Wednesday, September 19, 2007

400 Days till XPC 2008

I will boldly predict that there will be NG-LLC prize money for 2008. We only have ~400 days until the 2008 XPC, 280 days till the FAA permit app must be accepted. What are our plans? In no particular order...

1)Simplify.
Make one valve work, not two,
Go to blow down pressurization (for at least the 90 sec vehicle.)

2)Add more diagnostic automation.
Add some more feedback to the open loop vales so we can automagically determine their health.We need both position and current feedback from each valve. I may convert the valves to www.openservo.org derived control electronics.

3)Build a more robust vehicle.
Most plumbing, stainless not aluminum.
sturdier landing gear.

4)Find a more benign transport system.

5)Try other fuels and gasses
IPA (cleaner) and E85 cheaper.
Do at least one burn with 100% Nitrogen pressurization.
With our long thin tanks it might not be as bad as it is for Carmacks Spherical tanks. I've been told that a shot of He followed by N2 pressurization is not bad. the Russians use Nitrogen to pressurize their Lox tanks, and Nitrogen is a Lot Lot Lot cheaper than Hydrogen.
(Self presurized Lox might be similar....)

7)Put better data logging software in place.
( I write embedded S/W for a living and the shoemakers kids have no shoes.)

8)Convert the simulator to a hardware in loop tester.

9)Make the control system fly the helicopter, and publish ALL the results.

10)Try a impinging injector rather than a pintile.

11)Try Charles Pooleys Lox pre-burner idea.

12)Build and leave set up a good valve and injector flow test setup.


9 comments:

Anonymous said...

That's the spirit!

... and you probably labelled the tasks as: (necessary to compete at LLC), (increases odds of winning at LLC), (nice to have if time allows)... Since time will probably run out again next year :)

Like happened with some of this years competitors, even though they were doing it fulltime with bigger crews.

Well, good luck!

Anonymous said...

Hey! Check out http://www.helicycle.com/BJ/q11.htm

Helicycle is a kit helicopter. The page is about trailering the helicopter.

John Carmack said...

I would encourage you to assemble a complete backup vehicle, so you have one designated for level 1, and the other for level 2. A functional backup vehicle is the best collection of spare parts you can get.

Blowdown for level 1 and pressurized for level 2 is sensible.

Expect nitrogen pressurization to give some odd results during testing. The higher the pressure, the more it is going to cause problems. 50 psi for a pump fed rocket is one thing, but 300 - 400 psi for a pressure fed is something else. You can make hot flamey stuff just fine with nitrogen pressurization, but things aren't going to be as consistant, and you will wind up with a noticeable amount of extra weight. I really don't reccomend it...

We spent a lot of time on lox preburners, and basically concluded that for a throttled rocket engine you need to throttle the burner fuel, which adds an extra level of complexity.

Peter Lund said...

I hope you get around to items 1, 2, 3, 4, 7, 8, 9 before you even look at items 5, 10, and 11 ;)

Steve Harrington said...

I think you should work on altitude, airspeed, long range telemetry, operation in a vacuum and staging, instead of duplicating Armadillo's propulsion and attitude control efforts.

K.L. said...

I don't get your point Steve.

If you consider a very small team and a quite limited budget, isn't a LLC capable vehicle a very logical starting point? (considering there's a possibility to win some money while at it.)

I think it's very important to have a clear goal with any kind of development work.

Even if your idea is to aim for altitude (100km? whatever...) I can still see the point in working with low altitude _reusable_ vehicle, before going to the more demanding altitude-related issues. (Taking one step at a time.)

The fact that Armadillo has done it, doesn't mean the goal isn't worthy anymore. To the best of my knowledge, there aren't that many current VTVL-vehicles capable of LLC performance.

And if history gives any indication, there will be many failures among the ones trying at the moment. Having one group more is certainly a good thing.

I think the Unreasonable team has chosen an excellent goal. Keep it up!

Anonymous said...

Let's see, Armadillo spent about a million bucks and 7 years and they have not achieved shit for altitude.
Level 1 amateur rocket enthusiasts routinely go higher. Why have they avoided altitude? because the refuse to have anything to do with the aerospace engineering, preferring the cut and try method, which takes forever and costs alot. If Paul tries to duplicate their efforts, it will not be easy, because IT AIN'T EASY. High pressure LOX at 328 below zero causes trouble, Rocket exhaust at 3000 above causes trouble, getting it all to work is a pain. Then you have to get the attitude control system to work. By now you are doing the work of 6 engineers at big aerospace, and you have many more topics (aerodynamics, structures, vibration, orbital mechanics, etc) to figure out.
The trap these alt-space guys keep falling into is thinking they can do it all themselves. Then they burn out and give up and no-one benefits from their efforts.
A team effort is what is required, with each company doing what it does best and selling it to the system integrator, who builds a system which is the result of a consensus design of the major contributors. Sure it smacks of socialism but it will get an orbital rocket working, and it won't be a cheaper version of a Delta II. The mindless cheerleading or various people is great at feeding the Alt-spacers ego, but if they never get past a ground test of a workhorse engine, so what?

Anonymous said...

anon. Check out your facts. "team effort... system integrator..."
These guys are going for NG-LLC which has nothing to do with altitude or going to orbit.

There's a few million$ reasons to go for it...

As for Armadillos taking forever and costing a lot, we couldn't disagree more. Your quote of 1 mil. given to the traditional players would produce absolutely nothing of value, and sure they'd burn it in a few weeks or months.

"IT AIN'T EASY"
No Shit, Sherlock. If it was easy, there wouldn't be a 2mil$ prize purse in the first place.

What goes for cheerleading, there seems to be a large crowd of NAYSAYers as well. "It can't be done", "useless if not going for altitude", "takes forever"... Pick your lines dude. Being a pessimist and saying it can't be done is the one SURE recipe for failure.

"The trap these alt-space guys keep falling into is thinking they can do it all themselves. Then they burn out and give up and no-one benefits from their efforts."

Don't know if you're talking from personal experience or not, but yeah sure it's possible. One more reason to have more individual groups than just one single...

Just to point out the what AA and Breeds are doing, being open and reporting it all (mostly). Means that if these guys fail, the next bunch that comes along may learn from the priors. (yeah, probably being an optimist again, sorry for that. I think it's best if we just say it's too tough (tm), and give it up.)

Anonymous said...

"The trap these alt-space guys keep falling into is thinking they can do it all themselves. Then they burn out and give up and no-one benefits from their efforts."

I don't think that's true at all. OK, so if AA or Paul don't succeed, there is no guarantee others will learn from them, but, for example, Xcor is actually commercializing their efforts in the form of the engines for the rocket racing league. Money going into rocketry is *good*, and may well lead to bigger and better things.

Also, couldn't you call Burt Ruttan "an alt-space" guy? He did pretty good. Hit the edge of space, made some money, signed some contracts, and got bought out by big-money aerospace. He moved mainstream aerospace along.