Effect of No Flybar on a Scale Helicopter??
12-10-2004, 09:06 PM
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Effect of No Flybar on a Scale Helicopter??
I was looking in Model Aviation and as looking at the Top Gun or something, or in the Heliocpter section and I saw something about how a helicopter has to have a flybar, and cannot have a non-scale flybar or anything.
For, example, Peter Wales Lama has no flybars whatsoever (at least the one in the 2003 Top Gun of Model Aviation)...It just had three blades. And also in that same issue, there was a guy that had a Scale Bell Jet Ranger that just had two blades but no flybars at all.
Not that that's out of the way, I'm just wondering how cyclic (with I do believe the flybars help control) or any moving whatsoever is affected by not having a flybar.
Thanks,
~Michael~
For, example, Peter Wales Lama has no flybars whatsoever (at least the one in the 2003 Top Gun of Model Aviation)...It just had three blades. And also in that same issue, there was a guy that had a Scale Bell Jet Ranger that just had two blades but no flybars at all.
Not that that's out of the way, I'm just wondering how cyclic (with I do believe the flybars help control) or any moving whatsoever is affected by not having a flybar.
Thanks,
~Michael~
12-10-2004, 10:09 PM
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RE: Effect of No Flybar on a Scale Helicopter??
A real helicopter (Hiller) uses a very strong hydraulic system to move the main blades. Servos are tricky when it comes to this type of strength so this is why the flybar was adapted.
The flybar is easier for the servos to react and the movment of the flybar in turn moves the main blades.
I asked this question in the past and that is the short version of the answer I got.
Someone please elaborate for me because I know that it is a lot more involved than what I have stated.
Brent
The flybar is easier for the servos to react and the movment of the flybar in turn moves the main blades.
I asked this question in the past and that is the short version of the answer I got.
Someone please elaborate for me because I know that it is a lot more involved than what I have stated.
Brent
12-11-2004, 12:28 AM
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RE: Effect of No Flybar on a Scale Helicopter??
Thanks for the quick reply. I know I can always count on RCUnivers to get me a quick and simple answer.
I have also posted this question on runryder.com. I got an answer and it was about the same as your about the full scale having the hydrolics. That person on RunRyder just said the same, and about the servos used are huge 1/4 scale 200+oz. of torque and have the muscle to take the force.
Again, Thanks
~Michael~
I have also posted this question on runryder.com. I got an answer and it was about the same as your about the full scale having the hydrolics. That person on RunRyder just said the same, and about the servos used are huge 1/4 scale 200+oz. of torque and have the muscle to take the force.
Again, Thanks
~Michael~
12-11-2004, 10:04 AM
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RE: Effect of No Flybar on a Scale Helicopter??
Yes, think of it like this... On a model a flybar is really just a "lever" (though it also acts as a stabilizer as well). Look at the setup of it on your head and think about it. (Level the swashplate since that will make it easier to follow). Since the flybar is working kinda like a gyro all it's own (because of the speed of the rotation and orientation of the cg), you'll have to apply a basic knowledge of gyros. When a motorcyclist leans his bike over, and it turns instead of smashing him into the ground (hopefully at least) 
it's because of a phenomenon called gyroscopic precession. Basically when a gyro is "spun up", any force acting against it will cause a reaction 90 degrees later... Take a bicycle tire and spin it real fast while holding the shaft in your hand. Now if you try to lean it left and right (top and bottom) it will not only resist, but will try to MOVE left and right (front and back)... The force you apply results 90 degrees after it's input. Get it so far? Okay, if you start with the flybar straight with the boom, and apply full left cyclic. You'll see that it applies positive pitch to the "nose" side. The effect of it though doesn't come into play until 90 degrees later when the blades are now straight with the boom. At this point you will have 0 pitch (assuming you leveled the swashplate to 0 pitch, or you'll be back to whatever pitch your collective is currently set for). Here the pitch is back to normal, but this is WHERE it actually tilts. Now keep the blades straight with the boom and pay attention to them. Hold the flybar and give left cyclic, let it go, give it again... You'll notice now the input is given to the main blades... IF the flybar was locked down, like your holding it now... Now, make sure the flybar is straight, and give it full left cyclic. Notice the main blades? Now tilt the right side (if your standing behind the heli) up a bit... (remember our flybar has now tilted slightly because the input we gave took place to make it tilt 90 degrees later... The same position your holding it now... Notice that the "extra" pitch is added into the main blades? That's how the flybar helps the mains... Once again, the input to the mains is put in when they are straight to the boom, but does not take effect until 90 degrees later.. That's why all of the "inputs" go in at the nose side, but were talking about left cyclic... So, bottom line is, does a model, or any other heli NEED a flybar? No.... It just adds a little bit of stabilization as well as requiring less force from the servos to move the pitch on the mains.
it's because of a phenomenon called gyroscopic precession. Basically when a gyro is "spun up", any force acting against it will cause a reaction 90 degrees later... Take a bicycle tire and spin it real fast while holding the shaft in your hand. Now if you try to lean it left and right (top and bottom) it will not only resist, but will try to MOVE left and right (front and back)... The force you apply results 90 degrees after it's input. Get it so far? Okay, if you start with the flybar straight with the boom, and apply full left cyclic. You'll see that it applies positive pitch to the "nose" side. The effect of it though doesn't come into play until 90 degrees later when the blades are now straight with the boom. At this point you will have 0 pitch (assuming you leveled the swashplate to 0 pitch, or you'll be back to whatever pitch your collective is currently set for). Here the pitch is back to normal, but this is WHERE it actually tilts. Now keep the blades straight with the boom and pay attention to them. Hold the flybar and give left cyclic, let it go, give it again... You'll notice now the input is given to the main blades... IF the flybar was locked down, like your holding it now... Now, make sure the flybar is straight, and give it full left cyclic. Notice the main blades? Now tilt the right side (if your standing behind the heli) up a bit... (remember our flybar has now tilted slightly because the input we gave took place to make it tilt 90 degrees later... The same position your holding it now... Notice that the "extra" pitch is added into the main blades? That's how the flybar helps the mains... Once again, the input to the mains is put in when they are straight to the boom, but does not take effect until 90 degrees later.. That's why all of the "inputs" go in at the nose side, but were talking about left cyclic... So, bottom line is, does a model, or any other heli NEED a flybar? No.... It just adds a little bit of stabilization as well as requiring less force from the servos to move the pitch on the mains.
12-11-2004, 04:21 PM
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RE: Effect of No Flybar on a Scale Helicopter??
ORIGINAL: rusirius
Yes, think of it like this... On a model a flybar is really just a "lever" (though it also acts as a stabilizer as well). Look at the setup of it on your head and think about it. (Level the swashplate since that will make it easier to follow). Since the flybar is working kinda like a gyro all it's own (because of the speed of the rotation and orientation of the cg), you'll have to apply a basic knowledge of gyros. When a motorcyclist leans his bike over, and it turns instead of smashing him into the ground (hopefully at least) it's because of a phenomenon called gyroscopic precession. Basically when a gyro is "spun up", any force acting against it will cause a reaction 90 degrees later... Take a bicycle tire and spin it real fast while holding the shaft in your hand. Now if you try to lean it left and right (top and bottom) it will not only resist, but will try to MOVE left and right (front and back)... The force you apply results 90 degrees after it's input. Get it so far? Okay, if you start with the flybar straight with the boom, and apply full left cyclic. You'll see that it applies positive pitch to the "nose" side. The effect of it though doesn't come into play until 90 degrees later when the blades are now straight with the boom. At this point you will have 0 pitch (assuming you leveled the swashplate to 0 pitch, or you'll be back to whatever pitch your collective is currently set for). Here the pitch is back to normal, but this is WHERE it actually tilts. Now keep the blades straight with the boom and pay attention to them. Hold the flybar and give left cyclic, let it go, give it again... You'll notice now the input is given to the main blades... IF the flybar was locked down, like your holding it now... Now, make sure the flybar is straight, and give it full left cyclic. Notice the main blades? Now tilt the right side (if your standing behind the heli) up a bit... (remember our flybar has now tilted slightly because the input we gave took place to make it tilt 90 degrees later... The same position your holding it now... Notice that the "extra" pitch is added into the main blades? That's how the flybar helps the mains... Once again, the input to the mains is put in when they are straight to the boom, but does not take effect until 90 degrees later.. That's why all of the "inputs" go in at the nose side, but were talking about left cyclic... So, bottom line is, does a model, or any other heli NEED a flybar? No.... It just adds a little bit of stabilization as well as requiring less force from the servos to move the pitch on the mains.
Yes, think of it like this... On a model a flybar is really just a "lever" (though it also acts as a stabilizer as well). Look at the setup of it on your head and think about it. (Level the swashplate since that will make it easier to follow). Since the flybar is working kinda like a gyro all it's own (because of the speed of the rotation and orientation of the cg), you'll have to apply a basic knowledge of gyros. When a motorcyclist leans his bike over, and it turns instead of smashing him into the ground (hopefully at least)
it's because of a phenomenon called gyroscopic precession. Basically when a gyro is "spun up", any force acting against it will cause a reaction 90 degrees later... Take a bicycle tire and spin it real fast while holding the shaft in your hand. Now if you try to lean it left and right (top and bottom) it will not only resist, but will try to MOVE left and right (front and back)... The force you apply results 90 degrees after it's input. Get it so far? Okay, if you start with the flybar straight with the boom, and apply full left cyclic. You'll see that it applies positive pitch to the "nose" side. The effect of it though doesn't come into play until 90 degrees later when the blades are now straight with the boom. At this point you will have 0 pitch (assuming you leveled the swashplate to 0 pitch, or you'll be back to whatever pitch your collective is currently set for). Here the pitch is back to normal, but this is WHERE it actually tilts. Now keep the blades straight with the boom and pay attention to them. Hold the flybar and give left cyclic, let it go, give it again... You'll notice now the input is given to the main blades... IF the flybar was locked down, like your holding it now... Now, make sure the flybar is straight, and give it full left cyclic. Notice the main blades? Now tilt the right side (if your standing behind the heli) up a bit... (remember our flybar has now tilted slightly because the input we gave took place to make it tilt 90 degrees later... The same position your holding it now... Notice that the "extra" pitch is added into the main blades? That's how the flybar helps the mains... Once again, the input to the mains is put in when they are straight to the boom, but does not take effect until 90 degrees later.. That's why all of the "inputs" go in at the nose side, but were talking about left cyclic... So, bottom line is, does a model, or any other heli NEED a flybar? No.... It just adds a little bit of stabilization as well as requiring less force from the servos to move the pitch on the mains.
You know what, I actually about crashed my helicopter because I was setting up the helicopter with the gyroscopic progression in mind. But the helicopters are already set up for things like that.
I had a post about that. My kindergarden (sp??) teacher's husband has a kit build helicopter. I went over to his house and he was explaining that same principle to me. I thought that would be the same for my model helicopter so, when I changed recievers (after I bought it) it made it where when I moved the right stick left and right, the swash would move foward and backward, and when moved foward and backward, it would move left and right. Luckily I post a thread about that, like I said, and I was corrected. It's in the beginner section somewhere. I just learn something new everyday!!
But yeah, I know exactly what you are talking about. (I have certianly switched back where the servos are going in which channel and am going fine now)
So, really, the scale guys can get away without having a flybar because they use higer, VERY high torque servos that can "compensate" for the effects that the flybar would have..
Thanks for the clear up!!
Happy Holidays!!
~Michael~
12-16-2004, 12:00 PM
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RE: Effect of No Flybar on a Scale Helicopter??
Keep in mind that scale (and full scale) helicopters dont place near the load on the head that 3d flying that requires instantanious cyclic response either. The fly bar enhances the rotor heads on our models so we can fly in the manner that many of us do.
High torque servos, and mild manner flying such as a scale Jet Ranger would do are no problem with a flybarless head. Infact when I was visiting a club in CA I saw a guy doing full aerobatics with a flybarless head.
High torque servos, and mild manner flying such as a scale Jet Ranger would do are no problem with a flybarless head. Infact when I was visiting a club in CA I saw a guy doing full aerobatics with a flybarless head.
12-16-2004, 12:53 PM
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RE: Effect of No Flybar on a Scale Helicopter??
The way I understand it the fly bar acts sort of like power steering on a car. The paddles turn in the air flow and are forced up or down by the force of passing through the air. This in turn moves the main blades. Ulitmately the engine is forcing the flybar through the air and is what provides the power to move the blades, this allows smaller servos and smaller battery etc etc
12-18-2004, 08:43 PM
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RE: Effect of No Flybar on a Scale Helicopter??
thanks for all the input I've gotten so far...I really appreciate. You guys have really helped me out alot!!
~Michael~
~Michael~
