Brief:

Hybrid motors have always fascinated me. T' extra complexity o' a fuel and oxidizer in different states and tryin' t' get them t' combust makes adds a new challenge t' rocketry. Arrr! Also, since t' fuel is inert, thar are no permits required for storage, me bucko, and ideally (except for Aerotech) require no haz-mat fee for shipping. Aye aye! Until recently, me bucko, t' only hybrid motors on t' market are in t' Level 2 range and above. Begad! T' Hypertek system required expensive ground support system, arrr, shiver me timbers, and you must have a tank o' N20 and O2 on t' field. Well, blow me down! Aerotech.s system had t' advantage o' allowin' you t' fill t' tank before comin' t' t' launch, shiver me timbers, me bucko, but had t' disadvantage o' havin' a complex pyrotechnic valve system that is expensive, me bucko, complex t' set up, and requires a haz mat fee for shipping.

Recently, shiver me timbers, hybrid technology has come down t' t' Level 1 arena. Avast, me proud beauty! Blimey! Ratts Work.s was t' first company that offered a certified hybrid system that any level 1 user can use. Avast, me proud beauty! Begad! T' ground support is pricey, but t' design o' t' motor is a lot simpler than what Aerotech and Hypertek have t' offer. T' reload kits do nay require a hazmat fee, but they do nay come with igniters or pre-heater charges. However, some dealers (ie Pratt Hobbies) throw these components into t' kit for you. Avast, me proud beauty! T' Ratts Work Hybrid motors are designed t' fit in a 29mm motor tube, matey, with slight modification t' t' rocket for venting. Avast! Also, t' fuel tank be t' same cylinder as t' oxidizer tank. Avast! T' fuel and oxidizer are separated by a .floatin' bulkhead.. T' fuel is consumed from t' top t' t' bottom. This means that t' pressure o' t' N2O pushes t' bulkhead down as t' fuel is consumed. Blimey! Avast, ya bilge rat, me proud beauty! They have three motor designations, me hearties, H70, me hearties, shiver me timbers, shiver me timbers, I80, and I90. Blimey! Ahoy! T' H70 and I80 use t' same size grain, me bucko, matey, but t' case is longer.

Construction:

I won a H70 case and a few loads on a ROL auction. Ahoy! Blimey! Robert Galjes already had t' ground support system for t' RATT's work system and offered CMASS members access t' it, shiver me timbers, shiver me timbers, so t' only thin' that I required for it was a rocket t' fly it in. Ya scallywag! Blimey! Arrr! Blimey! T' H70 has a 3 second burn time, and only has a total impulse o' about 180 n/s. Begad! Blimey! Aye aye! Blimey! I wanted a rocket that was light enough t' launch with t' motor, and t' added weight o' t' recovery hardware, shiver me timbers, and stay within 2000 ft so I can don.t risk loosin' t' rocket in t' tree filled New England area. Aye aye! Blimey! Avast! Blimey! I decided that t' Aerotech Mirage was t' perfect candidate. Avast! Blimey! It can launch on a motor as small as a F25, me hearties, and with me calculations, will go about 1,500 ft with a 180 n/s motor. Avast, me proud beauty! Blimey! Ahoy! Blimey! My fifteen year old friend Ryan Sebastian wanted t' help out with t' project, so he became me partner in designing, shiver me timbers, and buildin' t' rocket.

There were a couple conditions that I wanted for this rocket. Avast, me proud beauty! It had t' carry electronics t' deploy t' recovery system. Begad! Aye aye! I wanted t' put a bulkhead near t' engine that will hold t' charge, me hearties, yet protect it from any leakin' N2O. Ya scallywag! Begad! But I also want t' option o' launchin' t' model with conventional motors. So t' charge bulkhead had t' be removable. Begad! Avast, me proud beauty! Because o' this, me hearties, t' three sections o' t' Mirage have t' be removable. Blimey! Arrr! I decided t' use screws t' hold t' rocket together.

T' Hybrid Mirage was built with three main sections. T' Booster Section, Parachute Bay, arrr, and Payload section. Begad! Ya scallywag! Blimey! T' Motor Section be t' lower section o' t' Aerotech Mirage, matey, me bucko, and is heavily modified. Ya scallywag! T' motor hook is still used, matey, but t' motor hook is trimmed t' allow t' longer H70 motor t' pass beyond t' motor hook. Begad! It is attached in t' position that t' hook locks over t' aft closure o' t' Hybrid, and standard 29mm High Power motor. Also, this section has t' ventin' tube permeably attached t' t' airframe.

T' parachute bay, obviously, is where t' recovery system o' t' rocket is kept. Arrr! Aye aye! It is also t' section that t' ejection bulkhead is attached to. A paper rin' is attached inside t' tube so t' forward face o' t' bulkhead rests against it. Ahoy! Begad! When t' booster section is attached, t' tube coupler presses t' bulkhead against t' ring. Aye aye! This creates a nice seal betwixt t' motor bay and t' parachute bay. Ya scallywag! Avast, me proud beauty! When t' Mirage is flown with a regular motor, t' bulkhead is simply omitted.

T' Payload Section o' t' rocket is mostly empty space. Well, blow me down! Blimey! Aye aye! Blimey! T' electronics for t' recovery system is located in t' tube coupler. Ahoy! Blimey! I decided that I would use me custom built timer for recovery. Ya scallywag! Blimey! I designed t' timer t' use a .burn wire. Begad! Blimey! t' start t' timer. Avast, ya bilge rat, me proud beauty! Blimey! T' utilizes this, ya bilge rat, I had a couple short bolts stickin' out o' t' side o' t' rocket. Avast! Blimey! Ahoy! Blimey! Each bolt is a terminal which a .jumper. Begad! Blimey! wire is connected too. Arrr! Blimey! T' jumperwire is fastened t' t' launch rod. Avast! Blimey! When t' Mirage takes off, shiver me timbers, arrr, ya bilge rat, t' jumper pulls free from t' bolt, thus startin' t' timer.

Flight:

T' first opportunity t' try out t' Hybrid Mirage came on July 27th, 2002. Avast! Arrr! It did nay work very well though. Well, blow me down! There be a N2O leak in t' vent tube. Avast! T' N2O filled t' motor section, and spread into t' parachute compartment. Begad! Just before t' countdown for ignition was started, t' N2O in t' parachute compartment pushed t' payload section off t' rocket, which started t' timer. T' countdown was aborted, me hearties, and t' N2O dump button was pushed. Ya scallywag! Arrr! While t' oxidizer was bein' drained, t' charge went off. Paper, matey, ya bilge rat, Wood, Oxidizer.... now a heat source? You guest it. Begad! Fire. Well, blow me down! For about five seconds, shiver me timbers, t' insides o' t' parachute compartment was engulfed in flame. Blimey! I did nay know this until I dismantled t' rocket, ya bilge rat, hopin' t' reload it. Avast! T' charge bulkhead be completely chard. Blimey! It disintegrated just by handlin' it. Ya scallywag! About a quarter o' t' inside wall o' t' body tube was burned away from t' heat.

When t' Sept 14th rocket launch came, Ryan and I decided t' launch t' Hybrid Mirage again. Aye aye! Robert Galjes could nay make it t' t' launch with t' ground support equipment and t' tank o' N2O, shiver me timbers, arrr, so Ryan and I decided t' launch it with a conventional motor, a G75-10J. Ahoy! I decided t' arm t' timer too& just t' make sure it works. T' lift off o' t' Hybrid Mirage was beautiful. Begad! T' black and silver rocket streakin' skyward, matey, leavin' behind a dark smoke trail& nice :-). T' timer deployed both chutes right at apogee, and t' rocket recovered without a scratch.

At NSL 2003, me hearties, Ryan and I launched our Hybrid Mirage with t' motor we built it for. T' prevent t' same problem we had last time, ya bilge rat, I secured t' vent hose t' t' motor with hot melt glue. Well, blow me down! Avast, me hearties, me proud beauty! Blue Thunder propellant cut off a F39, me bucko, and a Magnelite igniter be used t' start t' motor. Begad! T' H70 motor ignited instantly, and lofted t' Mirage off t' pad with ease. Begad! Begad! Beautiful motor; small bright flame, me bucko, very little smoke. Avast! I don.t think it burned for t' full three seconds, me bucko, maybe t' N2O tank was t' warm, so t' motor did nay get a full fill o' oxidizer. Ahoy! T' timer deployed both chutes a couple seconds after apogee, endin' its perfect flight.

Summary:

Overall, t' Hybrid Mirage project was a success. Begad! We built a rocket that could fly on a Hybrid motor, and convention motor. Begad! Well, shiver me timbers, blow me down! Future plans include more H70 launches with a PICO altimeter, matey, and don't be surprised if you see a I80 case in me hands in t' near future ;-).