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Author
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Topic: LAIKA - Pe2
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Tailslide
Pilot
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posted 07-31- 04:40 PM
   
Laika, please change the airInc on the wingtips to 1.5 and add airInc to the middle wing section set to 1.0 This will make the wing drop at high speed more pronounced and help tone down the turn rate. If this is not enough I can twiddle with the airfoil some more. TS ------------------
Patch It! TS Aircombat
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Laika 801
Pilot
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posted 07-31- 06:55 PM
Thanks Tailslide ! Anyway I'm stuck with the DM for the wings. I found the "B" and "BS" airfoils in a prg called "AeroFoil" or so, pretty interesting, but I don't understand that kind of things...See you !
Laika 801
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Tailslide
Pilot
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posted 07-31- 07:46 PM
Hi Laika, can you post a link to "aerofoil"? TS
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Laika 801
Pilot
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posted 08-01- 04:10 AM
http://aerolab.virtualave.net/airfoil/index.html IP: Logged |
Tailslide
Pilot
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posted 08-01- 12:15 PM
Ahh great news Laika ! I based the pe-2 airfoil on the mosquito, and the Raf-34 and B airfoils are almost identical. TS IP: Logged |
Laika 801
Pilot
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posted 08-01- 02:58 PM
I checked this too - yeah except that B is a bit more straighten above (is this called washout ?). And BS ? I don't know if OP/SDOE airfoil modelling is accurate enought for the small changes I see there. If you got the time you could try to build a new BS foil (if it makes sense to try). BTW - the 60 secs register clock is driving me craaaAAAZzzzy !LK IP: Logged |
Tailslide
Pilot
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posted 08-01- 05:38 PM
Laika, we still have the problem of not having the software to convert airfoil shapes into lift/drag/moment data needed for SDOE. TS
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Laika 801
Pilot
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posted 08-01- 06:01 PM
And that exactly is the point Sir ! I absolutely do knot know what we need and how to convert it and what all this numbers mean  !Of course I'll try my best to find a prg which converts the X and Y co-ordinatos into lift/drag-moment data. But - uhh - what exactly is this ? I guess some sort of expensive analysis software ? Hmm - we'll see ! LK IP: Logged |
Laika 801
Pilot
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posted 08-01- 06:33 PM
I think this one could do it :
http://beadec1.ea.bs.dlr.de/Airfoils/calcfoil.htm ??? LK IP: Logged |
Laika 801
Pilot
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posted 08-01- 06:36 PM
What about this program :
http://www.geocities.com/CapeCanaveral/Hangar/2524/nvfoil/nvfoilen.html
its free...
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Laika 801
Pilot
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posted 08-01- 06:40 PM
Uhhh - alot of funny stuff out there:
http://www.dreesecode.com/snack/ IP: Logged |
Laika 801
Pilot
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posted 08-01- 06:47 PM
http://www.dreesecode.com/snack/ here you can download free demos, lookt interesting too !
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Tailslide
Pilot
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posted 08-02- 12:27 AM
I looked all over none of them will work past stall. Pang had trouble with them giving funny values for the up and down positions too. TS
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Bishop
Cadet
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posted 08-02- 09:46 AM
Couldn't you just use values for a flat plate to model the airfoil after stall (flat plate data should be easy to find in a textbook). The CL and CD behaviour should be similar, I'm not sure about the CM.BTW- this is my first post ever! Hooray for me! IP: Logged |
Laika 801
Pilot
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posted 08-02- 10:18 AM
You're welcome Bishop ! IP: Logged |
Tailslide
Pilot
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posted 08-02- 10:52 AM
We have an airfoil run through cfl3d that is shaped exactly the same. Laika, I think you should do the FM.. once I got the turn rate toned down I was going to call it finished. Heres a list of whats been done if you want to continue. TS
V0.1
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Rough area counts from model in square feet
inner wing 105 (48%)
mid 60 (28%)
outer 52 (24%)
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217 From 225 total area this makes inner 108
mid 63
outer 54 Hstab 44
Vstab 21.5
Approx chord from model: outer 4.9 feet
mid 8.3 feet
inner 10.6 feet hstab 5.9 feet
vstab 4.4 feet Positioned airpts on flight surfaces 1/4 back Airadvantage on elevator set to 0.5
AirMax on elevator set to 0.5
AirMax on ailerons set to 0.6 Fully fuelled weight calibrated to 14423 lbs
adjusted chord length to match nacelle and fuselage length for drag airfoils
moved CG back some Time to 16,500 feet
Real pe2: 9.3 Minutes Ours 8.5 minutes Speed at sea level
Real pe2: 260mph ours: 270mph Speed at 16,500 feet
Real pe2: 335mph ours: 322mph V0.2
----------- per laika's diagram of the pe-2:
Elevator airmax set to 0.517 (31 degrees)
Rudder airmax set to 0.417 (25 degrees)
Aileron airmax set to 0.45 (27 degrees) Fully fuelled weight calibrated to 14423 lbs -drag airfoil set for wheels
-made a new airfoil for pe-2 by modifying mosquito airfoil to stall at 11 degrees AoA
-new pe-2 airfoil set for wings
-tail airfoil changed to my stallable naca0012 airfoil
-removed CG box from bomb bay
-moved plane CG back to aprroximate middle of bomb pylons
-washed in tips of wings to make plane tip stall like Laika's description.
-removed tail incidence to level plane with new airfoils, turns better now
new figures for top speed and climb of real pe-2. I will recalibrate to this after DM is done.
maximum speed 280mph / 452km/h at sea level
320mph / 516km/h at 10000ft / 3000m
335mph / 540km/h at altitude [? Did they mean 16400ft / 5000m ?]
...with a 1322lb / 600kg internal bomb load the aircraft took 9.2 minutes to reach 16400ft / 5000m , and its service ceiling was 29000ft / 8800m. Speed [Pe2 No.10/35 1941]
at sea level : 445 km/h / 276.5 mph
at altitude [16400ft] : 530 km/h / 329.3 mph Climb to 5000m / 16400ft : about 9.3 to 10 minutes **This is actually closer to what our FM is ! we are only off by about 5 mph and the climb rates should be close as I was testing without an internal bomb load. V0.3
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- trying to get wing drop at high speed mentioned in laika's notes
- Increased airinc in tips to 1.5
- increased airinc in mid to 1.0 [This message has been edited by Tailslide (edited 08-02-2000).] IP: Logged |
Pachy
Pilot
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posted 08-02- 12:38 PM
[whine]
quote:
we still have the problem of not having the software to convert airfoil shapes into lift/drag/moment data
I'm not a real expert in the CFD field, but all those "finite elements methods" or "partial differential equations" things sounded more complicated than data conversion.
[/whine]But hey, I'm sure this Pe-2 will be awesome.
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Falck
Pilot
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posted 08-02- 12:41 PM
quote:
we still have the problem of not having the software to convert airfoil shapes into lift/drag/moment data
Im working on that.
Dont expect it before christmas though IP: Logged |
Tailslide
Pilot
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posted 08-02- 12:44 PM
Pachy, the process is more complicated than a simple conversion but I dislike using big words to impress and confuse people when everyday words suffice to get the message across.
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Tailslide
Pilot
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posted 08-02- 12:53 PM
Falck, are you in the US? Can you just obtain CFL3d? Its free.
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Falck
Pilot
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posted 08-02- 01:40 PM
TS,Ill look into that. Though I'd kinda like to give it a go myself since its pertainent to what I want to do for the rest of my life. IP: Logged |
Tailslide
Pilot
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posted 08-02- 02:15 PM
It comes with all the source code and it's been in constant development by NASA for years might be interesting to have a peek inside it see how it works.. Heres some features: 2-D or 3-D grid topologies
Inviscid, laminar, and/or turbulent flows
Steady or unsteady (including moving-grid) flows
Multiple block options:
1-1 blocking
patching
overlapping
embedding
Convergence acceleration options:
multigrid
mesh sequencing
Turbulence model options:
Baldwin-Lomax
Baldwin-Lomax with Degani-Schiff Modification
Baldwin-Barth
Spalart-Allmaras
Wilcox k-omega
Menter's k-omega SST
Abid k-epsilon
Gatski-Speziale EASM k-omega
Gatski-Speziale EASM k-epsilon
Girimaji EASM k-epsilon TS
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Tailslide
Pilot
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posted 08-02- 02:32 PM
Bishop, that's basically what we did. We took the data for an existing airfoil with the same shape that we had correct data for past stall. I think by merging the stalled section of a similar airfoil with the unstalled region generated by the simpler software you would get something close. Pang's been having trouble generating good data for the up and down airfoils though. TS
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Pachy
Pilot
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posted 08-02- 03:31 PM
Tailslide, this is NOT only a question of vocabulary. A data conversion is supposed to be an exact process. A given CFD program has to be based on a particular computing method, and will produce DIFFERENT results than another program, and then again both may be valid to a certain extend because they are based on different numerical approximations of a complex natural process.I'll stop here my boring rant, keep up the good work guys, I'm sure this will be a major addition to this GAME. IP: Logged |
Tailslide
Pilot
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posted 08-02- 03:44 PM
Yes Pachy it is. Even when I try to write as clearly and simply as possible Laika and I have a hard time understanding each other sometimes. What is your problem with me exactly Pachy? I can't help but notice every post to me for the last 6 months has been criticism in one form or another. TS
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ArgonV
Pilot
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posted 08-02- 04:15 PM
Maybe hes just trying to be technical?  IP: Logged |
Tailslide
Pilot
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posted 08-02- 04:27 PM
Starting to think this wasn't such a good alternative to email Laika  I will try to setup another email account see if my mails will get through to you that way. TS
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Laika 801
Pilot
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posted 08-02- 04:57 PM
I'm confused ! Very confused ! [QUOTE]Laika, I think you should do the FM.. once I got the turn rate toned down I was going to call it finished[/QUOTE) - Tailslide, what exactly does this mean - Its just my not so good english, so I'm not sure ? Will you leave me alone outa here ? You know I got no glue about such stuff ! I would be lost. I know (cause I got one of the rare Pe-2's which are actually aviable )that the FM is good and for a new released a/c its is nearly perfect ! Of course there should be some changes by time, to make it even better (and harder) to fly ! I think this is a constant process - testing new methods etc. - same goes for the DM, if I find out that something could be better I will make it better...
"Laika and I have a hard time understanding each other sometimes." -- Yeah this is true - I do my best to understand all this technical english, but sometimes I fail - but the comunication with other people around the world is one thing I really like here !
Still had to tell you some more - Tailslide, you got my full trust in this case - you had to do the FM, at least all that crazy hard stuff with aifoils etc. !!!! ! Sorry Tail - I did not receive any mail from you in the last 24 hours - I'll send you a new mail adress... LK
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Tailslide
Pilot
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posted 08-02- 05:20 PM
Hi Laika, check your email all three of them
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Laika 801
Pilot
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posted 08-02- 06:56 PM
I checked, headbanged, and reply-ed ! LK IP: Logged |
Pachy
Pilot
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posted 08-03- 01:43 AM
quote:
What is your problem with me exactly Pachy? I can't help but notice every post to me for the last 6 months has been criticism in one form or another.
Tailslide I don't think I have a problem (I hope). Sometimes I'm nitpicking a little too much, sometimes I'm just asking questions maybe not in a very polite way. But I most appreciate the work you are doing here, whether on your planes (I love the Yak), or on FM work. This FM work is really vital for us (I mean the SDOE community). That's why I'm really anxious how the FM's will be, and I'm asking tons of questions. I'm really sorry if it sounded like random criticism directed at your work, and I owe you apology here.
You know, like Laika english is not my primary language, so often I may sound more direct than I meant. But in fact I'm like an admirer without manners.
So I apologise for complaining so rudely about the Spit MkIa guns positioning, the FW190 wings etc. Like I said before, keep up the good work, I'm confident Laika's and your work will produce a fantastic plane. IP: Logged |
Tailslide
Pilot
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posted 08-03- 02:03 AM
Ok, I was thinking you were mad about something, I am glad it's nothing serious ! I also wish that all aspects of the planes could be perfect but there are some limitations in openplane that make me realize this will never be, and you can probably tell by my posts this can be really frustrating ! How is the tempest coming by the way? TS
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