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Author	Topic: Boeing 117 airfoil request
Whirlwind Pilot	posted 08-08- 01:50 PM I no nothing about airfoils and am wondering if this airfoil already exists or whether someone could make it for me. IP: Logged
Whirlwind Pilot	posted 08-08- 07:55 PM No one is interested? IP: Logged
Jerry Pilot	posted 08-08- 08:47 PM Is that Boeing 117 or a typo for Boeing B17? IP: Logged
Whirlwind Pilot	posted 08-08- 09:38 PM Nope it is a Boeing 117 airfoil. No typo. IP: Logged
Aladar Pilot	posted 08-08- 09:39 PM What the hell is that? IP: Logged
Falck Pilot	posted 08-08- 09:43 PM Most american airfoils were designated as a NACA number, specifying thickness and camber. Any idea what the NACA equivalent of the 117 airfoil is? IP: Logged
Whirlwind Pilot	posted 08-08- 09:57 PM That is part of the excitement of figuring out what the NACA number is. Every ref I have for the plane says it uses the Boeing 117 airfoil, including Boeing's official history pages. One I saw it there, I noticed it was in every reference I had on it. The plane is the B-29. I have the basic body done, except the engine nacels. I need to split the tail plane into elevators and hstab yet. I am fighting over the idea of texture mapping the green house or cutting holes in the nose piece, which is gonna bite. She needs some work on the dof's for the airlons and textured, which is what I can't do. I also need to do lower level LOD's for it. I have more than enough info to get it done, but not enough info to figure out the 'Boeing 117' airfoil, much less put it in a sm file. IP: Logged
Michael Harrison General	posted 08-09- 10:26 AM If you can get a cross section of the wing, the airfoil can be estimated by measuring the length (chord) and thickness. If it has any camber, things get more difficult, but only slightly so. IP: Logged
Whirlwind Pilot	posted 08-09- 11:48 AM The cross section I have I don't have a lot of faith in being accurate, but it beats nothing. As it is, I am using the B-17 as a base, but will convert it to the Lanc as a base if it looks better than the B-17 so far. IP: Logged
Whirlwind Pilot	posted 08-09- 03:55 PM Is this the data I need? (From: http://www.wpafb.af.mil/museum/research/bombers/b3-30.htm) WINGS Airfoil section: Boeing 117 1. Root: 22% 2. Tip: 7% Chord Root: 17 ft. Chord tip (70 feet 10 inches from centerline of fuselage): 7 ft. 5 in. Incidence: 4 degrees Dihedral: 4 degrees 29 minutes 23 seconds Sweepback: 7 degrees 1 minute 26 seconds How does one construct an airfoil estimate from this data? IP: Logged
darthbob Pilot	posted 08-09- 04:03 PM yo i got your mail message. i would love to help on the b29. but i'm crap at this kind of thing. my attempts so far are rubbish. i do have engines done but they are not accurate. i will try. IP: Logged
Whirlwind Pilot	posted 08-09- 04:09 PM Cool beans! Them might be better looking than whatever I can come up with. I've gone with the rounded turet as opposed to the early block ones. I am still debating the best approach to do the green house. I might do it in Animation Master - a spline based modelling program or I can do it in a series of lines in AC3D which will be a pain. I'd then just need to match up the edges to the original model. No biggie. I am using a 1:1 scale in AC3D and it ports to SDOE just fine. If you fly the B-17 training mission (for all SDOE knows, it is still the B-17) you clip the kwanza hut along the edge of the runway with one of your wings. Nothing like going for a take-off and smacking ye old wing off. From: www.wpafb.af.mil - the Wright Patterson Airforce Base Museum [This message has been edited by Whirlwind (edited 08-09-2000).] IP: Logged
darthbob Pilot	posted 08-10- 12:35 PM truespace is very useful for cutting out windows etc.all you do is make the cuttout shape. position it then subtract it and thats it. IP: Logged
darthbob Pilot	posted 08-10- 12:54 PM could i have your b29 model,compare it then realise how crap mine is. cheers. IP: Logged
Whirlwind Pilot	posted 08-10- 01:04 PM I have few flaws in it (flickering panels aft the bombbays) but sure. I am going to try my hand at 'TurboCAD Pro' tonight to see if I can do a better one. I am thinking of just porting the parts that need holes cut in them to TurboCAD and back. This should be interesting... IP: Logged
Bishop Cadet	posted 08-11- 01:47 PM Whirlwind, Hopefully this can help (sorry I can't remember the exact web addresses): I found the b29 airfoil in the UIUC database (the site is listed by MH somewhere in the bibliography section). It's listed as Boeing117 in the aircraft section, in the actual database its listed as b29(root) and b29(tip). You can download these files, which have the coordinates of the airfoil. After that you have to find a program that will analyze the coordinates. In the bibliography section MH also gives the address for an on-line applet at DLR that can do this. I have also found alot of free programs to download (try just searching for airfoil analysis on the web) but haven't had a chance to try any of them yet. You will need these programs to determine CL (lift Coefficient), CD (drag Coefficient), and CM (moment coefficient)at different angles of attack. There is also a couple of programs around on the SDOE websites which will allow you to view and edit the SDOE airfoil files. They are called airEd and Wing Extractor (I think Tailslide's site has at least one of them for sure). You can play around with these to see what SDOE is looking for when it comes to airfoils. Now's the trick. Somehow you have to take the CL, CD, and CM data from the analysis package (chances are good that free software the data won't be valid past stall) and combine it with an existing airfoil (which has information for post-stall behaviour) Post stall is where the dCl, dCd and dCm values kick in, so if your airfoil can achieve higher angle of attack than the existing SDOE airfoil there is some playing around to do. Apparently Laika and Tailslide did this for the Pe2 (see the thread under Pe2). Searching for airfoil on this site will help with editing the airfoil data for SDOE and getting it into your .sm file without causing CTDs. I hope this helps. Theoretically, it all should work, but I haven't tried it yet (I'm just reaching that point in my current project). Tailslide and Falck know a hell of a lot more than I do about this so maybe he can correct me. Apparently, there are also some issues with the accuracy of airfoil data analyzed using the free software codes, if you can find wind tunnel data, so much the better (check on www.larc.nasa.gov, there is a THOROUGH document there by Abbot and Doenhoff (1945?) taht has a ton of airfoil data (probably all NACA but, again, I haven't had a chance to go through it yet). You might even find a different report more specifically relating to the B29 or B117 airfoil. Whew, my fingers are tired.... -Bishop IP: Logged
Whirlwind Pilot	posted 08-11- 02:46 PM Thanks! This should make life interesting . Maybe I can put that AE woman of mine to work for me for a change heheheh... IP: Logged
darthbob Pilot	posted 08-11- 02:53 PM it is a nice model indeed. but the tail is out of line and the wings should'nt be horizontal. i quickly whipped up some engine nacelles to see what they looked like see low res/quality pic at http://members.xoom.com/KMoynes/pics/ IP: Logged
Whirlwind Pilot	posted 08-11- 03:09 PM Oh, they get rotated to the proper angle in OPS. The next trick is to rotate the wing tips forward 7 degrees and change so that when I rotate the wings back in OPS, the sweep will be taken in account in SDOE. I cut the elevators out and they work nicely now. The gruesome task of doing the greenhouse is close at hand. I might cop out for now and get the pilot/copilot consoles done. The spinners are part of the prop aside from that, the nacells look good, darthbob. IP: Logged
ArgonV Pilot	posted 08-11- 03:37 PM And thus the B-29 race has begun......... Who will design the winner model? Will these two rivals duel it out? Stay tuned! Same place, same time. IP: Logged
Whirlwind Pilot	posted 08-11- 03:38 PM Same team, bunky IP: Logged
darthbob Pilot	posted 08-13- 04:11 AM those pics are incredible. nuff said. IP: Logged
FarmerJoe Pilot	posted 08-14- 04:35 AM Hey man I am working on the b17 Highly detailed mod and I can take a look at that green house you keep putting off. I can't promise it will get first priority but as soon as I am finished with the gunner models which will be soon then I can jump on that and probably have that done for you in a day or two. Assuming you have pictures in color also of the inside of this baby. Well just email it to jameso@cdsnet.com Texturing and cutting holes aint no thing ------------------ Subaltern FarmerJoe Axis West Three Amigo IP: Logged
Whirlwind Pilot	posted 08-14- 08:14 AM I actually got the green house done for the most part, I just need to tweak it a bit so I don't need to make it double sided. However, how'd you like to do the tail gunner position (I need to re-cut the tail section so the gunner's canopy stays with the plane.) Thanks! What format do you need? I am using AC3D right now. BTW, the above picture (the one of the B-29 and Mustang burning) was a result of a crash landing by the B-29. [This message has been edited by Whirlwind (edited 08-14-2000).] IP: Logged

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