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Thread: Spectrum Dx5e

  1. #1

    Spectrum Dx5e

    Hey there!
    I'm looking at buying a new transmitter since I've been out of the RC game for a long time.
    I do understand the limitations of the DX5e compared to the 6I etc.
    My question is. What do they mean by exponential and fully proportional. Does it really matter?

    Thanks to everyone that answers!

  2. #2

    Re: Spectrum Dx5e

    Here is an excerpt from rc groups that explains Exponential. if you like more here is the the rcgroups thread,


    Exponential changes the relationship between stick movement and surface movement. When using exponential, stick movement and surface movement will no longer be linear. What does that mean?

    Exponential is going to allow us to shift some of the rudder response so that we get a different amount in the early part of the stick movement as compared to the later part. Let's stay with the rudder example above.

    At 100% stick movement we would still get 100% surface movement, but at 50% stick movement we might only get 25% rudder movement. This would be like having low rates on the first half of the stick travel and high rates on the second half of the stick travel. That would give us a "softer" response around the center of the stick area, and a faster response toward the end.

    How is this beneficial? This gives us finer control when we are making those typical small adjustments to the plane when we are cruising around, just like low rates. However if we suddenly want a big surface movement to get out of trouble, to respond to a gust of wind or to perform that big stunt, we still have the big surface movements we need without having to manually switch to high rates. One of the criticisms of using a low rate for "flyability, is that it limits the pilot's ability to get out of trouble when you are on low rate.

    Let's look at that aerobatic or 3D pilot we mentioned above. He has BIG surfaces and BIG throws set which makes the plane very responsive to small inputs. If he were to set exponential rather than dual rates, then he could have a very soft center to the stick. He could make fine adjustments when needed to but get big response when he needed it and there would be not need to flip a switch during the flight. Cool?

    Let's try some examples that involve numbers. The numbers I am going to use may not map directly to your transmitter as different manufacturers have different interpretation of exponential and what the numbers mean, but the overall impact on flying is the same. They just express it differently.

    Let's say that under standard set-up conditions exponential will be expressed as zero. This means we have the same linear response we have always had. Now, if I put in -50% exponential, that might mean that for a 50% movement in the stick I only want to get 1/4 surface movement but when I move the stick to 100% I want full 100% surface movement. An input into the set-up menu of +50% might mean that for the first half of the stick movement I want more of the total surface movement. This would make the center area very responsive while leaving find grain control at the ends of the stick movement. I am not sure where this would be used, but that is how it would work.

    It is important to note that exponential does not imply a sudden change in rate. Rather it is a smooth change in rate. So the further we move the stick, the faster we get more stick movement. If we were to plot the percent stick movement to percent surface movement we would not get a straight line as we normally get. We would get a curved line indicating that the further we move the stick the less linear the relationship between the stick and the surface.

    This is one of those things you are just going to have to try to fully understand. At first it seems it would make it difficult to predict how the plane will behave depending on how much you move the stick. However in fact most people tend to fly more by input response. You move the stick and watch the plane. After a while you develop a good understanding of how the plane will respond to a given stick movement, but you know that it will be influenced by wind, air speed, and other factors.

    I typically set up my controls with about 35% exponential so that I have a softer response around the middle but gradually faster response as I move toward the extremes of stick movement. On my radio I have dual rates and exponential available and I can use them together. I can also set them by surface.

  3. #3

    Re: Spectrum Dx5e

    Thanks for the info! Keep up the good work guys!!

  4. #4

    Re: Spectrum Dx5e

    Your very welcome and keep em flying

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