# 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!

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.

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.

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!  😉

# Holiday Update

I found these maybe a year ago and put them on my BOM waiting list. Maybe a month ago I figured I better order them. The vendor sent the wrong item. When I contacted them to get the right item they find that they had no more in stock! I found another vendor that had them but one of the units arrived looking beaten with missing screws on the camlock. That seller finally replaced the item and now we have two beautiful sets. I did a test fitting a couple nights ago and they really look and feel substantial and will be fairly easy to integrate with the ejection seats.

I am not sure how much I posted about these little USB VGA adapters. I thought they were the best thing since sliced bread! However, when it comes to DirectX support you have to get a USB 3.0 version (it is unsupported in 2.0) and even then there is a lot of latency. The newer USB 3.0 adapters (like the one pictured above) require Windows 8 or 8.1 or are no longer based on MCT. Whatever the case, I can’t find any more of the Windows 7 MCT chipset 3.0 units (I have been through like 5 of them on eBay now). So I broke down and purchased a new low-profile SFF 4-head card to run the gunner station, EICAS, PFD, and MFD.

The HUD will continue to use the only compatible USB adapter I currently have. If I can find another I will use it for the gunner just because he will already have USB running to his station and there is no need for 15-wire VGA.

While I was at it, the EICAS monitor power is now routed through an AC Fotek which is powered by the cockpit essential DC bus (so it isn’t on all the time now).

I took delivery of these beauties and have another pending on the BOM. The stick has a yaw component, LED illumination, and feels more substantial than the FighterStick so I will be replacing the rudder and flight control with these and finally adding a thrust lever. Nothing to motivate you to get the engines up and running like a beefy new two-engine power quadrant!

The engines are being modeled from multiple components working together (starter motor, N2 spool, N1 spool, igniters, combustion chamber) all choreographed by the new FADEC module. I have been making a lot of progress and it has been slow but I have found that this is one of my favorite parts.

Finally, the backup compressor that resides inside the simulator burned up even though I coded it to follow the 10 minute duty cycle recommended by Goodyear.

I received a replacement but haven’t switched it on yet for fear the same will happen. I need to find the slow leaks maybe using an ultrasonic detector like the one pictured below but for now I will only run the compressor when I need to get in the box for some reason over the winter.

On the visuals front we have full-screen antialiasing (8x multi-sample) and 8x anisotropic filtering activated for the production lighting view in the Makeship tool and the display program. The mining tier extractor model is really looking nice!