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. Avast! Well, blow me down! Blimey! Also, since t' fuel is inert, arrr, me bucko, thar are no permits required for storage, and ideally (except for Aerotech) require no haz-mat fee for shipping. Begad! Aye aye! Blimey! Until recently, matey, arrr, t' only hybrid motors on t' market are in t' Level 2 range and above. Well, blow me down! Blimey! T' Hypertek system required expensive ground support system, and you must have a tank o' N20 and O2 on t' field. Begad! Aerotech.s system had t' advantage o' allowin' you t' fill t' tank before comin' t' t' launch, but had t' disadvantage o' havin' a complex pyrotechnic valve system that is expensive, shiver me timbers, arrr, complex t' set up, ya bilge rat, matey, and requires a haz mat fee for shipping.

Recently, arrr, hybrid technology has come down t' t' Level 1 arena. Ahoy! 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! Blimey! 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, me bucko, but they do nay come with igniters or pre-heater charges. However, me hearties, shiver me timbers, some dealers (ie Pratt Hobbies) throw these components into t' kit for you. Ya scallywag! T' Ratts Work Hybrid motors are designed t' fit in a 29mm motor tube, ya bilge rat, with slight modification t' t' rocket for venting. Begad! Also, shiver me timbers, shiver me timbers, t' fuel tank be t' same cylinder as t' oxidizer tank. Aye aye! Blimey! T' fuel and oxidizer are separated by a .floatin' bulkhead.. Well, me hearties, blow me down! Blimey! T' fuel is consumed from t' top t' t' bottom. Avast! Ya scallywag! Blimey! This means that t' pressure o' t' N2O pushes t' bulkhead down as t' fuel is consumed. Ahoy! Avast! Blimey! They have three motor designations, me hearties, me bucko, H70, matey, I80, matey, ya bilge rat, shiver me timbers, and I90. Well, blow me down! Avast, me proud beauty! Blimey! T' H70 and I80 use t' same size grain, matey, shiver me timbers, me bucko, but t' case is longer.

Construction:

I won a H70 case and a few loads on a ROL auction. Aye aye! 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 was a rocket t' fly it in. Begad! Blimey! T' H70 has a 3 second burn time, and only has a total impulse o' about 180 n/s. Begad! I wanted a rocket that was light enough t' launch with t' motor, and t' added weight o' t' recovery hardware, me bucko, and stay within 2000 ft so I can don.t risk loosin' t' rocket in t' tree filled New England area. Avast, me proud beauty! Blimey! I decided that t' Aerotech Mirage be t' perfect candidate. Blimey! Blimey! Blimey! It can launch on a motor as small as a F25, ya bilge rat, arrr, and with me calculations, arrr, shiver me timbers, will go about 1,500 ft with a 180 n/s motor. Begad! 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. It had t' carry electronics t' deploy t' recovery system. I wanted t' put a bulkhead near t' engine that will hold t' charge, yet protect it from any leakin' N2O. But I also want t' option o' launchin' t' model with conventional motors. So t' charge bulkhead had t' be removable. Avast! Ya scallywag! Because o' this, t' three sections o' t' Mirage have t' be removable. Blimey! I decided t' use screws t' hold t' rocket together.

T' Hybrid Mirage was built with three main sections. Begad! T' Booster Section, ya bilge rat, Parachute Bay, and Payload section. Well, ya bilge rat, blow me down! T' Motor Section be t' lower section o' t' Aerotech Mirage, me hearties, arrr, and is heavily modified. Ya scallywag! Avast! T' motor hook is still used, but t' motor hook is trimmed t' allow t' longer H70 motor t' pass beyond t' motor hook. Avast, me proud beauty! 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. It is also t' section that t' ejection bulkhead is attached to. Blimey! Ahoy! A paper rin' is attached inside t' tube so t' forward face o' t' bulkhead rests against it. Ya scallywag! Avast! When t' booster section is attached, arrr, me hearties, t' tube coupler presses t' bulkhead against t' ring. Begad! This creates a nice seal betwixt t' motor bay and t' parachute bay. Arrr! When t' Mirage is flown with a regular motor, t' bulkhead is simply omitted.

T' Payload Section o' t' rocket is mostly empty space. Ya scallywag! 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. Avast, me proud beauty! I designed t' timer t' use a .burn wire. Begad! t' start t' timer. Blimey! Avast, me proud beauty! T' utilizes this, matey, I had a couple short bolts stickin' out o' t' side o' t' rocket. Avast, me proud beauty! Arrr! Each bolt is a terminal which a .jumper. Arrr! Avast! wire is connected too. T' jumperwire is fastened t' t' launch rod. Begad! When t' Mirage takes off, 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. Arrr! It did nay work very well though. There be a N2O leak in t' vent tube. 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. Avast! Avast! T' countdown was aborted, and t' N2O dump button was pushed. Avast! While t' oxidizer was bein' drained, t' charge went off. Blimey! Paper, shiver me timbers, Wood, Oxidizer.... now a heat source? You guest it. Avast! Fire. For about five seconds, t' insides o' t' parachute compartment was engulfed in flame. I did nay know this until I dismantled t' rocket, hopin' t' reload it. T' charge bulkhead was completely chard. Begad! It disintegrated just by handlin' it. 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. Ya scallywag! Aye aye! Robert Galjes could nay make it t' t' launch with t' ground support equipment and t' tank o' N2O, me hearties, so Ryan and I decided t' launch it with a conventional motor, matey, a G75-10J. Well, me bucko, blow me down! I decided t' arm t' timer too& just t' make sure it works. Blimey! T' lift off o' t' Hybrid Mirage was beautiful. T' black and silver rocket streakin' skyward, leavin' behind a dark smoke trail& nice :-). Blimey! T' timer deployed both chutes right at apogee, arrr, and t' rocket recovered without a scratch.

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

Summary:

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