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RATTworks: Precision Hybrid & Tribrid Rocket Motors RATTworks: Precision Hybrid & Tribrid Rocket Motors
Tribrid Motors

RATTworks simple hybrid diagram
(interactive tutorial)

Tribrid motors are not certified by the Tripoli Rocketry Association

Silver Bullet 3 Bi-Propellant Hybrid

Biprop #1 Ted poses with a 700 lb. thrust LR-5 SS rocket.

The Flight Line (left to right):
1. Shadow 51 NOX/polypropylene hybrid
2. Silver Bullet III NOX/Alcohol
3. 3rd Generation NOX/Alcohol
4. LR-5
5. CPVC NOX Hybrid
Biprop #2

Biprop #3 Silver Bullet III held by Dave Griffith.

Dave prepares the Silver Bullet III for record-setting flight. Biprop #4

Biprop #5 Silver Bullet III being prepared for launch.

Lift off of Silver Bullet III to 17,000 ft. altitude test. Biprop #6

Biprop #7 3rd Generation R.A.T.T. motor being loaded.

Flight of 3rd generation R.A.T.T. motor. Biprop #8

Biprop #11 Static test of RATTworks L1000 Nitrous Oxide and Liquid Alcohol-Bi Propellant Motor

Fuel-Injected Hybrid

View the launch report for Silver Bullet 8, the fuel-injected hybrid (FIH).
RATTworks Newsletter, Issue 1 (13KB Word)

Video of two different FIH rockets, Silver Bullet 8 (1.6MB AVI) and an unnamed FIH rocket (1.5MB AVI).

View the assembly instructions for the FIH (1.3MB PDF).
Includes many detailed photographs.

Fuel Injected Hybrid preflight Silver Bullet 8, ready for flight.

Lift-off of SB8. Note the fuel-rich flame. Fuel Injected Hybrid flight

Fuel Injected Hybrid recovered The recovered SB8 after a successful flight. Show here is Bill Wood and Dave Griffith, the inventor of SB8. Bill Wood first proposed using nitrous oxide in hybrid and liquid rockets. Apparently, it works.

L700 Tribrid launch. (2.2 MB MOV) L700 Tribrid launch

K350/K500 Tribrid

Tribid composite photo

Static firing of the K500 "Tribrid".
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Static firing of the K500 "Tribrid"

Tribrid static #1
Ignition of the starter grain.
Tribrid static #2
Hybrid Mode (ABS/N2O)
Tribrid static #3
Tribrid Mode (ABS/Alcohol/N2O)
Tribird static #4
Bi-Propellant Mode (Alcohol/N2O). Note the nearly invisible flame, characteristic of this type of motor.

Graphical animation of motor operation by Andrew MacMillen.

Test Results of High Performance U/C Valve (543 KB PDF)

K350 Tribrid Thrust curve (58 KB PDF)
Note: You can see the transition from hybrid to tribrid at .55 seconds.

RATTworks makes history again!

On Saturday, February 13, 1999, at 12:00 pm, the people at RATTworks test-launched the first nitrous oxide fuel-injected hybrid. The rocket was a modified LR-5 liquid fuel rocket and the motor was a modified K240 hybrid.

Tribrid injector assembly
Top secret injector assembly.

Tribrid loading
Ted connecting the NOX
loading hose and igniter.
Fueling of the alcohol was done during assembly of the motor, and the nitrous oxide was loaded remotely with the rocket on the launch rail, ready for launch. At ignition of the igniter grain, the nitrous fueling line burned through as designed. The motor ran in hybrid mode for approximately one second, then the fuel plug burned through and released the alcohol. At that point, the motor was running in plastic and alcohol fuel mode, producing a ten foot long flame.

Approximately two seconds after liftoff, the plastic fuel was consumed and the motor was running in liquid-only mode. The visible flame was reduced to near zero, which is typical for alcohol motors.

The rocket seemed to kick into warp drive as its rate of acceleration quickly increased. Unfortunately, the rocket burned out of sight and the crew ran out of daylight before it could be found, with its onboard ALTACC accelerometer data. Estimated altitude was around 15,000 feet, total burn time was about six seconds.

Tribrid launch
Launch of the fuel-injected
liquid bi-propellant rocket.
Note the six foot long flame.

Dave Griffith & Tribrid
The inventor, Dave Griffith
This type of start-up sequence for nitrous oxide liquid-fueled motors will most likely become an advantageous way to go, as the motor runs extremely smooth and should not be subject to hard starts. Such circumstances can cause numerous problems, such as explosions, flame-outs, igniter blow-outs, back-flash, etc. In other words, a problem-free high power rocketry liquid motor appears to be in the works.

3 Phases of the Tribrid Rocket Motor
Photos by Gary Moratz Rocketography - 11/9/08

K700 tribrid - ignition
K700 tribrid
K700 tribrid - hybrid mode
K700 tribrid
Hybrid Mode
K700 tribrid - tribrid mode
K700 tribrid
Tribrid Mode
K700 tribrid - bi-propellant mode
K700 tribrid
Bi-Propellant Mode

The photos above show the 3 different phases of tribrid propulsion. Hybrid to bi-propellent mode is completed within a half second. Note the left over pieces of ABS plastic hybrid grain being ejected at the beginning of bi-propellant mode.

RATTworks: Precision Hybrid & Tribrid Rocket Motors RATTworks: Precision Hybrid & Tribrid Rocket Motors
RATTworks: Precision Hybrid & Tribrid Rocket Motors