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

Recently, matey, matey, hybrid technology has come down t' t' Level 1 arena. Aye aye! Avast! Ratts Work.s was t' first company that offered a certified hybrid system that any level 1 user can use. Aye aye! T' ground support is pricey, me hearties, matey, but t' design o' t' motor is a lot simpler than what Aerotech and Hypertek have t' offer. Begad! T' reload kits do nay require a hazmat fee, but they do nay come with igniters or pre-heater charges. 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, me bucko, me hearties, with slight modification t' t' rocket for venting. Also, t' fuel tank be t' same cylinder as t' oxidizer tank. Blimey! Ahoy! T' fuel and oxidizer are separated by a .floatin' bulkhead.. Blimey! Ahoy! 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. Avast, me proud beauty! Begad! They have three motor designations, matey, H70, me bucko, I80, ya bilge rat, and I90. Arrr! T' H70 and I80 use t' same size grain, me hearties, shiver me timbers, but t' case is longer.

Construction:

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

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

T' Hybrid Mirage was built with three main sections. Avast, me proud beauty! Begad! T' Booster Section, Parachute Bay, and Payload section. Well, matey, blow me down! T' Motor Section be t' lower section o' t' Aerotech Mirage, shiver me timbers, and is heavily modified. Blimey! Begad! T' motor hook is still used, ya bilge rat, 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. Also, this section has t' ventin' tube permeably attached t' t' airframe.

T' parachute bay, shiver me timbers, obviously, arrr, matey, is where t' recovery system o' t' rocket is kept. It is also t' section that t' ejection bulkhead is attached to. Avast, me proud beauty! Blimey! A paper rin' is attached inside t' tube so t' forward face o' t' bulkhead rests against it. Begad! Blimey! Ya scallywag! Blimey! When t' booster section is attached, t' tube coupler presses t' bulkhead against t' ring. Arrr! Blimey! This creates a nice seal betwixt t' motor bay and t' parachute bay. Ahoy! Blimey! When t' Mirage is flown with a regular motor, 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! Begad! I decided that I would use me custom built timer for recovery. Well, blow me down! Begad! I designed t' timer t' use a .burn wire. Begad! t' start t' timer. T' utilizes this, ya bilge rat, I had a couple short bolts stickin' out o' t' side o' t' rocket. Begad! Each bolt is a terminal which a .jumper. wire is connected too. Well, blow me down! T' jumperwire is fastened t' t' launch rod. Begad! When t' Mirage takes off, arrr, 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. Aye aye! It did nay work very well though. Avast! There be a N2O leak in t' vent tube. T' N2O filled t' motor section, 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, me bucko, which started t' timer. Arrr! Ahoy! Blimey! T' countdown was aborted, arrr, and t' N2O dump button was pushed. Avast, me proud beauty! Blimey! While t' oxidizer be bein' drained, t' charge went off. Ya scallywag! Well, blow me down! Blimey! Paper, matey, Wood, Oxidizer.... Begad! Avast! Blimey! now a heat source? You guest it. Fire. Avast! Arrr! Blimey! For about five seconds, t' insides o' t' parachute compartment be engulfed in flame. Avast, me proud beauty! I did nay know this until I dismantled t' rocket, me hearties, hopin' t' reload it. Avast, me proud beauty! T' charge bulkhead be completely chard. Begad! 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, shiver me timbers, shiver me timbers, 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, me bucko, so Ryan and I decided t' launch it with a conventional motor, a G75-10J. I decided t' arm t' timer too& just t' make sure it works. Ahoy! T' lift off o' t' Hybrid Mirage was beautiful. T' black and silver rocket streakin' skyward, leavin' behind a dark smoke trail& nice :-). Ya scallywag! Ahoy! T' timer deployed both chutes right at apogee, shiver me timbers, and t' rocket recovered without a scratch.

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

Summary:

Overall, shiver me timbers, t' Hybrid Mirage project be a success. Begad! We built a rocket that could fly on a Hybrid motor, shiver me timbers, matey, and convention motor. Begad! Well, blow me down! Future plans include more H70 launches with a PICO altimeter, ya bilge rat, and don't be surprised if you see a I80 case in me hands in t' near future ;-).