Brief:

Hybrid motors have always fascinated me. Well, blow me down! 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, shiver me timbers, thar are no permits required for storage, and ideally (except for Aerotech) require no haz-mat fee for shipping. Blimey! Avast, me proud beauty! Until recently, shiver me timbers, me bucko, matey, 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. 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, complex t' set up, ya bilge rat, arrr, and requires a haz mat fee for shipping.

Recently, hybrid technology has come down t' t' Level 1 arena. Begad! Ratts Work.s be 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. Well, blow me down! T' reload kits do nay require a hazmat fee, but they do nay come with igniters or pre-heater charges. Blimey! However, shiver me timbers, 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, shiver me timbers, with slight modification t' t' rocket for venting. Avast! Also, shiver me timbers, t' fuel tank be t' same cylinder as t' oxidizer tank. Ya scallywag! T' fuel and oxidizer are separated by a .floatin' bulkhead.. 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. They have three motor designations, H70, I80, matey, and I90. Arrr! T' H70 and I80 use t' same size grain, arrr, shiver me timbers, but t' case is longer.

Construction:

I won a H70 case and a few loads on a ROL auction. Blimey! Arrr! Robert Galjes already had t' ground support system for t' RATT's work system and offered CMASS members access t' it, shiver me timbers, ya bilge rat, so t' only thin' that I required for it was a rocket t' fly it in. Well, blow me down! T' H70 has a 3 second burn time, and only has a total impulse o' about 180 n/s. Avast, me proud beauty! I wanted a rocket that was light enough t' launch with t' motor, shiver me timbers, me hearties, and t' added weight o' t' recovery hardware, arrr, and stay within 2000 ft so I can don.t risk loosin' t' rocket in t' tree filled New England area. Blimey! I decided that t' Aerotech Mirage was t' perfect candidate. It can launch on a motor as small as a F25, and with me calculations, me bucko, will go about 1,500 ft with a 180 n/s motor. Blimey! My fifteen year old friend Ryan Sebastian wanted t' help out with t' project, matey, me bucko, so he became me partner in designing, me bucko, ya bilge rat, 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! I wanted t' put a bulkhead near t' engine that will hold t' charge, matey, yet protect it from any leakin' N2O. Well, blow me down! 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. Begad! Because o' this, t' three sections o' t' Mirage have t' be removable. Ahoy! I decided t' use screws t' hold t' rocket together.

T' Hybrid Mirage was built with three main sections. Avast, me proud beauty! T' Booster Section, Parachute Bay, and Payload section. Avast! Well, shiver me timbers, blow me down! T' Motor Section be t' lower section o' t' Aerotech Mirage, me hearties, and is heavily modified. Ahoy! Avast! T' motor hook is still used, me hearties, matey, matey, but t' motor hook is trimmed t' allow t' longer H70 motor t' pass beyond t' motor hook. It is attached in t' position that t' hook locks over t' aft closure o' t' Hybrid, and standard 29mm High Power motor. Well, blow me down! Aye aye! Also, ya bilge rat, this section has t' ventin' tube permeably attached t' t' airframe.

T' parachute bay, arrr, obviously, is where t' recovery system o' t' rocket is kept. Begad! Blimey! Well, matey, blow me down! Blimey! It is also t' section that t' ejection bulkhead is attached to. Avast! Blimey! A paper rin' is attached inside t' tube so t' forward face o' t' bulkhead rests against it. Aye aye! Blimey! When t' booster section is attached, me hearties, t' tube coupler presses t' bulkhead against t' ring. Blimey! Blimey! This creates a nice seal betwixt t' motor bay and t' parachute bay. When t' Mirage is flown with a regular motor, ya bilge rat, shiver me timbers, 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. Ya scallywag! I decided that I would use me custom built timer for recovery. Blimey! Blimey! I designed t' timer t' use a .burn wire. t' start t' timer. T' utilizes this, ya bilge rat, I had a couple short bolts stickin' out o' t' side o' t' rocket. Arrr! Each bolt is a terminal which a .jumper. Aye aye! wire is connected too. Begad! T' jumperwire is fastened t' t' launch rod. Aye aye! When t' Mirage takes off, arrr, t' jumper pulls free from t' bolt, ya bilge rat, thus startin' t' timer.

Flight:

T' first opportunity t' try out t' Hybrid Mirage came on July 27th, 2002. It did nay work very well though. There was a N2O leak in t' vent tube. Arrr! Ya scallywag! T' N2O filled t' motor section, shiver me timbers, and spread into t' parachute compartment. Just before t' countdown for ignition was started, t' N2O in t' parachute compartment pushed t' payload section off t' rocket, matey, shiver me timbers, which started t' timer. T' countdown was aborted, me bucko, and t' N2O dump button was pushed. Ahoy! Arrr! While t' oxidizer was bein' drained, arrr, t' charge went off. Avast! Paper, ya bilge rat, Wood, Oxidizer.... now a heat source? You guest it. Avast! Fire. Avast! Aye aye! For about five seconds, t' insides o' t' parachute compartment was engulfed in flame. I did nay know this until I dismantled t' rocket, me bucko, matey, hopin' t' reload it. Begad! Ahoy! T' charge bulkhead was completely chard. Avast, me proud beauty! It disintegrated just by handlin' it. Avast! 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. Arrr! 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, arrr, a G75-10J. Ya scallywag! I decided t' arm t' timer too& just t' make sure it works. Begad! T' lift off o' t' Hybrid Mirage was beautiful. Blimey! Well, blow me down! T' black and silver rocket streakin' skyward, ya bilge rat, leavin' behind a dark smoke trail& nice :-). Avast! Blimey! T' timer deployed both chutes right at apogee, me hearties, me hearties, 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! 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, and a Magnelite igniter was used t' start t' motor. Ahoy! Begad! T' H70 motor ignited instantly, me hearties, me hearties, and lofted t' Mirage off t' pad with ease. Avast, me proud beauty! Beautiful motor; small bright flame, shiver me timbers, me bucko, very little smoke. Avast, me proud beauty! Aye aye! I don.t think it burned for t' full three seconds, me hearties, maybe t' N2O tank was t' warm, so t' motor did nay get a full fill o' oxidizer. T' timer deployed both chutes a couple seconds after apogee, endin' its perfect flight.

Summary:

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