Digital Throttle Servo
 

Would a digital throttle servo improve the throttle response on a 2C engine? Is it worth it?

RE: Digital Throttle Servo
 

Improve? Yes. Worth it? No.

There isn't enough return to justify the added cost. It's still a crude fuel-air mix and you'll never get it down to millisecond response time. The throttle servo is the place to trim costs. On a helicopter it's a different story. Anything you can do to increase response and durability (which comes with the added $$$) will pay off in the long run.

RE: Digital Throttle Servo
 

RE: Digital Throttle Servo
 

I guess a four stroke is the way to go for the next plane. Just cant believe how much they cost over a 2 stroke. I was thinking of replacing with a digi for the H9 Pulse that I have....but if its not worth it - why bother.

RE: Digital Throttle Servo
 

Digital Servo for the throttle? Why would you go through all that setup and expense? A simple $19.00 basic servo will do just fine. In fact, some RC'ers have used the small micro servo's for the throttle just to save weight. It's just not needed.

Now, if you are FAI Pattern, where every movement of the sticks on the transmitter means points, well, I guess you could justify it. But otherwise.. a basic servo does just fine.

CGr

RE: Digital Throttle Servo
 

I was wondering more about the response time.

RE: Digital Throttle Servo
 

Heck, a $10 S3003 is all you need really.

RE: Digital Throttle Servo
 

Improvement for throttle not worth mentioning. Couple of milli-seconds?

RE: Digital Throttle Servo
 

On an airplane you probably wouldn't notice the difference unless you were replacing some old servo that you could time with a sundial.

Overcoming the intertia of the prop, and the ability of an IC engine to respond to throttle changes make it not worth the money.

RE: Digital Throttle Servo
 

Makes sense...thanks guys!

RE: Digital Throttle Servo
 

I've got to agree with what everybody else has said. Using digitals are a waste on throttles. The money you spend won't translate out to equal rewards. On my planes I will usually use my older servos for the throttle as it's the most non-critical control out there. Use a regular standard servo and you'll be fine.

Ken

RE: Digital Throttle Servo
 

RO, If you are trying to get fast / linear throttle response changing to a digital servo will not do much.
Try learning to tune the engine not just set the needles. Alot of people believe that if they set the low speed
needle to a good idle and the high speed needle to slightly rich that the engine is properly set. That may be true
for trainers and sport flying but as you get more experienced and want a linear feel ther is more to tuning.

First you need to setup the throttle servo to use maximum servo travel from idle to full throttle. This is
done by adjusting the linkages and setting the EPA. ( I use 0 epa at idle and 110 at full throttle / Neg for kill)

Next start by setting the needles to where the engine runs good (basic full throttle and idle pinch test). now
fine tune the adjustments by running the engine through the entire range. You will most likely find the engine
does not respond well at idle to 1/4 throttle and again at 3/4- full throttle. you may need to lean or richen the low
speed needle to get a smooth crisp low end transition and the same with high speed to achieve a good top end
transition. these adjustments will be very small. redo the pinch test and keep adjusting until you are happy.

Midrange is another story as this is a mixture of high and low speed needles, combined with backpressure
and exhaust design. OS engines usually have a good solid midrange. However some of the less expensive
engines have a less desireable midrange. the only way I know to get a vey good midrange is to put a pipe
on the engine and tune it properly. however I have been told by many competition pilots and have some experience
with PERRY carbs and they are easy to adjust and dramatically increase the performance and ease of tuning
for some of the less expensive engines,

RE: Digital Throttle Servo
 

On the other hand, if all you have laying around are digitals (like provided with a DX7) it may not make sense to go buy a standard servo. But that would be your decision.

RE: Digital Throttle Servo
 

I thought of that one after I posted. You still have to overcome the prop inertia - good on you BarracudaHockey.

Big selling point of digital servos is they return to null-point very precisely. That would be mid-throttle and a "so what" for practical value.

Do a good job of throttle linkage (short and unbinding) and you'll be much better for it. Proper throttles don't take much torque and a short, slop free run to a small servo is better than a long wonky run to a large one.