I'm putting my Hirobo P-47 together. It is going well, but I've run into several problems so far due to the ridiculously inadequate instructions. My main problem now is how to connect the tail gear. It uses an internal connector. Anyone know how to connect something like this? You can view more pictures here http://www.beergator.com/beergator/tailgear/

Thanks for any help,

Eirik

If this plane has a pull pull rudder like it looks it would be simple. Run another pair of cables back to the tailwheel parallel to the rudder's set but these would connect to the tailwheel. Instead of connecting the cable directly to the rudder arm I'd put a short springs in there to save the servo. This is only a guess on my part though. From the pics I wouldn't want to have to put this thing in but I do believe that would be a good way to rig it.

It looks from pix like the mounting plate is in the middle, steering arms inside fuse but projecting out the sides of fuse to be connected to something, and tail of course down on the ground. The simple heretic in me says you would probably do just fine to mount the wheel and to heck (to goshdarn heck! I say) with the steering arms--just let the wheel caster freely, and steer on the ground with prop blast on the rudder. I've done this at least a few times with never any problem.

(Works on nosewheel too, better I think than trying to connect linkage to nosewheel. I always enjoy the nice pictures on the plan of nosewheel linkage. I can draw pretty pictures too--lots easier than hooking it up and making it work right. I like building, and I like a challenge, but more than anything I like getting out and flying!)

If you want to do it right, though, you need to run soft coil springs from tips of tailwheel steering arms to corresponding arms at bottom of rudder, so when pushrod or pull/pull turns the rudder, the rudder tugs the tailwheel in the same direction. If you have pull/pull rudder, you can prob'ly use those arms to connect your springs to, but keep the springs connected inboard from where your pull/pull cables attach. You don't want the tailwheel to turn as much as the rudder for smooth ground handling. Spring connectors absorb ground shocks on tailwheel, save jerking on your rudder servo gears.

Thanks for the reply. It actually has no instructions for setting up the controls other than, "Set the controls as you like." The picture on the box shows a standard servo horn on the rudder. Never done a pull pull system before, and not sure how to go about it. Would it be possible to run to control rods off of one servo. Run one to the rudder, and one to the tail wheel?

The tail wheel control arm can be contained entirely in the body.

Ivarb, if you have not done a pull/pull before, I would wait for a fairly simple profile or stick where you have lots of freedom to improvise, rather than try to work out the complications on this model. I really would go for a simple solution. Simplest is to let the tailwheel caster freely. This is definitely the most reliable, foolproof solution as far as ground-handling and flying go.

If you feel you have to have a steerable tailwheel, the next simple solution is to have the tailwheel control arms stick out the sides of the fuse, stick a T-pin up into the bottom of the rudder and simply run rubber bands with light tension from control arms to the pin. Or springs instead of rubber band. If you want to buy another control horn just for the tailwheel, mount it opposite the pushrod control horn, and use inner holes on either side for the tailwheel springs.

I personally do not like the control horns that bolt through to a pad on the other side of the surface, although I admit they do work OK. My own preference is for Rocket City horns, now sold by Nelson Hobby. These use a threaded post and special pivot points. I run the post through a hole in a dowel that I glue into a hole in the control surface, giving a solid hard point and much better alignment than I used to get with nylon horns.

I'm not sure from your photo whether I'm looking at a bottom half shell of fuselage, which would permit adjustment of tailwheel controls inside the fuselage before gluing it all up forever. That might accommodate a more sophisticated solution, but if you are into sophisticated solutions you should first try all the simple solutions to convince yourself they don't work well (but they do).

To answer your question, I'm sure it would be possible, in principle anyway, to run two pushrods off of one servo wheel or arm, one to rudder and one to tailwheel. However I've never seen nor heard of such a rig on tailwheel, although it is conventional to control nosewheel this way. The disadvantage of direct pushrod to nose/tail-wheel is that every time the wheel hits a pebble the wheel takes a torsion whack which is transmitted via pushrod back to servo gears, causing premature wear and failure. There are gadgets to absorb these shocks, but they cost money, and in my view mainly serve to complicate a simple problem.