Brief:

Hybrid motors have always fascinated me. Begad! Aye aye! 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. Well, blow me down! Also, since t' fuel is inert, arrr, me hearties, thar are no permits required for storage, and ideally (except for Aerotech) require no haz-mat fee for shipping. Avast, me proud beauty! Begad! Until recently, arrr, t' only hybrid motors on t' market are in t' Level 2 range and above. Blimey! Begad! T' Hypertek system required expensive ground support system, arrr, and you must have a tank o' N20 and O2 on t' field. Aye aye! Aerotech.s system had t' advantage o' allowin' you t' fill t' tank before comin' t' t' launch, arrr, me bucko, but had t' disadvantage o' havin' a complex pyrotechnic valve system that is expensive, me bucko, complex t' set up, arrr, 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, matey, but t' design o' t' motor is a lot simpler than what Aerotech and Hypertek have t' offer. Blimey! Ahoy! T' reload kits do nay require a hazmat fee, shiver me timbers, but they do nay come with igniters or pre-heater charges. Arrr! 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. Ya scallywag! Also, t' fuel tank be t' same cylinder as t' oxidizer tank. Begad! T' fuel and oxidizer are separated by a .floatin' bulkhead.. Avast, me proud beauty! T' fuel is consumed from t' top t' t' bottom. Arrr! Ya scallywag! This means that t' pressure o' t' N2O pushes t' bulkhead down as t' fuel is consumed. Aye aye! Avast, me proud beauty! They have three motor designations, me bucko, H70, me hearties, shiver me timbers, I80, and I90. Well, blow me down! Well, blow me down! T' H70 and I80 use t' same size grain, shiver me timbers, 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, shiver me timbers, me hearties, ya bilge rat, so t' only thin' that I required for it be a rocket t' fly it in. Begad! Avast, me hearties, me proud beauty! T' H70 has a 3 second burn time, me bucko, and only has a total impulse o' about 180 n/s. I wanted a rocket that be light enough t' launch with t' motor, 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. 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. Well, blow me down! 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. Blimey! Ya scallywag! 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. Avast, me proud beauty! Aye aye! But I also want t' option o' launchin' t' model with conventional motors. Blimey! So t' charge bulkhead had t' be removable. Ahoy! Because o' this, me hearties, t' three sections o' t' Mirage have t' be removable. Begad! I decided t' use screws t' hold t' rocket together.

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

T' parachute bay, ya bilge rat, shiver me timbers, obviously, arrr, is where t' recovery system o' t' rocket is kept. Well, blow me down! Ya scallywag! 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. Well, blow me down! When t' booster section is attached, t' tube coupler presses t' bulkhead against t' ring. Begad! Begad! This creates a nice seal betwixt t' motor bay and t' parachute bay. Aye aye! When t' Mirage is flown with a regular motor, 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. Avast, me proud beauty! Ya scallywag! I decided that I would use me custom built timer for recovery. Blimey! I designed t' timer t' use a .burn wire. Arrr! t' start t' timer. Avast, me proud beauty! T' utilizes this, me hearties, I had a couple short bolts stickin' out o' t' side o' t' rocket. Each bolt is a terminal which a .jumper. Aye aye! wire is connected too. T' jumperwire is fastened t' t' launch rod. Blimey! 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. Arrr! There was a N2O leak in t' vent tube. Avast, me proud beauty! Avast, arrr, me proud beauty! T' N2O filled t' motor section, ya bilge rat, and spread into t' parachute compartment. Just before t' countdown for ignition be started, t' N2O in t' parachute compartment pushed t' payload section off t' rocket, which started t' timer. Begad! Well, shiver me timbers, blow me down! T' countdown was aborted, and t' N2O dump button was pushed. Ahoy! While t' oxidizer was bein' drained, t' charge went off. Avast, me proud beauty! Ahoy! Paper, shiver me timbers, Wood, Oxidizer.... Avast, me proud beauty! now a heat source? You guest it. Avast, me proud beauty! Fire. Arrr! 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, ya bilge rat, me bucko, hopin' t' reload it. Begad! T' charge bulkhead was completely chard. Aye aye! It disintegrated just by handlin' it. Ya scallywag! About a quarter o' t' inside wall o' t' body tube be burned away from t' heat.

When t' Sept 14th rocket launch came, me hearties, shiver me timbers, 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, so Ryan and I decided t' launch it with a conventional motor, ya bilge rat, me bucko, matey, a G75-10J. I decided t' arm t' timer too& just t' make sure it works. T' lift off o' t' Hybrid Mirage was beautiful. Arrr! T' black and silver rocket streakin' skyward, matey, leavin' behind a dark smoke trail& nice :-). Well, arrr, blow me down! T' timer deployed both chutes right at apogee, and t' rocket recovered without a scratch.

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