ShawnK
07-17-2006, 07:29 PM
I was talking to a couple people out at the field this weekend, and we couldn't come to any conclusion about a particular issue.
I've noticed that my Evo tracks pretty well, right up to a certain airspeed. Once it hits that speed, it becomes very pitchy.
For example... if I'm doing a small stall turn (20 ft. or so) and I'm coming back on the downline, I can pull level without too much drama. Evn up to 40 ft. or so, my downlines are usually pretty smooth with a nice, gentle radius at the bottom. However, if I got Big Air for some reason and had a huge stall turn (like 80' plus), my downline looks good, but as soon as I start to pull out at the bottom (with a lot of vertical speed), I've had instances where the bird just stands on it's tail and comes to a screeching halt.
The same thing with loops... relatively smaller loops go off without a hitch, but Big Loops with a lot of speed on the backside require me to get almost completely off the elevator, or it just stands on it's tail and stops. The more airspeed I get, I'm fine to a certain point and then *BAM!* it's like someone flips a switch and dumps 40% opposite expo in the elevator.
I've noticed that compared to some other machines that I've flown, the Evo has much more limited flybar tilt because of the way the seesaw wraps around the rotor hub. I'm guessing at a reason here, but could this have something to do with it? In my mind's eye, I'm thinking that when I get to a certain airspeed, I've used up all of the flybar's effective tilting range, and once it hits the rotor hub and can move no farther it turns from a system with a Bell-Hiller percentage to a system that's 100% Bell input, which would make it act like a flybarless helicopter.
Can anyone shed light on the dynamics of this? It's not an unlivable situation (I think I'm getting better at compensating for it), I'd just like to understand why it does it. If it weren't for the fact that there's a definite "threshold" where this pitchiness happens, I'd be more inclined to chalk it up to slop in the system somewhere.
I've noticed that my Evo tracks pretty well, right up to a certain airspeed. Once it hits that speed, it becomes very pitchy.
For example... if I'm doing a small stall turn (20 ft. or so) and I'm coming back on the downline, I can pull level without too much drama. Evn up to 40 ft. or so, my downlines are usually pretty smooth with a nice, gentle radius at the bottom. However, if I got Big Air for some reason and had a huge stall turn (like 80' plus), my downline looks good, but as soon as I start to pull out at the bottom (with a lot of vertical speed), I've had instances where the bird just stands on it's tail and comes to a screeching halt.
The same thing with loops... relatively smaller loops go off without a hitch, but Big Loops with a lot of speed on the backside require me to get almost completely off the elevator, or it just stands on it's tail and stops. The more airspeed I get, I'm fine to a certain point and then *BAM!* it's like someone flips a switch and dumps 40% opposite expo in the elevator.
I've noticed that compared to some other machines that I've flown, the Evo has much more limited flybar tilt because of the way the seesaw wraps around the rotor hub. I'm guessing at a reason here, but could this have something to do with it? In my mind's eye, I'm thinking that when I get to a certain airspeed, I've used up all of the flybar's effective tilting range, and once it hits the rotor hub and can move no farther it turns from a system with a Bell-Hiller percentage to a system that's 100% Bell input, which would make it act like a flybarless helicopter.
Can anyone shed light on the dynamics of this? It's not an unlivable situation (I think I'm getting better at compensating for it), I'd just like to understand why it does it. If it weren't for the fact that there's a definite "threshold" where this pitchiness happens, I'd be more inclined to chalk it up to slop in the system somewhere.