Rigging question

[Frank DeBartolo]

I have to hold a little right rudder and a little left aileron to maintain level cruise flight at cruise power setting. This keeps the ball centered and the wings level. Would rudder trim help or would it be better to more properly rig the airplane. Stall characteristics are good and the airplane does not break off at stall but the nose drops straight ahead. The airplane has a gentle stall. Intentional spin entry and recovery are straightforward. No bad characteristics other than having a tired right foot after an hour of flight. I have a good IA that helps me with my airplane--when he has time. Any feedback would be appreciated. The airplane is a '46 BC12-D.

Thanks,

Frank

[Guest]

Re: Rigging question

I have to hold a little right rudder and a little left aileron to maintain level cruise flight at cruise power setting. This keeps the ball centered and the wings level. Would rudder trim help or would it be better to more properly rig the airplane. Stall characteristics are good and the airplane does not break off at stall but the nose drops straight ahead. The airplane has a gentle stall. Intentional spin entry and recovery are straightforward. No bad characteristics other than having a tired right foot after an hour of flight. I have a good IA that helps me with my airplane--when he has time. Any feedback would be appreciated. The airplane is a '46 BC12-D.

Thanks,

Frank

Frank,

I have an aluminum rudder trim tab, helps a lot.

Have your mechanic wash out your left wing, that should help.

Might make sense to wash out the wing first.

Dave

[crispy critter]

Re: Rigging question

I have to hold a little right rudder and a little left aileron to maintain level cruise flight at cruise power setting. This keeps the ball centered and the wings level. Would rudder trim help or would it be better to more properly rig the airplane. Stall characteristics are good and the airplane does not break off at stall but the nose drops straight ahead. The airplane has a gentle stall. Intentional spin entry and recovery are straightforward. No bad characteristics other than having a tired right foot after an hour of flight. I have a good IA that helps me with my airplane--when he has time. Any feedback would be appreciated. The airplane is a '46 BC12-D.

Thanks,

Frank

Frank,the rudder trim may help rest your foot but you will still have to imput the left aileron.DO you have a climb prop?if so this could be causing a touque issue in cruise but not likely.My advice is to level the wings and then use rudder trim if nessesary.If your holding left aileron then the right wing is heavy,lower the angle of attack on the left wing by adjusting the left rear wing strut to make it longer or raise the trailing edge of the wing.This will decrease your angle of attack making the left wing loose a slight amount of lift.If this works it may also give you a little more speed.You can also do the same thing with reverse effects by raising the angle of attack on the right wing,this is done just the opposite.Adjust your right rear wing strut in to make it shorter therefore lowering the trailing edge of the right wing making and increasing the angle of attack on the right wing giving it more lift.This if anything will show down your speed but may increase your climb and short field performance.I would count on much of a noticable difference in speeds or climb but it will level your wings then you can trim the rudder as needed.It this really puts the ball way outside the lines on the rudder then you may have an alinement problemwith your fuslage or engine mount.Start with small adjustments until you narrow it down.

[jgerard]

Re: Rigging question

Make sure the instrument that holds the "ball" is installed level and not crooked to one side or the other. Level the aircraft by putting the tail on a saw horse and using a spirt level on the horizontal stab check both sides to make sure the tail is straight left to right and if not you may need to make some adjustments on the flying wires to get it straight. Compare your tail being level to the seat back cross bar or spar carry through tube if you don't have a headliner. I normally adjust the tire pressure to raise or lower what ever side needs it. Then run a sting from wing tip to wing tip across the top of the wing at the front spar like it says in the book and check your dihedral. Pull the string tight and hold a level across it in the center over the cabin to see if the string is level. HOPE that it is. Then measure the distance from the string down to the top of the wing attach fitting (must remove the wing root fairing) and compare left to right. Since the front strut on the Tcraft is not adjustable there is nothing you can really do to adjust dihedral, but you can swap front struts left to right and that may help. If that does not work then I would level the aircraft via tire pressure until the dihedral is equal on both wings. Check by holding a level up to the string stretched across the top of the wing. Then I would adjust the flying wires to pull the horizontal as need so that it is level to the wings. Then I would check the vert fin to make sure it is still vertical/perpendicular to the stab and adjust as necessary. Set the washout to equal amounts on both wings and test fly it. Worn out sagging engine mounts can also cause a plane to fly crooked. Best you can hope for is to have the tail level to the wings and hope that the fuse is some what close to level as it is merely hanging in the breeze and holding those two flying surfaces together. Really it does more than that aerodynamically, but without major surgery you wont be able to fix a twisted fuse.

[3Dreaming]

Re: Rigging question

Also you might want to make sure the ailerons are rigged correctly. Like these guys have said already rig the wings for hands off wings level while keeping the ball centered with rudder. Then trim the rudder as needed. I like adjusting the return spring tension as opposed to the bendable trim tab on the rudder. If you were closer I would tell you to fly on down and I would help you with it. Tom

[alwaysoar]

Re: Rigging question

Frank, The procedure for adjusting the rigging is in the Taylorcraft manual. Even that won't work 100% if the fuselage has got a little twist (Forrest once said a long time ago that most of them do after 60 years), so then some trial and error of adjusting the screws in the aft struts, taking a flight, and adjusting again and tweaking until it feels right. An A&P is required to make these adjustments because you have to disconnect the strut to make them, but it's a pretty simple task. You said you're holding right rudder and left aileron yet the ball is centered. That doesn't seem quite right. Are you sure? Holding right rudder could cause a skid that would increase the lift on the left wing thus causing it to climb requiring left aileron. What happens when you take your feet off the pedals? Does it level out? And if it does, does the plane then skid? In level flight, holding left aileron, are the ailerons lined up with the trailing edge of the wing, or is the left up and the right down to hold the plane level? This discussion is pretty convoluted. Just start with the struts as someone suggested a few posts before.
Ed

[Frank DeBartolo]

Re: Rigging question

Tribe,

Thanks for the well received information. I will be working on this will report back on how all this works. Just to let you know, I work slowly, so it may take some time to let all know how it went.

Again, Thanks.

Frank

[VictorBravo]

Re: Rigging question

On my 1940 BC-65, I have a slight problem with this too. I put in more than a little right-thrust offset, but the airplane still turns left at cruise. An eyeball check shows that the twist is FAIRLY close form one side to another, and the airplane is PRETTY straight. The plane is not nearly "crooked" enough to cause the amount of left yaw that it has. Since it does not turn or break left or right at stall, and it does not roll hands off, I have to assume it is close enough.

Worse yet, power off it turns right, which at least I expect because of the nuilt-in fin offset.

The last thing I noticed before I got mired down in the airspeed soap opera was that the rudder pedal return springs were apparently identical, even though the rudder pedal torque tubes were not the same distance from the firewall. This means that one spring would be pulling a little harder than the other one, which would definitely affect it when you took your feet off the pedals.

Now that the airspeed indicator issue is partly under control, I can take another look at this to see if the spriings need to be changed.

You might look at the rudder pedal return springs to see if they are identical... I think they probably need to NOT be identical because of the torque tube offset. Of course the final test would be to un-hook the springs and fly the airplane with your feet off the pedals.