Flight dynamics (important issues)

[jedra 11]

Cheers guys. I am beginning to understand how these things work slowly!

[beepee 10]

This might help a bit ;) ->

[fboes 10]

@Panther353: Thx for posting this PDF. This is really good stuff and a comprehensive guide to heli aerodynamics.

[jedra 11]

The guide is extremely useful - thanks for posting. It has lead to another question though!

So far, I have completely ignored the throttle in Take On Helicopters. I read with interest in this handbook that there are three ways in which the throttle is controlled in a helicopter; A correlator, a governor and neither. From what I can gather, the first two increase and decrease RPMs based on how much collective is applied, only needing to be fine tuned. The latter requires the Pilot to increase/decrease the RPM as they increase or decrease the collective. I hope I got that right!

Anyway - my question is what method is used for the helicopters in the game? I am assuming either correlator or governor, but I am not sure.

How much should I be worried about controlling RPMs myself while flying in the game?

[4 IN 1 0]

Just wondering, which version of the light in game have changed? the training version or the one that Tom use?

[armored_sheep 56]

Anyway - my question is what method is used for the helicopters in the game? I am assuming either correlator or governor, but I am not sure.

Rotorlib/TKOH simulates governor that takes care of engine RPM. Flight model documentation

Throttle is toggled only in three states FUEL SHUTT OFF / IDLE / FULL AUTO for startup, shut down or emergency autorotation landing.

Edited November 23, 2011 by Armored_Sheep

[Derbysieger 11]

The guide is extremely useful - thanks for posting. It has lead to another question though!

So far, I have completely ignored the throttle in Take On Helicopters. I read with interest in this handbook that there are three ways in which the throttle is controlled in a helicopter; A correlator, a governor and neither. From what I can gather, the first two increase and decrease RPMs based on how much collective is applied, only needing to be fine tuned. The latter requires the Pilot to increase/decrease the RPM as they increase or decrease the collective. I hope I got that right!

Anyway - my question is what method is used for the helicopters in the game? I am assuming either correlator or governor, but I am not sure.

How much should I be worried about controlling RPMs myself while flying in the game?

The helicopters in TOH have a governor.

€: damn ninjas

[jedra 11]

Cool - thanks for that - one less thing to worry about then!

[nightsta1ker 10]

Just wondering, which version of the light in game have changed? the training version or the one that Tom use?

I made no changes to the training version. Only the standard version.

[jedra 11]

Jedra,

This is normal behavior. Helicopters are naturally unstable beasts and you are always on the controls. The Rotorcraft Flying Handbook is a great place to get a basic understanding of helicopter flight dynamics.

Regards,

Chris

@The Moderators

Would it be possible to sticky this link somewhere? I have been reading it today and it is really, really useful. There are quite a few flight dynamics mentioned in here - especially on hover and take-off - that I had been experiencing and wasn't sure how to deal with. Having practiced for a couple of hours AFTER reading this I have found that I understand more about how the helicopter is trying to react.

For a manual produced by a government agency it is remarkably easy to read to boot!

I think it would be an excellent port of call for anyone new to Take on Helicopters who have no rotorcraft experience.

Thanks Panther353 for providing the link.

[Panther353 10]

Scott can correct me if I'm wrong but correlators are primarily found on piston based helos like the Robinson R22 and the Schweitzer 300 series. Governors are on turbine driven helos but may also be found on piston aircraft. I believe that correlators are an older technology.

[nightsta1ker 10]

I wouldn't say you are wrong Chris, but I can go into more detail about the subject.

Keep in mind that none of this applies to TOH in any way.

Correlators are devices that mechanically twist the throttle when you raise or lower the collective making it easier for the pilot to adjust for the rotor RPM changes that occur with coriolis forces and with power demands associated with pitch change. They are attached to the throttle/collective linkages by a spring assembly so the pilot can "override" the correlator. Helicopters that only have a correlator are a little trickier to operate because the pilot must make the fine adjustments to the throttle themselves. The funny thing about correlators is that they are calibrated to adjust for the intitial effects of coriolis forces on the rotors due to coning. As the pilot increases pitch on the main blades with collective input, the lift on the blades makes them want to rise at the tips while the weight of the helicopter keeps them low at the rotor hub. This is called coning. As the blades cone, the center of gravity of the blades move inward (imagine a doorway and put a mark on the center of the door. Then draw a line from the door hinge perpendicular to the door frame. As the door is opened, the center of the door moves closer to the line drawn from the doorframe. This is what is happening to the center of gravity of the rotor). The effect of this is that the blades will spin faster, even though more lift requires more power, the effects of coriolis force requires a DECREASE in throttle. Then, as more collective is added, at some point more power is required to keep the rotors turning against the induced drag. So if you were to be sitting on the ground with zero pitch, then raise the collective smoothly, you would need to reduce the throttle at first, then, as you keep raising the collective, you would need to start increasing it again. This takes many hours to acquire the muscle memory to do this automatically, and watching the rotor RPM takes the pilots eyes away from outside the helicopter and pilots can become "fixated" on the gauge in the cockpit. So I teach my students to listen to the sound of the engine. You can hear the pitch change if the rpms are too low or high and make your adjustments based on that.

Governors are electrically driven devices that respond to the rotor RPM and adjust the throttle with motors. These can also be overrided by the pilot's input. There is a small circuit that calculates any RPM change and decides how much throttle movement is required to adjust for it to keep the RPM steady. Most helicopters that have a governor also have a correlator as a backup. Very rarely do you see a helicopter in service that has neither.

[SpragClutch 10]

In reality, this will never be, nor should it ever be a true realistic flight sim. Only a few are going to be buying complete flight controls for a game, and the majority are going to be playing with a keyboard and mouse. I bought this like I bought ARMA2. As a game. A game that I want to be able to play and enjoy. I want to be able to control the helicopter as one should be able to fly a helicopter, with precision and control, being able to land on the spot I choose.(And believe me I know how one flies) Do this all with a keyboard and mouse. ARMA2 had it good. If only they could bring those Flight Models to Take on Helicopters. Then one could enjoy the campaign and the game.

So all I'm saying is, sure they can make it so realistic in expert mode. But at novice mode, one should be able to fly as one can fly in ARMA2.

My 2 cents.

[4 IN 1 0]

In reality, this will never be, nor should it ever be a true realistic flight sim. Only a few are going to be buying complete flight controls for a game, and the majority are going to be playing with a keyboard and mouse. I bought this like I bought ARMA2. As a game. A game that I want to be able to play and enjoy. I want to be able to control the helicopter as one should be able to fly a helicopter, with precision and control, being able to land on the spot I choose.(And believe me I know how one flies) Do this all with a keyboard and mouse. ARMA2 had it good. If only they could bring those Flight Models to Take on Helicopters. Then one could enjoy the campaign and the game.

So all I'm saying is, sure they can make it so realistic in expert mode. But at novice mode, one should be able to fly as one can fly in ARMA2.

My 2 cents.

FPDR

Keep beating the dead horse ain't you? We have already gone through this some 5 pages ago.

Edited November 25, 2011 by 4 IN 1

[samb 15]

@SpragClutch

Just fly with trainee difficulty settings. Let those who want realistic experience have their fun as it's not affecting Your gameplay in any way.

[nightsta1ker 10]

Gentlemen... lets please not get off topic. SpragClutch, if you read the entire thread you would see that these issues are being addressed already.

[Panther353 10]

The flight dynamics thread has gone quiet. Everyone still in a turkey coma?

[4 IN 1 0]

Busy at RL stuff I assume? Anyways, things will be ready, when it is ready.:)

[twisted 128]

The flight dynamics thread has gone quiet. Everyone still in a turkey coma?

totally keeping an eye out for nightstalkers update. but always RL > games.

[EagleEye-GER- 0]

The flight dynamics thread has gone quiet. Everyone still in a turkey coma?

Hastily release coma here.:( Waiting for patch3 and try community improvements...:j:

[Panther353 10]

Oh no worries guys. My tongue was firmly inserted in cheek.

[nightsta1ker 10]

Sorry gents. Real world stuff and the release of the XP10 beta have kept me away from TOH for a bit. I am back at it today. I want to try and fix two things before this next release. The first one is reducing the pedal effectiveness a bit because I feel the amount currently needed is not enough.

The second is increasing the roll rate. Sensitivity is not so much of an issue as the roll and pitch rates being too slow. I think I know HOW to do these things, now I just need to go do them. Don't worry, it's not dead, it was just on the backburner simmering for a few days.

I was supposed to be testing the new official patch as well, but I needed some permissions that I don't currently have, so after several exchanged emails on the subject, I let it slide. I just don't have time to do all this stuff right now. Once I get MY update done and available for the community I will test the new patch (if it hasn't released already).

[jedra 11]

Sorry gents. Real world stuff and the release of the XP10 beta have kept me away from TOH for a bit. I am back at it today. I want to try and fix two things before this next release. The first one is reducing the pedal effectiveness a bit because I feel the amount currently needed is not enough.

The second is increasing the roll rate. Sensitivity is not so much of an issue as the roll and pitch rates being too slow. I think I know HOW to do these things, now I just need to go do them. Don't worry, it's not dead, it was just on the backburner simmering for a few days.

I was supposed to be testing the new official patch as well, but I needed some permissions that I don't currently have, so after several exchanged emails on the subject, I let it slide. I just don't have time to do all this stuff right now. Once I get MY update done and available for the community I will test the new patch (if it hasn't released already).

Man, so many flight sims, so little time! I am surprised you get time to fly a real one! The motto of the community is and always will be "when it's ready" - so take your time and release when you're happy.

[samb 15]

Too bad You're gonna pass on testing upcoming patch NS. Hope Your update is going to be even better than BiS patch!

[nightsta1ker 10]

I actually hope just the opposite. I hope BIS and RTD nail it. But that's just me. I would have been alot happier if I did not have to do all this code/ test/ troubleshoot/ code/ test/ troubleshoot. It's tiresome and boring and gives me a headache. I do it because I seem to have a rudimentary understanding of what the numbers mean, and I happen to be a real pilot, so I know what they should feel like. I just mess with numbers until it feels right.

I am very pleased with what I have right now. I just shot an auto with throttle closed and it felt pretty all right. Much better than stock. Actually somewhat beleivable. I wish it acted that way with the throttle at idle...

One thing that is kind of annoying me that I can't figure out... I still need left pedal in the flare with power off, even though there is no engine driving the rotors. There should be no torque at that point!

Flight controls are feeling very nice. Some stability, but very sensitive. Not needing to overcorrect all the time and chase the helicopter around. Still have some wierd issues with torque. I find I need a LOT of right pedal with the collective all the way down, and a LOT of pedal with higher torque settings, but not a noticable amount at hover power, which is very odd feeling. I am hoping to get it released tonight. Issues or no. It's still a vast improvement. Most of the really hard stuff was done by b101_uk, I just played with control settings mostly and reduced some of the friction in the skids.