RE: Best engine for Sig Kadet LT40
I would normally disagree with DB here. I reccomend a 2 stroker for a complete newbie. It is simpler and less maintainance. But I see you have experience already. So in your case I heartilly reccomend DB's advice. A 4 stroke is a great way to go. I reccomend a Saito 72. As DB suggests you will need to use throttle management. But you should not have any problems. You can also use it in your next model or so.
As to the trainer 40, go for it. With some help from an instructor there is no reason you cannot use it. You already have experience. I am building the 60 sized one from RCM plans. I intend to use it as my way back in next spring. Money problems kept me grounded this year. I am gonna use an Irvine 61 in it. With a little buddy box time you should do just fine.
I also agree on the 7C issue. For a few dollars more you get a better radio. I think once again DB is right on the money here. The 7C will get you farther in the long run. Good luck and welcome back.
Mark Shuman