Brief:

Hybrid motors have always fascinated me. Ahoy! Well, blow me down! 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. Avast! Also, me bucko, since t' fuel is inert, thar are no permits required for storage, ya bilge rat, me hearties, 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! T' Hypertek system required expensive ground support system, ya bilge rat, and you must have a tank o' N20 and O2 on t' field. Begad! Well, blow me down! 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, me hearties, 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. 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, but t' design o' t' motor is a lot simpler than what Aerotech and Hypertek have t' offer. Avast! T' reload kits do nay require a hazmat fee, matey, but they do nay come with igniters or pre-heater charges. Ya scallywag! However, shiver me timbers, some dealers (ie Pratt Hobbies) throw these components into t' kit for you. Begad! Blimey! T' Ratts Work Hybrid motors are designed t' fit in a 29mm motor tube, with slight modification t' t' rocket for venting. Begad! Also, me hearties, matey, shiver me timbers, t' fuel tank be t' same cylinder as t' oxidizer tank. Avast, me proud beauty! Avast! T' fuel and oxidizer are separated by a .floatin' bulkhead.. Ya scallywag! T' fuel is consumed from t' top t' t' bottom. Avast, me proud beauty! This means that t' pressure o' t' N2O pushes t' bulkhead down as t' fuel is consumed. Aye aye! They have three motor designations, H70, I80, and I90. Ahoy! Arrr! T' H70 and I80 use t' same size grain, arrr, me bucko, but t' case is longer.

Construction:

I won a H70 case and a few loads on a ROL auction. Well, blow me down! 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. Aye aye! Well, blow me down! 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, matey, and t' added weight o' t' recovery hardware, arrr, 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 was t' perfect candidate. Blimey! It can launch on a motor as small as a F25, matey, arrr, and with me calculations, will go about 1,500 ft with a 180 n/s motor. Blimey! My fifteen year old friend Ryan Sebastian wanted t' help out with t' project, me hearties, 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. I wanted t' put a bulkhead near t' engine that will hold t' charge, yet protect it from any leakin' N2O. But I also want t' option o' launchin' t' model with conventional motors. So t' charge bulkhead had t' be removable. Ahoy! Because o' this, matey, me bucko, t' three sections o' t' Mirage have t' be removable. Avast! Avast! I decided t' use screws t' hold t' rocket together.

T' Hybrid Mirage was built with three main sections. Ya scallywag! T' Booster Section, Parachute Bay, and Payload section. Begad! T' Motor Section be t' lower section o' t' Aerotech Mirage, and is heavily modified. Blimey! T' motor hook is still used, me hearties, arrr, but t' motor hook is trimmed t' allow t' longer H70 motor t' pass beyond t' motor hook. Ahoy! Begad! 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. Blimey! Also, me hearties, this section has t' ventin' tube permeably attached t' t' airframe.

T' parachute bay, shiver me timbers, me bucko, obviously, ya bilge rat, is where t' recovery system o' t' rocket is kept. It is also t' section that t' ejection bulkhead is attached to. Avast! Blimey! A paper rin' is attached inside t' tube so t' forward face o' t' bulkhead rests against it. Avast! 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. Avast! Avast! When t' Mirage is flown with a regular motor, shiver me timbers, shiver me timbers, t' bulkhead is simply omitted.

T' Payload Section o' t' rocket is mostly empty space. Avast! Begad! Blimey! T' electronics for t' recovery system is located in t' tube coupler. Blimey! Arrr! Blimey! I decided that I would use me custom built timer for recovery. I designed t' timer t' use a .burn wire. Ya scallywag! Aye aye! Blimey! t' start t' timer. Avast, me proud beauty! T' utilizes this, me hearties, I had a couple short bolts stickin' out o' t' side o' t' rocket. Each bolt is a terminal which a .jumper. Ahoy! wire is connected too. Aye aye! Arrr! Blimey! T' jumperwire is fastened t' t' launch rod. Ahoy! Blimey! When t' Mirage takes off, ya bilge rat, t' jumper pulls free from t' bolt, me hearties, thus startin' t' timer.

Flight:

T' first opportunity t' try out t' Hybrid Mirage came on July 27th, 2002. Blimey! It did nay work very well though. Avast, me proud beauty! There was a N2O leak in t' vent tube. T' N2O filled t' motor section, shiver me timbers, and spread into t' parachute compartment. Just before t' countdown for ignition was started, matey, me hearties, t' N2O in t' parachute compartment pushed t' payload section off t' rocket, matey, which started t' timer. T' countdown was aborted, and t' N2O dump button be pushed. Begad! While t' oxidizer was bein' drained, ya bilge rat, t' charge went off. Paper, Wood, Oxidizer.... Avast! now a heat source? You guest it. Fire. Well, blow me down! For about five seconds, shiver me timbers, 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. Arrr! T' charge bulkhead be completely chard. 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, ya bilge rat, ya bilge rat, Ryan and I decided t' launch t' Hybrid Mirage again. Avast, me proud beauty! Ahoy! Robert Galjes could nay make it t' t' launch with t' ground support equipment and t' tank o' N2O, me hearties, shiver me timbers, so Ryan and I decided t' launch it with a conventional motor, a G75-10J. I decided t' arm t' timer too& just t' make sure it works. Begad! Begad! T' lift off o' t' Hybrid Mirage be beautiful. Aye aye! Aye aye! T' black and silver rocket streakin' skyward, arrr, leavin' behind a dark smoke trail& nice :-). Begad! Avast, me proud beauty! T' timer deployed both chutes right at apogee, matey, 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, me proud beauty! Avast! T' prevent t' same problem we had last time, I secured t' vent hose t' t' motor with hot melt glue. Arrr! Blue Thunder propellant cut off a F39, and a Magnelite igniter was used t' start t' motor. Well, blow me down! T' H70 motor ignited instantly, arrr, and lofted t' Mirage off t' pad with ease. Beautiful motor; small bright flame, me bucko, ya bilge rat, very little smoke. I don.t think it burned for t' full three seconds, maybe t' N2O tank be t' warm, 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, me hearties, t' Hybrid Mirage project be a success. Begad! We built a rocket that could fly on a Hybrid motor, and convention motor. Ahoy! 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 ;-).