Racing Rocket Engine
We have built a racing rocket engine, intended for installation on a small vehicle like a bike or a Go-cart.
Engine parts:
1. Composite Compressed Air bottle, 1.1 liter, 300 bar
2. Pressure control regulator.
3. SS Peroxide Tank 9 liters, 22 bar, with safety relief valve and pressure gauge.
4. ¾” flow control ball valve, SS
5. Catalyst package chamber. Di = 81 mm.
Catalyst package at testing was 37 discs of solid silver wire screens plus 95 discs of silver plated SS screens.
6. Rocket Nozzle. Throat D = 38 mm. Exit D = 52 mm
The engine has the following calculated performance at maximum peroxide pressure, 22 bar, in the peroxide tank:
Thrust 142 kp =1390 Newton
Peroxide consumption 0.95 liter/second. H2O2% =85
Running time with full tank, 9 liters 9.5 seconds
Performance calculations here
Static tests in test stand
The engine was tested in the test stand seen on the below picture. The rocket thrust was measured by the stand was pushing on a digital balance, placed between the stand and the cottage porch seen on the picture.
Three tests were made:
| Test 1 | Test 2 | Test 3 | |
| Peroxide Tank Pressure (appr.) | 2.5 bar | 4 bar | 8 bar |
| Measured Thrust (appr.) | 5 kp | 25 kp | 50 kp |
| Runtime with 9 liter peroxide fuel | 80 sec | 45 sec | 24 sec |
The tests can be seen here:
Low pressure test, 80 sec runtime
8 bar,50 kp,24 sec runtime
The conclusions from these tests are:
* The engine is running clean with no visible plume. That means the decomposition of peroxide is complete.
* The thrust at different pressures is as expected. That means that the calculated performance of 142 kp can be expected at maximum tank pressure, 22 bar.
Racing Performance Calculations
We have prepared an excel program for estimating the performance of the vehicle at racing. To download the program , click here
The first page is calculating fuel consumption, acceleration, top speed and travelled runway distance and time, considering no aerodynamic drag and no friction losses.
Input numbers are rocket thrust and peroxide volume in the tank.
The second page is calculating the “braking” force caused by the aerodynamic drag. The drag is needed to be subtracted from the rocket thrust to estimate the real performance of the vehicle.
One calculation example:
Input:
Thrust 50 kp
Fuel in tank 4.5 liters
Weight of vehicle 120 kg
Calculated performance (at zero drag):
Travelled distance at end of rocket run time: 0.25 miles (Standard Drag Racing Distance)
Top speed after 0.25 miles: 198 kmh (124 mph)
Time for travelling 0.25 miles (from stand-still): 13.4 seconds
The performance will be limited a bit because of the aerodynamic drag (page 2 in the program), but the thrust can be increased to more than compensate by increasing tank pressure/rocket thrust.
At estimated max thrust, 142 kp, we believe it is possible to break most world records for small vehicles!
This article was updated on August 26th, 2009