Hail,

What's the best way to get nice even throttle resolution on the walbro gas carb apart from expo?
I find that my throttle clicks cause varying acceleration too much in fact,
for example when trying to practice torque rolling the throttle blips often cause the plane to climb.

Would a larger servo horn help ?

You you 120 on top and 120 on bottom to get full stick resulition. Smaller horn on servo and futher out on carb hookup.

I always use the innermost hole on the servo arm, and the outermost hole on the throttle arm. DA engines have different holes on their throttle arms. ZDZ doesn't have different holes. I'm not too sure about other gas engine companies though.

On the ZDZ's I use a nose gear steering arm (way out on the hole) AND close in as possible on the servo arm. I believe you can also program in some sort of throttle curve into your throt. stick. Like they do on helicopters.

Thanks,
Gunny

Not sure what radio you are using, but on my JR 10X, I can set a "throttle curve." This allows you to tailor the throttle response. You can make the response flat in your "torque rolling" regime. For IMAC, I usually try to set the throttle curve to give very linear power output. Gas engines typically have a very non-linear throttle response - power goes up very quickly in the first half of stick movement and there just isn't much after that.

Ken

Most engines use carburetors larger than they need and run the engine in the lower part of the rpm curve...If an engine will run 9000 rpm and you select a prop that will only turn 7000, the last part of the throttle opening makes little difference in the power output, the engine won't turn that fast..
If you look down the venturi into the carb, you will see that the size of the opening changes more during the first part of opening the throttle than it does after about 3/4 open, because of the angle of the disc and the size of the shaft..A smaller carb matched to the maximum rpm of the engine would be much more linear....how come nobody does it ? Who knows, maybe a great big carb looks better on the engine than a smaller one...I tested a US 41 and some other engines with carbs from 3/8 venturi to 5/8 venturi, very little difference in max rpm.....

RCIGN,
I believe you just came up with a new product to enhance the performance of what's currently on the market. Someone with the ability to manufacture a venturi reducer that would permit more efficient use of a wlabro or Zama carb might have a new mousetrap.

What I use is a 5 point mix. You can set what you want the engine speed to be at each point and this makes maping your throttle response to what you want it to be.

What you need to do is get rid of the ratchet. Go to a heli-style no click throttle.

If you also need to fix the throttle stick does nothing during the last quarter problem,
expo is good. But you said "apart from expo" so I assume you're not using a computer radio.
This means you need to create expo mechanically.

You do this by setting up the arm on your servo so it's pointing almost directly away (or toward)
the carb at idle, and such that it's just a little past square with the carb at full throttle.

This makes it so that at low throttle settings the throttle stick doesn't do much (moves the carb
very little) and at high throttle settings the carb moves much more for a given stick movement.

I did like Tony did,
I programmed in my cuve; on the futaba I can choose a 14 point curve. I Plotted out points 1-14 and the corresponding RPM with a linear curve. Then I choose 14 equally spaced RPM values and programmed the 14 points for that curve. Result is a linear response on the throttle. I have to admit at first it felt unsettling - like I had no power, but the truth is I was just used to all the throttle being below 1/2 stick. Once you get used to throwing the stick around it feels good.
RickP

Well said RickP. Throt. curve, Just like in a helicopter.

Gunny