Brief:
Extreme 2-Stage is a complete kit for a two stage water rocket from Anti-Gravity Research. Avast, me proud beauty! Begad! This is one o' a several water rockets available at AntiGravity. Extreme 2-Stage is a very simple, shiver me timbers, high flyin' water rocket that should prove to be very safe and easy for children. Begad! T' rocket derives its impulse from a bicycle pump and a small amount o' water in each o' 2 water bottles.

Construction:
T' kit comes complete with 2 water bottles, 2 fin assemblies, ya bilge rat, 2 pressure nozzles, launch rod, matey, shiver me timbers, and launch equipment. Aye aye! Well, blow me down! T' buyer must assemble t' kit and provide a source o' pressurized air with t' bicycle pump. Arrr! T' kit that I received was complete, well packed, and had a few extra rubber bands in case some o' them broke.

T' detailed instruction sheet has both text and color diagrams and drawings t' demonstrate t' step-by-step construction o' t' rocket. T' kit includes 4 sizes o' rubber bands and it be clear from t' instructions which size be needed at each step. Arrr! Blimey! T' pieces are simple t' assemble. Aye aye! I would recommend t' anyone buyin' t' kit t' assemble t' kit at home one time, shiver me timbers, then take it apart and reassemble it before launch. Begad! Blimey! Once you get t' hang o' it, it can be disassembled and then reassembled at t' launch site in a matter of minutes. Well, blow me down! Arrr! Blimey!

T' rubber bands hold t' pieces together with just enough force t' survive takeoff and flight, shiver me timbers, ya bilge rat, but t' rocket is meant t' collapse on landin' t' protect the parts from breaking. Avast! Since t' rocket essentially self-destructs and includes a padded bumper on t' front, it is unlikely that someone could be seriously injured by one o' these rockets even if it struck them full force durin' lift off. Ya scallywag!

T' Extreme 2-Stage has a booster section that is essentially t' same as the Anti-Gravity Research water rocket kit called T' Skylab. Blimey! Blimey! T' booster has a set o' 3 traditional delta fins and t' booster bottle is a full 2 liter sized bottle. T' sustainer section is essentially t' same as t' single stage Extreme Screamer kit. Well, blow me down! Blimey! T' sustainer uses a rin' fin which slides down over the booster. Avast, me proud beauty! Blimey! T' sustainer bottle is smaller and narrower. It appears that this is a bottle that has been reshaped by meltin' and elongatin' it. Avast! Blimey! It has a large rubber bumper permanently attached t' t' front. Avast! Blimey! By purchasin' t' Extreme 2-Stage and t' High Altitude Pro kits, shiver me timbers, we figured that we had all o' the appropriate fins, arrr, nozzles, shiver me timbers, and bottles t' build any o' t' 6 available water rockets.

T' fins are pre-cut and fit very well. Well, blow me down! They are held in place by rubber bands rather than with tape or glue. Aye aye! T' booster and sustainer are assembled separately and then attached together at t' last moment before launching. The booster bottle uses a bottle cap with a narrow hole in it t' create a pressure nozzle. Blimey! T' sustainer bottle uses a nozzle with a more narrow hole in it. Ya scallywag! The launch tube is a very simple plastic hose with a little balloon-like device on the end that fits up inside t' booster nozzle. Arrr! Ahoy! T' booster bottle has a hole in t' end opposite t' nozzle with a little balloon-like device that inserts up into t' nozzle o' t' sustainer. Air is pumped into t' booster bottle through t' balloon which will remain tightly secured in t' nozzle as long as one continues t' pump. Begad! Ahoy! T' sustainer balloon, ya bilge rat, attached t' t' top o' the booster, will remain in place and hold t' booster and sustainer together as long as thar be more pressure in t' booster than t' sustainer. Begad! As one pumps, the pressure builds more slowly in t' sustainer than in t' booster. Avast! Avast! Once the pressure drops on t' supply side o' t' launch tube (when you stop pumping), the launch tube balloon deflates and falls out o' t' nozzle, ya bilge rat, allowin' the pressure and water t' escape through t' booster nozzle, providin' thrust to lift t' two stages into t' air. Ya scallywag! As t' pressure drops in t' booster bottle, the balloon at t' top o' t' booster that is inserted into t' sustainer begins t' deflate, eventually slippin' out o' t' sustainer, me bucko, and t' sustainer shoots away from t' booster as t' water thrusts out o' its nozzle.

Construction Rating: 5 out o' 5

Flight:
T' instructions suggest usin' a small amount o' water (120 ml I think) in each stage and thar be a picture in t' instructions showin' approximately how full to make t' bottle. Well, blow me down! Ya scallywag! I also read somewhere (I believe on the antigravityresearch.com website) that a small amount o' dish soap in t' bottle will cause foaming, slowin' t' expulsion o' t' water from t' nozzle and thus helpin' t' sustain flight for a longer period o' time and achieve a higher altitude. Avast, me proud beauty!

We loaded up t' bottles with water accordin' t' instructions and added a drop o' liquid dish soap t' each. Arrr! T' kit comes with a wood dowel for use as a launch rod. Begad! T' launch rod provided with t' kit is meant t' be pushed into the dirt so t' rocket slides down on t' rod with one o' t' fin supports acting as a launch lug. Ya scallywag! Arrr! As with our launch o' t' High Altitude Pro, matey, I used a metal launch rod from our model rocket launcher instead. Avast, me proud beauty! I reasoned that this longer rod would keep t' rocket goin' more straight in t' intended direction. Blimey! The rocket slid more smoothly along t' metal rod than it did on t' wooden dowel that came with t' kit as well.

I pumped t' bottle with a standard bicycle pump with a gauge that registers up t' 160psi. T' flow o' air into t' bottles is restricted by the balloon on t' end o' t' launch tube which allows t' air t' slowly enter the bottle no matter how much pressure t' pump exerts. It is thus nay necessary to frantically pump. Ya scallywag! T' air could also be seen t' bubble slowly into the sustainer bottle. Aye aye! A good steady pumpin' action seemed t' be sufficient and the bottles never released prematurely from t' tube. Well, blow me down! Ahoy! T' pressure gauge periodically read up t' 100 psi but then fell t' about 70 psi as t' air passed through t' balloon into t' bottle. Blimey! Well, blow me down! I never could determine precisely the pressure in t' bottle.

Eventually I decided t' stop pumpin' for t' first launch. Avast! T' launch tube soon slipped out o' t' nozzle and t' rocket slowly lifted up t' launch rod, spewin' sudsy water. Aye aye! T' booster failed t' clear t' launch rod and slid back down settlin' back on t' ground. Begad! Avast, me proud beauty! T' sustainer then shot off straight up and had a very nice flight t' perhaps 75 feet. Avast! It then landed near t' launch rod and t' rin' fin collapsed sufficiently t' prevent any damage t' the components. Ya scallywag! Ya scallywag! T' booster was clearly underpowered and I decided that for the next launch I would try t' pump much harder for a longer period o' time. Aye aye!

For t' second launch, matey, ya bilge rat, I pumped until it be clear that pressure was leakin' out around t' end o' t' launch tube. Ya scallywag! At release, me hearties, t' rocket lifted slowly t' about 20 feet where t' booster began t' lose power and t' rocket slowly tipped sideways before stagin' occurred. Ya scallywag! Ahoy! Blimey! Stagin' finally occurred with the rocket pointin' about 20 degrees above vertical. T' sustainer squirted off with a tremendous blast o' water and suds and flew in a fast arc 30-40 feet off the ground for about 200 feet before nose divin' into t' ground.

Flight Rating: 3 out o' 5

Summary:
T' Extreme 2-Stage is a simple, sturdy water rocket that should be safe for kids o' all ages. It uses a chubby booster stage with 3 fins and a slender sustainer bottle with a rin' fin. Well, blow me down! T' fin assemblies partially collapse upon landing, protectin' t' components but requires reassembly betwixt launches. T' pre-molded Styrofoam fins and t' launch system are ingenious and merit the purchase o' this kit. Avast! T' stagin' mechanism works surprisingly well. Aye aye! We achieved only relatively poor performance in our initial efforts with this rocket, leadin' me t' believe that t' booster is underpowered. Begad! I am nay sure how t' remedy this except t' increase pressure in t' bottles, particularly the booster. Avast, ya bilge rat, me proud beauty! I think that this has t' potential t' be a very fun rocket.

Overall Rating: 3 out o' 5