I have 2 of these jets and would not recommend using robart (their website:
www.robart.com) - used robart retracts and struts in a CBM A-10 and had problems. I used SpringAir in both with no problems (
www.retracts.com).
YS.45 is a great choice (have several) but am going to try a JETT .50 this time?? Anyone have thoughts on this engine?