Flight Modes

[NumbSkull]

I'm new to collective helis, and my head is full of the different types of flight modes.

I *think* I've got some of it, but a little help would be great. I've been flying fixed wing for some time, so I fully understand the need for different modes, so thats not the question, what I don't understand is if I have the terms right.

Is idle up the same as stunt mode?

Is the difference between stunt 1 and stunt 2 similar to high and low rates on a fixed wing plane?

What is throttle hold mode?

Thanks!

[norcalheli]

Starting with the basics. A CP heli produces lift through blade speed and blade pitch. Normal mode allows you to increase blade speed to that where the heli will fly, then increases pitch to produce lift. With real helicopters, or full scale, the pilot brings the blades up to speed with the throttle, then tries to maintain as steady an RPM as possible while changing pitch to alter lift. Idle up, or stunt mode, does essentially the same thing. We need the programming because in the RC helis, one stick controls both throttle and collective. For a full scale pilot, that's two different controls. Most either program in a flat throttle curve, or a shallow V curve. The pitch curves are set so that at 50% stick, the pitch is zero. Above 50% is positive pitch, and below 50% is negative, allowing for inverted flight. Those transmitters that have two idle up, or stunt, modes just allow you to program a more aggressive range of pitch and throttle for stunt 2. For example, idle 1 may be 85% throttle straight across, and +-10 degrees pitch. Stunt two may be 100% throttle, with the same +-10 degrees. Stunt two will be more responsive, for aggressive 3D. Throttle hold mode allows you to cut the power to the motor, but maintain full control of the pitch. On larger helis and fuel helis, this allows full control during an autorotation (no power) landing.

HTH
Bob

[Balr14]

Many fliers hit throttle hold instead of cutting the throttle when they are about to experience "undesired surface contact". Cutting the throttle induces negative pitch, which means you are going to come down faster and harder; not what you want in a crash situation.

[norcalheli]

Very true. You have never seen a quicker descent than a T-Rex 450 spinning 2500RPM and going full negative. :eek:

[agran1021]

You may already know this, but throttle hold is also a safety feature. Naturally, you turn on the Tx first followed by powering up the heli. It is safer to have the Tx set at throttle hold while you are powering up your heli (plugging in one of those VERY tight Dean's connectors, flicking on a power switch, etc.) so that if there is a momentary glitch at least the Rx believes no signal should be sent to the motor, and you stand less of a chance of getting dinged by the main rotor turning unexpectedly.

[Skarn]

In an electric heli, throttle hold cuts the throttle. It has it's own pitch curve so you can auto just fine.

I'm not sure what you mean Balr14 when you say "Cutting the throttle induces negative pitch"...

This is not the case for any heli I've ever owned or seen...

But anyway to the OP:

Stunt 1 and Stunt 2 only differ by whatever you decide to program them for. I have both the same right now in most of my heli's. I do have ST2 with a straight 100% throttle curve in my Trex 500.

Skarn

[norcalheli]

I'm not sure what you mean Balr14 when you say "Cutting the throttle induces negative pitch"...

Skarn
I probably should have been more clear, but I understood Balr14 perfectly. Most fliers who start out with an FP micro are told from day one that if they start to get into trouble, cut the throttle to minimize damage. That's what Balr14 was talking about, that habit of slamming the throttle stick all the way down before impact. Of course, on the little 4 channel micro FP, all that does is remove power to the blades. Then they move up to their first CP heli, and, at the first sign of trouble, they slam the "throttle" to its lowest position, not realizing that now it is also the collective, and most RTF CP helis have 3 to 5 degrees of negative pitch at low stick. He wasn't saying that cutting the throttle with the throttle hold would affect pitch, just the "throttle" stick.
Hope that clears it up.

[NumbSkull]

Hey Guys.

That's just what I was needing to know!! THanks for all the info!

[Andrew McGregor]

And an added wrinkle or two: your radio might let you select low or high rates based on the flight mode switch. And, this one is probably surprising, the trims are usually memorised separately for each flight mode (because if the headspeed changes, the trim probably does too). So don't be surprised the first time you go to idle-up, or try an auto, if the trim is off by a bit (corollary: make the trims match to whichever mode you have been flying in BEFORE you try that!)

[heli_addict]

Ultimately, it's up to how your individual electronics work, and what you want the modes to do. Personally, I like to keep it simple.

For my T-Rex 450, I do have a "normal" and "idle up" throttle curves (pitch curves are identical), but I almost never fly in normal mode. For the "normal" throttle curve, I use 0-25-50-75-100 (roughly), and for idle up, i use 100-100-100-100-100 and let the governor handle things.

For my Raptor e-620, my Castle HV-85 ESC is capable of three governor settings, based on the throttle input (from the radio) given during flight. So I use the three "modes" on the radio to be able to set the governor to 2000,2050 or 2100 rpm "on the fly" depending on what kind of flying I want to do (usually it's 2100). However, I run identical pitch curves (linear) in all modes. I have no "normal" throttle curve as it would not work as intended in governor mode.

Hope that helps.

P.S. As for throttle hold or cut, I believe those terms were mainly for fuel helis. Throttle hold would put the throttle to idle, while cut would turn off the motor completely. For my electrics, I use the "cut" and set it to simply cut throttle completely. The pitch curve does not change when throttle is cut; it's just for performing autos and landing.

[ATIS]

I probably should have been more clear, but I understood Balr14 perfectly. Most fliers who start out with an FP micro are told from day one that if they start to get into trouble, cut the throttle to minimize damage. That's what Balr14 was talking about, that habit of slamming the throttle stick all the way down before impact. Of course, on the little 4 channel micro FP, all that does is remove power to the blades. Then they move up to their first CP heli, and, at the first sign of trouble, they slam the "throttle" to its lowest position, not realizing that now it is also the collective, and most RTF CP helis have 3 to 5 degrees of negative pitch at low stick. He wasn't saying that cutting the throttle with the throttle hold would affect pitch, just the "throttle" stick.
Hope that clears it up.

Yeap, and its a hard habit to break... my B400 just expereinced the "accelerated ground attack"... main blades, grip shaft, main gear, fly bar, servo, my pride... LOL

[InfiniteHover]

i was going to start a thread abotu this but decided to ask here. deos anyone know if the flight mode in asia is flight mode 4.??

my dum ass has been flying mode 4 4ch helis for some time now and when i just got my esky 2.4 co commance. i didnt know what the hell was going on. even the manual has mode 4 in it...

so this is the asian way to fly>??

i might just stick with it...

peace from nyc.