SurfCity
04-09-2008, 08:22 PM
There's something magical about flight. Even the most humble.
Noob here, as you know. Never flown a single-rotor heli. In spare moments for six weeks I've been tinkering with my Gaui, fitting this, tightening that, upgrading whatever. Everything's mounted and wired. Battery's out front for balance, gyro's beneath the main shaft, the center of rotation. Receiver's out front in free space. All good locations. I've replaced a few stock plastic parts with CNC aluminum -- tail servo mounts, swashplate guide and canopy mounts, tiny parts from China that combined cost $22 (plus shipping) and add maybe three grams but work better. I added wooden blades, which are lighter and stiffer than stock plastic. I've checked and double-checked blade tracking. I've balanced the blades by feel, not weight, meaning now when they rotate they add no vibration. I've set blade pitch not with a gauge but by eye, which I trust. I've set throttle and pitch curves in the transmitter. I've set the gyro to "rate" mode, in which final yaw tuning must be done before converting to "heading-hold" mode. I've fussed over sticky links, which can adversely affect control, but you guys said don't worry about it; they loosen as they run in. Four months ago I knew none of this. It's been very engrossing.
My wife last week brought home from the grocery store a cheap, plastic lazy Susan, maybe 10" in diameter, to which I taped the heli so I could spool it up safely to check and correct yaw drift. I set zero blade pitch to occur at the recommended 50% throttle; below that there's slight negative pitch. Tonight I needed low head speed to adjust the tracking, so I dialed out the negative.
Well, okay, so I'm running the motor, blades on, and 50% throttle is FAST, probably 2,000 rpm. With each spool-up I've been daring a little more head speed. Pretty soon the heli's tugging at the tape, listing left, then forward, then right. Tiny corrections send it quickly the opposite way -- or semi-opposite way, or back or right or left, drunk. Feels like if it got loose from the tape it would INSTANTLY shoot across the room into a wall and a hundred pieces. This is not reassuring.
Still, I push it. Tape it tighter, then add more head speed. Settles into a smooth, steady hum. It's off the skids maybe a micron. Control still feels manic, though; I have NO IDEA how I'd correct (at least quickly enough) if it wasn't tied down. Still faster, slightly. Now it's pulling HARD but getting curiously steadier. Add a little more head speed -- now it's a low wail, and I'm SURE I haven't reached 60% -- and, just like that, quite unexpectedly, it lifts the plastic turntable completely off the floor! Airborne and free. And it just makes me giggle. Steady but extremely brief hover. Power down. First flight. A mere hop. But it's magic. Something about it is magic.
The lazy Susan is two-thirds the weight of the heli. Yet the lift appeared effortless. I imagine at full head speed and blade pitch, it could lift twice its weight, maybe more. And here we are, counting fractions of a gram.
So that's where I am tonight. I got out my Blade CX2 training wheels -- orange ping-pong balls on sticks -- attached them to the Gaui and set the turntable aside. Now the whole thing feels light. Power up again to 50% head speed -- it's still planted because there's no blade pitch -- throttle up just a little, slight pitch kicks in, and that's all it takes. Light on the skids. Steady, steady, then airborne. A whole inch this time. Yaws slowly left -- I'll have to adjust that -- but the heli's stable, more than its drunken sashaying suggested when taped down. Quite different from the Blade, which wants to be lazy and stable but is sloppy to control. This thing is serious; it wants to GO -- anywhere. Power down, shut everything off, and I'm grinning ear to ear. I don't know why.
I did notice that stick inputs do not equate directly to flight outputs; the heli's about an eighth-turn behind. Straight forward stick yields forward-left motion. Straight right stick yields forward-right motion, and so on around the circle. Has to do, I think, with precession -- the rotating-wing effect -- but I need to read up.
Stay tuned.
Surf
----------
Noob here, as you know. Never flown a single-rotor heli. In spare moments for six weeks I've been tinkering with my Gaui, fitting this, tightening that, upgrading whatever. Everything's mounted and wired. Battery's out front for balance, gyro's beneath the main shaft, the center of rotation. Receiver's out front in free space. All good locations. I've replaced a few stock plastic parts with CNC aluminum -- tail servo mounts, swashplate guide and canopy mounts, tiny parts from China that combined cost $22 (plus shipping) and add maybe three grams but work better. I added wooden blades, which are lighter and stiffer than stock plastic. I've checked and double-checked blade tracking. I've balanced the blades by feel, not weight, meaning now when they rotate they add no vibration. I've set blade pitch not with a gauge but by eye, which I trust. I've set throttle and pitch curves in the transmitter. I've set the gyro to "rate" mode, in which final yaw tuning must be done before converting to "heading-hold" mode. I've fussed over sticky links, which can adversely affect control, but you guys said don't worry about it; they loosen as they run in. Four months ago I knew none of this. It's been very engrossing.
My wife last week brought home from the grocery store a cheap, plastic lazy Susan, maybe 10" in diameter, to which I taped the heli so I could spool it up safely to check and correct yaw drift. I set zero blade pitch to occur at the recommended 50% throttle; below that there's slight negative pitch. Tonight I needed low head speed to adjust the tracking, so I dialed out the negative.
Well, okay, so I'm running the motor, blades on, and 50% throttle is FAST, probably 2,000 rpm. With each spool-up I've been daring a little more head speed. Pretty soon the heli's tugging at the tape, listing left, then forward, then right. Tiny corrections send it quickly the opposite way -- or semi-opposite way, or back or right or left, drunk. Feels like if it got loose from the tape it would INSTANTLY shoot across the room into a wall and a hundred pieces. This is not reassuring.
Still, I push it. Tape it tighter, then add more head speed. Settles into a smooth, steady hum. It's off the skids maybe a micron. Control still feels manic, though; I have NO IDEA how I'd correct (at least quickly enough) if it wasn't tied down. Still faster, slightly. Now it's pulling HARD but getting curiously steadier. Add a little more head speed -- now it's a low wail, and I'm SURE I haven't reached 60% -- and, just like that, quite unexpectedly, it lifts the plastic turntable completely off the floor! Airborne and free. And it just makes me giggle. Steady but extremely brief hover. Power down. First flight. A mere hop. But it's magic. Something about it is magic.
The lazy Susan is two-thirds the weight of the heli. Yet the lift appeared effortless. I imagine at full head speed and blade pitch, it could lift twice its weight, maybe more. And here we are, counting fractions of a gram.
So that's where I am tonight. I got out my Blade CX2 training wheels -- orange ping-pong balls on sticks -- attached them to the Gaui and set the turntable aside. Now the whole thing feels light. Power up again to 50% head speed -- it's still planted because there's no blade pitch -- throttle up just a little, slight pitch kicks in, and that's all it takes. Light on the skids. Steady, steady, then airborne. A whole inch this time. Yaws slowly left -- I'll have to adjust that -- but the heli's stable, more than its drunken sashaying suggested when taped down. Quite different from the Blade, which wants to be lazy and stable but is sloppy to control. This thing is serious; it wants to GO -- anywhere. Power down, shut everything off, and I'm grinning ear to ear. I don't know why.
I did notice that stick inputs do not equate directly to flight outputs; the heli's about an eighth-turn behind. Straight forward stick yields forward-left motion. Straight right stick yields forward-right motion, and so on around the circle. Has to do, I think, with precession -- the rotating-wing effect -- but I need to read up.
Stay tuned.
Surf
----------