In Answer to the query raised by Seacue reference the Arado 234 using RATO: Short Answer Yes and a good link to a nice series of images including a trolley launch is here:
http://www.kheichhorn.de/html/body_a...234_blitz.html
The units were Walter HWK 109-500 RI-201 "Cold" Rocket Assisted Take-Off Packs (Cold meaning Catalyst with HTP).
See:
The Hellmuth Walter Website
Which has another copy of Arado 235 RATO Pix and has information on other Walter Rocket uses including the Me163.
DIH