Dynam DC-3 And The Battery At The Back

...it's finally finished its migration

This afternoon I finally moved the DC-3's battery right back against the stop and gave it a fly. The only other change was that I flipped the battery around so that the leads were facing forward, so that I can connect the plug without having to remove the battery.

With the leads now facing forward the final move hasn't made much difference, with the centre of gravity at 75mm. The main bonus is that no care is required installing the battery; just slide it right back and you're done.

At 75mm CoG the DC-3 takes off very easily; it basically floats off the ground within a few metres, and it will cruise steadily at a fraction over half throttle. It's glide is also improved, although with power off you need significant elevator input to offset the effect of the wheels, but this would even be the case if you were coming in to land with retracts.

With the elevator now on on 100% travel, the Dak is fully controllable on landing, the final mass shift now allowing it to be floated onto the ground in a most pleasing manner, and provides a margin of safety for correction if you misjudge the sink rate a little.

The only drawback is that the Dak becomes light in the nose at low speeds, mainly evident when cruising into the wind. Here the extra airspeed gets it climbing and, without correction, the climb gets steeper as the negative moment from the undercarriage diminishes with reducing speed.

Left unchecked, the Dak will go into a spectacular vertical stall and then wing-over into a dive. Apart from that it is completely stable; all the aerobatic and stall maneuvers I've tried have not managed to induce any sort of spin or other unstable characteristic.

This seems a small price to pay for much improved behaviour of the Dak by having the battery at the back...