Throttle Cable Installation for the UL350is

So, you say, “DUH”, well, that is exactly what I would say if this engine had a normal throttle body set up.  It doesn’t.  If you are willing to use the kind of throttle cable that it was designed for, something like a motorcycle cable, then, yes, DUH.  However, I like the kind of cable that I learned to fly with, in an airplane.  That was the friction control push pull cable.  However, I really like the capability of the typical mixture control Vernier cables and always wanted to be able to fine tune my throttle setting like that.  I have found what I always wanted, a Vernier assist push pull friction control cable.  It comes from McFarlane Aviation and I think it is going to be fantastic.

Now the problem. The first cable that I ordered would only work in a flat push pull, no up and down or right and left movement.  This is fine on a throttle body with a slide venturi, however, this throttle body linkage has a circular motion and requires that the end of the cable be able to move up and down.  So, back to McFarlane and much to my surprise, they had already solved the up and down problem with a different model and it was there all along, I just did not know it.  Next, how to install it on the UL350is.

First I had to make some kind of bracket that could be attached to the back of the engine.  Apparently, UL realized that many builders would not like their recommended motorcycle cable set up and provided two threaded holes at the top of the case near the starter.  So, how do I get a bracket installed there?


Make something that will fit beside and up over the starter.  Then figure out how to get the mounting holes in exactly the right place.  I clamped it in the place where I need it to be.  Then I modified a M6-1.00 Allen cap screw to mark the spots.


Note how it is ground to a point at the tip.  I screwed it in enough to insure that I would have a good divot for starting the drilled hole.  With the part clamped in with two vice grips, I was able to apply considerable pressure.


Here is the result with good divots so I could get the holes in exactly the right place.


Here it is, screwed into place above and beside the starter.  I am using screws long enough to add a stop nut to the other side to guard against these backing out due to engine vibration.  The next step involved three other parts, two that I would make and one that I purchased from McFarlane.


This next part is to hold the cable housing that is behind the slot that will keep the housing from moving, and, to provide an area to bolt in the McFarlane part that will insure that the housing will not move.  The next few photos show it installed with those parts.  They also show that there is a full throw from stop to stop, with no binding.

2017-08-27_throttlebracket_10 2017-08-27_throttlebracket_11

This shows about half throttle and the one above shows full throttle.  The next and last photo shows the bracket from the prop end.  That part that is bolted in the center is the part from McFarlane.


Thank you McFarlane.