Simviation Forum - Flaps or airbrakes ?

Jun 13^th, 2003 at 7:29am

ajver Offline
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I have downloaded an aircraft from Simviation.com, but the flaps produce an airbrake effect. In other words, if you extend the flaps on take-off, the aircraft digs is nose into the runway. Likewise, if you extend the flaps on finals, it drops out of the sky like a brick.

Is it possible to correct (reverse) the flap effect ?

Unfortunately the author (designer) refuses to talk to me, so I can't get his opinion. Shocked

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Reply #1 - Jun 13^th, 2003 at 7:59am

Bob Boudoin Guest

Find this section in the aircraft.cfg file:
[Flaps.0]
type= 1
span-outboard= 0.600
extending-time= 11.000
system_type= 1
damaging-speed= 170.000
blowout-speed= 250.000
lift_scalar= 1.000
drag_scalar= 1.000
pitch_scalar= 1.000
try changing the line to read as this
drag_scalar= -3.000
If that does not work, I can show you how to change it using and air ed program to redefine the .air file.
Bob

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Reply #2 - Jun 13^th, 2003 at 8:03am

plainsman2 Offline
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I must have messed up the login, that is me.
BTW, You will need to make sure you make any changes using WordPad and NOT NotePad.
Also, keep in mind some aircraft use this type of device to slow the pane on landing. If it is that type, usually the lesser flap positions will have little drag, only the full flap position acting as a brake.
Bob

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Reply #3 - Jun 13^th, 2003 at 9:55am

ajver Offline
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Thank you very much for the advice. I will try the procedure as suggested. If it does not work, I will come back for that air ed information.

I'm back again. Tried the -3.000 in the drag_scalar line, and it now performs a perfect grasshopper stunt.

Could you please show me how to redefine the .air file ?

Thank you

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Reply #4 - Jun 13^th, 2003 at 11:10am

Felix/FFDS Offline
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I'm curious - why WordPad- while it can save as a text file, there's the "danger" to save it in its native format, vs using NotePad - a plain text editor?

Quote:

BTW, You will need to make sure you make any changes using WordPad and NOT NotePad.
Bob

Felix/FFDS

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Reply #5 - Jun 13^th, 2003 at 11:16am

plainsman2 Offline
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First, you will need to get an editor program. I prefer aired by William M. Roth. It will enable you to open and edit .air files.
Under 1101 (primary aerodynamics) you will open to a lot of lines. The three you will wan to try first sre the following:
Drag Coefficient*Flaps
Lift*Flaps
Pitch Moment*Flaps
I don't know your aircraft so I can't suggest values, but I would compare each of these to a similiar (weight and type) aircraft that flies well. You can then use that as a trial and error adjustment to get better flight.
From your discription, it would not surprise me you also have a problem with bad landing gear settings. That would be way to complicated to discuss in depth here, but there are some articles (at least there used to be) on how to set these.
Hope this helps,
Bob

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Reply #6 - Jun 13^th, 2003 at 11:58am

ajver Offline
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Thanks for the advice. I will try to edit the files as suggested.

Back again.
Tried it -- it's no use.
It is not my aircraft. It is a B-26c, downloaded from Simviation.com. I think the authorities who allow stuff to be posted for download should ask the designer to do the corrections.

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Reply #7 - Jun 13^th, 2003 at 1:00pm

Felix/FFDS Offline
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Wrong - if you were purchasing a commercial model, then you have a point, but freeware?

These sites provide a repository for the models, and are NOT an accuracy control center.

You may want to delete the flaps section from the aircraft.cfg file, assuming you've changed the *.air file as Bob suggested, and run it through FS2002 again. I understand that FS2002 will create the [FLAPS] section for you from the air file values.

Quote:

I think the authorities who allow stuff to be posted for download should ask the designer to do the corrections.

Felix/FFDS

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Reply #8 - Jun 13^th, 2003 at 1:21pm

ajver Offline
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Thank you Felix. I take your point, but I was always under the impression that aircraft that are posted for download must conform to rules that are laid down by Simviation.

I cannot believe that somebody would submit an aircraft without having flown it and making sure that everything is working as it should.

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Reply #9 - Jun 13^th, 2003 at 2:38pm

ajver Offline
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Posts: 224

I think I have pressed the right button -- I just don't know what it means.
I have replaced the complete flight dynamics section with one that I know flies well. No effect. Then I came across the following entries:

FS2K Unknown with values assigned. I made them all zero. Now I have no flap effect at all, but at least the aircraft is not digging its nose into the runway. What is the meaning of these entries ?

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