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HomeScaleAircraftHelicopterScale Model RC Helicopters › Pitch curves
01-15-2010 07:34 AM  8 years agoPost 1
flyer01460

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u/k

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What are the best pitch curves for a scale heli. sort of -6 +6 +12 or does it need to be less negative and positive? just looking for a ball park figure

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01-15-2010 07:54 AM  8 years agoPost 2
Dennisu

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Langley, B.C. Canada

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The normal method is to adjust the pitch for max. negative to max. positive mechanically which represents 0 to 100% of stick. Then the numbers of the pitch curve would represent that position between max. negative at 0 to max. positive at 100. 50% would be 0 pitch (half stick). 40% is minus 2 degrees. 45% would be minus 1 degree and so forth. Pitch curve:
40 - minus 2 deg.
45 - minus 1 deg.
50 - 0 deg.
75 - 5 deg.
100 - 10 deg.
This will set the helicopter to scale settings for a minus 10 degree to plus 10 degree mechanically set blade pitch. Of course the blades will never be at minus 10 degrees because the lowest number on the pitch curve is 40. This means that your total pitch really goes from -2 degrees to 10 degrees. This is roughly the same as my full scale ship.

He who dies with the most toys ..... Wins!

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01-20-2010 06:24 PM  8 years agoPost 3
flyer01460

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Cheers ive now set the pitch to -3 +5 +10 and the trottle to 0,24 55,75,100 or does anyone recoment a different throttle curve (trex 600n)

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01-20-2010 06:29 PM  8 years agoPost 4
Hoverup

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Golden Gulf Coast - USA

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I have my pitch curves set pretty much the same as these. My throttle curves are typically 0, 45, 90, 90, 90.

Cheers - Boyd
AMA 80393
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01-21-2010 03:34 PM  8 years agoPost 5
Dennisu

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Langley, B.C. Canada

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flyer01460

Use throttle curves like Hoverup to make it proper scale. Your pitch curves still need to be like I said to be scale. This replicates a full scale ship. You need zero pitch at midstick with the max throttle that you are going to use.

He who dies with the most toys ..... Wins!

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01-21-2010 04:27 PM  8 years agoPost 6
89X-CELL60

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Queen Creek, AZ

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Just my $.02 worth.

But why would you have 0 at mid stick? I have flown these helis since the late 80's and I have always had hover at mid stick.

I can see 0 degrees at mid stick if you also fly 3D, but if you are like me, then mid stick for hover works best. I do not 3D, nor will I ever try to venture there. Scale does not look good cutting grass

David

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01-21-2010 06:13 PM  8 years agoPost 7
Dennisu

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Langley, B.C. Canada

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89X-CELL60

0 pitch at midstick is not for 3D but for scale and normal flying. If you want to fly scale try the settings and see.

He who dies with the most toys ..... Wins!

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01-21-2010 06:35 PM  8 years agoPost 8
falcon

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UK

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When i flew scale over 15 years ago i always set hover point at mid stick this gave me good control of the pich above hover allowing good precision and i set neg at -3 ish to give me a good dessent without being to rapid.

I suppose it depends on your flying style i couldn't go back to hover mid stick since i changed to 3d seup many years ago.

Mid stick 0 pitch is handy though

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01-22-2010 02:01 AM  8 years agoPost 9
kennethw

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Toronto, Ontario - Canada

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Just my 2 cents worth ...

Because ( and one should never start a sentance or paragraphy with 'because' ) I have both Scale and 'normal' (can't say I can 3D) heli's, I set the 'Normal' curve the same so I don't have to remember what is what ... base setting +/- 10-12 degrees (depending on the heli), then ...

L-Point = 35%
Point-1 = INH
Point-2 = 50%
Point-3 = 62.5% - 70%
Point-4 = INH
Point-5 = INH
H-Point = 100%

Throttle is governed and at Point-1 the governer will take over.

This way, I put by Collective/Throttle Stick at Point-2 to spool up and wait for full rotor speed. When I push to Point-3, it is just light on the skids, but not quite taking off yet.

There is a difference in Point-3 depending on the Heli because of weight and number of blades, so lift is different. I try to tune it so that at Point-3 the heli is light on the skids.

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01-23-2010 08:53 PM  8 years agoPost 10
89X-CELL60

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Queen Creek, AZ

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Dennisu,

I do fly scale, so why would I change my pitch curves? Are you saying that 0 at mid stick is the only way for scale? Sorry, but I took your statement as saying my way of flying is wrong.

David

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01-29-2010 07:02 AM  8 years agoPost 11
Dennisu

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Langley, B.C. Canada

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89X-CELL60

Not saying it is wrong but if you are trying to tell someone how to set up a radio for easy scale then these numbers are easier for them to follow and adjust. The reason I said to use 0 pitch at half stick is to allow you to have the fine control over pitch in the bottom half of the stick if you need to do a scale style auto. It is just a factor of 3 or 5 step pitch/throttle curves in the radio. It also allows you to have your motor come up to full speed over the first half of movement while the pitch was going from -2 degrees to 0 degrees. This prevents the helicopter from burying itself during spoolup. If you want to have it hover at half stick then you loose this finesse and also it will make your pitch and throttle curves very compressed in the lower half of the stick. Try the settings I use and see what happens. On my full scale ship the turbine has an electronic governor so the engine stays at a constant speed but it is not brought up to flight max. unless the collective is set for 0 pitch or above. Granted the collective is not half way through its travel at this condition but then again I don't have a limited set of pitch curves as I have to handle them and not a radio and servos. Also the throttle is separate from the collective.

He who dies with the most toys ..... Wins!

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01-29-2010 12:47 PM  8 years agoPost 12
Peter Wales

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Orlando Fl

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Thats the strangest argument and pitch curve for a scale model I have ever heard!

The first half of your stick movement controls 2 degrees of pitch which gives you extremely fine control over the part of the pitch curve you rarely use. Thats just wasting the resolution of your radio. You only go below 3/4 stick when descending and landing and then you only get back to mid stick at 0 degrees or a little below.

Then you use the rest of the curve for flying the heli. In other words you have wasted half of the sticks motion and made it twice as sensitive as it needs to be.

If you want smooth control of the height of the model, you need the biggest stick range you can get, in the area where you will be flying. So, I would start with -2 +5 +9 for a pitch curve. Then for ultra fine control over hovering I would make an S curve so the pitch goes -1 +3 +5 +7 +9. You will find that most of your forward flight is coming in at mid stick as well so thats where you need the fine control

Peter Wales
http://scalehelicopters.org

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01-29-2010 12:56 PM  8 years agoPost 13
kennethw

rrApprentice

Toronto, Ontario - Canada

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Just a thought ... 0 pitch at mid-stick using semi-symatrical blades will generate enough lift to hover?

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01-29-2010 01:25 PM  8 years agoPost 14
iHover

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Berne , NY

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+1 Peter
Thats the basic curve Doorman had me setup when I started flying scale last year and it gives me good resoloution in the area of the stick that I'm actualy flying. As far as scale autos never had the guts to try them and I've yet to see anyone else do one.

You had me at Hover

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01-29-2010 07:23 PM  8 years agoPost 15
Dennisu

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Langley, B.C. Canada

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Peter Wales

With the curves I use for both the motor and the pitch I have the control for the half of the stick that has positive pitch because the motor is at full RPM only when the stick reaches and passes the half way point. That way the only thing that is changing for the upper half is the pitch and not the RPM. When you do a startup with the throttle curves I use you get a very scale looking spoolup.

He who dies with the most toys ..... Wins!

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01-29-2010 08:34 PM  8 years agoPost 16
Peter Wales

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Orlando Fl

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Stranger and stranger.

So you set up half of the stick control for spooling up and autos, which is maybe 1% of your flying time unless you are an auto junkie.

The other half is for flying!!

I would suggest that if you wanted to emulate your full size, what you should do is to have your throttle curve at 0,100,100,100,100 or whatever values you need to go with a pitch curve that uses -2,0,5,7,9

That way, you would be able to have the engine to speed at 1/4 throttle and 0 degrees pitch, if thats what you want to be your main criteria, and learn to move the throttle stick slowly so the engine speeds up slowly.

Personally, I want the engine speed controlled right through the pitch range so I will accelerate the engine to the selected headspeed and then switch to idle up which has an identical pitch and throttle curve but below that the engine rpms remain high. When I land I switch back to normal mode and the motor will slow down. I usually set this to be at the hover point. Spool up and take off, go to idle up one and fly using the full collective range. Land, bottom collective at -2 and then go back to normal and let the machine spool down.

Peter Wales
http://scalehelicopters.org

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01-29-2010 10:44 PM  8 years agoPost 17
Girard Ibanez

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Tucson, Arizona (formally from Guam)

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Personally, I would go back to the old days of setting up the pitch and using the full stick travel to gain resolution. With that said, hovering at 1/2 stick (50%).

Mechanically set up for servo spline differential so as not to rely on the electronics to obtain the pitch. Ray Hosteller's has some very good article on this.


Team Thunder Tiger
since 6/2005 to 12/2014

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01-29-2010 11:30 PM  8 years agoPost 18
oldfart

rrProfessor

Vancouver, Canada

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I spent most of my 25 years (Scale & FAI) flying helis that were set to hover at half stick.

Then when I got into 3D flying (also still fly FAI and scale) I found that the brain had a bit of trouble wrapping around hovering some helis at half stick and others at 3/4 stick.

What I found worked best for me, was to set them all up to hover right side up at 3/4 stick. The amount of pitch required will vary, depending on blade size, weight of heli, and rotor speed desired. So the pitch at 3/4 stick on a heavy scaler, that I may set for a 1200 or 1300 head speed, is a lot more then on the same size 3D machine that is turning at 1900 or 2100.

To maintain as much resolution as possible on my scale helis, I set for:

Low stick: -2 to -4 (depending on the weight - the heavier the heli, the less of - pitch

1/4 stick: 0 to -1

1/2 stick: 2 to 3

3/4 stick: 5 to 6

Full stick: Whatever amount of top end pitch my power system can keep the rotor turning at the rotor speed I have chosen for that heli.

Now I find it an easy transition, between any of my helis that I choose to fly, as mentally, I am now used to the feel of the stick at 3/4 when any of my helis are hovering right side up.

If one does not fly 3D or the current FAI aerobatics, he can set his heli to hover at 1/2 stick if that is what his brain/thumb pathway is used to. Nothing is written in stone!

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01-29-2010 11:35 PM  8 years agoPost 19
Copter Doctor

rrProfessor

Enterprise/ft.rucker ,al- home of army aviation

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this is why i dont usually use numbers or a pitch guage. i eyeball my blades for correct pitch with the intention of hovering at half stick, haveing a good scale-like or better climbout at full stick and a comfortable rate of descent when i lower the stick. i adjust the throttle curve so i maintain to the best i can a comfortable headspeed for me and the engine. when i take it from the bench to the field, i end up adjusting things anyway so why pay such close attention to numbers except for a starting point. this is all based on the old school way of setting up a heli where you have about 4 or 5 degrees at half, 7 or 8 at full and -2 or -3 at low stick. that feels good to me. now if you feel comfortable flying a scaler with what is known today as a 3d setup, coool!! thats what works for you and if with that you can make it look the same as a heli flying with the old school way of doing it, then double cool!
ideally, i recomend and set up for a beginner the old school way of doing it because i personally think life is a little less complicated that way, just my oppinion.

drive a rotary, fly a rotorcraft

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01-29-2010 11:48 PM  8 years agoPost 20
Girard Ibanez

rrVeteran

Tucson, Arizona (formally from Guam)

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The topic is pitch curve for scale helis. If you plan on flying your scale heli like your typical 3D style then set it up to mirror your normal 3D flying. That way when you get the itch to fly inverted, your scale ship will do just that.

On the other hand, if you want the resolution then set it up so that you use only the necessary amount of pitch needed mechanically and your scale ship flies like scale. In other words, you will make use of the total stick travel maximizing your pitch.


Team Thunder Tiger
since 6/2005 to 12/2014

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