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#1 SPR Phantasm Mar 09, 2011 07:46 PM

Noob Questions - Fixed Pitch/Coaxial/Gyro
 
Hi Everyone - I am new to the hobby and only have been flying for a week, so please bear with me -

I have a question about Fixed Pitched helicopters - I was on xheli.com and was interested in purchasing a Walkera HM CB180D and noticed that it had only one set of blades - Is that what fixed pitch means? Are they harder to fly?

Also, I noticed that many coaxial helicopters have built in Gyro systems - Are there any fixed pitched helicopters with built in gyros?

My last question is what is it like flying without a Gyro system? I understand a Gyro box is for balancing of the aircraft, so I was wondering if I would have a difficult time with a heli that is fixed pitched without a Gyro system -

Thanks for reading!

#2 Balr14 Mar 09, 2011 07:53 PM

That is basically what is meant by fixed pitch. There are no hobby grade helis that do not have gyros. Hasn't been one in years. It's hard to say if they are harder to fly, harder than what? You should know the CB180D has been replaced by the CB180Z, due to a number of issues. Parts could be a problem.

#3 KCinNC Mar 09, 2011 07:57 PM

i would say the Walkera HM CB180D/Z is a fixed pitch heli...and has the gyro built into the reciever :D there should be a whole thread about this heli in the "micro" section !!!

welcome to RCG

#4 SPR Phantasm Mar 09, 2011 09:07 PM

Quote:

Originally Posted by Balr14 (Post 17636600)
That is basically what is meant by fixed pitch. There are no hobby grade helis that do not have gyros. Hasn't been one in years. It's hard to say if they are harder to fly, harder than what? You should know the CB180D has been replaced by the CB180Z, due to a number of issues. Parts could be a problem.

Ok so what you are saying is that all heli's have built in gyros.

Thanks

#5 Balr14 Mar 09, 2011 09:32 PM

I believe there are many "toy" grade 2 and 3 channel helis that do not have gyros. Just FYI, the CB180Z with the 2403 transmitter is the best version of this heli. It has the biggest performance window, so you will get the most out of it.

#6 Frank_fjs Mar 09, 2011 10:06 PM

All modern hobby grade helicopters have gyros. In fact, even modern toy 2 and 3 channel helicopters have a gyro.

Regarding the different types of helicopters, they are generally split up into 3 main categories:
  • Coaxial:
    • Two sets of main rotors that spin in opposite directions. When they both spin at the same speed, the nose of the helicopter remains stationary. When one blade spins faster than the other, the nose of the helicopter will turn. Forwards, backwards and sideways movement is obtained by tilting the swashplate. They have a fixed pitch, are extremely stable and easy to fly. The downside is that this inherent stability comes at the sacrifice of performance. They move slower, are not be as manoeuvrable and don't handle outdoor conditions well.
  • Fixed pitch:
    • This term generally refers to a single rotor helicopter that has a fixed pitch. They have a tail rotor to hold the nose of the helicopter in place and to control pivoting. The spinning of the main rotor produces torque which makes the helicopter want to spin on the spot, the tail rotor counteracts this. Speed up the tail rotor and the nose will pivot in one direction, slow it down and the nose will pivot in the other direction. Directional movement is obtained in the same way as a coaxial, via tilting the swashplate. These offer more performance than a coaxial helicopter but require more skill to control.
  • Collective Pitch:
    • Have a single main rotor and a tail rotor, and also have the ability to alter the pitch of the blades. This means that inverted flight and other stunt type flying is possible (they can flip, roll, loop, fly upside down etc). They offer the most performance but are also the most difficult to fly and configure. You need a great deal of mechanical knowledge on top of flying skill to effectively fly one of these.

The toy 3 channel helicopters are coaxial, and do not have a moving swashplate. They obtain movement via a horizontally mounted tail rotor. If it spins in one direction, this will cause the nose of the helicopter to dip and create forwards movement, when it spins in the other direction, the nose lifts and creates backwards movement. They cannot travel sideways.

There are some rare exceptions to the above, for example there is a coaxial helicopter called the Lama 3 by Walkera that is collective pitch and there is also a 3 channel single rotor helicopter that has a moving swashplate and tail motor, the Double Horse 9100.

#7 SPR Phantasm Mar 10, 2011 03:51 AM

Thank you for the information! Now I have a better understanding.

#8 Balr14 Mar 10, 2011 07:59 AM

Nice write-up Frank.


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