The Shrike and the Swallow are best left to the sport 46/55 class engines. An engine thats resticted to a pylon prop wount have the thrust to get the most out of those two. With a good normal 46 sport engine, those two planes would see about 100mph. The same engine on the Viper would see about 125+. Ive had the ARF Shrike and just didn't like how it landed. The Viper will land very slow, almost trainer slow. Flys like it's on rails,( if you have expo dialed in). But you need to do mods to mount a DF engine in any plane not intended for Rear intake/ rear exhaust.
Speed Models has one working model and the Strega that could work for your DF engine. (still looks like rear carb clearence issues)
http://www.speedmodels.nl/
Or look at other planes (ARF's) and a new engine, The least time/easiest
