Well I can answer that question for you, CGR.

I had, note I said had, some little plane i don't remember what it was, a short kit from a mom and pop outfit, Ireally wish I could remember what it was it was a nice plane. Again with the past tense. any who weighted in at 3.5 lbs flying weight with a supertiger 75 on the front, weee this is gonna be fun. straight and level was FAAASSSSTTTTT was nearly in a constant turn to keep it in sight. so I thought, hmm better call the coroner now, I wonder how fast it'll go in a full power dive. so up i went, up, up, up till its a speck and down down down, think I heard a sonic boom as I pulled up either that or it was just both wings peeling off as it reached about thirty degrees nose up attitude.

So the answer to how far will a lawn dart go.

A long long ways