Tiger Moth Drag Problems HELP

Also posted at the designers forumWhen i land at a rough surface with a tiger moth i am unable to take off again. Seems like the aircraft is not powerfull enough or is unable to cope with extra drag involved. Since this aircraft was designed to be able to take off again from this kind of surfaces i wonder if it can be adjusted to the corrected settings.Also the floatplane is unable to take off again from a lake. luckyly it does float.Since i have no experience in designing and i dont want to destroy others work, i would like to ask the designer to take a close look at it. I fly the freeware tigermoth collection available from this AVSIM site.greetingsleon