Throttle and pitch curves (Normal)

[Chris Currie]

Hi all,

just a quick question to get some idea of how most people setup their pitch and throttle in normal(not idle-up) mode. From what I have read, most have pitch as a straight 0/50/100 as per idle-up, but I'm just not too keen on the idea of so much negative pitch on spool up/down. Is the thought process that perhaps this slows down the blades quicker or is it not worth worrying about.

I understand the basic principle of keeping pitch the same around mid stick or hover position to prevent ballooning when switching modes, but it seems there's a bit of scope to "personalise" things in normal mode for take off/landing etc. particularly below half stick.

For throttle, I'm using governor mode on my speed controllers so have 0 at bottom stick, then a flat 30% from 15% stick position. I could use throttle hold but I suppose it's a bit of belt and braces. Does anyone see any issue with this?

Sorry if these seem like basic questions, I'm still new to heli's and nobody in my current club flies this type of thing. I've just joined a dedicated heli club so hope to get some more advice but thought I'd get some info here first.

Any help appreciated as always.

Thanks
Chris

[tomatwalden]

I think most people beyond beginners don't use a normal (not idle-up) mode, hence why everyone has a linear pitch curve. When I was learning however, I always had less negative pitch than positive. This is particularly important when your natural reaction to a panic situation is to "drop the throttle" rather than hitting throttle hold.

I see no advantage in running a full linear pitch curve with a throttle curve that cuts power at bottom stick.

Just my 2p.

[kenny d]

For pitch In normal mode I use 30-40-50-75-100 , this allows plenty of head speed for lift off , keeps it more solid & not floaty
i don't use governed so its linear throttle for me in normal

[Grumpy]

I dont see the point of using normal mode on an electric heli.. It's just a crash waiting to happen when you forget what mode you are in and try to fly inverted. There is hardly any normal mode user that hasent crashed that way. Normal mode also reinforces the bad habit of pulling collective back when you want to stop the motor, rather than using throttle hold.

There are plenty of ways to prevent accidental spoolup other than using the collective pitch stick as a throttle 'on-off'.

[myxiplx]

Yup, I used to have a normal mode, but now I just have the same pitch curve in all flight modes, and rely on the ESC soft start to spool up. I have my collective at mid-stick during spoolup because it does add more work for the motor if you have pitch on the blades.

I always make sure I have two safety switches though, I've had switches fail before and if you don't have a normal mode and your TH switch fails, you don't have any other way to cut the throttle.

On my Jeti I have both a Throttle Hold and Throttle Cut switch assigned. It makes it much safer for bench setups as both switches need to be disengaged before the model spools up, and even if one switch fails I still have a way to kill the motor.

[coolice]

Hey buddy.

I make use of all 3 of my available pitch curves and you'd certainly be no worse off doing so yourself for many reasons. Unless I am doing an auto I take off and land in normal mode, I have this setup to be much calmer and with lower head speed so it's less twitchy when you don't need thr responsiveness.

All my pitch curves are the same from mid-stick up, so zero centre stick to +12/13 at the top, but the lower range differs according to flight mode. This way I can switch between flight modes in flight, which I do, but not have sudden height changes only subtle ones as rotor rpm settings change.

Here is an example of my pitch settings I run on all my models.

In normal I run: -3 ~ 0 ~ +12/13
Idle up 1 (F3C style): -6 ~ 0 ~ +12/13. In this case enough negative to roll and control stall turns only really.
Idle up 1 (3D): -12/13 ~ 0 ~ +12/13
Idle up 2 (3D and F3C) -12/13 ~ 0 ~ +12/13
Throttle hold: -4 ~ 0 ~ +12/13

I do also use my pitch curve points to S curve the response so it's not just simple straight lines from point to point and I can smooth out the middle pitch response band to my liking.
Cramming a full 10+ degrees of pitch into half a stick movement can make things lively, so we can help smooth this a bit with our pitch curve function.

There is good reason not to run the full pitch range in normal mode and that is to avoid dumping full negative pitch on spool down, as this has proven may times to induce ground resonance if the pilot accidentally does this and the model runs the risk of tipping over. I know it's a conditional thing and you learn not to, but as it's not needed why run the risk? You can just condition yourself to fly hovering style manoeuvre's in normal mode and any circuits/aero stuff in idle up.

At the end of the day there is no specific right way, it's what suits you the best, so look at all options and settle on what suits you and makes you feel comfortable with your model.

Ian Contessa

[Alfie]

To a degree it depends on youre 'mind-set'.
I trained my brain 'natural reactions' 20 years ago to focus my transmitter control soley on Throttle Hold!
In terms of esc's, by the time they reach headspeed you naturally have the TR @ midstick so no negative pitch, and upon landing i always switch the TH @ touchdown anyway.
Each to there own, but linear pitch curves in all flight modes (conditions), does make setting up translucent !

col

[Chris Currie]

Hi all,

many thanks the replies, I've had a hectic with heading back to work(Angola) so am jus getting round to catching up.

When I started flying helis I was using small blades etc. so I tended to treat them like toys and never really paid attention to throttle hold. Now that I have a 550 and 700, I am very aware of the dangers so using throttle hold is now very much part of my routine. It's still natural for me to chop the throttle stick on touch down, so last time out I dropped the negative pitch in normal mode which reduced the ground effect Ian mentioned noticeably.

I agree with the fact you may accidentally flip upside down in normal, I found myself hesitating a little before trying as I had to double check. I'll play around a little more and see how I go, it's been an interesting learning curve setting up these helis without just copying a set of numbers from the instructions. Lot's more to learn it seems, I also need to work on all aspects of flight so a pure 3D setup is not really what I'm after just yet. I like the idea of an F3C type setup which may help me progress quicker.


I just wanted to get some opinions on what's common but it seems like most setups, there are no hard and fast rules. I just make sure that from the moment I connect the lipos, I treat the blades as though they may spin up at any time.

Thanks again for the help, feel free to add some more opinions.

Cheers
Chris

[tomatwalden]

Maybe a good time to learn throttle hold landings ... what some people call "mini autos" (despite there being no actual auto-rotation!). This involves hovering a foot or so above the ground and hitting TH there. You then use the remaining energy in the blades to gently land the heli - slowly *increasing* the collective pitch as the head speed drains off.

This may help you get out of the habit of "chopping the throttle" ...

[myxiplx]

Yup, work on that throttle hold reflex. You need to unlearn the habbit of chopping the throttle stick down once you move to CP helicopters.

Baby autos are a great way to practice. And also work on throttle hold anytime you fly a micro or a sim, try to hit throttle hold just before any crash. The more you practice it, the quicker you get, and a good throttle hold reflex can reduce the damage done in a crash and save you a lot of money in the long run

[Chris Currie]

Hi Tom,

funny you should mention that, this is what I have started to do now that I have flown a 700(only in the last week), I found it a little lively to put down on the ground so opted for throttle hold, this is what prompted me to ask about pitch curves in normal mode. I was surprised how long it retains the energy but it's the way forward for me now. I haven't been brave enough to try a full blown auto, but I'm sure I will at some point.

Thanks
Chris

[mutna]

That's what I've been trying also, progressing from throttle hold landings to trying to auto