Sunday, August 30, 2009


I've posted a newer F-5E model. Still no cockpit, and lots more animating and painting to go. I did put a hook on it, and "someguy" and I have been trying to do carrier traps with it, with about a 15% success rate. Oh well, it wasn't meant for carrier ops anyway. Like most Air Force airplanes the hook was only meant for use in catching a departure-end cable. I'll be checking it against the BAK-12, and if it catches that (departure-end) OK then I'll consider the hook done. Also, as someguy noticed, the yaw damper needs to be turned up a bit, or the base yaw stability derivative needs to be increased a bit. Either way.

Saturday, August 29, 2009

VX-4 paint for the F-4J

Gary Brown has released a repaint of the F-4J in the colors of Navy Squadron VX-4, "The Evaluators". The squadron was known for their use of the Playboy bunny logo on their airplanes. You can fetch the repainted F-4J at Gary's hangar.

Tuesday, August 25, 2009

Douglas A-4E Skyhawk

I just started a conversion of a Denis and Daniel da Silva model of the Douglas A-4E Skyhawk. It may be a long time before I can get to it. Is anyone looking for a project? A screenshot of the model as shown in AC3D is posted at the Hangar.

Sunday, August 23, 2009

Over G

Some of the Hangar models have an over-g handling system that will cause the model to freeze in position if the airplane is over-g'd. You can regain control by pushing the stick forward. I haven't added this system to all the models because I'm not sure if users will find it desirable, and I'd like feedback on this. Like all systems, you can turn it off by removing the line that activates it from the JSBSim configuration file.

Friday, August 21, 2009

Gun Effects

Last I checked there is no default key or button binding in FlightGear for a trigger, so you have to define your own. I use the trigger on my joystick, which is the most obvious choice. Just modify your joystick configuration to bind the trigger to the property "/controls/armament/trigger". While you're there I recommend binding the "hat" fore/aft axis to "/controls/flight/elevator-trim", which is how a real aircraft stick works anyway.

Thursday, August 20, 2009

Nice video of F-4N and Nimitz

"TheFGBlaze" has just posted a nice video of the F-4N model and the carrier Nimitz in FlightGear.

Wednesday, August 19, 2009

DavePack bug fix

"Jano" discovered a leading-slash bug in DavePack, so this has been fixed now. Thanks Jano! The leading-slash was causing the user's afterburner effect to also appear on other multiplayer airplanes. I also had to include a new JSBSim system, called "ab_workaround", that works around a multiplayer limitation, namely that the afterburner state is not sent over the multiplayer protocol. So far only the F-4J and F-4N have been converted, and I could use some testers. Please let me know if the afterburner animations of these two aircraft work properly over multiplayer.

Monday, August 17, 2009

The AOA lights

Some time in the 1950's the Navy, and later the Air Force, started putting AOA annunciator lights on top of the instrument panel to aid in holding proper angle of attack for landing. The top light tells you your AOA is too low (fast), the middle light tells you you're right on, and the bottom light tells you your AOA is to high (slow). The funny thing is the Navy and Air Force couldn't agree on what colors of light should mean what, so they ended up using different schemes. In the Navy scheme the light colors from top to bottom are green, yellow, red. In the Air force scheme they are yellow, green, red. So, in a Navy jet you want to see a yellow circle displayed while on final approach, and in an Air Force jet you want to see a green circle.

Vigilante Trivia

Did you know the RA-5 Vigilante, shown above in the title graphic, had no rudder, no ailerons, and no elevators? You can amaze your friends with this one! Actually it's a bit of a cheat. Instead of a rudder the entire vertical stabilizer rotated about a point. Same for the horizontal stabilizers, sometimes called "slabs". Instead of elevators the whole slab rotated about a point, which is standard procedure now in supersonic fighters. Instead of ailerons the Vigi used spoilers, with some differential slab movement mixed in. All in all this setup was pretty advanced for the times.

Aerial Refueling

Many of the models have refueling switches. These switches extend the refueling probe (or open the refueling door) and begin the refueling process. A green light on the fuel gauge lets you know that refueling has begun. My airplanes used to honor the air refueling "box" behind the tanker, so that you had to be in position there to refuel. Someone changed this in FlightGear, requiring refuelers to have a nasal script installed in order to honor the box. I've decided not to support this change, so my models can now refuel anywhere. Sorry about that.

Saturday, August 15, 2009

Adverse Yaw

If you've flown the F-100D model from the hangar, and flown it hard, you'll notice that adverse yaw is included in the flight dynamics model. Most swept wing jets of this era had an adverse yaw problem, even though designers tried to lessen the effect by using spoilers for roll control, or by combining spoilers and ailerons. At high angles of attack (AOA) the pilot needed to limit aileron deflection and use rudder instead to roll the airplane. The F-100D model needs to be flown like this, which means flying at high AOA will be very difficult for you unless you have a handy way to control the rudder. For most of us that would be accomplished by using the "twist grip" feature of a computer joystick. Some of you may have actual rudder pedals to use as input (the ultimate solution), and some of you are stuck using the keyboard or mouse.

So, here's my dilemma. I want to add adverse yaw to my most popular models, the F-4 Phantoms, however this will cause some current users to stop using the models when they find it difficult, if not impossible, to fly at high AOA. My inclination is to go ahead and do it, using the reasoning that users who want to avoid the expense of a joystick are asking too much of the simulation to adapt to them.

What do you think?

Chengdu F-7

I've posted the Chengdu F-7 as a new project. It's a Chinese derivation of the venerable MiG-21, with a Chinese built engine, a new double-delta wing, and upgraded avionics. The model represents the airplane used by the "August First" or "8.1" aerial demonstration team. As such there is a working smoke generator, activated by the "shift-S" key combination.

Remaining work to be done: wheel wells, canopy. I might add a centerline "travel pod", as I've seen these in many photos of the airplane, but I'm not sure if they carry these during the show or just when traveling between shows.

The texture is pretty, but could use some work as well. The fuselage is texture-mapped left/right, which makes it difficult to get a sharp edge where the blue areas angle together at the top and bottom of the fuselage. Mapping top/bottom would cause the same problem to appear at the left/right edges. I was able to solve this problem in the Thunderbirds F-4E model by exaggerating the angle of the paint edge as it approaches the texture's edge.


Welcome to the Dave's Hangar blog. I've set the blog up in order to announce updates to Dave's Hangar. If the comments feature works well I can also use this blog to answer questions, or host discussions on what Dave's Hangar users would like to see in the models. I'm on the road a lot, so this might be a convenient way to stay connected. As always, I can be reached at my POP3 email account at the address shown at the top of Dave's Hangar, or at the Facebook group on FlightGear, or at the JSBSim developer's email list. I lurk at the FlightGear forum, and the FlightGear users and developers email lists. I sometimes log into the #fg_cantene channel at