36 Estes D-12 Class engines strapped t' a Christmas Tree. Begad! We used Google t' look up t' data sheet for an Estes D12 model rocket engine. We took t' average thrust o' one engine (10 Newtons) and multiplied it by 36 (number o' engines we had) t' calculate t' total thrust available. Avast! We then subtracted from that t' force due t' gravity actin' on t' tree t' figure out how much force was available t' lift t' tree. T' estimated acceleration o' t' tree was then calculated usin' Newtons second Law (F=ma). Well, blow me down! T' estimate t' height, t' calculated acceleration was applied t' t' kinematic equation with t' engine burn time o' 1.5 seconds as taken from t' online data. Begad! Without includin' t' air resistance o' t' tree, or t' large spike in thrust (up t' 30 Newtons in t' first .25 seconds). Avast! We conservatively predicted a height o' around 95 feet. (Looks like we exceed that.) T' most important calculations were those done t' assure that t' tree flew straight and did spin wildly out o' control under power. Arrr! In order t' assure this, arrr, t' center o' mass must be towards t' front and more importantly in front o' t' center o' pressure caused by t' drag o' t' tree. We were able t' achieve both o' these things by attachin' a large wooden star at t' end o' an old pool cue t' t' front o' t' tree.