Monthly Archives: December 2014

Airfoil Modelling

Testing the flight physics one thing that struck me was that beyond the critical AOA for a given airfoil we were simply setting the coefficient of lift to 0.  I think the reason is that most of the charts only continue plotting maybe 5 degrees beyond the critical AOA.  However, I found a source for a symmetrical airfoil (no camber) which was taken all the way through 180 degrees of AOA!

cl-vs-alpha-180deg[1]

The lift coefficient pretty closely follows a f(x) of sin(x/90*pi-0.04)+0.04 except for in those laminar flow regions from alpha 0 to 25 and 155 to 180. Although the drag is absurd at 45 degrees AOA, the lift produced is almost equal to that at the critical AOA of 15!

Mining Tier Atmosphere

So I was coding the scale-height-based density calculations and to verify some of the calculations I ran it at 60km and ended up with an atmospheric density equal to that of Earth’s.

However, I ran it again at 50km and the density is twice as much already!  At 35km (where we parked the first extractor) it is almost 7 times the density as it is at sea level on Earth.

fig15d3

It looks like we are at the 100 PSI level at 35km. As long as there is an inert gas like Helium making up 95% of the volume it is survivable. You would have to carry an oxygen breather which exhausts the CO to the atmosphere.

Long-term exposure to that pressure will cause aseptic bone necrosis similar to underwater exploration here on Earth.  The deep-dive record is above 30 atmospheres, we are only talking about 7 atmospheres here.

FADEC Tests

Quick demo to show you my progress. The needles don’t move yet but the digital displays for the left engine are working. FADEC will start the engine, stabilize at ground idle, then I run it up to a full power static test, then back to ground idle, then shutdown.

A lot is going on behind the scenes simulating these 6 different engine components and the airflow… I would wager that there isn’t any simulator out there that takes it this far!  😉