Throttle/ pitch curves

[Edgeflyer]

As a beginner to cp helis I am setting up an align 450dfc flybarless with mini kbar with an frsky X20 tx running ethos and getting confused with the throttle pitch curve mixing. I know that with cp a constant head speed is needed from a flat throttle curve of  about 75 pc and a pitch curve which is roughly -100 to 100 pc.

But when the pitch channel is mixed to the throttle channel the pitch curve seems to be ignored. Would it make sense to just control throttle from a switch to give say 0, 75, 78 pc and have the pitch channel controlled just by the left stick independently?

[GrumpyGnome]

Not being a heli expert (although I have a couple), I'd say 'no, you need proper pitch and throttle curves on throttle stick'.

 

For my helis, I've downloaded the model setups for my EdgeTX radio from forums - US forums, although there may be some Ethos heli users on here......... 

[Jon H]

While i am no heli expert i have built a trex 500 and taught myself to fly helicopters using a blade 400.

 

If you are new to collective pitch helicopters then you are looking at the wrong side of the coin here. Having a pitch range of +100 and -100 is only for use in aerobatics and 3d type flight. In that case you will still need a variable throttle curve to maintain the headspeed as increased pitch will increase load on the motor and need more motor power to keep the head speed up. 

 

But, as i already said that lot is only something you need to worry about if you are new to collective pitch helicopters and you need a standard non aerobatic setup on the heli for the moment. 

 

The manual should give you two different setups for the heli. One will be 'normal' and one will be 'aerobatic'. The wording might vary but thats what i am calling it. Its been a while, but from memory the normal mode will have 0 degrees pitch at mid stick, +X degrees at full stick and i think about -3 degrees pitch with the stick at the bottom. Equally, the throttle will be 0 at the bottom, around 50% at mid stick and maybe 75% at full stick. The exact curve will be in the manual for both pitch and throttle. The idle up/aerobatic mode will be 0 degrees pitch at middle stick, +100 at the top and -100 at the bottom. Throttle will be something like 70% at mid stick rising to 100% at the top and the bottom.  you normally use the 'normal' model for general takeoff and flying, and then flip your idle up switch to access the aerobatic mode when you want to beat the sky into submission. 

 

With that out of the way, if you radio is ignoring the mixing commands its likely the tx is not configured correctly. Both of my heli's used a 120 degree spaced CCPM swashplate setup and i had to tell the radio this, along with the orientation of the plate (ie, single arm on the swashplate facing fore/aft). Now i have never used a flybarless setup, but i would imagine you still need to tell the radio the swash setup you are using. It will then mix the channels automatically. 

 

The trex 450 is a very powerful and capable machine. Many of the tutorials and setup guides on youtube or forums will be aimed at experienced guys looking to thrash the pants off it and these will be totally unsuitable if you are just learning to fly. What you want is to detune it to the point where you stand a fighting chance of learning to fly it and smash it, or yourself, to bits. 

 

With that in mind, make sure you remove the rotor blades (main and tail) when doing any sort of setup work on the bench and disconnect the motor unless you are specifically testing something involving the motor. When i used to work in a model shop a guy came in who had been shredded by a 450 size heli he was setting up on the bench when he accidentally reversed the wrong channel and it exploded into life. He had actually left the main blades off, but was beaten up by the flybar and tail rotor and spent the rest of the day in A&E being put back together. 

Edited January 7, 2023 by Jon - Laser Engines

[Colin Carpenter]

I agree totally with Jon ! 3D settings are a boom killer when learning to fly. I only use about -3 deg as I’m not an aerobatic flyer and have never been able to orientate on pod and boom helis ! 😢Used to use idle up on ic helis but don’t bother on my T Rex’s. Just too old now. Spekkie AR 7200 handles everything beautifully and I just adjust curves till I get the feel I want ! Colin

[Edgeflyer]

Thanks for the advice. I had a feeling I didn't need negative pitch except at initial startup.

Richard has sent me some sample kbar settings to experiment with and yes all blades are off.

[Frank Skilbeck]

Phil, I found this video which explains how to set up a Heli on Ethos including setting up throttle and pitch curves, The Aileron, Elevator and Pitch inputs to the flybarless controller will then do the mixing to the cyclic servos. (I haven't used Ethos so I hope this is what you were after)

 

[Allan Bennett]

My aim, if I'm not using a governor, is to get a reasonably constant head speed by increasing the curve value across the range, to account for the extra load as you're also increasing the pitch.  As an absolute beginner I used a 7-point curve with the first point being zero.  That was because my first instinct from fixed-wing flying was to shut the throttle if I need to stop the motor in an emergency.  Later I became acustomed enough to reach for the kill switch in emergency, so I then set my first throttle point at 65% IIRC.

 

As for pitch, the Align manuals suggested -3 degrees to about +10 degrees for 'normal' flight.  I adjust the pitch curve to give about +3 degrees at mid-stick, for that's the pitch that's needed to give a steady hover.  I found that negative pitch is sometimes necessary to counter the uplift one gets with a sudden gust of wind.

[Helibilly]

I had a raptor 50  a few years ago that I set the headspeed to 1500 rpm using a Governor. The left stick controlled pitch only, with the governor taking care of any changes in using the pitch or cyclic sticks by maintaining the headspeed at 1500 rpm. 
Bill W.

[Paul De Tourtoulon]

You will never get a constant speed, as the motor is loaded going up and unloading coming down, -3° is not enough, in gusty conditions it won't come down, try -5° and +9°

 

 Opps, I think my Raptor is 1.700 to around 2.000rpm for 3d flying.

Edited July 25, 2023 by Paul De Tourtoulon
opps

[Airmonkey]

Pitch curve should be -100 to +100. Pitch range is set during swash setup in the FBL software typically +/-10 deg. Reducing the rates on the X20 to 60% or so on both cyclic axis (ail & ele) will tame things down for learning. If your ESC has slow start use that & instead of a -100 to +100 throttle curve set a straight one, (in Ethos +40 to +50 equates to 70-75%). If no slow start you will have to set a normal curve say 0 40 40 40 40. Governor not essential during learning stages (hovering etc) but there is one you may as well set it, if it’s a HW use gov store mode. Also if HW disable low voltage cutoff & active freewheeling. Hope that helps. 

Edited August 31, 2023 by Airmonkey

[GaryW]

Ive been flying helicopters for a number of years and yes I admit I'm a very basic heli flier,, I don't fly aerobatic or 3D, ( maybe the odd stall turn now and then when I'm in the mood to )   I can fly aerobatic/3D  but it bores me just to watch that style of heli flying ,,,, I prefer to fly a heli the way it was designed to,, Up the right way

 

With both my Mini Titan & Shuttle, i leave the throttle curve as set as default 0, 25, 50, 75, 100 and set my pitch curve as needed to give main head pitch angles of -3 at idle, 5-6 at hover & +9 at top end which is more than enough for my style of flying and the odd auto rotation landing if needed

[Paul De Tourtoulon]

I can't see myself flying with your throttle curve, I program my throttle curves to give me a constant head speed.

[GaryW]

On 01/09/2023 at 16:12, Paul De Tourtoulon said:

I can't see myself flying with your throttle curve, I program my throttle curves to give me a constant head speed.

 

Hi Paul... I had the Maiden/Setup Test flight with my new Shuttle on Sunday,, Heres my setup & final settings and a video of the flight which yes throttle curve is a slight bit different than i said in my previous post/comment

 

Engine OS 32F Heli

JR DS 8411 - Cyclic

JR DS 811 - Tail Servo

JR DS 8417 - Pitch

Futaba 3001 - Throttle

Futaba GY401

Align 2in1 Regulator/on board Glow

2150 2s Rx Lipo

 

Transmitter - Spektrum DX7s

Receiver - Spektrum AR6710 DSMX

Throttle Curve

Low - 0%

25% - 30%

50% - 60%

75% - 80%

High - 100%

 

Main Blade Pitch

 

Idle -3   Hover +5   Full Power +9

 

Pitch Curve 

Low - 13%

25% - 30%

50% - 55%

75% - 70%

High - 86%

 

 

 

 

 

Edited September 12, 2023 by GaryWebb

[Paul De Tourtoulon]

Your pitch curve sounds good but how en earth can you fly with those throttle settings, you're hovering circles in the wind mast look like it is on a yo-yo string.

 

 Your 540's show that you don't have any throttle control, so it's 3/4 throttle and buzz around the sky,,,🤐

Edited September 12, 2023 by Paul De Tourtoulon
540

[GaryW]

24 minutes ago, Paul De Tourtoulon said:

Your pitch curve sounds good but how en earth can you fly with those throttle settings, you're hovering circles in the wind mast look like it is on a yo-yo string.

 

 Your 540's show that you don't have any throttle control, so it's 3/4 throttle and buzz around the sky,,,🤐

 

Not quite sure i fully understand what ur saying there paul but thanks for your views on my flying skills..... I admit im not a fantastic heli flier but I can do good enough to take it bring it home in one piece at the end of a flying session

[Paul De Tourtoulon]

A 540 'should' start with a near vertical climb pitch close to 2/3° then 0° and input the tail rotor, but you seem to do it with 5° and 60% throttle, with your throttle set up you engine would probably be at around 25% when the tail input is put in, with the extra force on the motor you would probably down to around 20% 😗

[GaryW]

All I do Paul is pull on the sticks and see what happens and just hope it pulls out of it

[Paul De Tourtoulon]

That's exactly what I see, you flying a helicopter like a plane,,,😄

[GaryW]

2 minutes ago, Paul De Tourtoulon said:

That's exactly what I see, you flying a helicopter like a plane,,,😄

 

If it works then why not....,, Might try flying a plane like a helicopter one day and see what happens...lol

 

Edited September 13, 2023 by GaryWebb

[Paul De Tourtoulon]

That's how I flew my Micro Moulds Lark in the 70's, fixed pitch and no mixers or gyro, and that sort of worked,,,