Wing rib lofting
03-21-2002, 01:40 AM
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Wing rib lofting
Can anyone out there give me input on how they decide what rib design to loft for any given scratch built design? I am currently designing a Macchi 202 and have used the actual wing rib scale drawings to compare with a table of NACA coordinates, then I plan to loft these with Compufoil. Does anyone else do this? Should I adapt them in any way for my 1/5 scale?
03-21-2002, 02:30 AM
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Airfoils and scale
I don't think there's a hard a fast answer for this. That aircraft, at 1/5th scale, will probably do fine with scale airfoils.
Many scale builders insist on using scale airfoils (I do) as a matter of accuracy. There are "issues" with Reynolds numbers, when scaling down airfoils, but with the scale models I've built, nothing tragic so far.
Many scale builders insist on using scale airfoils (I do) as a matter of accuracy. There are "issues" with Reynolds numbers, when scaling down airfoils, but with the scale models I've built, nothing tragic so far.
03-21-2002, 05:39 AM
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Problem, Maybe
That scaling down of real airfoils to model doesn't always work.
I have gone through the loops to find airfoil numbers from old magazines, and then had an equally hard time in locating coordinates for it, only to find the scaled down version is too thin. There is insufficient thickness for currently available model A/C retractable landing gear. Model A/C airfoils seem to be a bit thicker, and thus provide the clearances necessary for all the hardware and frame involved with the gear. We had a scaled down airfoil last year which at it's thickest point was not quite one inch, surface to surface. How dow you stuff a L.G bracket which is 1-1/4 inch high into that?
Wm.
I have gone through the loops to find airfoil numbers from old magazines, and then had an equally hard time in locating coordinates for it, only to find the scaled down version is too thin. There is insufficient thickness for currently available model A/C retractable landing gear. Model A/C airfoils seem to be a bit thicker, and thus provide the clearances necessary for all the hardware and frame involved with the gear. We had a scaled down airfoil last year which at it's thickest point was not quite one inch, surface to surface. How dow you stuff a L.G bracket which is 1-1/4 inch high into that?
Wm.
04-13-2002, 11:48 PM
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Wing rib lofting
To "Bentbalsa"
Thanks - I am aware of this. I prefer to start with a blank sheet of paper when beginning a new project, otherwise I feel I'm building someone else's airplane. The travelling is much more rewarding than the destination itself.
Thanks - I am aware of this. I prefer to start with a blank sheet of paper when beginning a new project, otherwise I feel I'm building someone else's airplane. The travelling is much more rewarding than the destination itself.
01-15-2007, 07:53 AM
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RE: Problem, Maybe
ORIGINAL: CoosBayLumber
That scaling down of real airfoils to model doesn't always work.
I have gone through the loops to find airfoil numbers from old magazines, and then had an equally hard time in locating coordinates for it, only to find the scaled down version is too thin. There is insufficient thickness for currently available model A/C retractable landing gear. Model A/C airfoils seem to be a bit thicker, and thus provide the clearances necessary for all the hardware and frame involved with the gear. We had a scaled down airfoil last year which at it's thickest point was not quite one inch, surface to surface. How dow you stuff a L.G bracket which is 1-1/4 inch high into that?
Wm.
That scaling down of real airfoils to model doesn't always work.
I have gone through the loops to find airfoil numbers from old magazines, and then had an equally hard time in locating coordinates for it, only to find the scaled down version is too thin. There is insufficient thickness for currently available model A/C retractable landing gear. Model A/C airfoils seem to be a bit thicker, and thus provide the clearances necessary for all the hardware and frame involved with the gear. We had a scaled down airfoil last year which at it's thickest point was not quite one inch, surface to surface. How dow you stuff a L.G bracket which is 1-1/4 inch high into that?
Wm.
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