Re: Ground Effect in YASim
James Turner <[email protected]> Fri, 7 Mar 2025 10:04:35 +0000
| Newsgroups | gmane.games.flightgear.devel,gmane.games.flightgear.flightmodel |
|---|---|
| Message-ID | <[email protected]> |
--===============4949661134645558401== Content-Type: multipart/alternative; boundary="Apple-Mail=_8989BA97-50AA-4865-A396-C03A68294C81" --Apple-Mail=_8989BA97-50AA-4865-A396-C03A68294C81 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=utf-8 > On 5 Mar 2025, at 19:08, _ __ <[email protected]> wrote: >=20 > YASim currently calculates ground effect as a linear lift increase = starting from one whole wingspan above the ground. In a previous email = <https://sourceforge.net/p/flightgear/mailman/flightgear-devel/thread/CAF9= yP-fcYZKR%3DF%2B_j%3DwUeRL4A9s6DuGW1Ndxz8uzYRGNYo_%2BrA%40mail.gmail.com/#= msg58834280> I mentioned that this should be a non-linear increase, and = custom compiled my own version with a low effort fix. >=20 > I am now back with a more detailed proposal, following equation 11 = from this study = <https://www.researchgate.net/publication/269047238_Lifting-Line_Predictio= ns_for_Induced_Drag_and_Lift_in_Ground_Effect>, using the following code = (the bolded stuff is the new stuff): Hi Joel, YASim is in some sense unmaintained, so the issue here (as we=E2=80=99ve = had with a few other changes in the past years) is how to manage getting = the changed applied and tested. With a previous change we had to add a config option to allow the old / = new behaviour, but it looks as if you=E2=80=99re expecting the new = formula to be universally better than the previous one, but also = backwards compatible - is that a fair statement? We=E2=80=99d also need to extend the unit (automated) test coverage in = this area, to establish the changed code is actually doing something. Are you happy to undertake the =E2=80=98admin=E2=80=99 steps of making a = fork on GitLab of flightgear, pushing your changes to it, etc, or are = you asking for some assistance in doing that? Kind regards, James --Apple-Mail=_8989BA97-50AA-4865-A396-C03A68294C81 Content-Transfer-Encoding: quoted-printable Content-Type: text/html; charset=utf-8 <html><head><meta http-equiv=3D"content-type" content=3D"text/html; = charset=3Dutf-8"></head><body style=3D"overflow-wrap: break-word; = -webkit-nbsp-mode: space; line-break: after-white-space;"><br = id=3D"lineBreakAtBeginningOfMessage"><div><br><blockquote = type=3D"cite"><div>On 5 Mar 2025, at 19:08, _ __ = <[email protected]> wrote:</div><br = class=3D"Apple-interchange-newline"><div><meta charset=3D"UTF-8"><div = style=3D"caret-color: rgb(0, 0, 0); font-family: Helvetica; font-size: = 12px; font-style: normal; font-variant-caps: normal; font-weight: 400; = letter-spacing: normal; text-align: start; text-indent: 0px; = text-transform: none; white-space: normal; word-spacing: 0px; = -webkit-text-stroke-width: 0px; text-decoration: none;">YASim currently = calculates ground effect as a linear lift increase starting from one = whole wingspan above the ground. In a<span = class=3D"Apple-converted-space"> </span><a = href=3D"https://sourceforge.net/p/flightgear/mailman/flightgear-devel/thre= ad/CAF9yP-fcYZKR%3DF%2B_j%3DwUeRL4A9s6DuGW1Ndxz8uzYRGNYo_%2BrA%40mail.gmai= l.com/#msg58834280">previous email</a><span = class=3D"Apple-converted-space"> </span>I mentioned that this = should be a non-linear increase, and custom compiled my own version with = a low effort fix.</div><div style=3D"caret-color: rgb(0, 0, 0); = font-family: Helvetica; font-size: 12px; font-style: normal; = font-variant-caps: normal; font-weight: 400; letter-spacing: normal; = text-align: start; text-indent: 0px; text-transform: none; white-space: = normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; = text-decoration: none;"><br></div><div style=3D"caret-color: rgb(0, 0, = 0); font-family: Helvetica; font-size: 12px; font-style: normal; = font-variant-caps: normal; font-weight: 400; letter-spacing: normal; = text-align: start; text-indent: 0px; text-transform: none; white-space: = normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; = text-decoration: none;">I am now back with a more detailed proposal, = following equation 11 from<span = class=3D"Apple-converted-space"> </span><a = href=3D"https://www.researchgate.net/publication/269047238_Lifting-Line_Pr= edictions_for_Induced_Drag_and_Lift_in_Ground_Effect">this study</a>, = using the following code (the bolded stuff is the new = stuff):</div></div></blockquote></div><br><div>Hi = Joel,</div><div><br></div><div>YASim is in some sense unmaintained, so = the issue here (as we=E2=80=99ve had with a few other changes in the = past years) is how to manage getting the changed applied and = tested.</div><div><br></div><div>With a previous change we had to add a = config option to allow the old / new behaviour, but it looks as if = you=E2=80=99re expecting the new formula to be universally better than = the previous one, but also backwards compatible - is that a fair = statement?</div><div><br></div><div>We=E2=80=99d also need to extend the = unit (automated) test coverage in this area, to establish the changed = code is actually doing something.</div><div><br></div><div>Are you happy = to undertake the =E2=80=98admin=E2=80=99 steps of making a fork on = GitLab of flightgear, pushing your changes to it, etc, or are you asking = for some assistance in doing that?</div><div><br></div><div>Kind = regards,</div><div>James</div><div><br></div><div><br></div></body></html>= --Apple-Mail=_8989BA97-50AA-4865-A396-C03A68294C81-- --===============4949661134645558401== Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Disposition: inline --===============4949661134645558401== Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Disposition: inline _______________________________________________ Flightgear-devel mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/flightgear-devel --===============4949661134645558401==--