RE: Douglas DC-7
Several years ago I designed and built a 1/10 scale DC7 about 139 span with 4 OS 91 and Ziroli style construction. It flew great except unstable in uncontrolled pitch up when nose raised up over about 20 degrees the nose rose higher and higher and only increasing power and full down elevator would lower nose then it would fly great. moving Cg forward did not help finally lost it close to ground.
I am presently building a 1/10 scale DC4 which has shorter nose to see if the lifting was caused by the long DC7 nose or some other reason. ANY IDEAS John