RE: ESM FW D-9
I'm not an aeronautical engineer but I have built and flown aerial targets for the USA military. We had our own soviet fixed and rotary wing assests in 1/4 scale. In addition to the soviet fleet we also produced USA airforce airframes in the same scale. The airframes ranged in weight from 65 lbs to 150 lbs. No two flew alike based upon wing loading. I have flown ESM products and they are all built overweight. Once airborne they fly but we both no that takeoff and landing are the most critical part of any flight.