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Bothersome

Question about Flight Model

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I fly real RC helicopters. (Raptor 50)

Does anyone here fly real helicopters?

My question is when we fly faster forward, is it normal to have to counter a right roll tendency with left cyclic the faster we go? (on a right to left (counter-clockwise) rotor helicopter)

In RC, we tend to use gyros and Bell-Hiller head setups and this compensates for most of the cyclic adjustments. The faster you go the more the fly-bar is tilted (forward for forward movement).

To me, it seems the flight model is wrong in this game having to hold more left cyclic to counter a right hand roll. The advancing blade is moving quicker on the right. So it needs less attack angle. The blade on the left is receding and thus needs more angle of attack. To make that happen you need "Forward" cyclic. It's a 90 degree precession thing.

But since I never flew a full scale helicopter, I might need instruction on this. Thanks.

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Another question: when you turn to hard with high airspeed and the nose picks up straight toward the sky or sometimes even steeper - it seems pretty easy to recover yet it feels as if that helo should really start to drop out of the sky at that angle. Is this true helo physics?

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The rolling tendency on a helicopter is due to dissemetry of lift, but it is acounted for by allowing the blades to flap up and down at different points in their rotation, at least until forward velocity exceeds the rotor hubs ability to compensate, at which point you would see a roll on the retreating blade side coupled with a nose up tendency.

In any case, the right roll people are seeing in TOH is not accurate. The blades are counter clockwise rotating, for one, so the retreating side is on the left. If there were going to be any roll present, it would be on that side. Secondly, as stated above, withing the aircrafts authorized operating speed range, the pilot should not notice much change at all because the rotor system is designed to take care of these things on it's own. Just don't exceed your speed redline.

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Another question: when you turn to hard with high airspeed and the nose picks up straight toward the sky or sometimes even steeper - it seems pretty easy to recover yet it feels as if that helo should really start to drop out of the sky at that angle. Is this true helo physics?

Not real sure I'm following you but I'll try to explain what I think you are referring to.

Lets say you wanna do a sharp right hand turn. High air speed. 60 degree banking turn.

A helicopter REALLY needs rudder input to assist in this turn. Too many airplane pilots just want to use ailerons and elevator only to make turns. This is actually wrong. Airplanes too need to be done using some rudder also... This is especially pronounced in helicopter flight.

There is some "weather veining" in helicopter turns but rudder greatly assists in getting the nose around.

Now if you are going to be doing an 80 degree turn (severe stunt) then you would have mostly up elevator (back on cyclic) like an airplane. This works well on small RC helicopters, but I wouldn't think a full scale could tolerate the stresses.

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Ok thanks - am going joystick shopping today as I'm guessing I just don't use rudders enough right now. Also what I was referring to seems to only be true at Trainee level -seemingly extreme angles of the Helo not causing it to lose lift. On expert, it certainly loses lift!

Edited by froggyluv

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as i posted this answer on SimHQ i think it's worth posting it here too :)

this is not just some random numbers and features on top A2: OA copter flightmodel

being aware of the shortcomings identified by the real sim enthusiasts in the A2OA helicopters,

we decided to work together with the RTD FDM (http://www.rtdynamics.com/v2/wp/2008/rotorlib-fdm/).

We've tried to identify the real 'missing' parts of the simualtion (like Vortex Ring State)

and continue to suport improvements to the FDM in future patches. on top of that....

we had on our disposal multitude real helicopters and theirs pilots,

some staff flew portion of these helicopters themself

some members of staff even took flight training for pilot licenses on helicopters

we even built our own helipad next to HQ building, to have copters close as possible

on top there is openness to modifications (xml)

and then addition of our extra engine features (fuel consumption, dynamic weight load, maintenance and damage simulation)

there were added new parameters in addon *.cfg files allowing even more modification

ofcourse it's first game then as well as simulation

and the key point is to have fun while flying these copters

so i hope You will enjoy the game

and i can't wait to read Your evalution of our new FDM"

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Thank you Dwarden - I look forward to the updates

can you say if there will be a 'fly by' camera view added to external view options?

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the right rolling tendency happens even when you're below the VNE(never exceed airspeed) limit. it also happens as you flare to drop airspeed, you drift to the right with alarming speed and requires stupidly large amounts of left cyclic input to correct for it, you can see this in the heavy helicopter. the ground effect ballooning of the helicopter is still there but it's not as bad as before, i don't think they understand when we tell them it's a cushion of air when we're IGE and that it requires LESS collective/blade pitch to hold a steady hover. i do agree that there is a ballooning effect in helicopter during hovering but it's not caused by ground effect. this is the only reason why i can see it ballooning, say if we do a left pedal turn and do not add more collective which means power is transferred to the tail rotor and there's less power available for the main rotor so we slowly descend, and when we see that descend we add more power but add too much and now we're gaining altitude and we just keep chasing the collective up and down. same thing for right pedal turns and not decreasing collective because we're using less power on the tail rotor so the main rotor has more power so we balloon up a little bit and forget to lower collective, then we lower the collective when we realize we're ascending and we lower too much and we drop down again etc. however none of that is a big spring that bounces the helicopter back up 20ft when we descend down to the ground. how it should look like is we're descending and maybe 25ft above ground and we slowly increase collective to arrest the descend, as we're coming near the ground but still descending we stop adding collective and let the helicopter come into IGE and that extra cushion of air will stop our descend and we come into a hover, what it does NOT do is bounce us back up into the air unless we've added too much collective in the descending process which would result in us flying straight and level anyway. another way it can balloon up and down is if the helicopter is in a hover and the wind is gusting 16-24 knots and the helicopter is pointing directly at the directing of where wind is coming from. the wind will basically bring the helicopter into ETL and out of ETL when hits the rotor blades and when it stops and that can potentially create a ballooning effect. also they still haven't fixed the helicopters needing too much nose up attitude to slow down in a reasonable amount of time. they also still haven't fixed full collective down and you're barely descending in the light helicopter, but the medium and heavy helicopter seems to be reacting better but it still needs more sink rate. also there's almost 0 torque effect in expert mode, i don't even need to use my pedals when i take off in the light or medium helicopter, only when i fly the heavy i notice small amounts of torque effect and i actually need to use a little bit of left pedal to keep the heading constant.

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maybe things like torque and collective effectiveness should be on a slider - to give each user their own 'feel' for whats right...

like the 'realism' settings in FSX (for those who are familiar)

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Not real sure I'm following you but I'll try to explain what I think you are referring to.

Lets say you wanna do a sharp right hand turn. High air speed. 60 degree banking turn.

A helicopter REALLY needs rudder input to assist in this turn. Too many airplane pilots just want to use ailerons and elevator only to make turns. This is actually wrong. Airplanes too need to be done using some rudder also... This is especially pronounced in helicopter flight.

There is some "weather veining" in helicopter turns but rudder greatly assists in getting the nose around.

Now if you are going to be doing an 80 degree turn (severe stunt) then you would have mostly up elevator (back on cyclic) like an airplane. This works well on small RC helicopters, but I wouldn't think a full scale could tolerate the stresses.

Sorry mate, this is incorrect. Helicopters need almost no pedal to assist in the turn. Pedals are there to counter torque and to "yaw" the helicopter. Though some adjustment to keep the helicopter in "trim" may be required, I find that most of my flying is done without moving the pedals.

Large pedal movements come as an adjustment to rotor torque is made. A reduction in torque requires right pedal, an increase requires left pedal.

In short, the pedals are only used to "turn" the helicopter in a hover. In forward flight, they are not used much and pretty much stay put. Quite a few helicopters out there don't even have a slip indicator! It's not considered important enough! I don't know where you got your information on this, but it's wrong.

By the way, TOH does not model this behavior correctly, so if you are basing your opinion off that, you would be making a mistake. :D

Edited by nightsta1ker

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I get it from flying real RC helicopters.

Granted in heading hold mode (gyro controlled) is an absolute truth.

In heading slip mode (heading hold is off) the heli does a bad looking turn as the tail is kept aft from the wind.

Much prettier turn when giving rudder input.

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I get it from flying real RC helicopters.

Granted in heading hold mode (gyro controlled) is an absolute truth.

In heading slip mode (heading hold is off) the heli does a bad looking turn as the tail is kept aft from the wind.

Much prettier turn when giving rudder input.

I know what you are talking about. I fly RC helis too. Not the same ballpark as the real ones though. They have some very different behaviors due to size, weight and rotor RPM. Comparing flight behavior is a stretch at best.

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