Cardinal7:

A set of B&Ds will cost the $70 I mentioned, the air pump is another $30 - $100 bucks for the first plane, and since you have the air pump, the next plane costs $70.

Or the $20 mechanical retracts. Yes, they do exist. But instead of a standard servo to work the air valve you have to use a special $100 servo to operate them.There are some off brand retract servos coming on the market, but even at $60 for the servo you're not coming out better on a per plane cost.

Retracts on grass? No reason why not. Generally speaking, fixed gear is stronger than retracts, but if you always land in a reasonable manner the retracts are more than strong enough, and we always do gentle landings, don't we?

Until your skill is polished, when flying off grass the fixed gear tends to last longer.

Your plane, though, follow your own wishes.

Bill.