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, and ideally (except for Aerotech) require no haz-mat fee for shipping. Until recently, t' only hybrid motors on t' market are in t' Level 2 range and above. Arrr! Well, blow me down! T' Hypertek system required expensive ground support system, me hearties, and you must have a tank o' N20 and O2 on t' field. Begad! 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, and requires a haz mat fee for shipping.

Recently, hybrid technology has come down t' t' Level 1 arena. Aye aye! Ratts Work.s be t' first company that offered a certified hybrid system that any level 1 user can use. Ahoy! Aye aye! T' ground support is pricey, me bucko, me hearties, 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. Avast! Blimey! However, me bucko, 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. Also, t' fuel tank be t' same cylinder as t' oxidizer tank. Arrr! Well, blow me down! T' fuel and oxidizer are separated by a .floatin' bulkhead.. Begad! T' fuel is consumed from t' top t' t' bottom. This means that t' pressure o' t' N2O pushes t' bulkhead down as t' fuel is consumed. Arrr! They have three motor designations, H70, I80, 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. Avast! 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 be a rocket t' fly it in. Well, blow me down! T' H70 has a 3 second burn time, me hearties, 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. Ya scallywag! I decided that t' Aerotech Mirage be t' perfect candidate. Avast! It can launch on a motor as small as a F25, and with me calculations, arrr, shiver me timbers, will go about 1,500 ft with a 180 n/s motor. Avast, me proud beauty! Ya scallywag! 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. It had t' carry electronics t' deploy t' recovery system. Avast! I wanted t' put a bulkhead near t' engine that will hold t' charge, me hearties, yet protect it from any leakin' N2O. But I also want t' option o' launchin' t' model with conventional motors. Avast! So t' charge bulkhead had t' be removable. Aye aye! Aye aye! 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 be built with three main sections. Aye aye! T' Booster Section, matey, Parachute Bay, and Payload section. T' Motor Section be t' lower section o' t' Aerotech Mirage, ya bilge rat, and is heavily modified. Begad! Begad! T' motor hook is still used, shiver me timbers, but t' motor hook is trimmed t' allow t' longer H70 motor t' pass beyond t' motor hook. Ahoy! It is attached in t' position that t' hook locks over t' aft closure o' t' Hybrid, matey, matey, and standard 29mm High Power motor. Also, this section has t' ventin' tube permeably attached t' t' airframe.

T' parachute bay, obviously, shiver me timbers, is where t' recovery system o' t' rocket is kept. Well, blow me down! Blimey! It is also t' section that t' ejection bulkhead is attached to. Ya scallywag! Blimey! Begad! Blimey! A paper rin' is attached inside t' tube so t' forward face o' t' bulkhead rests against it. Begad! Blimey! When t' booster section is attached, t' tube coupler presses t' bulkhead against t' ring. Begad! Blimey! This creates a nice seal betwixt t' motor bay and t' parachute bay. Avast! Blimey! When t' Mirage is flown with a regular motor, arrr, shiver me timbers, t' bulkhead is simply omitted.

T' Payload Section o' t' rocket is mostly empty space. Avast, me proud beauty! T' electronics for t' recovery system is located in t' tube coupler. Ahoy! I decided that I would use me custom built timer for recovery. Begad! I designed t' timer t' use a .burn wire. Ahoy! 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. Arrr! wire is connected too. Begad! T' jumperwire is fastened t' t' launch rod. Ya scallywag! Well, blow me down! When t' Mirage takes off, me bucko, 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. Well, arrr, blow me down! It did nay work very well though. Avast, me proud beauty! There be a N2O leak in t' vent tube. T' N2O filled t' motor section, and spread into t' parachute compartment. Blimey! Just before t' countdown for ignition was started, ya bilge rat, t' N2O in t' parachute compartment pushed t' payload section off t' rocket, which started t' timer. Well, blow me down! T' countdown was aborted, arrr, shiver me timbers, and t' N2O dump button be pushed. Begad! While t' oxidizer was bein' drained, t' charge went off. Avast! Blimey! Paper, Wood, Oxidizer.... Ahoy! now a heat source? You guest it. Begad! Arrr! Fire. Well, blow me down! For about five seconds, matey, matey, t' insides o' t' parachute compartment was engulfed in flame. Arrr! I did nay know this until I dismantled t' rocket, arrr, hopin' t' reload it. T' charge bulkhead was 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, 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, matey, ya bilge rat, ya bilge rat, so Ryan and I decided t' launch it with a conventional motor, a G75-10J. Avast, me proud beauty! Blimey! Ahoy! Blimey! Blimey! Blimey! I decided t' arm t' timer too& just t' make sure it works. Arrr! Blimey! T' lift off o' t' Hybrid Mirage be beautiful. Well, blow me down! Blimey! Begad! Blimey! Blimey! Blimey! T' black and silver rocket streakin' skyward, leavin' behind a dark smoke trail& nice :-). Avast, me bucko, me proud beauty! Blimey! Blimey! Blimey! 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. Avast! T' prevent t' same problem we had last time, matey, I secured t' vent hose t' t' motor with hot melt glue. Begad! Blue Thunder propellant cut off a F39, arrr, and a Magnelite igniter was used t' start t' motor. T' H70 motor ignited instantly, and lofted t' Mirage off t' pad with ease. Arrr! Beautiful motor; small bright flame, very little smoke. I don.t think it burned for t' full three seconds, arrr, maybe t' N2O tank was t' warm, matey, arrr, so t' motor did nay get a full fill o' oxidizer. Blimey! Blimey! T' timer deployed both chutes a couple seconds after apogee, endin' its perfect flight.

Summary:

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