I am very into model rocketry, and I have always liked the idea of a boost glider. In the 2002 Estes Catalog it says the retail for the i28 Impuse is 129.99 and the T25 Centurian retail is 139.99. This is way too much for me considering that the "E" engines are approx. $5.00 a peice, you have to provide the raidio system, and it goes to 600 ft in a few seconds (meaning you could lose your expensive raidio equipment). It can be converted to a .49 Cox glow engine if that interests you. Also, if something is wrong during takeoff it can hit the ground going at a tremendous velocity. I have seen a similar boost glider do this (control surfaces were off about 1/16 an inch) and it was completely demolished. . .