Brief:

Hybrid motors have always fascinated me. Ahoy! Blimey! Well, blow me down! Blimey! 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. Ya scallywag! Blimey! Also, since t' fuel is inert, ya bilge rat, me bucko, thar are no permits required for storage, and ideally (except for Aerotech) require no haz-mat fee for shipping. Ya scallywag! Blimey! Until recently, t' only hybrid motors on t' market are in t' Level 2 range and above. Avast! Blimey! T' Hypertek system required expensive ground support system, shiver me timbers, me hearties, and you must have a tank o' N20 and O2 on t' field. Begad! Blimey! Well, me bucko, blow me down! Blimey! 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, me bucko, and requires a haz mat fee for shipping.

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

Construction:

I won a H70 case and a few loads on a ROL auction. 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 be a rocket t' fly it in. Avast, me proud beauty! T' H70 has a 3 second burn time, 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, ya bilge rat, 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 was t' perfect candidate. Arrr! Ahoy! It can launch on a motor as small as a F25, and with me calculations, matey, 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, 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! It had t' carry electronics t' deploy t' recovery system. Aye aye! Avast! I wanted t' put a bulkhead near t' engine that will hold t' charge, arrr, yet protect it from any leakin' N2O. Begad! But I also want t' option o' launchin' t' model with conventional motors. Blimey! So t' charge bulkhead had t' be removable. Because o' this, t' three sections o' t' Mirage have t' be removable. Ya scallywag! Arrr! I decided t' use screws t' hold t' rocket together.

T' Hybrid Mirage was built with three main sections. Well, blow me down! T' Booster Section, me hearties, matey, Parachute Bay, me hearties, ya bilge rat, and Payload section. Avast! Begad! T' Motor Section be t' lower section o' t' Aerotech Mirage, shiver me timbers, and is heavily modified. Begad! T' motor hook is still used, 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, matey, and standard 29mm High Power motor. Also, shiver me timbers, matey, matey, this section has t' ventin' tube permeably attached t' t' airframe.

T' parachute bay, obviously, arrr, is where t' recovery system o' t' rocket is kept. Arrr! Begad! It is also t' section that t' ejection bulkhead is attached to. Ya scallywag! Avast, me proud beauty! A paper rin' is attached inside t' tube so t' forward face o' t' bulkhead rests against it. 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. Well, blow me down! Ahoy! When t' Mirage is flown with a regular motor, 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. I decided that I would use me custom built timer for recovery. Well, blow me down! I designed t' timer t' use a .burn wire. Begad! t' start t' timer. Avast, me proud beauty! T' utilizes this, shiver me timbers, I had a couple short bolts stickin' out o' t' side o' t' rocket. Avast, me proud beauty! Each bolt is a terminal which a .jumper. Ahoy! Avast, ya bilge rat, me proud beauty! wire is connected too. T' jumperwire is fastened t' t' launch rod. Ya scallywag! When t' Mirage takes off, me bucko, 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, ya bilge rat, 2002. Blimey! It did nay work very well though. There be a N2O leak in t' vent tube. Avast, shiver me timbers, me proud beauty! T' N2O filled t' motor section, matey, and spread into t' parachute compartment. Blimey! Begad! Just before t' countdown for ignition was started, me bucko, t' N2O in t' parachute compartment pushed t' payload section off t' rocket, which started t' timer. Ya scallywag! T' countdown be aborted, ya bilge rat, and t' N2O dump button was pushed. Blimey! Begad! While t' oxidizer was bein' drained, ya bilge rat, t' charge went off. Paper, me hearties, Wood, shiver me timbers, Oxidizer.... Begad! now a heat source? You guest it. Blimey! Avast! Fire. Ya scallywag! For about five seconds, t' insides o' t' parachute compartment be engulfed in flame. Well, blow me down! I did nay know this until I dismantled t' rocket, arrr, hopin' t' reload it. Aye aye! Blimey! T' charge bulkhead be completely chard. Ya scallywag! 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, me bucko, so Ryan and I decided t' launch it with a conventional motor, me hearties, a G75-10J. Ya scallywag! Begad! I decided t' arm t' timer too& just t' make sure it works. Avast, me proud beauty! Ahoy! T' lift off o' t' Hybrid Mirage was beautiful. Ahoy! Aye aye! T' black and silver rocket streakin' skyward, leavin' behind a dark smoke trail& nice :-). T' timer deployed both chutes right at apogee, and t' rocket recovered without a scratch.

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

Summary:

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