Tuesday 13 March 2012

More vintage helicopter material and custom dynamics

Struggling to find some progress to demo, the past week has been picking up threads and licking Combat-Helo back into shape with a HTR flight model update and repairs from my aggressive (frantic?) debugging sessions from a while back (mostly sorted now). Almost done with the HTR update, some small things came out while doing it which I might as well share.

During a recent visit into the attic to dig out research material I came upon some of the more interesting clippings from World Air Power and assorted journals. Including one glossy sales leaflet from Boeing which I've scanned in and posted below (showing rear page). Bypassing the somewhat aggressive tone, if you examine the "Baseline Performance Specification" table it does illustrate the effect of temperature on performance. It's worth noting that published data like this varied greatly especially after upgrades to engines and rotor system. This leaflet from an air-show is a little old.


One of the cool aspects Helicopter Total Realism (HTR) for FSX is it enables pilots to tweak and test how their helicopter flies in a simple manner. For example

[Helicopter] 
helicopterType= 1
simType = 0
length = 50.74
velocityNeverExceed = 172
emptyWeight = 10670
simEmptyWeight = 10670
maxGrossWeight = 14415
meanAerodynamicChord= 6
emptyWeightCOG = 0.48
...
...

The dynamics of each helicopter are edited easily enough with HTR by changing values in the .CFG file that lives in each helicopters "dynamics" directory. As this file is likely to updated at our end and therefore updated during any pushed game update it was prudent to add a check for a "aircraft_user.cfg" file so any edits should be saved into this file which should remain untouched. Good news if you want to plug in WHA-64 specs.

It should be possible to hot-swap between the two in game via the chat/command console to make comparisons.


A quick shout out to "Pixel Perfect" who has been working on his own flavour of lip-sync in Leadwerks (Facial animation test) which I think would be a really nice touch for our crewmen and seems pretty simple enough once you have the datafile containing all the phonemes and timing data. It does require some extra bones in the heads (Leadwerks does bone animation not vertex). That hard part I think is sorting out the model conversion but the concept seems to work. And it has to be slightly better than flapping heads. Although I'll have to run the details past Dave since it's his dept. see if we can't shoehorn that into the roadmap somewhere.



And now, from Fort Rucker a sweet introduction film (and rare in that it's been encoded in HD)


United States Army Presents: Sikorsky H-19 Helicopter Flight Training (30mins)




Parting Shot

Thanks for the feedback on last weeks video, the mini-tutorial on using the KBU Keyboard Unit (I keep wanting to type Unity which is another 3D engine I use from time to time). I've since found FOUR functions for it, the altitude bugs low and high, manual range input and .... barometric pressure. Which is right next to the bug settings. See the default pressure of 29.92 which represent inches of mercury inHg at sea level. You shouldn't need to set this at all as boarding the aircraft sets the value to the ambient pressure outside (we use the standard atmospheric model in Combat-Helo).

Also in the video I set the high bug to 3,000 feet. I realised a couple of days later that this setting is for the RADAR altimeter....and at what altitude does the radar alt disappear? (AH64 trivia question there for you Janes junkies) Answer, about half that. So 3,000 didn't make a lot of sense however if you want to enter silly values you can. I decided to leave it unless I find data that says otherwise.

3 comments:

  1. Nice Update. Yes, would be really cool to have lip-sync talking crewmen...but thats of course something for later implementaion if that.
    Also thanks for pointing to that Army heli flight training vid, I somewhat like these old films.:-)

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  2. those videos are so bad they're great.

    Ive found the FSX helos seem to be "sort of off" in the way they fly (Im no expert)... they just feel like there is too much main rotor torque and retreating blade stall effects. And, as in all FSX aircraft, they always seem to require pushing the inputs a bit too far then suddenly the aircraft reacts to the input, almost like the sim is lagging, then you have to counter the input.

    Sure would like to try CH's Flight model... soon...

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  3. I wonder how much of that is down to design of the hardware and how some drivers and software (sometimes both) insert dead-zones around the middle to prevent twitching, uncommanded input.

    Anyway it would be nice to get any kind of input working this morning, I'm pulling apart the input code to fix various problems and nothing is working atm :)

    It's going to be one of those days I can tell.

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