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jcomm

ceci n'est pas an avion....

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It's a MOD, with due credit to the original Columbia 400 author, the aircraft that comes by default with X-Plane10 is one of those I fly the most. It's also a good way to start training your Plane-Maker skills :-)

 

What I did was a little tweaking in the RoGs, control phase-out and some art stab too :-/

 

IMPORTANT: For best results please make sure your Art Stab sliders and Joystick linearity are full left!!! The nullzone doesn't have to be zero, like in the image bellow...

 

 

 

If you want to test, please:

 

1) Make a backup of the original c400.acf file, or, even better so that you can keep the original aircraft, and test both versions, create a copy of the original "Columbia-400" folder under General Aviation (it can be a simple Windows copy name like "Columbia-400 - Copy", and place there the file linked bellow in this post, replacing the original one.

 

2) Start X-plane10 and navigate to the "Columbia-400 - Copy" folder, selecting the acf file in there. Go flying.

 

 

 

You can set some x-wind on the rw, to see that although it still veers, the tendency of the aircraft while heavy on it's nose gear is to stay more or less under directional control, unless too strong a x-wind component is set.

 

In flight, you'll notice that as it gains speed ( and thus dynamic pressure builds up over it's wings and lift generation surfaces as a whole ), the aircraft becomes more stable, also in roll, and above a certain speed (around 126 KIAS) you will no longer notice any roll due to torque tendencies... Try not to set any aileron trim during acceleration so that you can more easily notice this effect.

 

You can easily edit the ACF file in Plane-Maker and adjust it to your liking. 

 

Get the file from here ;-)

 

Please do not expect very good results. It was just a minor tweak, not having access to the required information about the aircraft. I did google for it, just to get reference speeds, but that's about all. A lot more can be done with an aircraft, preferably trying to build the model with the closest to real world data we can get, including the blue prints, engine data, prop geometry and characteristics, airfoils, etc...  Weight & balance is also very important.

 

After test flying your model, then use the remaining options in Plane-Maker to fine tune it. I strongly believe that very good results can be achieved. Some of the default aircraft in X-Plane v10.21 already received some attention from the dev team, and the results are there for us to notice.

 

Does it still require updates (I mean, the core FDM in X-Plane)? Of course it does, like with any other simulator! But, honestly, it's already good enough for me, even having DCS World as a base example of what can be achieved when a good FDM and access to precise data are available. Also, bare in mind that DCS offers a Physics Model SDK, and a LOT of low level programming must be done in the background, while with X-Plane wou have a generic, very detailed work bench, Plane-Maker but also plugin programming to get deeper into details, and are certainly able to model a flying vehicle without having to be an aeronautical engineer!

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Hi JComm....

 

It would be interesting to get some more real world feedback on the Columbia. My hunch is that the feel for the need of aileron trim has disappeared within a speck of time after takeoff, instead of 126 kias. I have pics of my RV wings on the initial climbout, and both ailerons are even with the flap edges, which means all are neutral. There may be a wing dip the second the wheels are off the ground, which is corrected by aileron, but that's it. In the meantime, I had to compensate for a lot of left yaw on the takeoff roll. And if I applied full power at low airspeed such as a touch and go, the torque was enough to compress the left landing gear. Then, you could really feel it, and compensate with aileron.

 

Just looking to get the XP takeoff experience to feel correct. On the otherhand, I have no sim CPU at this time, to try it.

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My hunch is that the feel for the need of aileron trim has disappeared within a speck of time after takeoff, instead of 126 kias...

 

Ah Larry, great input. THX!  I will correct it ASAP when near to my X-Plane10 PC :-)  !

 

It would be great if you could test it. As a matter of fact I thought of using the RV6 for this thread, but that one is rather incomplete... But!  Since you have certainly a good deal of data, including prop geo, trim tabs, control limits, engine/empennage cant,  etc... it would be great to work on that one day....

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Here's a new version according to Larry's suggestion :-)

 

link

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Very nice Jcomm.  I will try it out tomorrow, when Im off.

The columbia is one of my favorite of the default planes, so its nice to see it get some attention.

 

Rob

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At least Austin mentions getting rid of any roll tendency, with his turbine Lancair test flights. My RV also had a heavy wing on initial test flights. But it would roll to the right, which is opposite of what torque would cause. Didn't take much stick pressure to level, but full aileron triim wouldn't keep it llevel. Just needed to squeeze the trailing edge of the left outboard aileron about 1/32" for 18 inches. The radius was just slightly fatter than the right aileron. The paint job wasn't effected, and that's all it took, to get an airplane that trimmed very well.

 

Some experimentals as well as factory need tabs, wing tweaks, etc....... To make up for slight deficiencies in the airframe construction.

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