Ever since I got hooked on the Alien Conquest theme I've wanted some type of transport vehicle for my ADU troops. I toyed with the idea of buying a second Earth Defense HQ set and modifying the trailer section to hold troops and gear. Then I saw pics of the Heavy-Duty Helicopter (set 4439) and knew that I had found my transport vehicle.
I started by building the model per the instructions but leaving out the bumper wall that prevents the ATV from rolling too far forward. Once the model was built, I set out modifying it for the ADU.
While the original model had an ADU-friendly color scheme, it needed more yellow. I added a yellow stripe that runs the length of the fuselage. In the process, I fixed the windows so they're all at the same level (in the original model, the windows on the doors were set slightly lower). I also added some greebly details here and there and removed the white plates from the engine assemblies.
The original model has an annoying design flaw with the cockpit doors. Each door has a 2x4 blue plate in it which hits the pilot in the head when the door is closed. I replaced the plates with 1x4 plates and now the pilots can sit unmolested by the doors. They still sit too far back and too high up for my taste, but those are the specs of the original model and I don't yet have the ambition to tackle a structural redesign.
I added a pair of laser guns to the nose of the ship as well as a boom. I'm not sure what the boom is for, I just really like the look of it.
At the rear, I added another pair of lasers on turrets that can cover the troops as they're exiting or boarding the ship.
As I mentioned earlier, I left the bumper wall out of the interior which leaves incredible amounts of space inside the helicopter. I added long benches to each side which can easily accommodate 4-6 troops. (There's room for even more troops but one would need small hands to get them inside and seated.)
At the rear of the ship, just inside the door, I added space for weapons and gear. On the port side there are clips for rifles. On the starboard side there is a rack for pistols as well as a cabinet. The cabinet/rack can be easily popped out of the helicopter for easier access.