This doesnt add up...

[Guest]

When flying virtually any copter in fs I've found that a full reduction of throttle/collective will reduce the tail rotor's "thrust" to either side quite a bit... even in autorotation with plenty of main rotor head speed.Shouldnt it have ample control effectiveness so long as main rotor speed is kept in its normal range?

[PeterR 9]

There are a few things going on here. The power from the engine is split between the main and tail rotor. If you decrease the throttle, there's less power overall for both and, hence, if the torque on the main rotor stays high, there may not be enough power for the tail rotor to keep the body from rotating. If you reduce the collective, which reduces torque on the engine and hence torque against the body of the helo, you have to reduce power to the tail rotor or the body will rotate. In each case, the body will rotate in one direction or the other depending upon which way the main rotor rotates.Hope that helps. In general, all the controls in the helo are interdependent, so changing one requires compensation in the others.

[Guest]

Thanks Peter,From what I understand, there is no form of "differential" in a [normal] helo that would allow the tail rotor to vary its rotational speed in relation to the main rotor. Its a constant ratio as I understand it.So... IF you maintain a steady main rotor speed (rpm), the tail should always be in its normal speed range and capable of providing "standard" amounts of thrust regardless of what the powerplant is doing.. or not doing. Right?In the sim, with the gauge showing the main rotor rmp in the correct range, the tail *should* have loads of thrust because it's ability to produce a twisting action is not dependent on anything other than main rotor rpm due to an assumed direct connection between the tail and main rotors. On the other side of this, too much tail swinging without a powerplant running should also bleed off main rotor rpm because of the extra load.I come up with all of this after years of flying R/C copters... and once in awile I would mess around and let it run out of fuel in mid flight. When this would happen, the tails ability to swing around did not vary so long as the main rotor had ample rpm.

[PeterR 9]

I do know that being too heavy on the pedal can bleed a fair amount of power from the main rotor, thereby reducing the amount of lift it can produce. That's why countering the weathervane effect in a strong crosswind isn't recommended; takes a lot of power to stay pointed in the direction of flight. I'm not sure about the converse (main rotor bleeding power from the tail). Maybe someone familiar with the mechanics of the real thing will pop in and shed some light.

[Guest]

You're more likely to run out of pedal before power with a strong wind in my experience. The chances are in that case you shouldn't be in the air in the first place. Sometimes you have no choice than to hover crosswind, although it is obviously always preferable to hover into wind.As for bleeding power from the tail, if you think about it logically, yoou're talking about the torque producing rotation around the blades' axis of rotation. For the tail rotor, this would cause the body of the chopper to revolve like a ferris wheel around the tail rotor, which simply doesn't happen. Therefore, the power is related directly to the speed of rotation (which should be roughly constant) and the angle of attack of the tail rotor blades.

[Guest Calb]

I think you've over-analyzed the problem. In fact, it is a simple bug in the helicopter flight model that was uncovered during beta testing but nothing was done about it before final release.Calhover long and prosper

[Guest]

Well for starters, in an Auto-Rotation (in US Version Helicopters) as soon as you loose engine power you would apply FULL RIGHT pedal plus dump ALL of the Collective to counteract the no torque effect and to keep the Main Rotor RPM's up, then you just adjust speed with the Cyclic. So in that situation, you shouldn't have to worry about that problem. Now on to actual aircraft, In a Helicopter with a Turbine Engine there is no need to worry about the Tail Rotor bleeding off RPM from the Main Rotor RPM's. The engines are manufactured with a device that prevents this from happening, for example in a UH1H, it is called a "Droop Cam Compensator", and what it does is keep the Engine at a Constant RPM so there is no need to worry about RPM loss in flight, other than an Engine Failure of course.In an Helicopter such as the Schweizer 300C running a Reciprocal engine, this is done through the Throttle on the collective at the time of increased torque manually, there is no automated systems other than the pilot LOL.The only effect that I would watch for is that when you apply Left Pedal Helicopters have a tendancy to lose a bit of altitude and vice versa with Right Pedal. However MOST Helicopters today have some sort of a FADEC or Droop Compensator or just plain Computerized Control System, so I would say that it is probably a bug in the FS Programming Code...My Experience:US Army Aviation Logistics: PowerPlant Repair (Engine Mech)Over 1800 hours Maintence Flight Time in US Army Helicopters including:UH60's, UH1H's, OH58C's, AH1F'sand Maintence Time All US Army Helicopters including:AH64's, CH47's, OH58D's, and Schooling on the new T800's for the Comanche.And some Simulator time in the UH60 and UH1H Full Motion Sims...

[Guest]

In small piston engine helicopters, there is sometimes a similar system to the "Droop Cam Compensator". Firstly there is a correlator, which is a direct physical link to the butterfly in the carburretor, so that as the collective is raised, the engine provides more power, and vice versa. This is a bit "rough and ready" although it does work surprisingly well with very little adjustment needed to the throttle during flight.Then there is the governor, which as its name suggests, automatically increases or decreases engine power to maintain exactly 100% power. In fact, with this system working, you need never touch the throttle at all.

[Guest]

What you have to consider is the difference in the function of the tail rotor vs. the function of a rudder in a conventional fixed wing. The tail rotor is not a 'rudder' but rather a 'torque compensator'. When you dump the collective/throttle, you remove torque from the main rotor, which means that you need 'less compensation' from the tail rotor. If you will notice, as you add power (collective/throttle), you increase torque and need to use 'left' pedal (more torque compensation via increased tail rotor thrust) and as you decrease power (collective/throttle) you decrease torque and therefore need to use 'right' pedal (or less left pedal) as there is less torque to be compensated for. This all goes back to the old "for every action there is an equal and opposite reaction." The body of the helicopter will be the opposite reaction to the rotation of the rotor, and hence the need for tail rotor compensation. The above representations are given from the standpoint of any ship having a conter-clockwise rotating main rotor (such as Bell, Hughes/ Schweitzer, MD, Sikorsky, Enstrom, etc.). The Aerospatiale/Eurocopter ships (in real life) use a clockwise rotating main rotor so the control inputs for the pedals would be reversed (e.g.: more right pedal with more power, and more left pedal with power reductions). The helicopter is a very complex aerodynamic wonder, and at times, it will put you in very different conditions. For example, a descending left turn will often require the use of right pedal, and likewise, a climbing right turn may require a good bit of left pedal. Remember, more power equates to more torque, and less power relates to less torque. The tail rotor is for torque control. Don't confuse it's operation with a rudder, nor tie it to rotor RPM. It can be argued that as rotor RPM slows, so does tail rotor effectiveness (as it slows in relation), but I do not believe that is your issue as presented in the discussion. I hope this helps...........Rexbo