Tuesday, August 25, 2009
We will be flying the last two days of the contest.
October 30 and October 31st at FAR. This gives us the maximum time to prepare and guarantees that we know what we are aiming for for given any tie breakers.
You can see the Xprize press release here
(I could not find it on the xpf site so I linked to Space transport news instead.)
Some notes on the other dates:
Masten has reserved October 28,29 so that means any not-yet registered teams could
fly on the 26t/27th in the Mojave area or earlier else where.
This in effect moves the registration deadline for any other teams up to
September 9th or September 12th
If Armadillo fails on the 12th-13th they can register to try again and just sneak in under the time window. In talking to others it somewhat clear that Armadillo choose the latest date that would allow them to try again.
Thursday, August 20, 2009
In spite of the whimsical picture and title this is a serious post.
I can make rocket parts, or I can buy rocket parts. I can grow my own fruit or I can go buy fruit.
I design embedded electronics as my primary profession. When I first started I built elaborate breadboards and test circuits, I even played with etching my own PCB's. Now I order pcb's from the prototype PCB vendor for everything. Even test circuits. What changed?
I'm much more experienced and my designs have a lot more experience behind them. I've learned what works and what does nott I can read a data sheet (including what is not in the data sheet, often the most important part.) I've also learned that spending the money getting a proper prototype PCBs and assembly is a more cost effective use of my time.
At home we have a peach tree, it grows wonderful peaches to the point that we are all tired of peach pie by the time it drops the last peach. There is a sense of satisfaction from growing your own. All the rest of our food we purchase.
When I started working on rockets it my attitude was more hobby and satisfaction from doing oriented. You can see from the old blog posts we built valves, gearoxes and even weird tanks.
As the project has matured and we've started actually doing work for customers I'm starting to realize the value in off the shelf stuff. My attitude is becoming more business like.
For a number of years now we have been sending drawings and material to thunderbird waterjet here in San Diego and having them cut out parts. We had the hemispheres for our tanks spun by AMS industries. Yet the vast majority of our parts have been fabricated by us for us. We don't generate elaborate 3D models and then fabricate the parts, we build a little, scratch our head and build some more. If we did not have in house machinging capabilities it would significantlyy impede our progress, having to wait for an outside vendor to fabricate every bracket and doodah would take forever. I think this lack of inhouse capabilities is one of the things that has slowed Masten down. Yet fabricating everything in house does not make sense either . Some things like the regen rocket motor I documented on this bblog were fabricated in house from detailed drawings. I think that was an error. I'm in the process of fabricating a new regen motor from stainless. I sent the drawings out for quote on MFG quote and was astonished at the price quote I got. The stainless part among the fruit is the first signifcant custom part we have not fabricated in house. Several more parts of that assembly are due soon. I can't imagine the nightmare of machining that part out of solid stainless, yet the vendor did a really good job for a very fair price. (I'll talk more about the vendor and ordering process when I get the full set of parts, so far I'm pleased.) One of the down sides is that our welder is going on vacation for 10 days and the ordered parts are going to just miss his departure, so we won't be testing much for about two more weeks.
Its not always easy to know what to build and what to contract out, I think its really important to have in house fabrication skills and equipment, but I also think we have erred in not sending more work out.
A final question for the peanut gallery, I'm 90% sure the vendor making these parts underbid the job. They had a couple of programming problems and probably scrapped more metal than their profit margin. As a business man I feel strongly in win win arrangements with vendors.
If the business is not win win then eventually the vendor won't be there next time you need him. Would you bring this up with the vendor and offer to cover some of their loss?
(Clearly by the terms of the quote I don't have to)
Saturday, August 15, 2009
... Its 10:30 PM I'm done for the day.
I Fabricated two beefy bearing holders and gearbox adapters for to the ball screws that will be the gimbal actuators on the silver beast. I also machined the ball screw ends and made a planetary spider to ball screw adapter. Its going to be a light, strong, fast and brush less gimbal actuator.
They are about 1/2 the weight and cost of the bug actuators everyone else is using. (assuming my time is worth zero, any realistic valuation of time and there insanely expensive.)
I also spent about 4 hours at Flometrics testing injector concepts for the Bi-prop and Steve an I built a flow visulization test setup. Many thanks to Steve! We used Flometrics Pistonless Rocket Pump as the drive the injectors, we could dial up any pressure from 50 to 400PSI and it just worked. It was flawless. Some of the misting spray nozzles have a maximum pressure, we discovered that one of the tested spray heads had unstable flow above its rated pressure. It was a swirl nozzle and it had cavitaion where the flow was really erattic. That was about the only real supprise everything else tested as one would expect it to.
I'll post some pictures of the tests. Sunday I hope to turn what I learned from the testing into a set of drawings to Fabricate the injector. I also ope to compeltly finish my actuators.
It was nive to spend the weekend making stuff rather than driving out to the desert/FAR.
Thursday, August 13, 2009
I'm lucky in that I was born in the united States. Our family has multiple cars, a house to our selves, more food than we should eat. Our standard of living by any real measure is better than any group in history. The United States has about 5% of the world population and consumes about 30% of its resources. Personally our family is probably above average in resource consumption even for US citizens. So I'm going to ask and answer a series of questions.
1)Are citizens of China, or Sub Saharan Africa inherently inferior to my family?
NO they are not,I believe all humans are born with certain inherent value.
2)Do they have a right to aspire to what I have.
Yes they do.
3)Do we think that global terrestrial resource production can be increased 6 fold from what it is now?
No I don't think that is reasonable outcome.
4)Is there any process where U.S citizens will voluntarily reduce there standard of living by a factor of 6. No I don't think that will happen.
5)Do we the U.S have the right to use force to prevent others from having what we have?
No we do not.
6)Will some combination of conservation and increased production create a factor of 6 when adjusted for the ongoing population growth in the world?
This is the option that all the traditional "Greens" or environmentalists are betting on. They naturally feel that if we just cut back a little bit everything will be better. I just don't see it. It is such a violation of natural human striving tendencies I can't see getting to a factor of 6.
So unless you want to change the answer to one of the 6 questions above "we" the population of the world are in a no win scenario. Some things like good batteries and low cost fusion power could help significantly, but its not enough. Just imagine how much steel it would take to give every family on earth 2 cars? (Recent studies have shown that mass transit when fully accounted over the life cycle of the system are just as resource intensive as a small Car. )
Where will the additional resources come from?
Where can we do dirty industrial process where we don't soil the environment?
Where can we find unlimited energy?
Unlimited expansion space?
(Don't nit pick Unlimited in this context means several orders of magnitude more than we have now)
The only two answers are a 6 fold reduction in earth's population or expansion into space.
We are spending trillions on the assumed option in question 6 and simple math shows its not possible. Where are the trillions helping us expand in a way that can work?
Just something to think about....
Sunday, August 09, 2009
We tested again Saturday. This was the first time I was responsible for the FAA notification and not just piggy-backing on the FAR standard waivers. The Airspace at FAR is interesting. From ground from ground level to 1200 feet AGL we are in uncontrolled airspace. From 1200 ft AGL l to 18000 ft MSL we are under the FAA jurisdiction, from 18000fto to 50K ft we are under the jurisdiction of the Edwards 2508 restricted area. Since I’m under 1200 ft AGL for tethered (or free) flights I don’t need a waiver or authorization to enter controlled airspace. Since I’m not entering controlled airspace. Yet the new FAR 101.27 requires I notify the nearest ATC facility between 24 and 72 hours before the event. A lot of the stuff flown at FAR goes above the 18K limit so when I asked FARS primary Pyro op who to notify I was given the 2508CCB contact. They did not want the notification because we aren’t in their airspace. When I called the loacal High Desert ATC facility
ATC: how high,
ATC: Why are you telling me this.
ME:Can I have your Fax number.
ATC:Here it is xxx.xxx.xxxx
ATC:What am I supposed to do with the document your faxing?
ME:I don’t really know I just know I have to send it to you. It does not effect your airspace were chained to a 10000lb forklift.
ME: FAR 101.27 says I have to tell someone. I’m crossing my t’s and dotting my i’s.
ATC I see.
So I faxed the notification required of 101.27 to the High desert ATC facility.
A few weeks ago our FAA representative asked if he could come out a watch us fly so Wynn came out to observe our flights and flight preparation. We were all setup by 9 am and were attempting to do a 90 second Tethered hover. We had never successfully flown at that weight. We didn’t do it on Saturday either. You can see the heavy takeoff video here our vehicle is VERY light without payload or propellant we weight less than 100 lbs. Since we are using a low performance propellant so we need a lot of it so our weight with payload and full fuel is about 400lbs. This means that we have a 3:1 weight change in flight. From the video its obvious that with a 3:1 weight change we need to do some gain scheduling as we had plenty of thrust, plenty of control authority we just weren’t stable. We continued to do short hops until we had dissipated enough propellant to fly stably. We eventually got an absolutely perfect 65 second flight but that happened after the one remaining video camera ran out of battery. So no video. We will try again soon.
I think that Wynn (our FAA rep) was impressed with how remote the FAR site is. You just can’t get a feel for how remote things are by looking at google earth. Standing on site and seeing the total desolation in every direction gives you a better feel. I think Wynn enjoyed the show, I’m glad we got at least one successful flight off for him.
Thoughts on the stability issue: With a gimbals system the forces generated by the thrust vector scale directly with the motor thrust. With vanes the relationship is not so clear as one increases thrust one increases the density of the gasses within the cone that the vanes act in. So its not clear if the vector forces are linear with thrust (thrust is a good stand in for weight and a marginally good stand in for rotational inertia) or if they increase or decrease? Looking at the video this looks a lot like earlier problems where the differential gain was too high. I don't really know if I should just lower all the attitude gains or if I should vary the P,D terms differently.
I have not yet reviewed the data, I hope to do so this week.
I also added another wiggles video from onboard.
Saturday, August 01, 2009
Friday was propellant day, I was out at FAR all day.
- I received an order of 85% from XL Space.
- I built the forms for the base of the generator that will complete my processing facility.
- I fixed a leaky valve on the safety water supply pump.
- I built a frame to hold the Refrigerated air dryer up on a shelf off the ground to give more floor space.
- I cleaned up around the site a little bit.
One more long day to finish my processing facility and I’ll have three sources of propellant.
180 second status: I’ve put together both an order and a RFQ for stainless versions of the regen biprop motor to replace the dead aluminum one. After examining the dead motor its really clear that something bad happened in the region of the pressure port. It was more than a a bad weld. We either had the port through the wall leak fuel rich stuff into the cooling jacket or we have some kind of contamination there. On the next motor this is going The new motor will have an uncooled section thats identical to the top of the blue ball motor and will weld to a cooled lower section. There will be no joints through the cooling jacket wall.
Realistically we get one more shot at the 180 second motor and the way rockets go that has to be considered a hail mary.