Power System Theory And Execution

 Not to harp on power ratings and such, but it is worth talking about balancing the power system to the airfame. Again, I am more and more seeing the benifits of not grossly overpowering a 3D plane. Sure, gut busting grunt is a lot of fun to fly, but it is harder work than flying a plane that is better balanced to it's power system. The Mini Slick with the 72 gram motor, for example, is the perfect package this way. There is enough power to punch respectfully out of a hover, but it is not so much that the throttle makes the plane jumpy or difficult to place where you want it.

The most common misconception is that you need unlimited power to get yourself out of bad situations. This is something I used to subscribe to religeously. At least in the beginning of learning 3D, you are going to fall out of hovers and harriers simply due to bad form. After you have saved yourself a time or two by hammnering the go stick, the habit of relying too much on the throttle is reinforced, especially if you are starting with too much power to begin with. I believe this actually hampered my progress, because I was flying overpowered planes that were difficult to master, not to mention trying to learn a whole new style of flying.

Here is one of my last flights with my 5s overpowered 55" Extra SHP. If you listen to the throttle applications, you can see the bursts of power are when I get wobbly and lose smoothness. At the time I was pretty proud of this video, but considering what I have learned since, it now is a tool to show others what not to do.

What I learned from the Mini Slick is that is it better to have a balanced power package that flies better. You get into less trouble to begin with like this, but it is still hard for many to believe you can actually fly better with less.

The magic number seems to be between 130 to 180 watts Per pound (WPP). Being the lazy type, I don't often weigh the plane or check my wattage. It is too easy to rely on 3DHS' recommendations, simply because the planes are so well developed that all you need to do is buy what they say and go fly it. Not having done the math I can't swear to anything, but I'm guessing that 3DHS' low power set up for any particular plane falls within the 130-180WPP range.

We did figure out the Mini Slick with a 72G motor and 3s packs is right around 180WPP. While this is still a little more than pros like Andrew Jesky seem to like, it is not so overbearing that the power system overwhelms the airplane. I draw the comparison to driving a dragster in the rain, or driving something like a Nissan Altima. For those conditions, the Altima is obviously going to be the easier package to drive smoothly and precisely, while the dragster is going to spin it's tires alot, slide around and scare the crap out of it driver.

In this video, you can easily see how much less difficult it is to fly something as finely balanced and a 180WPP Mini Slick.

What hammered all of this home was that after the Mini Slick, I carried this knowledge over into setting up my 55" planes. On 5s the big jobs were so seriously, and stupidly overpowered that they were a definate handful to fly. As an experiment, I dropped a 4s pack into my 55" Edge. I didn't have the right prop, so I just used what was already on the plane. It was underpowered for sure, but it was definately easier to control, though it was scarey to get into trouble and not have enough grunt to get out as easily as before. This led me to later correctly prop the plane for 4s and give it another try. Now with a better balanced power system, the Edge was perfect all the way around. It was still a little too much, but so much easier to control the throttle that it was a completely new plane.

This also led to using the 4s system on my new 57" Extra SC. Now I was truely learning how to fly the airplane rather than yank it around with the throttle. What was different now was that balancing the power to the airframe created a better package that is easier and smoother to fly.

Certainly power is still important, especially in alpha flight, because that's where your vectored thrust comes from. Remember though, that dropping down in power allows you to use a bigger prop, which blows a bigger cone of aiflow over the plane. This bigger cone is very useful to vector over the control surfaces and gain more control authority, especially at sub stall speeds.

The 55" Extra SHP and the 57" Extra SC are so similar that it is valid to use them comparing power systems. Remembering how ragged the previous 5s 55" SHP video looked, now see how much better and smoother the more reasonably powered 4s Extra SC is.

I know that power addicts are going to find all of this difficult to believe, just like, in the beginning, I did. However, video is a good illustration of the difference, and people have noticed my flying style and technique have improved since I have cut my power back to a more reasonable and controllable level.

All I know is that since I have cut my power back to the 130-180WPP range, I am working much less hard, feel much more in control, and at last to me, the videos look smoother.

Finally, here is an instant contrast, with the same plane, same pilot, on the same day. First is my 55" Edge on 5s, followed by dropping down to the more reasonably powered 4s with a bigger propeller and corresponding increase in vectored thrust. To me the diffrerence is rather stark hopefully this will be a good way to illustrate my point.

Special thanks to Andrew Jesky for sharing with me his sage insight into balancing the power system to the airframe.