Wing Rib Spacing ???
John Roncallo
Im looking for some engineering guidlines on wing rib spacing. I cant
seem to find this in any text. Anyone Know any rules of thumb or a good
paper or text on the subject. I am currently considering either aluminum
of fabric.
Thanks
--
/---------------------------------------/
/ John Roncallo /
/ John.R...@Worldnet.Att.Net /
/---------------------------------------/
David Munday
John Roncallo <John.R...@WorldNet.att.net> wrote:
>Im looking for some engineering guidlines on wing rib spacing. I cant
>seem to find this in any text. Anyone Know any rules of thumb or a good
>paper or text on the subject. I am currently considering either aluminum
>of fabric.
Well, for a rule of thumb, you could take your tape measure to the
airport and measure a bunch of planes. The more they are like one
another the more likely, you've found a rule of thumb. (Ragwings
mostly seem to have like rib spacing, aluminum planes could be of the
many rib, thin skin catagore or of the few rib, thick skin category)
Once you've got a proposed wing design, check the math for your
expected dynamic preasures.
--
David Munday - mund...@miavx1.acs.muohio.edu
Webpage: http://www.nku.edu/~munday
PP-ASEL - Tandem Flybaby Builder - EAA-284 (Waynesville, OH)
When I was a boy I was told that anybody could become President;
I'm beginning to believe it -- Clarence Darrow
Johnny
David Munday wrote:
>
> Well, for a rule of thumb, you could take your tape measure to the
> airport and measure a bunch of planes. The more they are like one
> another the more likely, you've found a rule of thumb. (Ragwings
> mostly seem to have like rib spacing, aluminum planes could be of the
> many rib, thin skin catagore or of the few rib, thick skin category)
> Once you've got a proposed wing design, check the math for your
> expected dynamic preasures.
The Grumman AA-* series uses 16 inch spacing and .020 skins. But, the
skin has a tendency to look like fabric when in flight sometimes.
-j-
brian whatcott
In article <33BC57...@WorldNet.att.net>,
John.R...@WorldNet.att.net says...
>
>Im looking for some engineering guidlines on wing rib spacing. I cant
>seem to find this in any text. Anyone Know any rules of thumb or a good
>paper or text on the subject. I am currently considering either aluminum
>of fabric.
VP1 16 inches
Teenie II 12, 16, 18 inch spacing from root on out.
BD4 10 inch
Piper was pinged by the FAA for reducing the # of ribs in a certificated
airplane.
On an allied topic, fuselage bulkheads are found at similar spacings on a wide
variety of aircraft. This should be a hint that this is a cultural choice as much as
anything.
Regards brian whatcott <in...@intellisys.net> Altus OK
J. Reid Howell
brian whatcott <in...@intellisys.net> wrote in article
<5pj2ij$4...@snews5.zippo.com>...
> In article <33BC57...@WorldNet.att.net>,
> John.R...@WorldNet.att.net says...
> >
> >Im looking for some engineering guidlines on wing rib spacing. I cant
> >seem to find this in any text. Anyone Know any rules of thumb or a good
> >paper or text on the subject. I am currently considering either aluminum
> >of fabric.
>
There really is no "rule of thumb".
The spacing will depend upon the structure required to carry the load into
the spars.
In general, some of the variables include:
Wing area
Wing loading
Type of skins and stringers
Thickness of skins and stringers
Thickness of ribs
Etc.
You need to find an engineer to work with you.
To simply "copy" or estimate another design without fully understanding the
parameters is a good formula for disaster.
Lee McGee
brian whatcott wrote:
>
> In article <33BC57...@WorldNet.att.net>,
> John.R...@WorldNet.att.net says...
> >
> >Im looking for some engineering guidlines on wing rib spacing. I cant
> >seem to find this in any text. Anyone Know any rules of thumb or a good
> >paper or text on the subject. I am currently considering either aluminum
> >of fabric.
>
> Teenie II 12, 16, 18 inch spacing from root on out.
> BD4 10 inch
Acroduster Too aerobatic biplane
10.5 inch, 5.25 inch spacing on noseribs (a fabric covered design)
This is very typical of the small biplanes.
--
Lee McGee leem...@well.com, leem...@home.com, le...@cnet.com
http://www.well.com/user/leemcgee/
brian whatcott
In article <33BDD5...@home.com>, leem...@home.com says...
>...
>Acroduster Too aerobatic biplane
> 10.5 inch, 5.25 inch spacing on noseribs (a fabric covered design)
>This is very typical of the small biplanes.
>
Here's a quote from "Understanding Aircraft Structures" pp11-
John Cutler BSP Professional Books
"A glance at these post-1955 designs shows very clearly that the
structures of big aircraft are not just little aircraft structures scaled-up...
in fact, whatever the size of the aircraft, the fuselage frames are always about
20 inches apart and have between 3 in and 6 in. deep cross-sections."
...so it looks like 5,10,20 is a favorite series!
David Munday
Lee McGee <leem...@home.com> wrote:
>brian whatcott wrote:
>>
>> In article <33BC57...@WorldNet.att.net>,
>> John.R...@WorldNet.att.net says...
>> >
>> >Im looking for some engineering guidlines on wing rib spacing. I cant
>> >seem to find this in any text. Anyone Know any rules of thumb or a good
>> >paper or text on the subject. I am currently considering either aluminum
>> >of fabric.
>>
>> VP1 16 inches
>> Teenie II 12, 16, 18 inch spacing from root on out.
>> BD4 10 inch
>Acroduster Too aerobatic biplane
> 10.5 inch, 5.25 inch spacing on noseribs (a fabric covered design)
Bowers Flybaby
15 inch between main ribs, half that between nose ribs.
David Munday
"J. Reid Howell" <cape...@flash.net> wrote:
There really is no "rule of thumb".
>The spacing will depend upon the structure required to carry the load into
>the spars.
>In general, some of the variables include:
>Wing area
>Wing loading
>Type of skins and stringers
>Thickness of skins and stringers
>Thickness of ribs
>Etc.
All true, but
>You need to find an engineer to work with you.
>To simply "copy" or estimate another design without fully understanding the
>parameters is a good formula for disaster.
I think you're overstating the difficulty here. If we confine
ourselves to low speed aircraft (say up to 150 mph) then you'll pretty
well do fine by peeking under the skin of any old cub, champ, or
t-craft and faithfully copying what you find there. The problem gets
more complex fast as you increase speed, and admittedly the original
query didn't say anything about the speed or wing loading of the
project.
Low speed aero and structures need not be rocket science, they can be
simply a matter of following long established practice. If you want
to make your plane out of something exotic, or make it on an unusual
planform, or make it go like hell then you'd better be prepared to do
some serious engineering, but you can bet your bottom dollar that
Taylor et. al. didn't know much about fancy engineering. Sometimes I
wonder if they even had to resort to a slide rule, or if they did all
their figgerin' on the back of an envelope and then built the thing to
see if it'd fly.
BBCuda
I think you better follow the advise of Mr. Howell, he is 150% right.