Part 3, 22 October, 2004
By Mark Uitendaal and Leon Krancher
- Spectre II, part 1, 30 June, 2004
- Spectre II, part 2, 7 July, 2004
- Spectre II, part 4, 13 January, 2005
- Spectre II, part 5, 9 June, 2005
- Spectre II, part 6, 23 September, 2005
- Spectre II, part 7, 2 January, 2006
- Spectre II, part 8, 15 April, 2006
Disclaimer: all liability waved! The contents of this page is presented for informational purposes only. Do not try to recreate any experiments presented in this page. The NAVRO and the author of this article cannot assume responsibility for any use readers make of this information. In The Netherlands it is forbidden by law to own this type of propellant if you do not have an exemption of the "Wet Explosieven Civiel Gebruik" (WECG).
On NLD20 (3 September, 2004) we conducted a flight test with the Shock and Awe. The flight went very well and we have again some data to analyse. Our new igniter works very well in staging conditions. The separation and initiating the second stage went very well, so we are confident that we can use the same techniques in the Spectre II project.
Also this flight made clear where the stress point is in recovery. Because the horizontal velocity is very high at high altitude flights, especially with staging, we need an extremely robust recovery system. We have bought many metres of tubular-nylon which is normally used in mountaineering. This band has the advantage of being very strong and also zipper proof. The tubular-nylon we are going to use has a massive overkill, because it has a rupture strength of 25000 Newton.
Also the new concept of "shock absorption" has to be investigated. A shock absorber temporarily stores some kinetic energy of the components at the end of the shock cord. This absorber will be made of some sort of elastic material. During the staging manoeuvre and second-stage motor-burnout the rocket is going to experience some negative acceleration probably in the range of -3g. We don't want to loose some sliding components like the nose cone or fin canister in this stage of the flight so we are going to do some tests with nylon shear bolts. The purpose of these shear bolts is to prevent that sliding, but they must fail when we fire the ejection charge.
We are currently producing the bulkheads for the electronics canister. We started the project with them, because we can use them in the static testing of the shear bolt assembly. We have also made the grain casting moulds of the new 75mm motor. The nozzle moulds are currently ready. It is made by Benjamin Wilkosz and he did a perfect job as always. We are also finished with the camera hatch. Only this part will have to be laminated with glass fibre/epoxy to increase its general strength. You can see a picture just below.
In the next weeks we hope to make some progression with this motor and the manufacturing of the airframe, to have it ready for the static ejection test. Also a marriage jig must be made for our fin set. In order to have a very clear camera picture we need to minimize our rolling motion. Therefore the fins must be exactly aligned to the rest of the tube. To do this, we will construct some sort of jig in which we can position all our parts, before we attach and laminate them.
We have just finished the inhibitor mould. This is just a round tool of 63mm diameter to roll our paper inhibitors to the right size...
Progression on the booster! We have made a 75mm concrete nozzle with washer ring! It is just massive! The picture tells his own story! The nozzle is a single stage convergent/divergent (CODI) nozzle from quick setting concrete. It