Iron Sky: Invasion

On my first playthrough I swapped to the Xerg just before the third chapter and the Dundee disappeared from the game. I finished the Invasion and got all achievements save this one. So to ensure you don't miss this achievement grab the Dundee bomber from the International Space Station at the end of chapter II - Double Trouble, after escorting Renate to the Moon, and keep a hold of it.

The Dundee Bomber is by far the best ship in the game, the Chaingun alone can destroy every type of enemy very efficiently once fully upgraded. Do all the side missions by periodically returning to the NWO (Indian) space station, the Korean Space Station and the ISS. Collect every possible piece of salvage you encounter and try to farm fighters when you are battling the Zeppelins.

To upgrade your Dundee use the map and then find either the ISS, the NWO or the Korean Space Stations, use to fast travel to them and then fly over to the glowing red dot and press when you're are close enough to dock. Use to select 'Sell Salvage' and again to sell any salvage you have. Press to return to the menu and then select 'Upgrade ship' and move the to highlight the upgrade you desire then to buy it if you have enough cash.

Whenever you're facing a large group of enemies take out the fighters first (unless there are Zeppelins around), then target Wotans but be sure to use to target there engines first, this will gain an extra salvage and stop them from moving so you can target their much weaker underbelly's. After the Walkyr and Wotans are gone take out the Alberich's and if any Hundings are around be sure to target their engines and cannons first and collect all the extra salvage. If you're also going for:

be sure to target the Hundings before your allies take them out, there are only 16 in the game and your allies tend to target these ships the most and steal your kills.

You should use the tactical map and fast travel to space stations during fights to upgrade as and when you collect salvage, this also saves the game. Upgrade your Chaingun and shields to max first, then do your engines, after that it doesn't really matter. Your Chainguns will be very efficient for everything from the smaller Walkyr to the Hundings and even Zeppelins.

Once you have fully upgraded every part of the Dundee the achievement will unlock, unlike the Xerg there are no extra weapons to unlock for the Dundee.