Hi Ya Rastus 21 - I don't now if you've seen the thread or not, but down in the Scale Forum we've had a Cropduster thread going for at least a couple of years now. Lots of info on kits and now some arfs. Some of the AirTractor's are getting up over 80". Mine just happens to be 83.5"WS. There has also been a lot of discussion about the different types of spray systems that work, and don't work.....

Here is the link to the thread - [link=http://www.rcuniverse.com/forum/m_1639293/tm.htm]Crop Dusters[/link]

Hope it helps a little and welcome to the club