Now that I have the Chaos finished except for tossing out the old leaky Rhom retracts and installing new spring air I went ahead and ordered a short kit Curare from Eureka last week. Should be here in another week or so. He's waiting on a supply of balsa. I'm thinking about Spring air retracts again. Any comments on Spring air v. Robart. I am also thinking about an OS 61 FX. In late '70s when I got into RC I had a couple other makes of engines but could not keep running in air. Went to OS then and haven't owned anything else since, even in the 4 stoke type. However, since I will need to purchase another engine, any suggestions on something cheeper.