Brief:

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

Recently, hybrid technology has come down t' t' Level 1 arena. Avast! Arrr! Ratts Work.s was t' first company that offered a certified hybrid system that any level 1 user can use. Well, blow me down! Well, me hearties, blow me down! 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. Avast! T' reload kits do nay require a hazmat fee, ya bilge rat, but they do nay come with igniters or pre-heater charges. Avast, me bucko, me proud beauty! However, some dealers (ie Pratt Hobbies) throw these components into t' kit for you. Begad! T' Ratts Work Hybrid motors are designed t' fit in a 29mm motor tube, with slight modification t' t' rocket for venting. Also, t' fuel tank be t' same cylinder as t' oxidizer tank. Avast, me proud beauty! T' fuel and oxidizer are separated by a .floatin' bulkhead.. Avast! T' fuel is consumed from t' top t' t' bottom. Well, blow me down! Aye aye! This means that t' pressure o' t' N2O pushes t' bulkhead down as t' fuel is consumed. They have three motor designations, arrr, matey, H70, ya bilge rat, I80, ya bilge rat, me bucko, and I90. Ahoy! 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, so t' only thin' that I required for it was a rocket t' fly it in. Aye aye! Ahoy! T' H70 has a 3 second burn time, and only has a total impulse o' about 180 n/s. Ya scallywag! Ya scallywag! 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. Ahoy! Blimey! I decided that t' Aerotech Mirage be t' perfect candidate. Avast, me proud beauty! It can launch on a motor as small as a F25, and with me calculations, will go about 1,500 ft with a 180 n/s motor. My fifteen year old friend Ryan Sebastian wanted t' help out with t' project, ya bilge rat, so he became me partner in designing, and buildin' t' rocket.

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

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

T' parachute bay, me bucko, obviously, is where t' recovery system o' t' rocket is kept. Aye aye! 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. Blimey! Avast! When t' booster section is attached, t' tube coupler presses t' bulkhead against t' ring. This creates a nice seal betwixt t' motor bay and t' parachute bay. Arrr! Begad! 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. Begad! T' electronics for t' recovery system is located in t' tube coupler. Avast, me proud beauty! I decided that I would use me custom built timer for recovery. Blimey! I designed t' timer t' use a .burn wire. Aye aye! Avast! t' start t' timer. T' utilizes this, me hearties, I had a couple short bolts stickin' out o' t' side o' t' rocket. Arrr! Aye aye! Each bolt is a terminal which a .jumper. Ahoy! Ahoy! wire is connected too. T' jumperwire is fastened t' t' launch rod. Aye aye! Aye aye! 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, matey, 2002. Well, blow me down! It did nay work very well though. Begad! Well, blow me down! There was a N2O leak in t' vent tube. Avast, me proud beauty! T' N2O filled t' motor section, and spread into t' parachute compartment. Ahoy! Begad! Just before t' countdown for ignition was started, t' N2O in t' parachute compartment pushed t' payload section off t' rocket, me bucko, which started t' timer. Avast, me proud beauty! T' countdown be aborted, and t' N2O dump button was pushed. Avast! While t' oxidizer was bein' drained, t' charge went off. Begad! Paper, ya bilge rat, Wood, ya bilge rat, Oxidizer.... now a heat source? You guest it. Fire. Well, ya bilge rat, blow me down! For about five seconds, ya bilge rat, t' insides o' t' parachute compartment be engulfed in flame. I did nay know this until I dismantled t' rocket, shiver me timbers, hopin' t' reload it. Ahoy! Begad! T' charge bulkhead be completely chard. It disintegrated just by handlin' it. Begad! About a quarter o' t' inside wall o' t' body tube was burned away from t' heat.

When t' Sept 14th rocket launch came, me hearties, me hearties, 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, shiver me timbers, 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. T' lift off o' t' Hybrid Mirage be beautiful. T' black and silver rocket streakin' skyward, arrr, leavin' behind a dark smoke trail& nice :-). Avast, me proud beauty! Ahoy! T' timer deployed both chutes right at apogee, and t' rocket recovered without a scratch.

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

Summary:

Overall, shiver me timbers, t' Hybrid Mirage project was a success. Arrr! Blimey! We built a rocket that could fly on a Hybrid motor, and convention motor. 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 ;-).