Hi all,
I'm having a bit of a problem when landing my RC Guys Decathlon. After touchdown, during rollout, I can't seem to steer the airplane. Our field is grass, so sometimes steering is needed to stay out of the weeds as the rollout goes on.

My tail wheel setup is the standard springs to the rudder horn rods, (Dubro heavy duty), attached all the way out to the ends. I increased the spring tension also. I'm using high rates on the rudder and while it helps, I just don't seem to have the control I'd like, (I've made it a weed-eater more times than I'd like!) Takeoff is no problem. Do I need a different tail wheel setup?

opinions?
thanks all!

Get in touch with them and describe your problem. They would know best. Dan.
[email protected]

A picture of the tail wheel setup would help.

This is during roll out after a fairly high speed "wheel" landing, or the slower "3 point" style landing? Taxi to/from the flight line/pits OK? Could you have installed one of the wheel collars tight enough to be causing a bind on one of the wheels?

As Speedracer suggests, a picture would help. How far off horizontal are the springs from the rudder horn(s) to tailwheel horn? The more vertical they are, the less effective the control.

Good luck,

Bedford

Toe-in.

Here's the pic. What do you think? My thinking is that I have good steering on takeoff because prop wash is making the rudder active and upon landing, as the speed bleeds off, the rudder stops steering and the tail wheel takes over. It seems that the springs aren't strong enough to let the wheel turn in the grass.

When taxiing, I blip the throttle and have no problem turning the plane. The problem comes in when the speed drops off during roll out. If I'm heading for the side of the runway, due to inconsistencies in the turf, then that's where the plane is going and I don't have enough control to turn it away, even with full rudder. It's like the tail wheel just remains straight.

Thanks for the help!

Sorry, the pic was inverted!

I have an RC Guys Decathlon and have no trouble on our grass field. Your picture appears to show the tail wheel not directly in-line with the rudder. I think you should try to elongate the front or rear hole in the tail wheel bracket and get the tail wheel centered. You may have to elongate both holes to get enough play to correct it. Also as soon as airspeed bleeds off, up elevator helps a lot. Hope you get it corrected=it's a nice flying bird
Frank

Thanks for the suggestion, but actually the rudder was offset in the photo. I just checked and the bracket is dead on center.

My instincts tell me that the springs are too weak to overcome the weight of a plane of this size. I do apply up elevator on roll out when I'm sure in will no longer fly,(don't want ballooning).

After looking at the photo, I would suggest that you take a two giant scale control horns and bolt one on each side of the rudder so that they are in line with each other. Then take a 4-40 bolt 1.5" long and screw them down through both control horns all the way to the end of the bolt. They must be full thread bolts so the head of the bolt stops at the horn. Use a 4-40 aircraft lock nut to hold these bolts in. Use strip aileron screw on links, the ones where they screw on to the threads of the 4-40 bolt. Stop screwing them on to the bolts when the threads are flush to the outside of this fitting. Attach your springs to the strip aileron fittings. This should give you more steering as the springs are in line with the tiller arm on the tail wheel. Let me know how this works out......

Larry

You need stronger springs. They look very soft. Your local hardware store should have a very good selection. You wnt them stiff, but not solid so as to protect your rudder or servo. They are so stretched out, I can tell they are not stiff enough. I always end up changing out my springs from the stock ones supplied with most wheel assemblies.

Too many times we attribute poor ground handling with the tailwheel.First of all I would like to know how well your plane tracks on roll out and takeoff. I would suspect you have the same problem. If so the common problem is due to torque. Overpowering a plane with more engine than it needs, which means that the large prop is more that it needs, thus giving the plane too much torque and poor ground handling. just my thoughts, jmpups

He said take offs are no problem. That is when mis aligned mains really rear their ugly head. I wonder about taxi? That is when the tail wheel problems really show up. I can tell by the photos those springs are no good. They are totally stretched out.

i can see exactly whaT IS wrong. ditch those long slinky springs. either get shorter stronger springs or get rid of them. no wonder it seems that they arent steering. then get the wheel aimed right up with the rudder.

Hi, Check the clearance on the main wheel to wheel pant and also use good wheels. Sullivan solid rubber are really good in wheel pants applications. When you land the planes weight can make soft wheels bulge out catching the wheel pant and cause loss of steering and may pull to one side. The load on the wheels is getting lighter when taking off but heaver when landing. I also use the largest diameter wheel that will fit in the wheel pant and be sure there is no slide play on the axel.

I agree, the biggest tail wheel will server you best. the small wheel has little effect on steering.

While many may not agree with my methods,I got rid of steering springs on tail wheels long ago. I usually fashion a small tiller arm on the bottom of the rudder that extends forward of the hinge line and connects directly to the tailwheel steering arm with a short link rod. The interconnect link usually has ball links on each end. This is very effective and to date has never over stressed a rudder servo. You have to be careful with arm lengths though or your tailwheel will have too much steering. On smaller planes I commonly use the type of tailwheel that has the steering rod tiller that goes back and attaches under the rudder. These are also very effective and offer a bit of spring action from the small tiller wire.

Loose the stretch springs and either go with medium silicon fuel tubing or better yet compression springs.

I agree, if you must use springs, compression springs are the best way to go but may require some fabrication.

One of my springs fell off mid summer and I didn't fix it, never noticed. I would look at the mains, wheel pants and the like. Is it possible the main gear is on backward moving the wheels back nearer the cg?

On all my scale planes I do a separate pull pull to the tail wheel, it works so much better then the spring and ruder style. Here is a pic of my 100cc Sbach, same as my cub and all my large scale planes. You can use the same servo as the ruder, or install a second servo for just the stirring. This is what I did on my Sbach, I can trim the tail wheel independently from the ruder, comes in handy when you are trimming the plane for flight and don't have to mess with the tail wheel.

TB

Very nice Tony. Some of us are too lazy to do it your way though ....

Thanks, I guess it's a mater of one "scale looks" and two, do you want to steer it, I like both.


TB