Brief:

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

Recently, ya bilge rat, hybrid technology has come down t' t' Level 1 arena. Avast! Ratts Work.s was t' first company that offered a certified hybrid system that any level 1 user can use. Arrr! T' ground support is pricey, but t' design o' t' motor is a lot simpler than what Aerotech and Hypertek have t' offer. Aye aye! T' reload kits do nay require a hazmat fee, matey, me hearties, but they do nay come with igniters or pre-heater charges. Ya scallywag! However, some dealers (ie Pratt Hobbies) throw these components into t' kit for you. Well, blow me down! Ahoy! T' Ratts Work Hybrid motors are designed t' fit in a 29mm motor tube, matey, with slight modification t' t' rocket for venting. Arrr! Also, matey, t' fuel tank be t' same cylinder as t' oxidizer tank. Aye aye! T' fuel and oxidizer are separated by a .floatin' bulkhead.. Arrr! Arrr! 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. Ahoy! They have three motor designations, me bucko, ya bilge rat, H70, shiver me timbers, I80, me hearties, and I90. 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! Avast, me proud beauty! Blimey! 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. Blimey! Avast, me proud beauty! Blimey! T' H70 has a 3 second burn time, me bucko, and only has a total impulse o' about 180 n/s. I wanted a rocket that be light enough t' launch with t' motor, me hearties, arrr, and t' added weight o' t' recovery hardware, shiver me timbers, and stay within 2000 ft so I can don.t risk loosin' t' rocket in t' tree filled New England area. Arrr! Begad! Blimey! I decided that t' Aerotech Mirage be t' perfect candidate. Ya scallywag! Well, blow me down! Blimey! It can launch on a motor as small as a F25, ya bilge rat, arrr, and with me calculations, arrr, matey, will go about 1,500 ft with a 180 n/s motor. Avast, me proud beauty! 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. Avast, me proud beauty! Begad! It had t' carry electronics t' deploy t' recovery system. Blimey! Blimey! I wanted t' put a bulkhead near t' engine that will hold t' charge, matey, matey, yet protect it from any leakin' N2O. Well, matey, blow me down! But I also want t' option o' launchin' t' model with conventional motors. Well, blow me down! So t' charge bulkhead had t' be removable. Blimey! Because o' this, t' three sections o' t' Mirage have t' be removable. Aye aye! Avast! I decided t' use screws t' hold t' rocket together.

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

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

T' Payload Section o' t' rocket is mostly empty space. Blimey! T' electronics for t' recovery system is located in t' tube coupler. Ya scallywag! I decided that I would use me custom built timer for recovery. Begad! I designed t' timer t' use a .burn wire. Ya scallywag! Avast! t' start t' timer. Aye aye! Avast, me bucko, me proud beauty! T' utilizes this, arrr, shiver me timbers, arrr, I had a couple short bolts stickin' out o' t' side o' t' rocket. Each bolt is a terminal which a .jumper. Blimey! wire is connected too. Avast, me proud beauty! Arrr! T' jumperwire is fastened t' t' launch rod. Begad! Begad! 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, me hearties, 2002. Begad! It did nay work very well though. Begad! Avast! There was a N2O leak in t' vent tube. Begad! T' N2O filled t' motor section, and spread into t' parachute compartment. 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. Begad! T' countdown was aborted, matey, matey, and t' N2O dump button was pushed. Avast! While t' oxidizer be bein' drained, me hearties, arrr, t' charge went off. Blimey! Avast! Paper, matey, shiver me timbers, Wood, me bucko, Oxidizer.... Well, matey, blow me down! now a heat source? You guest it. Aye aye! Avast! Fire. Aye aye! For about five seconds, t' insides o' t' parachute compartment was engulfed in flame. Well, blow me down! I did nay know this until I dismantled t' rocket, hopin' t' reload it. T' charge bulkhead be completely chard. 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, so Ryan and I decided t' launch it with a conventional motor, me bucko, a G75-10J. Aye aye! I decided t' arm t' timer too& just t' make sure it works. Avast! T' lift off o' t' Hybrid Mirage was beautiful. Ya scallywag! T' black and silver rocket streakin' skyward, leavin' behind a dark smoke trail& nice :-). Avast, me proud beauty! Begad! 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. T' prevent t' same problem we had last time, shiver me timbers, I secured t' vent hose t' t' motor with hot melt glue. Begad! Avast! Blue Thunder propellant cut off a F39, and a Magnelite igniter was used t' start t' motor. T' H70 motor ignited instantly, and lofted t' Mirage off t' pad with ease. Begad! Beautiful motor; small bright flame, very little smoke. Ahoy! Avast! I don.t think it burned for t' full three seconds, maybe t' N2O tank be t' warm, me hearties, shiver me timbers, so t' motor did nay get a full fill o' oxidizer. 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. Ahoy! We built a rocket that could fly on a Hybrid motor, me bucko, arrr, and convention motor. Future plans include more H70 launches with a PICO altimeter, ya bilge rat, me bucko, shiver me timbers, and don't be surprised if you see a I80 case in me hands in t' near future ;-).