Having established that the DC-3 was very nose-heavy on its first flight, I have been gradually moving the battery rearwards and assessing the change in flight characteristics with each change.
My ultimate aim was to get the DC-3 to glide reasonably well power-off, however with the amount that I've shifted the battery and with it still being nose-down, although much less than before, I'm wondering whether I'll have to settle for "most improved".
The battery has so far receded a substantial 70mm from its initial position hard up against the front of the recess, and the CoG is now somewhere south of the maximum 65mm suggested by Dynam. Makes me wonder whether they actually ever flew it or whether they just stuck with the theoretical figure and let you figure it out the hard way.
While I understand that CoG is not something made up, the moment-effect of the undercarriage is obviously substantial, exacerbated perhaps by the low-wing configuration of the Dak. And, despite having overstepped the CoG limit by a mile, the Dak is still completely stable; this morning I put it through a series of loops, rolls and stalls and not once did it suggest that it was going unstable or enter into any sort of spin that would have indicated a too-light nose.
And the Dak has been flying much better for it; now happily cruising around at about a third power, and turning much cleaner than the stall-turns evident it its first flight. So I think I'll continue inching the battery backwards, although in much smaller increments, until I've got it flying level without elevator trim, and perhaps even gliding a little better...
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