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Sunday, August 31, 2003

Armadillo Aerospace News: FMC 50%, Spring cannon, Misc
chabot imageWe received four drums of 50% concentration rocket grade peroxide from FMC. It came with the restrictions that we can’t concentrate it or use it for flight tests, but it will allow us to rule out catalyst poisoning due to the food grade peroxide in our mixed monoprop tests. If our problems go away with the better peroxide (and we can’t attribute it to any of the other changes we are making), we will have to negotiate with FMC about flight testing, or have Don Stark run commercial peroxide through his deionizer for us.
The FMC propulsion grade 50% registered 5 ppm on the TDS meter, compared to 18 ppm for the Solvay food grade 50%, and 232 ppm fpr the FMC technical grade.
We also got 20 gallons of lab grade methanol to use in place of the industrial methanol we have been using. Both read 0 on the TDS meter, but the lab grade may have less non-mineral contaminants. It is one less question for us in the future testing. Read More

Wednesday, August 27, 2003

Scaled Composites news: Second glide flight of SpaceShipOne.
chabot imageObjectives: Same objectives as the aborted flight 31LC/04GC earlier today. Second glide flight of SpaceShipOne. Flying qualities and performance in the space ship re-entry or "feather" mode. Pilot workload and situational awareness while transitioning and handling qualities assessment when reconfigured. As a glider, stall investigation both at high and low altitude and envelope expansion out to 200 kts and 4 G's. More aggressive, lateral directional characteristics including adverse yaw, roll rate effectiveness and control, including 360 degree aileron roll, and full rudder side slips.
Results: Clean separation from launch at 48,200 feet and 105 knots, 8 miles north east of Mojave. First maneuver was a full stall, resulting in 70 KEAS at about 19 alpha. Good lateral control at minimum speed with ailerons and even better with rudder allowing timely control of roll-off tendencies. Second maneuver was unlocking the wing and commanding the full feathered mode (65 deg wing/tail jackknife). Transition to the feather mode occurred at 43,000 feet and 90 knots. As the tail booms and aft wing transitioned upward, the vehicle body smoothly pitched up and then returned to an approximately level pitch attitude during about 70 seconds of fully-feathered descent. The pilot noted the expected airframe buffeting and found the ship was very stable at an angle of attack of about 70 degrees. He was able to turn the vehicle both left and right with either rudder or aileron controls. As expected, full pitch control inputs had little effect on the flight path. Average sink rate was greater than 10,000 feet per minute. Reconfiguration back to the normal glider mode occurred at 30,000 feet with a positive wing lock indicated by on-board instrumentation and cameras. Third and forth maneuvers were the airspeed and G envelope expansion which were flown without incident. Fifth maneuver was roll-performance, which resulted in a low amount of adverse yaw but lower roll rates than expected. Three-axis vehicle flight characteristics again showed close correlation to the vehicle simulator. Shifting winds at the field during later stages of the descent allowed the pilot to exercise the avionics' flexibility for landing cuing back to Runway 12 vice the planned runway 30 at Mojave. A smooth touchdown was made ten and a half minutes after launch. The video cameras mounted on the spaceship recorded dramatic views particularly during the unique feather maneuver. Observers in the chase Starship were treated to a closeup bizarre view of the spaceship plunging downward in a rock-stable near vertical feathered descent. First public showings of these videos will be on 26 September at the annual SETP symposium in Los Angeles. Read More

Scaled Composites news: Second glide flight of SpaceShipOne (Flight was aborted)
chabot imageObjectives: Second glide flight of SpaceShipOne. Flying qualities and performance in the space ship feather mode. Pilot workload and situational awareness while transitioning and handling qualities assessment when reconfigured. As a glider, deep stall investigation both at high and low altitude and envelope expansion out to 200 kts and 4 G's. Lateral directional characteristics including adverse yaw, roll rate effectiveness and control including aileron roll and full rudder side slips.
Results: The flight was aborted about 20 minutes before launch, after a GPS navigation malfunction occurred in the SpaceShip avionics system. The mated pair continued to test other systems including Spaceship fuselage heating, then returned for a mated landing. Read More

Sunday, August 24, 2003

Armadillo Aerospace News: Plumbing complete, suit pressurization
chabot imageAll engine plumbing and wiring is complete on the big vehicle. We loaded water into the big tank and tested all the valves, with pretty good results. Our distribution manifold has a leak in the weld which will need to be fixed, and the fill port 2” threads were loosened during the filling process when the giant hose pressurized itself and whipped around a bit. We can’t just weld the inlet fittings, because the check valve is stainless steel, while the rest of the hardware is aluminum, so we may need to weld flanges onto each side and bolt them together.
If there was catalyst in the engines, the big vehicle is now capable of flight, but we still need to get the drogue cannon worked out before it can land properly. We also need to make some honeycomb panels to protect the base of the tank from exhaust at launch, but we are running out of things to do on it. The base will need a fair amount of rework when we put the full size engines on it, but the basic layout will probably remain the same. Read More

Saturday, August 16, 2003

Armadillo Aerospace News: Miscellanious, Cabin temperature tests, Open catalyst tests
chabot imageWe performed some very interesting tests, running engines with the nozzle removed so we could directly watch the catalyst surface during operation.
We tested the 4” thick ceramic catalyst on the new spreading plate engine first. In tests with the propane preheat, we still needed 10 20 mesh screens between the spreading plate and the catalyst block to avoid any noticeable hot spots as the catalyst heated. This was a bit of a surprise, because that was the same number needed on the previous spreading plate that had only a quarter the hole count, with holes four times as big.
We used a small cavitating venturi to limit the flow to about 140 g/s, since the engine was obviously not going to have any back pressure.
We wound up with a richer than usual propellant mixture, because I didn’t bother pumping more peroxide out to make it perfect, but there was a HUGE amount of flames coming from the catalyst pack on our tests, especially considering that we were only flowing the equivalent of about 50 lbf thrust worth of peroxide if there had been a nozzle on. I’m curious how much of the difference is due to the richness versus the fact that nozzle exhaust is a lot cooler than catalyst exhaust. Read More

Sunday, August 10, 2003

Armadillo Aerospace News: Russian space suit, Small vehicle work, Big vehicle work
chabot imageWe bought a used Russian space suit on Ebay. Our plan has always been to have a pressurized cabin, but an extra layer of safety is probably justified if we can get this working without too much trouble. It has a few holes that will need patching, but most of the material looks in good shape. We will have to fabricate some adapters to go from the Russian fittings to AN fittings, but that shouldn’t be a problem. The big issue is that the gloves are missing, even though the offer explicitly had them. The seller claims they were sent in a separate box, but it has been several additional days, and it hasn’t arrived yet. Hopefully, he just forgot to include them, and they are on the way from Russia now, and we aren’t actually being ripped off…
Related to this, we did some cabin airflow tests on Saturday. In 100+ degree Dallas weather, being inside the cabin even with the hatch open for very long gets uncomfortable pretty quick, which we notice when doing electronics work inside. Now that we have a tank of breathing air and various flow meters, we are able to start testing our plan of using open loop air venting to provide both breathing air and cooling. We ran a hose from the air bottle into the cabin, and closed everything else up. We didn’t actually seal it to the point that it pressurized, but it was reduced to venting the air past a few known places. With 1 CFM of air flowing out the hose at your face, you don’t have any trouble breathing, but the cabin does continue to rise in temperature due to body heat. You could deal with it for an X-Prize flight, but it will probably be better to increase flow until a comfortable steady state is reached. We will probably do some more precise tests with thermometers, timer, circulating fans, and increased flow rates next week. Read More

Thursday, August 07, 2003

Scaled Composites news: First glide flight of SpaceShipOne
chabot imageObjectives: First glide flight of SpaceShipOne.
Results: The space ship was launched at 47,000 feet and 105 knots, 10 nm east of Mojave. Separation was clean and positive with no tendency to roll off or pitch bobble. An initial handling qualities evaluation was very positive, supported close correlation to the vehicle simulator and with that confidence, the first flight test cards were executed as planned. The flight provided handling quality and performance data over 60% of the expected subsonic flight envelope from stall to 150 knots. Trim sensitivity, stick forces, control harmony and L/D performance were all as expected. The on-board avionics and energy management cueing displays performed flawlessly, the gear extension rapid, and the vehicle made a smooth touchdown at 7:56 local on Runway 30 at Mojave. The entire flight, from launch to landing, was viewable from the ground and SpaceShipOne with its unique planform was intriguing to watch as it cut gracefully through the air and was put through its paces. See photos in the Tier-1 section. A special thanks to Robert Scherer, www.bobscherer.com for his flight test support and his beautiful Starship that provided primary chase for this milestone event. Read More

Saturday, August 02, 2003

Armadillo Aerospace News: Engine work, big vehicle work
chabot imageWe are seeing reduced catalytic activity in our test motor, which is worrisome. There are several possibilities:
It may be poisoning from the stabilizers in food grade peroxide. If true, it should be possible to clean.
It may be soot deposits from the propane preheating. That should also be cleanable, and possibly avoidable with lean preheat or hydrogen.
It may be a degrading of the mechanical structure, allowing more channeling around the outside. Welding in the anti-channel rings should help.
Worst case, it is an actual stripping of the platinum from the support base. We may have aggravated this with some preheats that got out of temperature range, but if it is stripping due to fluid flow, all we can do is make sure we even out the flow as much as possible.
We welded two stainless AN fittings to the top of the engine to allow us to plumb in the propane or hydrogen and forced air without going through any pipe taped connections. This turned out to be a bad idea, because the air and fuel did not mix well before flowing through the spreading plate, resulting in a very rich mixture on the side by the fuel, a very lean mixture on the side by the air, and a very hot stoichemetric mixture near the middle, which melted some screens. We capped the fittings and went back to mixing the air and fuel together above the engine. Read More

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