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Author
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Topic: SHAME SHAME SHAME !!! - and some questions...
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Laika 801
Pilot
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posted 04-08- 01:14 PM
   
I got some time to go on with the I-16. And guess whahat ? Somehow I mixed up the airfoils in the final (dunno why !), so it does not come with the clarkYH as it should. Damn ! DAMN ! I realized it when I was playing with the new (not working  ) RS-82 rockets. Flight model was strange. DAMN !Oh my god. I fixed it, plane behaves better now. For the next update I would need some more answers ! Some things are not clear, I simply dont understand it: AirWash ? Can someone explain how I measure the correct angle (with the scale plans) or how I should use it ? What about the scale value, for the p51 it is set to 0.9 - Huh ? Should it be smaller for the I16 ? Rockets - I found a property not mentioned in the OP-Specification: gunExplosiveForce, what is this for ? It is set to the same value on all rockets (44). What about the phyPounds thing ? Also for all rockets the same value (106), why is it definied in the .sm file ?, isnīt the weight of the rockets set in the loadout ? Please help ! LK IP: Logged |
Kraftwerk
Pilot
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posted 04-10- 09:45 AM
I can only speculate, but wouldn't the airWash property have something to do with downwash from the wing's upper surface and correlate to the pitching moment?IP: Logged |
Tailslide
Pilot
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posted 04-10- 10:18 AM
It's prop wash on the control surfaces. You hard code certain prop wash values as prop wash isn't simulated. The whole thing is a bit stuffed IMHO but most planes use a value of 0.6 or 0.7 with zero angle. Using non-zero angle values can cause some strange behaviour. TS ------------------
Patch It! TS Aircombat
[This message has been edited by Tailslide (edited 04-10-2000).] IP: Logged |
Laika 801
Pilot
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posted 04-10- 10:27 AM
No way to measure it somehow ?IP: Logged |
Tailslide
Pilot
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posted 04-10- 11:15 AM
No matter how you mesure it, the propwash setting does a poor job of simulating prop wash Can someone tell me how the 'clarkyh' airfoil was generated? I don't think it's a standard SDOE foil. TS [This message has been edited by Tailslide (edited 04-10-2000).] IP: Logged |
Laika 801
Pilot
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posted 04-10- 01:07 PM
Does the clarkYH does not come with the PP 5.3 ?I know that the clarkyh.ppf comes with the hurricane, so is the clarkyh.sm necessary ? IP: Logged |
Bryan Russell
Pilot
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posted 04-10- 06:45 PM
The ClarkYH airfoil is just the typh airfoil with a bit more drag and a little more lift. I attempted to make a ClarkYH using some of those 2d CFD (?) tools around but the scale of the Cl, Cd etc plot looked a bit off. The ClarkYH was only meant to be a place holder so that the airfoil could be improved later, maybe I should have called it something less generic. In my limited knowledge and testing methodology, the Hurricane had top speed and stall close, and possibly turn. So I don't know if that means the airfoil's close as well or not, probably not.
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Laika 801
Pilot
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posted 04-10- 11:17 PM
I tested the ClarkYH airfoil with the I-16 and I was impressed how it changes the FM of the plane. The I-16 behaves now (for me) like Mark Hanna wrote in his article. I tested all the other airfoils but not with so good results. I would keep it !IP: Logged |
Bryan Russell
Pilot
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posted 04-11- 12:41 AM
I think the Yak-3 uses the ClarkYH as well (in real life, probably not SDOE  ) so I'm thinking my generic use of the name 'ClarkYH' might cause some problems. There are some variants of the ClarkYH. the Hurricane was meant to use ClarkYH19% and ClarkYH12.2%. It probably isn't a good idea to share a ClarkYH airfoil, if yours is meant to be a different variant. I might change the hurricanes foil to be ClarkYH19 or something like that just in case I have to tweak something in it later, or more likely, incase someone who knows what they are doing needs to tweak something later. A Q for TS and Zur. Do you artificially tweak the airfoil to get the result you want or do you try to get the airfoil right? I hope you can understand that dribble. [This message has been edited by Bryan Russell (edited 04-11-2000).] IP: Logged |
Laika 801
Pilot
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posted 04-11- 06:11 AM
What should I do now ? I would really keep the actuall clarkYH for the I-16 cause it works fine. Should I rename it ? What files should I add to the zip file, so that everyone who downloads the I16 can use it ?Best thing would be if someone could make the TsAgi airfoils (used on the real I16)  LK IP: Logged |
Tailslide
Pilot
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posted 04-11- 08:51 AM
Hi Bryan, thanks I'll give the clark a try on the Yak then. I agree that we should have a seperate airfoil for each plane, but I don't specifically tweak the airfoil to get a plane to fly a certain way. I found that the airfoil is a very small part of how a plane flies. All I did to the airfoils in the planes I worked on was to get rid of the Cm 'bumps' that seemed to be added to the default airfoils to push the plane out of a stall. I also made it so the drag increased at the point the wing stalled instead of after. I believe these were the two changes that were made to the airfoils to prevent them from stalling. I hope to make these changes to the rudder and elevator airfoils as soon as everyone starts using the copies of these I made for the propeller. TS
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Patch It! TS Aircombat
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charmstar
Pilot
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posted 04-11- 11:44 AM
Laika-
It is very easy to copy an AF and change its name, so maybe you should just do that. The main thing is you need to keep the name to the same number of characters as it has currently. Also, there are 4? places in the .sm file (all at the beginning) where the name occurs. You can edit it in wordpad to change these. Of course you also have to add it to the startup.ppf file, and change references in your plane!charm IP: Logged |
Laika 801
Pilot
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posted 04-11- 12:02 PM
Actually there is no existing clarkYH (7?) sm file on my computer. But it works. I only got the clarkYH.ppf:" Parsoft Property File,,,,,,
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obData 'ClarkYH..." Does the number of charakters still matter ? LK IP: Logged |
jedi
Pilot
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posted 04-11- 12:44 PM
I think the .ppf file is an alternate method of defining the airfoil. Some planes use the .sm file, but others have no .sm file and have a .ppf file instead. The .ppf file consists of all the same values you see when you open an .sm file in the wing editor.I would suspect that renaming the .ppf file would be even easier than renaming the .sm file. One of the sources in the airfoil database indicates that the Corsair used the same airfoil sections as the FW-190, so I'm going to set it up to use the 5.3 FW-190A airfoil and see how that works. It has an .sm file so I'll try renaming and including it as a separate "F4U1D.sm" airfoil file. TS-- what was that blurb about the prop airfoils? The Corsair currently just uses the "RAF34" or whatever it's called. Is there a refined propeller airfoil set I should be using? I'm about to start some serious testing and tweaking on the F4U so I want to be using the most advanced aero model stuff we've got so far.
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--jedi-- IP: Logged |
Tailslide
Pilot
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posted 04-11- 12:50 PM
Jedi, there is a problem with using the default propeller airfoils that the original planes used.. they're also shared by other things like the rudders and the wings of other aircraft ! All the original planes had the same propeller shape and airfoil so I made copies of the airfoils called prop1, prop2 etc. Take a look at the propeller definition on the 5.3 typhoon for an example. TS ------------------
Patch It! TS Aircombat
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jedi
Pilot
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posted 04-11- 02:17 PM
Ah, OK, so that's what those things are Presumably I can track down the appropriate "new" propfoil by looking at the 5.3 planes in OPS and use that instead of the old one, or I guess just pick whichever one works the best in testing. Another clue leaks into my head...
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--jedi-- IP: Logged |
Tailslide
Pilot
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posted 04-11- 06:53 PM
The props in SDOE are actually comprised of four different airfoils changing from root to tip (if you look at a real prop it's shape and thickness changes along the length). You may want to use all the propx airfoils but change the propelements part to affect blade width and twist if you need to make changes. TS IP: Logged |
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