Performence Testing of the New Rotor Tip Rocket System
The new system with an atmospheric peroxide tank and blade integrated cat.packs, described in my previous report has now been performence tested and matured.
The system is capable of spinning up the rotor to 300 rpm in less than a minute. This speed allow for zero roll take offs, and also true verticle take offs, with a gyroplane! The fuel consumption for achieving this speed was around 1 liter (1/4 gallon) of hydrogen peroxide 85% conc. The blade tip temperature was estimated to have been maximum 70 oC (160 oF) during rocket operation.
1. Tests, using the air hand pump at start
Such a test can be seen on the movie file in the previous report. The rotor spinned up to around 100 rpm only and could not accelerate any more. The reason was probably that there was a lot of gas in the lines. The rockets were “spitting”.
I than drilled up the nozzle throat diameter from 4.5 mm to 6 mm. This should give more thrust at low pressure, but it did not help much; the rotor speed increased to around 140 rpm only.
2. Tests, using both the air hand pump and a new peroxide hand pump at start
With this starting method it was easy to achieve 300 rpm and more!
One test is shown on this movie file: Test with peroxide hand pump.
The new peroxide hand pump and the check valves before and aft the pump can be seen on the below picture. Also the tank with the air hand pump can be seen
Remaining Problems and Conclusions
Atmospheric Tank System.
There is still a “spitting” tendency. If one stops the hand pumping, the fuel supply to the rockets is lost after a few seconds only. My original goal, that the rotor should work as a centrifugal pump is still only partly fulfilled, because the rotation helps to increase the pressure substantially, but it is not maintained over a longer period of time, without the help of hand pumping. I believe this is because of too much gas in the lines. This gas can be there of several reasons. One such reason can be that decomposition is taking place in the lines already before the cat. pack.
My conclusion is that the system is already matured enough to be used for pre-rotation and zero roll take offs with gyro planes. For continuous rotor operation, like for a helicopter, the CO2 pressurized fuel tank, described in previous reports, is still to prefer.
The new rockets are working very well! The thrust is as expected and the decomposition is complete. I will now start to offer these rockets for sale, in case someone out there is interested in testing the system.
Surprisingly enough the blade temperature does not become higher than maximum 70 oC (160 oF). This temperature is an estimation only, because I have not yet been able to measure directly at operation. Anyhow, immediately after operation I can put my hand on the blade tips without being any near of burning myself. I have some PVC tape at the tips that is still completely unaffected of any heat. It still looks as new. The same goes for the painting..
After about 15 minutes of accumulated rocket operation, the activity of the silver screen cat.pack is still unaffected. No need of any re-activation of the catalyst so far!
The silver screen catpack at installation can be seen on the below picture.
Two modifications will be made on the next set of rockets to be fabricated:
* The “counter flange” to the “nozzle flange” will be made thicker, because the present thinner flange tends to bend at operation and the rockets start to leak in the flange. As it is now, I have to tighten the bolts between each test.
This so called "counter flange" is seen on the above picture.
* The prototype rocket cat.packs have the diameter 20 mm. They fit well in NACA 8H12 rotor blades with 8 inch chord. I plan to make the next set of rocket cat.packs with 18 mm diameter, so they fit better in the more common 7 and 7.5 inch chord rotor blades.
This article was updated on November 30th, 2006