I own an electrajet and i use an 8 cell 700mah sanyo battery pack. the electrajet has tons better climb performance with a 9x6 prop. I just tried this the other day and it climbs almost twice as fast! After all that i couldnt stop there, so I put one more cell on my pack and it gave it a really good boost in speed and climb rate, but it shortened the flights by a minuet or so. Most of my flights lasted for about five min. with just 8 cells. today I taped a smoke bomb left over from the fourth to the vertical tail and it put on a show for about ten seconds before it ran out of smoke, but it was really cool!