I'm looking for as much background as possible on the Imperial army during the time of the heresy and great crusade. most importantly i need to find out if the Imperial army were allowed to wear the imperial Aquila, i know marines weren't but I'm not sure about anyone else.

Also I know Plasma Tech was a lot more common especially within the guard.

Is their anything else I should know?

Swifty

Never read anything about the Aquila. Personally I have filed all of them off my Cadian body based Imperial/Traitor Army regiment and also taken off the winged skulls.

The HH Novel by Dan Abnett featuring the Alpha Legion is the biggest lot of fluff about a Rgt. (See the Imperial Army section of this forum.) However there were thousands and thousands of regiments from worlds with different cultures and tech levels etc so concrete rules are hard to pin down. Just been reading the new IG codex and it states that the Leman Russ Executioner (Plasma variant) was in wide usage.

There are lots of other bits of info scattered about the forums so go hunting. May be worth cataloging them?

The IA was organised almost exactly the same as the IG, except PDFs were known as 'garrisons' and everything was a lot more specific to the leaders and locations... i.e. Hurgan's Scrappers as a regiment name, or the Davin Garrison force.

The regulations on the use of the Aquila only seem to apply to the Astartes legions. Many non-traitor regiments are shown displaying the Aquila on armour and banners. Personally I prefer not to use it anyway, and have gone for the winged skull instead!

Ironic that plasma weaponry was more often used by the IA, since they are more likely to get burned while using it.

Have a look here for info on what vehicles were available - its worth noting that there is background that states the Imperial Army was allowed to use certain vehicles which are now restricted to the Marines, such as Land Raiders, Predators, Rhinos, and Land Speeders.