Monday, November 24, 2008

Thanksgiving week...

While we all enjoy the company of friends and family during this thanksgiving holiday, don’t forget the men and women of our armed forces that may not get the chance to be home this holiday season. I’ve given something to LBEH for the last 7 years to try and help. Some bloggers have a tip jar, I ask that you send any tips there instead.


Offical comments on 2009 LLC


Friday, November 21, 2008

A Quick update...

My next rocket project is to finish up some test stand work for a paying customer I can’t talk about.

As for the LLC projects :

I’ve been exploring a number of catalyst options for peroxide. I’m looking at silver plated nickel screens, and commercial catalysts from several different vendors. These include the commercial catalysts from CPILINK that John Carmack was kind enough to send me. If that catalyst is still commercially available then its high on my list. All of the parts and pieces to build an electrically pumped biprop peroxide test have been ordered. I have all the parts on hand to both convert the 90 Second vehicle to a solid catalyst and to build a biprop version of very similar design capable of doing 180 seconds.

The plans for next years LLC have stirred a bit of controversy and I’m not sure what side of the debate I agree with. The basic problem is this: The LLC is supposed to be an impartial contest, yet you have the head of the Xprize, Peter on video telling John Carmack that they will expedite the 2009 contest so Armadillo does not have to wait a full year to win the prize. That was an astonishingly ill conceived video. Peter has a personal business relationship with Armadillo, so even if there are a million legitimate reasons to accelerate the contest and change its format, that one video could be used by anyone with an axe to grind to trash both the concept of government prizes and the xprize organization in particular.

I’d really like to see the 2009 LLC be a first to demonstrate at any location like the original Xprize. This would simplify the contest for all competitors as you would only have to get permission to fly in one location, not both your testing base and the LLC venue. It would also reduce the financial burden on the xprize organization as the local logistics would be resolved by the team and not Xprize. From a personal stand point It would improve our odds of winning the 2nd place 90 second prize and enable us to then switch our focus to taking a shot at the 180 2nd place prize when we were ready rather than at some specific date. . Unfortunately I’ve personally received enough private E-mail from multiple people just steaming mad about this that I can’t see the possibility of any change in the LLC format without it ending up in court.

The sad part about this is that after spending two years working on this I have a feel for the difficulty level and I don’t see that any of the new not yet flown teams have a shot at getting a 180 second vehicle ready by October, its just too hard. Other than armadillo we are the only currently registered team that has fired a motor to thermal equilibrium with the necessary performance to do 180 seconds (Our Lox Ethanol motor) and we have chosen to take a different direction.

Monday, November 10, 2008


90 Second Vehicle.

John Carmack was really kind and sent me some peroxide catalyst material Armadillo was no longer using. I’m going to rebuild the present motor with these cataylsts. I’ll try to provide some pictures. I’ve ordered some stainless parts and some sintered stainless screen to spread the peroxide out. I figure about 4 days of work and this will be ready.

Things to fabricate /do:

  • Fabricate New Motor upper section.

  • Revise my safety plan with no liquid catalyst and get the waiver extended/approved for this configuration.


180 Second Vehicle. #1

We have a pressure fed 180 second airframe 95% fabricated.  It will be a Peroxide RP1 biprop. To finish this vehicle we need to design a chamber and  switch to thrust vector controls. If we get the same percentage of theroretical perfomance as we got with our monoprop vehicle this will hover for about 195 secondds in blow down mode. If we put active presurization on the vehicle it will hover for 240 seconds. My friend Steve Harrington of Flometrics is dying to try out a liquid nitrogen presurization system modeled after the liquid helium system on the origional apollo lunar lander system.  So if we don’t quite get there from a performance stand point with blow down we will add this Ln2 system.

Things to acquire fabricate/do for this vehicle:

  • Fabricate a regen chamber. Currecnlty working on an aluminum design, have stainless and nickel designs sketched out, but will try aluminum first.

  • Fabricate TVC controls, both Masten and Armadillo are using Bug actuators, a bit pricey, but I’ll probably go that way.

  • Fabricate  valves usign the existing valve design(s) we have.

  • Start the paperwork process so we can do tethered flights in Jan/Feb time frame.


180/300 Second vehicle concept development work:

I’ve done a lot more modeling of a 4 engine electrically pumped vehicle. I really like the results I’m seeing. Even more I like the fact that the propulsion is almost 100% decoupled from the tank design.We are going to go ahead and purchase one set of parts to build 1/4 of the propulsion system. I’ve found a vendor for a positive displacment peroxide compatible pump that is the right size for a 4 engine pumped vehicle.I’ve alos found a vendor for the the motor and speed control of the approriate size.  If this works the parts could be easily transfered from a hovering  LLC vehicle to a 100Km+ capable reusable suborbital sounding rocket. If the all the LLC $$ had  been won this would be my primary project.  If this sounds interesting to anyone my priorities can be altered with the proper application of funds ;-)

Things to change in the flight test program:

The Rough terain forklift worked really well so it is going to return for an encore performance. Since construction is slow in california the rental prices have really fallen. One problem with the testing I did for the 90 second vehicle was the cost of each full fuel test. I’m going to modify the vehicle(s) to carry lead bricks to simulate a full fuel load. This way I can verify I have the necessary propulsicve performance without burning up 2K of peroxide for each test. I can put in a single Jug of peroxide and time the hover with the weight and know if I have the proper performance.


Monday, November 03, 2008

Lessons Unlearned

In 2007 we tried to build a 4 engine Lox Ethanoal rocket. When we were done it had 39 valves and was just wayyyy too complicated to work reliably. My present 180 second fantasy goes back in that direction a tiny little bit. If youmake the following assumptions:

  • Electrically driven peroxide and RP-1 pumps.

  • Catalyst decomposition with lots of pressure drop for relability

  • 1000 to 1200 PSI feed pressure

  • 700–800 PSI chamber presure.

  • Four engines.

  • 80% of theoretical ISP.

Then what drops out is

  • Off the shelf small aluminum frame hydralic pumps (Possibly with one section redone with stainless gears)

  • Off the shelf  Pump motors,batteries and gearing from  high end 600 sized RC helicopters.

  • Hover times of 240 seconds+ with payload.

  • A rocket with two manually operated valves (Vent and drain)

  • Tanks with a pressure safety factor >4 so humans can be near the presurized rocket.

  • A rocket with no active valves. (All control is from the pump speed control)

  • Precise Mixture control.

  • Safety system is all electrical, power stops to motors and down it comes.

I’ve ordered a pump to evaluate its peroxide compatibility and life time running unlubricated.  The pump was only $72.