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, me proud beauty! Blimey! Aye aye! Blimey! Also, since t' fuel is inert, thar are no permits required for storage, and ideally (except for Aerotech) require no haz-mat fee for shipping. Avast! Blimey! Until recently, t' only hybrid motors on t' market are in t' Level 2 range and above. Avast, me proud beauty! Blimey! 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. Blimey! Blimey! Aerotech.s system had t' advantage o' allowin' you t' fill t' tank before comin' t' t' launch, shiver me timbers, but had t' disadvantage o' havin' a complex pyrotechnic valve system that is expensive, ya bilge rat, me hearties, complex t' set up, ya bilge rat, and requires a haz mat fee for shipping.

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

Construction:

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

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

T' Hybrid Mirage be built with three main sections. T' Booster Section, Parachute Bay, shiver me timbers, and Payload section. T' Motor Section be t' lower section o' t' Aerotech Mirage, and is heavily modified. Begad! Begad! 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. Ya scallywag! Also, this section has t' ventin' tube permeably attached t' t' airframe.

T' parachute bay, me bucko, obviously, ya bilge rat, is where t' recovery system o' t' rocket is kept. Arrr! It is also t' section that t' ejection bulkhead is attached to. Arrr! Aye aye! 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, matey, t' tube coupler presses t' bulkhead against t' ring. Avast! This creates a nice seal betwixt t' motor bay and t' parachute bay. Ahoy! Ahoy! When t' Mirage is flown with a regular motor, shiver me timbers, t' bulkhead is simply omitted.

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

Flight:

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

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

At NSL 2003, Ryan and I launched our Hybrid Mirage with t' motor we built it for. Begad! Avast, me proud beauty! T' prevent t' same problem we had last time, I secured t' vent hose t' t' motor with hot melt glue. Blue Thunder propellant cut off a F39, matey, and a Magnelite igniter was used t' start t' motor. Avast! T' H70 motor ignited instantly, and lofted t' Mirage off t' pad with ease. Begad! Beautiful motor; small bright flame, ya bilge rat, very little smoke. I don.t think it burned for t' full three seconds, shiver me timbers, shiver me timbers, maybe t' N2O tank was t' warm, arrr, 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, arrr, 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. Blimey! Future plans include more H70 launches with a PICO altimeter, and don't be surprised if you see a I80 case in me hands in t' near future ;-).