How we roll

teststandwheelie
After topping off liquid oxygen, the Lynx propulsion test stand is wheeled into place for a cold flow test.

Lynx has been engineered from day one to be as efficient and cost effective as possible for daily, routine flight. The all-composite construction, 100% reusable engines, non-toxic liquid propellants, and piston pump technology all allow Lynx to achieve its flight objectives without the use of a carrier aircraft. This reduces the potential for failures and results in reduced overhead and turnaround time, lower cost per operation, and a safer flight.

Such efficiency and effectiveness also extends to our testing through seemingly small changes. Just about everything at XCOR is on wheels, including our test stands. With no fixed test facility we can test at our remote location in the morning, be comfortably back in the hangar the same afternoon, and working on modifications for another test the following day.

Wheels on test stands also have a positive impact on our “build a little, test a little” approach, including added effectiveness in work culture. With test stands on wheels, our people are able to operate inside the hangar and out of the elements, with all the benefits of cost, comfort and safety that entails.

Convenient access to the test stand also increases productivity. Engineers who design parts can work on the test stand alongside shop technicians, and machinists can be more involved with the integration of their parts. In our experience, everything works better, is completed faster, costs less money, and has fewer maintenance issues than more traditional organizations with less integrated teams.

Tomorrow you get to ask “what is a schlieren?” and yes, you will have an answer!

XCOR Lynx: DIY Aerodynamics


Engineer Mike Valant drives an XCOR wind test truck back and forth on the taxiways of the Mojave Air and Space Port during a test series.

In 2009 XCOR built a highly precise sub-sonic wind tunnel test model of the Lynx. For some preliminary data before actual wind tunnel visits, we ran tests using our ‘DIY truck tunnel’ as shown above. The truck and its fixtures include precisely instrumented appendages, structures and bit of computing and data recording capability. We also used the truck tunnel after the sub-sonic wind tunnel tests to experiment with some additional design features before returning to the real tunnel a second time.

By the way, this is not the first time that this particular technique has been applied in Mojave and “other places” in the Antelope Valley for aerodynamic development. We wish we could say we invented this technique but we did not. It has been used for many years by both neighbors in Mojave and neighbors to the west and south of us.

Stay tuned tomorrow as we answer your questions and update you on where you can find us on the road!

Build a little, test a little


XCOR’s Derek Nye and Ray Fitting prepare the Lynx truss for a test day.

XCOR follows a rapid design-build-test approach to developing new products and systems critical to the success of all XCOR programs. We excel at the fast hardware design, build and test of non-toxic liquid propulsion systems. This includes our Lynx main engines, as discussed last week. While non-toxic systems are critical to the overall safety of the Lynx system, they are also vital to the low cost of operation and ownership of Lynx.

“Build a little, test a little”

This “build a little, test a little” approach allows for many Lynx concepts to be evaluated, physically validated and changed rapidly using inexpensive and practical analysis and test methods, rather than relying solely on costly and time-consuming modeling and simulation. It also allows for other projects to generate serious results.

For example, other programs have received multimillion dollar contracts to study pumps without building any hardware. Eventually, a pump may be produced for many more millions of dollars. On the other hand, over a period of 2 years and at dramatically less cost, XCOR has worked with ULA to produce a working liquid hydrogen pump that demonstrates convincingly that it will work for a similar-sized engine with much higher reliability and reusability, and again, at far lower cost. Such outcomes are possible due to frequent and routine testing followed by fast iterations. This produces truly innovative results, and a serious increase in safety and reliability.

When fast iteration is pursued, XCOR focuses on critical operational parameters and requirements for propulsion such as low production costs, ease of maintenance, long life, full reusability and long term producibility. For long-term producibility, we are designing to anticipate the related techniques, materials and processes that may be readily available 20 to 30 years from today.

There are further critical elements, and by focusing on these parameters we drive down total cost of ownership of our systems through upfront procurement cost, maintenance man hours per flight, vehicle turnaround time, life of the product, cost of replacement parts, and reduced support crew and equipment. This positive feedback loop is a benefit to our customers, but also enables enhanced safety. The lower cost of the system to operate, the more that system may be flown. The more it is flown, the more we learn. And the more we learn, the safer we can be.

Design-build-test and XCOR culture

Mobile test stands also feed into our approach. With only minimal fixed test infrastructure at remote locations, we eliminate the need for separate crews reporting to different parts of a larger organization. This fosters a unified design-build-test culture in our company. All equipment and personnel return to the hangar at the end of each test day. Propulsion systems under test are worked on in the comfort of the hangar with all tools and personnel available, then taken to the nearby test site. All engineers and technicians work together toward the common goal of a working product.

Nothing is duplicated, we are one team, costs are contained and safety improves yet again.

Tomorrow: The importance of an actual Lynx cockpit engineering model