posted 12-27- 08:40 AM               

What I am getting at is: would it be possible to edit an airfoil to make a general change to increase drag at higher AOA?

I need to get my SE5a to bleed more speed in turns and other maneuvers...

Thanks for an insight into this!

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-Sv =FC=

WWI in SDOE!

posted 12-27- 09:04 AM               

Try to find Tailslides FM docs it might have something about it in there.

posted 12-27- 10:41 AM               

Where are the airfoil files located? Are they binary files, or will un-bigging the right .par file get them into a text file?

I would just check now myself, but I'm stuck at work

...just in case anyone knows off-hand

posted 12-27- 06:41 PM               

I just edited the airfoil, it works! Sooo cool!

And to thank you, here is a hack to rename the airfoil:

Just open the airfoil.sm file in wordpad and edit the path that shows up near the top so it points to the new name, then name the file that name. I am quite sure that you must keep the name the exact charecter length as the original so you don't screw up the binary file. I could be wrong though. I renamed the FW190.sm to SE5a0.sm and it seems good so far!

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-Sv =FC=

WWI in SDOE!

posted 12-27- 07:50 PM               

It will open with the WingExtractor, but this new file crashes SDOE

I even went as far as to edit the FW190.sm airfoil file with a binary editor - all I changed was the path and the other stuff like FW190foil stuff to be: SE5a0foil SE5a0foilup SE5a0foildn - etc.

Then I changed my wing airfoil to use "SE5a0foil" and it crashes SDOE to desktop as soon as the mission loads

Anyone have a clue how to do this??? I know it can be done because I see one for the HE100 in the planepack! If someone could send me the FW190.sm airfoil file renamed as SE5a.sm that would rule!!! Or even better, let us know the magic secret

Much thanks,

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-Sv =FC=

WWI in SDOE!

posted 12-28- 06:12 AM               

Where is that file? It is not mentioned in the OpenPlane documentation as far as I can see - I searched for "start".

What does this file do?

posted 12-28- 10:44 PM               

Thanks! Now it's working

posted 12-29- 01:42 PM               

I'm glad you asked. I needed this info as well. So is there a place on the graph (in excel) that effects AoA? I would ultimately LOVE to see my F-15C coming in for a landing with it's typically HIGH AoA (looks just awesome in real life, especially at touch down when the big air brake is open and they ride that wheelie for a good length of the runway).

I'm asking because I'm on lunch break right now and won't have time to check it out until later tonight.

Thanks.

posted 12-29- 02:01 PM               

If you can, could you produce a doc on editing airfoils as well. I realize it will slow you down but will help alot.

Tailslide produced some doc on editing the FM's not sure if it included airfoils. Check the OPPs website.

------------------
Kopper

Fortunae Nihil
(Nothing to Chance)
OPPs Making SDOE a Dangerous place.
One plane at a time.

posted 12-29- 02:52 PM               

From what I know Pete, this is the way it works:

1. Download the wing extractor app on Tail's website.

2. Load an existing airfoil that most closely matches your plane. The SDOE standard airfoils come with the wing extractor, or unbig the par file and look in the media/aircraft/airfoils folder.

3. Update the data - more on this below

4. Save the airfoil to the media/aircraft/airfoils directory. Name it to match your plane or whatever.

5. Open this new airfoil.sm file in a binary editor - you can download one from www.shareware.com or whatever.

6. Edit all occurences of the name of your airfoil. In my case I named my airfoil SE5a0.sm - so I replaced the 4 occurences of this, stuff like FW190.sm in the media path and FW190foil, FW190foilup, FW190foildoen - all became SE5a0.sm, SE5afoil, etc. Now save this file again.

7. Open up startup.ppf in the media folder. You must unbig a parfile to get this, or someone can send you one - I'll post it at my site. Now add your airfoil to the list of airfoils. I added "Se5a0foil"

8. Now open your plane in OPS and look at the property for any air object - change the foil to be your airfoil, in my case, "Se5a0foil". Save the plane

9. Try it! I bet is sucks

OK, the only hard part here is editing the airfoil data. The app still confuses me. Anyway, you will see a chart. The x axis is AOA - from 180 degress neg om the left to 180 degrees plu on the left. The Y axis is the cooficiant - green line of co. of drag, the red line is the co. of lift. There are other lines - but I dont understand how they effect FM - like Cooefficiant of Momentum.

Here is my trouble: how to best edit the curve? I though I would be clicking and draging points - no! Instead you choose a range from the X axis (00 - 50?) and a "left multiply" and "right multiple" - this will alter the curve in that AOA range - tricky work to get what you want. Also it is hard because you don't see AOA in degress labeled on the chart. 25 is 0 degrees angle of attack.

I'm sure using the chart is hard for me only because I don't understand the problems related to airfoil data editing.

Anyway, for my SE5a I simply increased the drag coef. at AOA at about 8 degrees and above to try to get more speed bleeding when maneuvering. It worked, but no my SE5a is dead at low alt, and flys super good at 10,000 feet - slight turns at low alt cause the speed to drop real fast - at high alt (10,000 feet) I can turn sharp circles forever with not enough drag to slow the plane down.

My guess is that my prop is to efficiant at high alt or something. Anyone have any prop tips?

More later...

------------------
-Sv =FC=

WWI in SDOE!

posted 12-29- 04:23 PM               

I only edited the "normal" chart - not the "upper" and "lower" chart. I am guessing that the foilup chart represents the drag and lift when the aileron is fully up, and the foildown represents the wing with the aileron fully down.

Here is the question though: Does SDOE interpolate the lift/drag coef. between the foil and the foilup charts depending on how much aileron deflection there is???

I would guess yes - am I correct?

Thanks for any input on this...