[NSRCA-discussion] Wing Sweep Angle?

[rcmaster199 at aol.com]

Jim,

The root and tip chords do not have ACs per se, but you know that already. The AC of a wing panel is located at 25% MAC and everything I've read on the subject seems in agreement, at least for full scale, so I use that value for my models. I think that's what Smith is alluding to

The actual angle I think is relative to the fuse CL...So if the wing is rectangular, sweep is considered zero by convention (I think) (Ron correct me if there is no convention on this). If sweep is aft, the angle should be straight forward to measure or calculate. If sweep is fore, same thing except the sign is reversed.

For the model wings I use (much higher root to tip ratios than every one else uses), sweep at 25% chord is about 20 degrees to the rear. I haven't found it excessive or insufficient. It doesn't affect the parameters I use for wing vertical location on the fuse (given a specific dihedral angle). This has been tested on 6 original designs so far over the years with somewhat variable sweep angle (a few degrees, maybe as much as 5 degrees delta). The dihedral effect delta has been nil. 

regads
Matt


-----Original Message-----
From: J N Hiller <jnhiller at earthlink.net>
To: General pattern discussion <nsrca-discussion at lists.nsrca.org>
Sent: Sun, Dec 8, 2013 8:04 pm
Subject: Re: [NSRCA-discussion] Wing Sweep Angle?


Thank you that's exactly what I wanted to know. I've changed it on different
airplanes and wanted to use a 'correct' standard reference when listing
design parameters. I'm finding some sweep is good more isn't, in my opinion.
Jim


-----Original Message-----
From: nsrca-discussion-bounces at lists.nsrca.org
[mailto:nsrca-discussion-bounces at lists.nsrca.org]On Behalf Of Ryan Smith
Sent: Sunday, December 08, 2013 2:21 PM
To: 'General pattern discussion'
Subject: Re: [NSRCA-discussion] Wing Sweep Angle?

Hi Jim,

I was always taught to use the aerodynamic center of the root and tip, and
project a line down the span of the wing across these two points. It's
pretty close to 25% generally; it may be a few percent off, but for the
purposes of calculation, it's really close. There are enough variables in
the scheme of things to render that exact enough for our purposes.

I hope this helps.

Best regards,

Ryan

-----Original Message-----
From: nsrca-discussion-bounces at lists.nsrca.org
[mailto:nsrca-discussion-bounces at lists.nsrca.org] On Behalf Of J N Hiller
Sent: Sunday, December 08, 2013 4:17 PM
To: NSRCA Mailing List
Subject: [NSRCA-discussion] Wing Sweep Angle?

Question!
How dose one measure wing sweep angle on tapered wing panels? Is it located
as a percentage of cord?
Jim Hiller



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