Small steerable tailwheel
08-15-2003, 03:00 PM
#1
Small steerable tailwheel
A while back, I wanted to put a steerable tailwheel on my GWS tiger moth and the hobby shop didn't have what I was looking for. I decided to homebrew something, rather than pay $5 or more to order something so simple. I vaguely remembered that in my basement, I had tons of old Klett hinges from my first failed foray into R/C 15 years ago. I'm sure this is not a new idea, but I thought the results might interest some of my fellow RCUers, so here goes:
You'll need:
A tailwheel--store bought, scavenged from toy car, made from soda bottle cap, etc. The idea is to be creative and use whatever you have - I cheated.
Wire--appropriate diameter for the tailwheel axle and hinge, in my case, .032 x about 3-1/2" long.
Thread--any old sewing thread will do, and frankly, you probably don't even need it.
A pinned hinge--The Klett hinges in my basement worked out perfectly, but any generic pinned hinge will work, as long as it's plastic with a metal pin(hence, pinned hinge).
First thing to do is bend the wire to the appropriate shape. The pic below will give you a general idea what I did. Near one end, bend a 90* angle, leaving enough wire at the end to fit your tailwheel and a keeper of some sort. Leaving enough room the clear the wheel, bend another 45* the same direction, then 45* back at the point where the wheel centerline will be. Now that this part is bent, determine how far you want the tailwheel below the fuselage and make another 30-45* bend perpendicular o the previous three bends to let the tailwheel trail behind the hinge point. For now, leave the top part of the wire that will go through the hinge straight.
Next, determine what size you want the hinge body to be and cut it down. My hinges came with 2 rings per side. I trimmed the side that will fit into the rudder down to 1 ring, and trimmed a gentle curve into the plastic, since part of the hinge will be exposed.
Once this is done, insert the wire into the hinge, and if you are satisfied with the results, make sure the tailwheel axle is facing the correct direction and bend the wire that protrudes from the top of the hinge down flush with the top, and trim the excess.
Now, wrap the wire to the hinge (drill 2 or 3 holes in the hinge if needed) with a few passes of the thread, and CA the whole deal together, taking EXTRA care not to let the CA wick into the hinge pin.
Finally, you're ready to put the tail wheel on.
Once this is accomplished, you can mount the tailwheel to your plane. This is very simple.
In order to the hinge to work, the pin has to be centered at the hinge line of the rudder. With this in mind, make a slit with an xacto knife, butter knife, thumbnail, whatever to the length and depth that will allow the tailwheel assembly to fit. You may have to cut away a small amount of foam at the bottom of the rudder. Once done, trial fit the hinge into the slot. Deflect the rudder both ways and check for binding. If all is well slop a little probond or 5 minute epoxy into the slot and onto the hinge, and insert it. Be very careful to keep it aligned properly. Now you can taxi around the house and chase the cat!
You'll need:
A tailwheel--store bought, scavenged from toy car, made from soda bottle cap, etc. The idea is to be creative and use whatever you have - I cheated.
Wire--appropriate diameter for the tailwheel axle and hinge, in my case, .032 x about 3-1/2" long.
Thread--any old sewing thread will do, and frankly, you probably don't even need it.
A pinned hinge--The Klett hinges in my basement worked out perfectly, but any generic pinned hinge will work, as long as it's plastic with a metal pin(hence, pinned hinge).
First thing to do is bend the wire to the appropriate shape. The pic below will give you a general idea what I did. Near one end, bend a 90* angle, leaving enough wire at the end to fit your tailwheel and a keeper of some sort. Leaving enough room the clear the wheel, bend another 45* the same direction, then 45* back at the point where the wheel centerline will be. Now that this part is bent, determine how far you want the tailwheel below the fuselage and make another 30-45* bend perpendicular o the previous three bends to let the tailwheel trail behind the hinge point. For now, leave the top part of the wire that will go through the hinge straight.
Next, determine what size you want the hinge body to be and cut it down. My hinges came with 2 rings per side. I trimmed the side that will fit into the rudder down to 1 ring, and trimmed a gentle curve into the plastic, since part of the hinge will be exposed.
Once this is done, insert the wire into the hinge, and if you are satisfied with the results, make sure the tailwheel axle is facing the correct direction and bend the wire that protrudes from the top of the hinge down flush with the top, and trim the excess.
Now, wrap the wire to the hinge (drill 2 or 3 holes in the hinge if needed) with a few passes of the thread, and CA the whole deal together, taking EXTRA care not to let the CA wick into the hinge pin.
Finally, you're ready to put the tail wheel on.
Once this is accomplished, you can mount the tailwheel to your plane. This is very simple.
In order to the hinge to work, the pin has to be centered at the hinge line of the rudder. With this in mind, make a slit with an xacto knife, butter knife, thumbnail, whatever to the length and depth that will allow the tailwheel assembly to fit. You may have to cut away a small amount of foam at the bottom of the rudder. Once done, trial fit the hinge into the slot. Deflect the rudder both ways and check for binding. If all is well slop a little probond or 5 minute epoxy into the slot and onto the hinge, and insert it. Be very careful to keep it aligned properly. Now you can taxi around the house and chase the cat!
