HeliDinoRC
Senior Rc-Help Member
I just read something and the light bulb went on in my old brain. Paul made a statement yesterday in my build thread which made me start thinking and doing some additional research. I realize I've been flying helis totally in the dark. Please correct me if I'm wrong here…...
I started as a kid flying airplanes and on the Tx the throttle was for going fast or slowing down by increasing or decreasing the propeller speed. Now, flying helis the "prop" is on top and a new set of rules comes into play. I don't have the whole story here but this is my basic understanding of how these things work together. I think coming to this realization will help me pilot my birds as well as setup my build.
Up until this moment I have flown helis by using or thinking of the throttle for what it was or what I thought it was. I know that the throttle stick also controls collective but in my mind when the stick was at 0 the motor stopped and pitch was at whatever was set in the pitch curve for stick position 0, L or 1, (whatever your Tx uses). Again, in my mind, this is what happens: As I move the stick up the motor speeds up from 0 AND the pitch of the main rotor blades go positive (or negative) according to the pitch curve. In my tamed down (hover practice) pitch curve my 0 stick was +3 degrees pitch, ¼ stick +4, mid stick +5, ¾ stick +6, full stick +7. So, in this case as I moved my throttle stick up, the motor got faster and more positive pitch was applied to the main blades creating the necessary lift to take off and hover. At about mid stick the bird would lift off and hover. At mid stick I'm at 50% motor power and pitch is +5, which is, theoretically, where a heli will hover. And mine does after tweaking a degree or two. In turn, I was thinking that in order to go up (direction) give it more gas (throttle stick). To come down back off the gas (throttle stick). This is true; however, where I didn't make the connection is that the other and real reason the heli goes up and down: Main Rotor Blade Pitch. Ahhhhhh……...
Lately, I have been reading a lot about idle up settings and FBL setups because I am currently in the middle of a Goblin 630 build and I am at the point of setting up the electronics. However, I wasn't quite sure of what was meant by statements like, "I have my Flight Modes/Setups, IU1, IU2, IU3 at a head speed of 1800/2000/2250 so when I idle up I can do ………," "I had to increase my head speed……," "What pinion do I need to get a head speed of……," etc., etc. I wasn't sure what, why, or how idle up was being used. Again, prior to today, idle up wasn't a switch but a movement of my left throttle stick. Now, I am understanding that the aforementioned FMs are synonymous with IU1, IU2, IU3, and they refer to setups which are then mapped to a switch (only two FMs or IU1, IU2 are utilized if your Tx doesn't have a three position switch) when in a certain FM/Setup a constant head speed is very useful and necessary for 3D. Now, I am understanding that a FM 1 or IU1 at 1800 head speed, FM 2 or IU2 = 2000, and FM 3 or IU3= 2250 (arbitrary numbers for this writing) together with flat throttle curves of 100% across the board, 80%, etc., flying the heli becomes easier as, for all intents and purposes, once the motor starts, depending on how your Tx and devices are programed, the throttle stick only controls one thing: Collective Pitch.
Now it makes more sense……..Fast forward to flying and the simulator. I never got to the point of programming and utilizing a flat throttle curve, as stated above. Again, in my mind the motor should speed up with forward stick and slow down with backward stick. Now, I have sen the light and this is not necessarily so in the world of RC heli flying. What I came to understand this morning is that by setting a flat throttle curve of 100% the motor will run at top speed. This is where the governor comes in. By setting the governor, say for FM 1 at 1800, when in FM 1 (head speed of 1800) and a flat throttle curve of 100%, 100% = 1800 RPM no matter where the stick is, theoretically, of course. This means that as soon as you hit the throttle the bird either shakes itself apart trying to spool up or it shoots to the moon before you even know what happens……no, not really…..by programming the ESC to soft start the motor will spool up according to that setting and when it reaches the desired head speed as set in FM 1, you then control up and down with the throttle stick; however, not because the motor is spinning faster, as I thought prior to today, but because you are introducing positive or negative pitch to the main rotor blades with the movement of the stick……motor speed is constant. Once in the air you switch to FM 2 or IU2 and the main rotor blades spin faster and you are able to perform certain maneuvers without worrying about controlling motor speed, but only controlling collective pitch.
Certain flying maneuvers and helis require a faster or slower head speed depending on your flight style and build. So, by programming a faster or slower head speed for FM 2 or IU2, for example, set head speed at 2000, and a flat throttle curve of your choosing, you go faster and continue to control up and down with the throttle stick but by increasing or decreasing main rotor blade pitch not by motor speed. The same holds true for programming FM 3 or IU3 with a head speed of 2250. So, in a sense, the throttle stick really isn't throttle. You can think of it as a start stick. When you lift the stick off of 0 position (depending on your setup and programming), the motor starts and the blades begin to spin. Motor speed control is then handed over to the ESC, Throttle Curve, and Governor. The left stick then turns into the collective pitch range control stick.
As I backtrack and think about this a little, motor speed will help lift the heli; however, main rotor blade pitch is what creates the lift. With no lift you can run the motor until she blows and the bird will not budge. It will shake itself apart but will not lift off the ground. This is where pitch comes in. Together with pitch you need the blades spinning at a certain RPM to create the "lift" necessary to fly the heli; without the blades spinning, you can introduce positive pitch all day long and the bird will sit there. You need both for lift to be created.
There are uses for a stepped (correct???) throttle curves i.e. 0%, 25%, 50%, 75%, 100% as well as flat curves i.e. 100%, 100%, 100%, 100%, 100% depending on your flying style and what you want to accomplish with your FM's and bird. But, a pitch curve of -10, -5, 0, +5, +10 (degrees of pitch) with a "stepped" throttle curve will not work because when the throttle stick is moved two things happen. At 0 stick position the motor is stopped and the main blades are pitched at -10 degrees. When the stick is moved forward the blades are actually pushing down on the bird until 50% stick is reached. Keep moving up and the blades begin to be introduced with positive pitch; however, the motor is almost at 75% of power and once there is enough pitch to create lift, the bird rockets up and out of control. On the other end of the spectrum, once in the air and you begin to move the stick backward, two things happen: The motor slows down AND you introduce negative pitch on the main blades and the heli will descend very quickly when you hit mid stick and half power. in other words she will drill down into the dirt before you can blink your eyes. However, a pitch curve of -10, -5, 0, +5, +10 will work with a flat throttle curve because head speed is maintained and as blade pitch changes lift remains because motor speed is constant. That being said, when you move from + to - pitch for inverted flight. As the bird flips over negative pitch turns to positive pitch when the bird is upside down. Due to the fact that you are only controlling pitch with the "throttle" stick the blades are still creating enough lift because the motor speed does not decrease as the stick is moved down.
I started as a kid flying airplanes and on the Tx the throttle was for going fast or slowing down by increasing or decreasing the propeller speed. Now, flying helis the "prop" is on top and a new set of rules comes into play. I don't have the whole story here but this is my basic understanding of how these things work together. I think coming to this realization will help me pilot my birds as well as setup my build.
Up until this moment I have flown helis by using or thinking of the throttle for what it was or what I thought it was. I know that the throttle stick also controls collective but in my mind when the stick was at 0 the motor stopped and pitch was at whatever was set in the pitch curve for stick position 0, L or 1, (whatever your Tx uses). Again, in my mind, this is what happens: As I move the stick up the motor speeds up from 0 AND the pitch of the main rotor blades go positive (or negative) according to the pitch curve. In my tamed down (hover practice) pitch curve my 0 stick was +3 degrees pitch, ¼ stick +4, mid stick +5, ¾ stick +6, full stick +7. So, in this case as I moved my throttle stick up, the motor got faster and more positive pitch was applied to the main blades creating the necessary lift to take off and hover. At about mid stick the bird would lift off and hover. At mid stick I'm at 50% motor power and pitch is +5, which is, theoretically, where a heli will hover. And mine does after tweaking a degree or two. In turn, I was thinking that in order to go up (direction) give it more gas (throttle stick). To come down back off the gas (throttle stick). This is true; however, where I didn't make the connection is that the other and real reason the heli goes up and down: Main Rotor Blade Pitch. Ahhhhhh……...
Lately, I have been reading a lot about idle up settings and FBL setups because I am currently in the middle of a Goblin 630 build and I am at the point of setting up the electronics. However, I wasn't quite sure of what was meant by statements like, "I have my Flight Modes/Setups, IU1, IU2, IU3 at a head speed of 1800/2000/2250 so when I idle up I can do ………," "I had to increase my head speed……," "What pinion do I need to get a head speed of……," etc., etc. I wasn't sure what, why, or how idle up was being used. Again, prior to today, idle up wasn't a switch but a movement of my left throttle stick. Now, I am understanding that the aforementioned FMs are synonymous with IU1, IU2, IU3, and they refer to setups which are then mapped to a switch (only two FMs or IU1, IU2 are utilized if your Tx doesn't have a three position switch) when in a certain FM/Setup a constant head speed is very useful and necessary for 3D. Now, I am understanding that a FM 1 or IU1 at 1800 head speed, FM 2 or IU2 = 2000, and FM 3 or IU3= 2250 (arbitrary numbers for this writing) together with flat throttle curves of 100% across the board, 80%, etc., flying the heli becomes easier as, for all intents and purposes, once the motor starts, depending on how your Tx and devices are programed, the throttle stick only controls one thing: Collective Pitch.
Now it makes more sense……..Fast forward to flying and the simulator. I never got to the point of programming and utilizing a flat throttle curve, as stated above. Again, in my mind the motor should speed up with forward stick and slow down with backward stick. Now, I have sen the light and this is not necessarily so in the world of RC heli flying. What I came to understand this morning is that by setting a flat throttle curve of 100% the motor will run at top speed. This is where the governor comes in. By setting the governor, say for FM 1 at 1800, when in FM 1 (head speed of 1800) and a flat throttle curve of 100%, 100% = 1800 RPM no matter where the stick is, theoretically, of course. This means that as soon as you hit the throttle the bird either shakes itself apart trying to spool up or it shoots to the moon before you even know what happens……no, not really…..by programming the ESC to soft start the motor will spool up according to that setting and when it reaches the desired head speed as set in FM 1, you then control up and down with the throttle stick; however, not because the motor is spinning faster, as I thought prior to today, but because you are introducing positive or negative pitch to the main rotor blades with the movement of the stick……motor speed is constant. Once in the air you switch to FM 2 or IU2 and the main rotor blades spin faster and you are able to perform certain maneuvers without worrying about controlling motor speed, but only controlling collective pitch.
Certain flying maneuvers and helis require a faster or slower head speed depending on your flight style and build. So, by programming a faster or slower head speed for FM 2 or IU2, for example, set head speed at 2000, and a flat throttle curve of your choosing, you go faster and continue to control up and down with the throttle stick but by increasing or decreasing main rotor blade pitch not by motor speed. The same holds true for programming FM 3 or IU3 with a head speed of 2250. So, in a sense, the throttle stick really isn't throttle. You can think of it as a start stick. When you lift the stick off of 0 position (depending on your setup and programming), the motor starts and the blades begin to spin. Motor speed control is then handed over to the ESC, Throttle Curve, and Governor. The left stick then turns into the collective pitch range control stick.
As I backtrack and think about this a little, motor speed will help lift the heli; however, main rotor blade pitch is what creates the lift. With no lift you can run the motor until she blows and the bird will not budge. It will shake itself apart but will not lift off the ground. This is where pitch comes in. Together with pitch you need the blades spinning at a certain RPM to create the "lift" necessary to fly the heli; without the blades spinning, you can introduce positive pitch all day long and the bird will sit there. You need both for lift to be created.
There are uses for a stepped (correct???) throttle curves i.e. 0%, 25%, 50%, 75%, 100% as well as flat curves i.e. 100%, 100%, 100%, 100%, 100% depending on your flying style and what you want to accomplish with your FM's and bird. But, a pitch curve of -10, -5, 0, +5, +10 (degrees of pitch) with a "stepped" throttle curve will not work because when the throttle stick is moved two things happen. At 0 stick position the motor is stopped and the main blades are pitched at -10 degrees. When the stick is moved forward the blades are actually pushing down on the bird until 50% stick is reached. Keep moving up and the blades begin to be introduced with positive pitch; however, the motor is almost at 75% of power and once there is enough pitch to create lift, the bird rockets up and out of control. On the other end of the spectrum, once in the air and you begin to move the stick backward, two things happen: The motor slows down AND you introduce negative pitch on the main blades and the heli will descend very quickly when you hit mid stick and half power. in other words she will drill down into the dirt before you can blink your eyes. However, a pitch curve of -10, -5, 0, +5, +10 will work with a flat throttle curve because head speed is maintained and as blade pitch changes lift remains because motor speed is constant. That being said, when you move from + to - pitch for inverted flight. As the bird flips over negative pitch turns to positive pitch when the bird is upside down. Due to the fact that you are only controlling pitch with the "throttle" stick the blades are still creating enough lift because the motor speed does not decrease as the stick is moved down.
) And I use soft-start features on all of them. 
