Well, the .dds file is not really a template so far as I'm aware, but instead that's an actual graphic file for use in the game engine. Converting this .dds file to .psd will only reveal the flat image that was exported from the "real" template.
The filesize might be correct for a single layer. Sometimes a file can contain one or more alpha layers for special effects. These are essentially extra images overlayed on the visible painting itself, and easily increase the file size.
What you need is a real template kit. As an example of what to expect, take a look at this IL2 CloD template a user has uploaded here at SPS:
http://www.simmerspaintshop.com/foru...plate-psd-239/
Looking through this file in Gimp will show the kind of detail you'll have in a proper template.
Finding a proper template for the aircraft you want will take some asking around. I'm not familiar with the IL2:CloD community, but back in the days of the original IL2 releases, there was a website where hundreds of templates and finished skins were shared. Perhaps some other website has filled this role today for IL2:CloD. We do welcome proper user template uploads here at SPS, though so far only one has been submitted.