Well, we have all been amazingly busy around here these last weeks. Building a VTVL rocket vehicle turns out to be quite a challenge, unsurprisingly (especially with an engineering staff of 3). We have managed to prove to ourselves, at some times quite painfully, that the devil is indeed in the details. Having a solid design is certainly an important foundation for any project, but the path between the drawing board and operational prototype is a long and arduous one.
Despite this, we have had significant success all over the place. It turns out that, much like with our engine development, we are fairly adept at getting components on line and functioning – or proving that they won’t. Thankfully, we are now at the point where just about every part of our vehicle has been received, assembled, and thoroughly tested at the component and sub-system level.
We have put our engine control computers together and have finally worked all the bugs out of the electronics hardware. This has allowed us to get to the point of converting our engine firing procedures over from the old PLC based system on our test trailer to the micro-controller based system of our flight hardware. The result is as good as we had hoped, and the engines operate well with the new system. I would offer some video, but as it turns out Mojave’s notorious wind kept knocking our camera’s tripod over during that phase of testing.
In the process of testing this, we have uncovered a small problem with our throttle valves. It appears that, while the valve actuation scheme we were planning on using works OK, the performance is not quite where we would like it. The concern we have is that when we try to dynamically control the vehicle, the throttle response will not be rapid enough to prevent some degree of oscillation. We are currently investigating some straightforward solutions to the problem and hoping that they will be sufficient. If not, we may decide to take a first stab at flying the vehicle with the current system anyway and see how real the problem is. Nothing shuts up a room full of quibbling engineers like empirical data.
On the subject of arguing engineers, we have solicited the help of our EE neighbor here in Mojave, Brian Bernhard (Bernhard System Corporation). He has been extremely helpful in our attempts to get our control electronics working with the sort of reliability we feel is important. Subtle 2nd order effects can play havoc on a complicated electrical system – especially when it is being implemented by two mechanical engineers. Having Brian’s expertise on hand has been indespensible in our progress thus far.
As many of you who read this blog occasionally may have started to deduce by now, we are not meeting the schedule we needed in order to field a viable entry for this years Lunar Lander Challenge. While this is disappointing to us personally, we have always maintained (and most of the reason we haven’t talked much about it as of late) that while the competition was something we would love to participate in if it lined up with our development path and schedule, it is not our company’s main focus.
While the competition is still close enough to our intended development path, our schedule has been forced back by several hitches in design implementation. As a result, we have decided that it is not something we are going to attempt this year. Best of luck to John and his crew at Armadillo, It seems like they have a very good chance of claiming at least some of the prize money. Despite this, we do still intend to attend the competition and perhaps do some rocket demonstrations of one type of another.
Independent of our progress on a vehicle capable of participating in the competition, we have actually seen the progress on our overall vehicle architecture accelerate in some key areas. Some of the problems that we have been forced to solve with the idea of attempting the X-prize competition have resulted in systems that are much more robust that they originally would have been at this point, and are closer to systems that we will actually use to get to space.
All in all, our progress over this last month has been rapid. While it is hard to forecast things like flight dates with some non-finite concerns still lurking, we can say that we will be attempting to fly “soon”. One thing that is important to remember is that, while we all want to see the vehicle fly and move into that phase of testing, what we all really do not want to see is haste result in unnecessary expensive failures.
Until next time, Ian…