Elevator deflection
01-03-2008, 10:19 PM
#1
Junior Member
Thread Starter
Join Date: Dec 2007
Location: Winnipeg,
MB, CANADA
Posts: 1
Likes: 0
Received 0 Likes
on
0 Posts
Elevator deflection
I just finished building my Ultrafly ultimate. I have built three Ultrafly foam planes and I like them fine. On thing I have a problem with is deflection of the elevator.
Here is the problem. The right side elevator/tail section is separate from the left, a light grade U shaped steel wire connects them together.... I am sure you have all seen what I am talking about. Ok , so when the elevator is actuated, in flight, the right side tail section is held firm by the servo, but the left side has some 'play' It seems to me (and I am a newb) that this design is flawed. The differential in wind deflection caused by the ability of the left 'flap' to move while the right is held firmly by the servo means that a 'spin' would develop when the elevator is applied at speed, say during take off.....
I am wondering if any of you have experianced this and have anyway of dealing with it, or is it just something I have to deal with?
any ideas?
Here is the problem. The right side elevator/tail section is separate from the left, a light grade U shaped steel wire connects them together.... I am sure you have all seen what I am talking about. Ok , so when the elevator is actuated, in flight, the right side tail section is held firm by the servo, but the left side has some 'play' It seems to me (and I am a newb) that this design is flawed. The differential in wind deflection caused by the ability of the left 'flap' to move while the right is held firmly by the servo means that a 'spin' would develop when the elevator is applied at speed, say during take off.....
I am wondering if any of you have experianced this and have anyway of dealing with it, or is it just something I have to deal with?
any ideas?
01-16-2008, 04:49 PM
#2
My Feedback: (4)
Join Date: Jul 2004
Location: Lakeland,
FL
Posts: 7,906
Likes: 0
Received 0 Likes
on
0 Posts
RE: Elevator deflection
Yes it can happen. Umm couple of ways of correcting it. You could use a heavier wire. Use dual servos, or if feasible you could Y connect the halfs to a single servo.
The Y connection is used on EFlite's Cub for the elevator. 2 control rods, one each connected to the elevator half. Inside the fuselage, they come together to form the Y. One rod is cut short, and attached to the other with nothing more then a couple of wheel collars. The longer rod runs to the servo. Simple set up, you loosen the wheel collars, equalize the elevator halfs, and tighten the collars. now you have matched halfs.
Or as I now do, instead of attaching a control horn to one side of the elevator, I've started silver soldering a tab in the center of the wire joiner. I connect the control rod to it. Does two things, you get same amount of travel on each elevator half, and your controls are now hidden to clean up the bird.
I've done it so far on my Hangar 9 P40, and CMP 120 class Corsair. Both on the elevator and the rudder. And on the Corsair, I'm using a similar method to actuate the ailerons.
The Y connection is used on EFlite's Cub for the elevator. 2 control rods, one each connected to the elevator half. Inside the fuselage, they come together to form the Y. One rod is cut short, and attached to the other with nothing more then a couple of wheel collars. The longer rod runs to the servo. Simple set up, you loosen the wheel collars, equalize the elevator halfs, and tighten the collars. now you have matched halfs.
Or as I now do, instead of attaching a control horn to one side of the elevator, I've started silver soldering a tab in the center of the wire joiner. I connect the control rod to it. Does two things, you get same amount of travel on each elevator half, and your controls are now hidden to clean up the bird.
I've done it so far on my Hangar 9 P40, and CMP 120 class Corsair. Both on the elevator and the rudder. And on the Corsair, I'm using a similar method to actuate the ailerons.
01-16-2008, 05:16 PM
#3
Join Date: Feb 2004
Location: Kitty Hawk,
NC
Posts: 2,048
Likes: 0
Received 0 Likes
on
0 Posts
RE: Elevator deflection
I had this problem too. I made a Y in the elevator rod and put a control horn on the other side so both have a control horn being controlled by one servo. It helped alot and then found out that some of my spin was from a high speed stall from having to much elevator throw(and I wasnt even at the recommended throws yet)
