Thankyou all very much for this thread.
Just finished over a dozen successful launches with my Hi Start. Without this thread I would not have been able to achieve this so thank you to all for the wonderful input and excellent comments to make this a success and keep my new molded beauty intact!
I purchased a hi start 3 meter from aerofoam which is a convertible model.
The field I used today is my neighbors, it is 12 acres and only enough room for 150 feet of rubber and 250 of line. I have started very conservatively and only stretched the cord out 80 feet for the first launch after a few hand tosses to set up camber and trim for launch. She went straight up the and flew of the hook at about one hundred feet above ground.
I am now stretching the line out to about 150' she is going up straight and flying straight off at 240 feet above ground.
Have not measured tension with a fish scale at 150' of stretch but it is easy to hold the plane ahead of the wing and javelin throw her with about 20 deg of pitch up as many on this thread have noted. After the toss she rotates and goes straight up.
My plane is a NAN Shadow 3.7 X Tail. CG is 109 and tow hook is at 105 behind leading edge.
Attached is PDF of the launches, Green line is altitude, you can see the hand tosses to set trim and the gradual build up in line tension as I get more relaxed with comfortable with having a rubber band pull my plane up.
Tomorrow I will add another 50' of stretch and try again
To all reading this thread, you can do it. If I can you can.....
I had it go sideways once at about 100' up the line a little rudder brought it right back very quickly, the guys on this are right on. It only took a little oppisite rudder and she was back on track
I love this new bungee thing..