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Re: Kitfox 4 left turning tendencies.
My rudder trim tab is a piece of thin aluminum 4x6. It is bent at 2", so 2" sticks to the fabric with double sided 3M foam auto trim tape, leaving 2"x 6" bent in the wind. I also put a piece of contoured wood over the part stuck to the fabric to make it look better, but I'm not sure that was successful. The vertical center of the trim tab is located 29" up from the bottom of the rudder (SS7).
Re: Kitfox 4 left turning tendencies.
Thank you Jim. Did you move it from top to bottom during testing or did you put it on and leave it?
Re: Kitfox 4 left turning tendencies.
Did you try tightening up the spring on the right rudder pedal. Just a little bit might get you the right yaw your looking for.
Re: Kitfox 4 left turning tendencies.
Quote:
Originally Posted by
JimS
Did you try tightening up the spring on the right rudder pedal. Just a little bit might get you the right yaw your looking for.
I don't think that is true because the rudder on a Kitfox is just going to streamline itself with the airflow. The end result will be your rudder pedals will be offset.
This suggestion will work only if there is a centering mechanism to hold the rudder pedals centered. This is how the tricycle Cessna single engine planes do it, the nose gear extends and centers holds the rudder pedals in the neutral position. Rigging of the rudder system is done with it in this centered position.
Re: Kitfox 4 left turning tendencies.
I think Jim S may have a point though. It may offset the pedals just a tad, but maybe not enough to notice. Obviously, if you put a strong enough spring on, it would pull the pedal to the floor, a weaker one, a lesser amount. Maybe it just needs a little bit. I'm thinking of an elevator trim system I've used on Avids for nose up trim. Tie a light duty bungee cord around the seat truss, loop around the joystick, and back to the seat truss. If the bungee is at the right tauntness, it will stay where you put it on the stick. The higher up you go on the stick, the more nose up trim you get. Basicly making something else do some of the work for you. I think it's worth a try, as I don't think it can hurt anything, and it's easy to go back to the way it was. JImChuk
Re: Kitfox 4 left turning tendencies.
I had seen other trim tabs in roughly the same location, so I just put mine there and it has worked fine. No need for further experimentation. Way easier than messing with spring or bungee adjustment.
Re: Kitfox 4 left turning tendencies.
And I followed Jim's design and it has worked perfectly for 400hrs.
cheers
r
Re: Kitfox 4 left turning tendencies.
I once saw an Avid Flyer that the owner had made a trim tab that was attached to the fuselage through the trailer hitch attachment holes. Basically a bent piece of aluminum with a hole in it that a very long threaded rod went through with nuts on either side of fuselage to hold it in place.
Taylorcraft at one time had done something similar on their aircraft, with the idea of moving the entire fuselage over rather than just the rudder. Technically it should be aerodynamically cleaner, as the fuselage is what is yawed going through the air, so if you could move it into place where it belongs with a fuselage tab it might be a better way to do it?
I don't know if it worked well or not, but it would be simple to try.
Re: Kitfox 4 left turning tendencies.
Quote:
Originally Posted by
PapuaPilot
I don't think that is true because the rudder on a Kitfox is just going to streamline itself with the airflow. The end result will be your rudder pedals will be offset.
This suggestion will work only if there is a centering mechanism to hold the rudder pedals centered. This is how the tricycle Cessna single engine planes do it, the nose gear extends and centers holds the rudder pedals in the neutral position. Rigging of the rudder system is done with it in this centered position.
Actually my suggestion would not work if the rudder pedals were locked in their centered position. They have to be free to move to whatever position results in straight flight. Bottom line is you need more right rudder in cruise for coordinated flight, right? Multiple ways to get it. One other suggestion is to unhook your rudder right rudder cable at either end and add a few twists to it. That will shorten it a bit and the pedal return spring in front of the pedal will pull a bit more on it.
Re: Kitfox 4 left turning tendencies.
Thanks for that tid bit Jim. That can save a guy a bunch of work shortening a cable. Bet it would come out too short also if I cut it down.