Baron Johnson
Posts: 143
Joined: 12/24/2002
From: Ocala/Gainesville,
FL, USA
Status: offline
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Hey Jon,
Well, I think there are pros and cons with both light and heavy planes, but let's see what we can come up with...
First of all, as you know, I lightened my Edge that I flew at Lakeland and I think it made a more agile 3D plane, but I didn't fly much precision with it. I don't have to tell you the advantages of a light 3D plane!!!  However there are also downsides in some 3D situations with a light plane, but the question was about precision flying, so let's get to that.
Now, for wind/turbulance dampening. I'm not sure if it's the overall mass, or the distribution of mass, or both, but I do feel that in general the heavier line of planes tend to be more solid going through turbulance. The mass has a dampening affect on any motion (and this also affects control... more on that later). On the flip side, everything other than overall weight being equal, a steady wind may seem to affect heavier planes more in certain conditions. If both are going vertical at full throttle, the lighter plane will have a greater velocity, and therefore will require less of a yaw or pitch angle to compensate for a given wind. This is not necessarily an advantage or disadvantage to either, I don't think. You just have to get used to each plane's characteristics.
Light wings are nice, however, I think a large part of the gust/turbulance dampening is the distribution of mass, so then with light wings you lose much of the dampening affect in the roll axis. Just like anything else, it's a trade-off.
The dampening affect would also apply to a desired movement. Here, the distribution of mass is making it harder for you to move the plane. Is this good or is this bad? I haven't thought about this aspect until now, but i think it may help the smoothness of one's flying. For one, small, inadvertant stick inputs - or variations in constant inputs - will be dampened out. (read that 'less jerky or twitchy') However, to create the exact same pitch, yaw, or roll force (all other variables equal), a heavier plane will require more throw of the control surface. This shouldn't really be an issue for general flying because you should set up every plane to fly the way you like it to feel, regardless of differences in throws. Is more throw or less throw better? Again, I think there is a tradeoff: The plane with less throw (lighter plane) will conserve more energy through a maneuver like a snap roll, but a heavier plane will acquire more drag while creating the same force, which when concentrated near the tail, acts like the feathers on an arrow to help keep the plane straight. I'm not sure how big of a difference in control throw a couple pounds would make or if it would even be detectable, but it would certainly be interesting to test out.
I'm sure there are a LOT of other factors than what I hit on. But, I think the bottom line is it's almost always a trade-off. There is a too heavy and a too light, IMO. However, most of the dramatic differences in weight come in the form of different manufacturers. All that I've said up until this point has been assuming identical aircraft. As far as tracking (or any other aspect of precision flying), there are a lot of factors in the aerodynamic design that probably affect it as much as or more than the weight itself.
Baron
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