@Flatfoot
Thanks so much for sharing your hobby and the video links. The detail is amazing and the trimming skills are awesome. How do you balance the twin engines - hard to get the same power / run time but they seem to work?
The speed and power ratio looks perfect on these models. RC aircraft can be hard to photograph and never seem to truly match real aircraft characteristics in flight. Yours really fly / look amazing. Apart from the prop sizes you could be watching a full scale flypast - really enjoyed those / thanks again :0)
@Omegafanman, glad you enjoyed the videos.
The trimming of a finished model is a challenging process sometimes. It's a balancing act of maintaining stability longitudinally and laterally, plus finding the best prop size and motor cross section. After building and flying a number of birds, it becomes easier to predict stability problems, and work to overcome them in the design phase. Of course, we are surrounded by others who do this, so there is a very active sharing of information and "tribal knowledge" among all of us builders and flyers. The people who do this are just simply a whole lot of fun to hang out with. I'll be spending the better part of a week in upstate NY at Geneseo this July with about 200 others who build and fly these birds. And timing my flights with a Speedmaster!
For twins, most folks make counter- rotating (C/R) props. One prop spins one way, and the other spins the opposite way. Consequently there is no asymmetrical torque effect problems from the paired C/R props when compared to having both props spin the same way. Careful counting of the turns added to each rubber motor while winding, and ensuring smooth consistent unwinding of each motor gives the best shot at having a nice smooth flight. If one prop/motor binds up early in flight, there is the near certainty of a crash. ...Ask me how I know...
😵💫. And ask any multi-engine rated pilot!
If you have even a casual interest, I can point anyone in the right direction to attend a FF meet nearly anywhere in the USA, or the U.K. /Europe and learn more first hand. FF scale emphasizes building- there are very few RTF models you can buy. But there are some really good, simple kits available to start with, and a phalanx of people willing to help you get them trimmed and flying.