Brief:

Hybrid motors have always fascinated me. Arrr! 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. Avast! Also, since t' fuel is inert, thar are no permits required for storage, shiver me timbers, and ideally (except for Aerotech) require no haz-mat fee for shipping. Arrr! Until recently, t' only hybrid motors on t' market are in t' Level 2 range and above. Ahoy! T' Hypertek system required expensive ground support system, 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, me bucko, me hearties, me bucko, but had t' disadvantage o' havin' a complex pyrotechnic valve system that is expensive, complex t' set up, and requires a haz mat fee for shipping.

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

Construction:

I won a H70 case and a few loads on a ROL auction. Well, blow me down! Robert Galjes already had t' ground support system for t' RATT's work system and offered CMASS members access t' it, so t' only thin' that I required for it be a rocket t' fly it in. Avast! T' H70 has a 3 second burn time, and only has a total impulse o' about 180 n/s. Ahoy! I wanted a rocket that was light enough t' launch with t' motor, me bucko, 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. Begad! Ya scallywag! I decided that t' Aerotech Mirage be t' perfect candidate. Blimey! Arrr! It can launch on a motor as small as a F25, matey, and with me calculations, matey, will go about 1,500 ft with a 180 n/s motor. My fifteen year old friend Ryan Sebastian wanted t' help out with t' project, so he became me partner in designing, and buildin' t' rocket.

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

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

T' parachute bay, obviously, arrr, is where t' recovery system o' t' rocket is kept. 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. Begad! When t' booster section is attached, t' tube coupler presses t' bulkhead against t' ring. Ya scallywag! This creates a nice seal betwixt t' motor bay and t' parachute bay. Ahoy! When t' Mirage is flown with a regular motor, arrr, arrr, t' bulkhead is simply omitted.

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

Flight:

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

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

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

Summary:

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