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ground turn radius

PostPosted: Tue Feb 26, 2019 12:31 pm
by bvolcko38
I am flying a stock per plan Xenos, hand breaks, standard tailwheel. My turn radius on the ground is close to 100' I need to tighten up the radius without changing too many geometries. Staying with hand breaks and factory tailwheel. What is the turn radius for the standard Sonex?

BV

Re: ground turn radius

PostPosted: Tue Feb 26, 2019 12:44 pm
by Direct C51
I really don't think you are going to tighten the turn radius without making significant changes. You will probably need something like a breakaway full castering tailwheel. The Sonex has a little tighter turning radius, but that is because it is about a foot and a half shorter. Or you can do what I do, get out and pick up the tail.

Re: ground turn radius

PostPosted: Tue Feb 26, 2019 12:52 pm
by bvolcko38
I do get out and pickup the tail!!! I thought I was the only one doing it!!!

Re: ground turn radius

PostPosted: Tue Feb 26, 2019 3:13 pm
by rauburg
We put a Peter Anson tailwheel and steering strut on our Xenos and it made a huge difference. Instead of a straight steering strut for the tailwheel the Anson model has offsets on both ends that make the rod connect in a horizontal attitude rather than on an angle. I think that this is the biggest improvement, possibly eliminating binding in the control rod. The narrow wheel probably helps a great deal too. Taxiing is a breeze now and I never worry about over shooting a turn. BTW, we bought gray tire initially and it didn't last long in the West Texas Mesquites. It looked like a wheel chair tire and we have upgraded to the black tire and it is much more substantial. We will see how it holds up.

RAndy
Xenos 024
N5234
Jabiru 3300

Re: ground turn radius

PostPosted: Tue Feb 26, 2019 4:34 pm
by bvolcko38
Randy, thanks. I will check it out

Re: ground turn radius

PostPosted: Wed Feb 27, 2019 6:27 am
by peter anson
I fitted very simple differential brakes to my Sonex. I have the original pressed steel drum brakes operated by two levers. The brake levers are in the centre, forward of the joystick - see photo below -
Image
It's not as controllable as toe brakes but works OK using two fingers to pull on the brakes. I don't have a castering tail wheel but the 3300 Jabiru has enough grunt so that it easily drags the tail around on loose surfaces like gravel or grass. I can even spin it around on sealed surfaces but I avoid that as it's a bit hard on the tire and there is always the risk of a nose-over. Sonex don't approve differential brakes because they put heavier side loads on the tail wheel caster but I haven't had any problems with my own wheel and caster. I don't know if this would work as well on a Xenos which I think has a higher load on the tail wheel and a larger polar moment of inertia from that big wing.

Peter

Re: ground turn radius

PostPosted: Wed Feb 27, 2019 10:09 am
by Rofomoto
Im also going to use the two lever mechanical brakes with full swivel tailwheel.
Image

Re: ground turn radius

PostPosted: Fri Mar 22, 2019 2:59 pm
by bvolcko38
I modified the tailwheel control arm by drilling another hole inboard of the factory hole. Now, when the rudder is at the stops, so is the tailwheel.

Re: ground turn radius

PostPosted: Fri Mar 29, 2019 8:08 am
by Direct C51
Have you tried taxiing with your modified control arm? My initial thoughts are that it might make the steering rather sensitive. Also, your tailwheel might not be in coincidence with your rudder and could possibly cause some skidding upon landing.

Re: ground turn radius

PostPosted: Fri Jun 07, 2019 8:18 am
by bvolcko38
I can turn on the runway now. Steering is more sensitive but not overly so. Rudder and tailwheel hit stops simultaneously now.