Brief:

Hybrid motors have always fascinated me. Avast! 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. Blimey! 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. Begad! Until recently, t' only hybrid motors on t' market are in t' Level 2 range and above. Ya scallywag! T' Hypertek system required expensive ground support system, shiver me timbers, and you must have a tank o' N20 and O2 on t' field. 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, and requires a haz mat fee for shipping.

Recently, me hearties, hybrid technology has come down t' t' Level 1 arena. Avast! Well, blow me down! Ratts Work.s was t' first company that offered a certified hybrid system that any level 1 user can use. Avast! T' ground support is pricey, but t' design o' t' motor is a lot simpler than what Aerotech and Hypertek have t' offer. Avast! Aye aye! T' reload kits do nay require a hazmat fee, matey, but they do nay come with igniters or pre-heater charges. Aye aye! However, some dealers (ie Pratt Hobbies) throw these components into t' kit for you. Avast! Ahoy! T' Ratts Work Hybrid motors are designed t' fit in a 29mm motor tube, me bucko, with slight modification t' t' rocket for venting. Ya scallywag! Also, t' fuel tank be t' same cylinder as t' oxidizer tank. T' fuel and oxidizer are separated by a .floatin' bulkhead.. Begad! T' fuel is consumed from t' top t' t' bottom. Aye aye! Well, blow me down! This means that t' pressure o' t' N2O pushes t' bulkhead down as t' fuel is consumed. Begad! Ahoy! They have three motor designations, H70, I80, and I90. Well, blow me down! Well, me bucko, blow me down! T' H70 and I80 use t' same size grain, arrr, arrr, 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. T' H70 has a 3 second burn time, and only has a total impulse o' about 180 n/s. Well, blow me down! Ahoy! I wanted a rocket that was light enough t' launch with t' motor, and t' added weight o' t' recovery hardware, ya bilge rat, 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, me proud beauty! Arrr! It can launch on a motor as small as a F25, matey, and with me calculations, matey, will go about 1,500 ft with a 180 n/s motor. Aye aye! My fifteen year old friend Ryan Sebastian wanted t' help out with t' project, matey, me hearties, shiver me timbers, 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, me proud beauty! Blimey! Begad! Blimey! Blimey! Blimey! I wanted t' put a bulkhead near t' engine that will hold t' charge, yet protect it from any leakin' N2O. Avast, me proud beauty! Blimey! But I also want t' option o' launchin' t' model with conventional motors. Begad! Blimey! Blimey! Blimey! Blimey! Blimey! So t' charge bulkhead had t' be removable. Ahoy! Blimey! Because o' this, t' three sections o' t' Mirage have t' be removable. Aye aye! Blimey! Well, blow me down! Blimey! Blimey! Blimey! I decided t' use screws t' hold t' rocket together.

T' Hybrid Mirage was built with three main sections. T' Booster Section, shiver me timbers, Parachute Bay, and Payload section. Begad! Blimey! Blimey! T' Motor Section be t' lower section o' t' Aerotech Mirage, and is heavily modified. Avast! Avast! Blimey! 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. Aye aye! Blimey! Also, this section has t' ventin' tube permeably attached t' t' airframe.

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

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

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

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

Summary:

Overall, t' Hybrid Mirage project was a success. We built a rocket that could fly on a Hybrid motor, ya bilge rat, and convention motor. 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 ;-).