question for pilots

I'm not a helo pilot, but I did stay in a Holiday Inn Express last night...

An alternative to flying full scale helos is to get involved with radio control helicopters. They follow all of the same rules of aerodynamics as their full scall bretheren and require even more concentration because the pilot is not inside the machine with all those instruments to help out.

Darwin, O.F.

This is so intersting for me, I have always dreamt of flying them, and have never had the chance to chat with pilots about how to fly one. If any of you pilots have yahoo im, I would love to chat about this. Thanks guys.
lee

No throttle application with collective is required in turbine powered helicopters - you just wind the throttle to the stop prior to takeoff and the power turbine controller keeps the rotor rpm constant. (There are some emergency situations where you have to twist the throttle - it helps to have flown a piston powered helicopter if that is required.) Some piston engine powered helicopters have some sort of mechanical throttle coordination with collective, but you still have to fine tune the power to maintain constant rotor rpm. The Model 47/H-13 doesn't provide any help - in fact the turbo charged TH-13T power lagged noticeably behind the throttle which further increased the pilot workload.

With respect to pedal application, Yes and no - a tandem doesn't need any pedal with collective changes because anti-torque is accomplished by the two rotors turning opposite directions. You pull up, you go up. Pedal with collective is required in single rotor helicopters if they don't have compensation - most don't.

Further, the tandem is insensitive to wind direction in a hover while the single wants to weather-vane into the wind. This isn't a big deal in Sikorskys, which have terrific tail rotor control power, but in most Bells a quartering tail wind in low speed flight gets a lot of your attention - ask a Bell pilot about "Loss of Tail Rotor Effectiveness".

What's worse with a single rotor helicopter in a hover is that changing collective means changing tail rotor thrust (for the torque change) which also adds side thrust which means adjusting the cyclic to kill off the sideways movement which slightly reduces lift which requires a little collective change which...

Another question guys. If the controls have a diffrent effect, do you fly a tandom rotor the same, meaning up collective, up throttle and left pedal to correct torque? Hope my question makes sense.
Lee

Both a single rotor helicopter and a tandem can pivot around any point you want, including a point in space outside the helicopter. But just using the pedals, they both pivot roughly around the center of gravity, which is under the rotor on a single and about halfway in between the rotors on a tandem.

Tandem controls also include differential collective for pitch control and cruise trim.

Thanks Frank, that makes perfect sense. So a tandem rotor chopper does not pivot around one or the orhter main rotor, as a single rotor chopper, it pivots from the cneter of balance? Interesting. Thank you sir!
Lee

Hi Lee,

Hope this finds you well and you've had a happy 4th!

To tell you what is really going on at the head when certain controls is
applied is beyond my ability to explain and your ability to understand. (maybe so if we were Flight Engineers) However, it can be simplified to server for explaination:
Imagine the rotor "disks" can be "tilted" by the controls. Fore and aft cyclic tilts both in the same direction. Lateral cyclic tilts both left and right. Pedals tilts them opposite one another. Left pedal would tilt the forward disk to the left and the aft disk to the right, thus allowing the helicopter to pivit around the center. In flight, the pedals are just used for trim, as long as the SAS (stability augmentation system ) is working. If the SAS is off, you have to use the pedals much like taxiing a tail dragger.

Of course, on a tandem rotor aircraft, one set of blades cancels out the torque created by the other set.

Hope this helps a little,
Take care,
Frank