Brief:

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

Recently, hybrid technology has come down t' t' Level 1 arena. Arrr! Begad! 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. Begad! T' reload kits do nay require a hazmat fee, matey, ya bilge rat, 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, ya bilge rat, arrr, with slight modification t' t' rocket for venting. Aye aye! Ya scallywag! Also, matey, me bucko, t' fuel tank be t' same cylinder as t' oxidizer tank. Arrr! Avast, me proud beauty! T' fuel and oxidizer are separated by a .floatin' bulkhead.. Blimey! T' fuel is consumed from t' top t' t' bottom. Blimey! This means that t' pressure o' t' N2O pushes t' bulkhead down as t' fuel is consumed. Arrr! Arrr! They have three motor designations, me hearties, ya bilge rat, H70, me bucko, me hearties, I80, me hearties, and I90. Avast, me proud beauty! 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. Arrr! Robert Galjes already had t' ground support system for t' RATT's work system and offered CMASS members access t' it, shiver me timbers, ya bilge rat, so t' only thin' that I required for it be a rocket t' fly it in. Blimey! Arrr! T' H70 has a 3 second burn time, and only has a total impulse o' about 180 n/s. I wanted a rocket that was 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! I decided that t' Aerotech Mirage be t' perfect candidate. Ya scallywag! It can launch on a motor as small as a F25, and with me calculations, shiver me timbers, me bucko, will go about 1,500 ft with a 180 n/s motor. Begad! My fifteen year old friend Ryan Sebastian wanted t' help out with t' project, so he became me partner in designing, me hearties, 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! Well, arrr, blow me down! I wanted t' put a bulkhead near t' engine that will hold t' charge, yet protect it from any leakin' N2O. Aye aye! But I also want t' option o' launchin' t' model with conventional motors. So t' charge bulkhead had t' be removable. Because o' this, t' three sections o' t' Mirage have t' be removable. Aye aye! I decided t' use screws t' hold t' rocket together.

T' Hybrid Mirage be built with three main sections. Ya scallywag! Blimey! T' Booster Section, shiver me timbers, Parachute Bay, matey, arrr, arrr, and Payload section. Aye aye! Ya scallywag! T' Motor Section be t' lower section o' t' Aerotech Mirage, me bucko, and is heavily modified. Aye aye! T' motor hook is still used, but t' motor hook is trimmed t' allow t' longer H70 motor t' pass beyond t' motor hook. Avast! 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, shiver me timbers, 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. Avast, me proud beauty! Ya scallywag! It is also t' section that t' ejection bulkhead is attached to. Ahoy! Well, me bucko, blow me down! A paper rin' is attached inside t' tube so t' forward face o' t' bulkhead rests against it. Begad! Avast, me proud beauty! When t' booster section is attached, t' tube coupler presses t' bulkhead against t' ring. Ya scallywag! This creates a nice seal betwixt t' motor bay and t' parachute bay. Begad! Begad! When t' Mirage is flown with a regular motor, 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. Blimey! I decided that I would use me custom built timer for recovery. Begad! I designed t' timer t' use a .burn wire. Aye aye! t' start t' timer. Avast, me proud beauty! Ya scallywag! T' utilizes this, I had a couple short bolts stickin' out o' t' side o' t' rocket. Begad! Each bolt is a terminal which a .jumper. Begad! wire is connected too. T' jumperwire is fastened t' t' launch rod. Ahoy! When t' Mirage takes off, shiver me timbers, t' jumper pulls free from t' bolt, ya bilge rat, me hearties, 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 was a N2O leak in t' vent tube. Ahoy! Arrr! T' N2O filled t' motor section, and spread into t' parachute compartment. Begad! Begad! Just before t' countdown for ignition was started, shiver me timbers, t' N2O in t' parachute compartment pushed t' payload section off t' rocket, which started t' timer. Avast, me proud beauty! Well, blow me down! T' countdown was aborted, arrr, shiver me timbers, and t' N2O dump button was pushed. While t' oxidizer was bein' drained, me bucko, t' charge went off. Paper, Wood, ya bilge rat, Oxidizer.... Begad! Ahoy! now a heat source? You guest it. Begad! Arrr! Fire. For about five seconds, t' insides o' t' parachute compartment be engulfed in flame. I did nay know this until I dismantled t' rocket, hopin' t' reload it. T' charge bulkhead was completely chard. Avast, me proud beauty! It disintegrated just by handlin' it. About a quarter o' t' inside wall o' t' body tube was burned away from t' heat.

When t' Sept 14th rocket launch came, Ryan and I decided t' launch t' Hybrid Mirage again. Begad! Robert Galjes could nay make it t' t' launch with t' ground support equipment and t' tank o' N2O, me hearties, so Ryan and I decided t' launch it with a conventional motor, ya bilge rat, arrr, a G75-10J. Ahoy! Avast! I decided t' arm t' timer too& just t' make sure it works. Begad! T' lift off o' t' Hybrid Mirage was beautiful. Arrr! T' black and silver rocket streakin' skyward, leavin' behind a dark smoke trail& nice :-). Avast, me hearties, me proud beauty! T' timer deployed both chutes right at apogee, ya bilge rat, me hearties, and t' rocket recovered without a scratch.

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

Summary:

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