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MAIW MCAI de Havilland Canada DHC-1 Chipmunk Conversion Support

Post all questions and problems with official MAIW Conversion Packages for FSX and P3D in this forum. Each package has a dedicated thread for support.
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MAIW MCAI de Havilland Canada DHC-1 Chipmunk Conversion Support

Post by gsnde »

Post support related comments for the MAIW MCAI de Havilland Canada DHC-1 Chipmunk conversion in this thread.
Cheers,
Martin
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Re: MAIW MCAI de Havilland Canada DHC-1 Chipmunk Conversion Support

Post by TimC340 »

Martin, I popped into Swinderby yesterday and found the EFTS Chipmunks wandering around the airfield trying to find the taxiways. I'd noticed this behaviour with my own conversion of the Chippy for Finningley and haven't found an answer, but it seems the Chipmunk's taxiing turn radius is too large. I'm not an expert on FDE stuff, so perhaps you (or someone!) can suggest a fix?
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Re: MAIW MCAI de Havilland Canada DHC-1 Chipmunk Conversion Support

Post by John Young »

I have a Chipmunk in my archive, but I have no idea where it came from. The contact points in the aircarft.cfg file are like this:

[contact_points]
point.0 = 1, -16.052, 0.00, -1.85, 1800.0, 0, 0.332,45.0, 0.10, 2.5, 0.65, 0.0, 0.0, 0, 0.0, 0.0 //Tailwheel
point.1 = 1, 0.830, -4.412, -5.60, 1600.0, 1, 0.752, 0.0, 0.70, 1.7, 0.65, 0.0, 0.0, 1, 0.0, 0.0 //Leftwheel
point.2 = 1, 0.830, 4.412, -5.60, 1600.0, 2, 0.752, 0.0, 0.70, 1.7, 0.65, 0.0, 0.0, 2, 0.0, 0.0 //Rightwheel

Have a look at what you have and perhaps reduce the first value (-16.052) which is the distance in feet the tail wheel is behind the CG which is at 0,0,0. The other two values (-4.412 and 4.412) are the distances in feet that the wheels are spaced either side of the centre line. Reducing these should also give a tighter turn but the aircraft may flip over on a bend if over done.

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Re: MAIW MCAI de Havilland Canada DHC-1 Chipmunk Conversion Support

Post by petebramley »

Tim, I have had the same problem with all the HTAI Tail-draggers in P3Dv4 and still have not found the answer after several forlorn attempts to correct them. I keep looking but no solution seen as yet.
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Re: MAIW MCAI de Havilland Canada DHC-1 Chipmunk Conversion Support

Post by TimC340 »

Cheers guys. John, I'll have a look at the contact points. I did notice that the stock J3 Cub had similar problems when used as AI by Just Flight's Traffic Global (as well as trying to fly - unsuccessfully - at 30kts!). I might have a look and see if there is a taildragger that does work correctly and then see if I can spot what the differences are.
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Re: MAIW MCAI de Havilland Canada DHC-1 Chipmunk Conversion Support

Post by Firebird »

I am obviously more or less thinking out loud here, as I can't check it myself.

If the tail wheel steering angle is big enough but the issue is still there try adding a steering angle for the main gear legs as well. It obviously is nothing like reality but it might help.

Otherwise as Johns suggests try moving the tail wheel contact forward but keeping in mind that you will need to adjust the height of the tailwheel so that the actual wheel still keeps contact with the ground in game. You will need to adjust the static_pitch and possibly the static_cg_height parm but only do so once you know it works when moving.
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Re: MAIW MCAI de Havilland Canada DHC-1 Chipmunk Conversion Support

Post by TimC340 »

John, those numbers are pretty much identical to the Rick Piper flyable Chipmunk. I'll give them a go.

Steve, I can't find any reference to tailwheel steering angle - in either the Cronin or Piper Chipmunks.
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Re: MAIW MCAI de Havilland Canada DHC-1 Chipmunk Conversion Support

Post by John Young »

Tim, in the example contact points I posted, the value "45.0" in the first line is the steer angle. It's always the 7th value across, ignoring the type (1).

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Re: MAIW MCAI de Havilland Canada DHC-1 Chipmunk Conversion Support

Post by TimC340 »

Aha!
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Re: MAIW MCAI de Havilland Canada DHC-1 Chipmunk Conversion Support

Post by Firebird »

Yes try adding some steer angle to the equivalent point.1 and point.2 entries. The look in game won't change as they are not animated but it might be worth a try to see if it will turn any quicker. You could also try increasing the tail wheel angle to see if that helps as well.

I have seen aircraft in FS9 have a problem turning tightly and quite often it is due to the wheel base of the aircraft. The taxy speed of an aircraft can also contribute but lets ignore that for the time being.
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Re: MAIW MCAI de Havilland Canada DHC-1 Chipmunk Conversion Support

Post by gavinc »

There must be something sim specific to the sim as well. When I did my testing of the conversion it (and most other tail draggers I tested) taxi reasonably well. They wander slightly off the center line while taxi-ing (especially when following curved taxiways) but nothing as severe as what you describe.

I do remember seeing that behavior once when I tried to use the default FSX Cub as an AI.

Could it possibly have anything to do with the AFCAD file? Maybe the size of the taxiway? Are you using an AFCAD with 0 width taxiways? Just a random thought.

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Re: MAIW MCAI de Havilland Canada DHC-1 Chipmunk Conversion Support

Post by TimC340 »

Hi Gavin. No, the taxiways are conventional width. The airport I’m using is essentially Brian Clarke’s Swinderby. His parking is tight, and I’ve modified that to give the AI a bit of a chance. I agree that this behaviour is, at least partly, sim related. I had the same problems in my version of Finningley (still a work in progress) for P3D with my own basic conversion of the Cronin Chipmunk, which had worked fine in other settings in FS9, and reasonably well in FSX.

I’m still working on it, but I’ve managed to improve the behaviour somewhat. Making the main wheels steerable does result in some strange manoeuvres. I noticed that you’d set the tail wheel to a max steering angle of 90°(or maybe that’s the original setting), but it seems to work a little better set to 60°, which in itself is surprising. Once on open taxiways, away from the parking, it’s now coping pretty well, but the turn radius for the typical (and annoying!) 180 off the parking spot is still around 4x the wingspan.

I’m not at my computer just now, but I’ll post up my settings later on and you can try them for yourselves.

Edit: just a thought, but I wonder if increasing the maximum differential braking might help?
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Re: MAIW MCAI de Havilland Canada DHC-1 Chipmunk Conversion Support

Post by petebramley »

You could try changing the distance between the main wheels and even the wheel radius. I have had some success when I had problems with the turning circle of the TFS Dash8's and some of the HTAI aircraft.
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Re: MAIW MCAI de Havilland Canada DHC-1 Chipmunk Conversion Support

Post by TimC340 »

Thanks Pete. Yes, I was going to give that a go later on. I’m in the middle of ‘designing’ a planning application just now, which is turning out harder than anything to do with flight sims! Once that’s done, I can get back to playing with this.
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