaining values between the 0 position and mid stick to give you a straight line.

So you should now have a pitch curve that has a straight line from your low stick position (whatever PC value you set to give you -3 degrees of pitch) to your mid stick position and another straight line from your mid stick position to your high stick position.

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04-07-2015 02:33 PM  3 years agoPost 10
emederos

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Miami, Fl Dade

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I have neg 3 low stick, 5 deg mid stick and 10 deg full stick

Based on the rpm calculation

23x1400=32,200 rpm 100% throttle

12t/162m =0.074

32,200 x 0.074= 2382 HS / 80% throttle = 1900 rpm

2144 rpm 90%
1906. Rpm 80%
1787. Rpm 75%
1668 rpm 70%
1430 rpm 60%

What should i target?

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04-07-2015 03:26 PM  3 years agoPost 11
Pistol Pete

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Seffner, FL

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What should i target?
Your target is your "desired" head speed(s).

ie: If you want three head speeds you set throtle curve:
Norm 0-75-75-75-75
Idle1 0-80-80-80-80
Idle2 0-90-90-90-90

The first ZERO allows you to turn off motor in any flight mode given you are not 3D'ing, otherwise its omitted in both IdleUp 1/2

Set Pitch Curve the same across all flight modes including Throttle Hold.

If you need to set ESC lower than 75% to obtain "desired" head speeds, your gearing needs revision.

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

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04-07-2015 04:26 PM  3 years agoPost 12
dela

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Stillwater Oklahoma

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You can do what you want with pitch and stick position.

Modern 3D and sport flyers (since roughly 1999) want ZERO pitch at mid stick. Makes total sense for mixed upright and inverted flying.

Prior to modern times (somewhat before my time) I think that pitch was set to HOVER at mid stick.

Please note: MY next sentence is a QUESTION, not a statement:

For SCALE ONLY FLYERS, I wonder if it would make more sense to hover at mid stick? What to "serious" scale pilots do?

Ron D.

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04-07-2015 05:27 PM  3 years agoPost 13
Pistol Pete

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Seffner, FL

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how serious?
Although I do mix in some 3D in my flight routine, I mostly fly scale and have a "Hover/Scale" flight mode set up based on a -3 +5 +9 pitch curve for a total pitch range of 12°.

So, the bottom half of throttle stick (0-50%) has 8° of pitch travel to deal with while the upper half (50-100%) has only 4° of pitch travel.

Calculating throttle to pitch ratio a.k.a. "BOTiTA"

Lower half stick (0-50%)(-3° to +5° = 8° of pitch travel )
50% / 8° = 6.25% of throttle stick travel per 1° of pitch.

Upper half stick (50-100%)(+5° to +9° = 4° of pitch travel)
40% / 4° = 12.5% of throttle stick travel per 1° of pitch.

Meaning more precise hovering and why it makes sense for "scale" flying.

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

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04-07-2015 06:03 PM  3 years agoPost 14
dela

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Stillwater Oklahoma

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I suppose a "serious scale flyer" cares about scale flying more than their 3D flying, and doesn't mind the difference in feel when they transition between a "mid-stick hover" mode and a "mid-stick zero pitch" mode of flying.

I am neither serious scale nor serious 3D, so I'm really just asking a question in hopes that the answer will be useful to the OP.

Ron D

PS to Pistol_Pete: Pistol Pete is the mascot at Oklahoma State University (and at least one other university that I won't name). Do you have any connection to OSU?

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04-07-2015 06:10 PM  3 years agoPost 15
emederos

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Miami, Fl Dade

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Some suggested using TC 80,82.5,85 to compensate for pitch increase but others say its better to have flat TC to only fly with pitch management???

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04-07-2015 06:18 PM  3 years agoPost 16
dela

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Stillwater Oklahoma

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Most people would aim/wish for a constant head speed, regardless of what is happening with pitch. That is the reason throttle curves were critical for Nitro powered heli's. For nitro's, the throttle curve controlls power, not speed.

An electric motor (at a constant speed controller setting) "tries" to maintain constant speed regardless of the power requested, but can't quite do it. That is the reason for slight increases in the throttle curve at higher pitch. Modern speed controllers usually have a "governor" feature, that offers automatic control of headspeed, if you set it up correctly.

Of course none of this works when the pitch/power requested exceeds the peak capacity of the motor/speed controller/ battery system. That is when "pitch management" really comes in to play.

Ron D.

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04-07-2015 06:36 PM  3 years agoPost 17
emederos

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Miami, Fl Dade

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So for scale flight you would not go with flat TC instead the one mentioned above?

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04-07-2015 07:48 PM  3 years agoPost 18
rcflyerheli

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Granbury, TX USA

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This is my personal opinion of doing anything but acro flying. It is the same for learning as well as non acro (scale) flying.

I feel that controlling only one function (blade pitch) is always better than trying to control both blade speed as well as blade pitch. So I would recommend that you set a constant throttle curve for each of your flight modes, and make sure that your pitch curves are the same for all three flight modes. That way, all you change at any one time is either blade pitch, or blade speed if you change flight modes, but not both at the same time.

Goblin 700, Trex 700DFC, Gaui X7, Logo 690SX, Logo 600SX; Trex 470 Trex 500
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04-08-2015 04:18 AM  3 years agoPost 19
dela

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Stillwater Oklahoma

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So for scale flight you would not go with flat TC instead the one mentioned above?
Try both and see what you like.

I have setup enough nitro helis that I aim for constant head speed almost out of habit. For a scale heli, that will always fly upright, I can't think of a good reason not to use a little "throttle curve" on an e-scale-heli. For slow flight, slow climbouts, very little compensation would be needed to maintain constant head speed.

I am not a scale flyer, so my opining is pretty much worthless, but I don't think there is a right or wrong answer.

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04-08-2015 05:15 AM  3 years agoPost 20
rcflyerheli

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Granbury, TX USA

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For slow flight, slow climbouts, very little compensation would be needed to maintain constant head speed.
Dela, I am not in any way disagreeing with your thoughts. I'm just thinking that scale flying is really more flying level than doing a lot of climbs or acros. Thus, since blade pitch doesn't change much, you really don't see much change in blade speed for the type of scale maneuvers that I have witnessed.

That would be taken care of by using different flat line curves in the different flight modes. I do think that setting a TC of 82.5, 80, 82.5 is essentially a flat curve, just because that 2.5% change doesn't affect very much. I see a big part of scale flying being in the hover mode, unless one is flying a scale Airwolf or Hughes 500 that can do some limited acro. After hover, it is just forward flight and turns, and depending on how fast one would need to do climbouts, just setting a higher TC for your I1 and I2 modes would allow a more spirited flight.

I suppose any scale bird could be setup to mimic 3d helis, but then that flying would not be scale flying. A suggestion would be to look at the scale flights that were done at the Cajun HeliFest last week. There is a good flight by Eric Babineaux who took first in the masters or expert, and it will give you some more idea of what kind of flying you will be looking at.

However you finalize on the setup, good luck.

Goblin 700, Trex 700DFC, Gaui X7, Logo 690SX, Logo 600SX; Trex 470 Trex 500
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HelicopterMain Discussion › pitch curve question
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