---------------------------------------------------------- TeamGrumman-List Digest Archive --- Total Messages Posted Sat 01/28/12: 5 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 05:51 AM - Aileron weight missing (James Grieco) 2. 05:53 AM - Aileron mass balance (James Grieco) 3. 07:09 AM - Re: Aileron mass balance (Ned Thomas) 4. 07:12 PM - Re: Aileron mass balance (Gary Vogt) 5. 10:57 PM - Re: Aileron mass balance (Gary L Vogt) ________________________________ Message 1 _____________________________________ Time: 05:51:41 AM PST US Subject: TeamGrumman-List: Aileron weight missing From: James Grieco I think there is a misconception about the weight. Its specific job is as a mass balance about the hinge line. If you draw a free body diagram of the aileron with the weight and a chord wise cut of the aileron, the two masses balance around the hinge bracket. When you apply a vertical gust, the inertia load on both sides of the hinge is the same, and in the same direction, so the hinge bracket gets wacked with combined load of the aileron mass + the counter weight mass X the vertical gust factor. This means the aileron wouldn't rotate, but there would be a large bending moment at the junction of the weight to tube welded joint. With rust and continuous fatigue loading it could break. Since no aileron rotation occurs, the rod would not hit the stop. An estimate of the Max load and rod stress seen can be found by determining the ultimate capability of the hinge bracket. Since I gather it did not fail, the bending moment applied to the rod would be 1/2 the bracket ultimate load capability X the length of the rod to the CG of the mass. The gust factor would be 1/2 the bracket ultimate load divided by the weight of the counter weight up to the weld. ________________________________ Message 2 _____________________________________ Time: 05:53:08 AM PST US Subject: TeamGrumman-List: Aileron mass balance From: James Grieco I think there is a misconception about the weight. Its specific job is as a mass balance about the hinge line. If you draw a free body diagram of the aileron with the weight and a chord wise cut of the aileron, the two masses balance around the hinge bracket. When you apply a vertical gust, the inertia load on both sides of the hinge is the same, and in the same direction, so the hinge bracket gets wacked with combined load of the aileron mass + the counter weight mass X the vertical gust factor. This means the aileron wouldn't rotate, but there would be a large bending moment at the junction of the weight to tube welded joint. With rust and continuous fatigue loading it could break. Since no aileron rotation occurs, the rod would not hit the stop. An estimate of the Max load and rod stress seen can be found by determining the ultimate capability of the hinge bracket. Since I gather it did not fail, the bending moment applied to the rod would be 1/2 the bracket ultimate load capability X the length of the rod to the CG of the mass. The gust factor would be 1/2 the bracket ultimate load divided by the weight of the counter weight up to the weld. ________________________________ Message 3 _____________________________________ Time: 07:09:28 AM PST US Subject: Re: TeamGrumman-List: Aileron mass balance From: Ned Thomas <923te@att.net> Very good engineering analysis. Reminds me of the core classes back in college days. It is consistent with what the pilot reported as well. Didn't the report also say that BOTH counterweights departed the aircraft? Ned Sent from my iPad On Jan 28, 2012, at 7:50 AM, James Grieco wrote: > > I think there is a misconception about the weight. Its specific job is as a mass balance about the hinge line. If you draw a free body diagram of the aileron with the weight and a chord wise cut of the aileron, the two masses balance around the hinge bracket. When you apply a vertical gust, the inertia load on both sides of the hinge is the same, and in the same direction, so the hinge bracket gets wacked with combined load of the aileron mass + the counter weight mass X the vertical gust factor. This means the aileron wouldn't rotate, but there would be a large bending moment at the junction of the weight to tube welded joint. With rust and continuous fatigue loading it could break. Since no aileron rotation occurs, the rod would not hit the stop. > An estimate of the Max load and rod stress seen can be found by determining the ultimate capability of the hinge bracket. Since I gather it did not fail, the bending moment applied to the rod would be 1/2 the bracket ultimate load capability X the length of the rod to the CG of the mass. The gust factor would be 1/2 the bracket ultimate load divided by the weight of the counter weight up to the weld. > > > > > ________________________________ Message 4 _____________________________________ Time: 07:12:00 PM PST US From: Gary Vogt Subject: Re: TeamGrumman-List: Aileron mass balance OK, but, to get the weight into the slipstream far enough to get dragged on , it has to move past the stop. -Otherwise, there would be a lot of torn off weights.=0A=0A=0A________________________________=0A From: James Grieco =0ATo: TeamGrumman =0ASent: Saturday, January 28, 2012 5:50 AM=0ASubject: TeamGrumman-List: A eco =0A=0AI think there is a misconception about the weight. Its specific job is as a mass balance about the hinge line. If you draw a free body diagram of the aileron with the weight and a chord wise c ut of the aileron, the two masses balance around the hinge bracket. When yo u apply a vertical gust, the inertia load on both sides of the hinge is the same, and in the same direction, so the hinge bracket gets wacked with com bined load of the aileron mass + the counter weight mass X the vertical gus t factor. This means the aileron wouldn't rotate, but there would be a larg e bending moment at the junction of the weight to tube welded joint. With r ust and continuous fatigue loading it could break. Since no aileron rotatio n occurs, the rod would not hit the stop. =0AAn estimate of the Max load an d rod stress seen can be found by determining the ultimate capability of th e hinge bracket. Since I gather it did not fail,- the bending moment appl ied to the rod would be 1/2 the bracket ultimate load capability- X the l ength of the rod to the CG of the mass. The gust factor would be 1/2 the br acket ultimate load divided by the weight of the counter weight up to the w ==================== ________________________________ Message 5 _____________________________________ Time: 10:57:03 PM PST US Subject: Re: TeamGrumman-List: Aileron mass balance From: Gary L Vogt I appreciate the lessons in strength of materials and statics, but it's more than just a missing counterweight. I wish I'd taken pics. The end of the to rque tube was sheared at the aileron bearing bracket. That degree of force h as to be transferred to the aileron stop, if and only if, the bolt that does the stopping is still there. Gary Sent from my iPad On Jan 28, 2012, at 7:08 PM, Gary Vogt wrote: > OK, but, to get the weight into the slipstream far enough to get dragged o n, it has to move past the stop. Otherwise, there would be a lot of torn of f weights. > > From: James Grieco > To: TeamGrumman > Sent: Saturday, January 28, 2012 5:50 AM > Subject: TeamGrumman-List: Aileron mass balance > m> > > I think there is a misconception about the weight. Its specific job is as a mass balance about the hinge line. If you draw a free body diagram of the a ileron with the weight and a chord wise cut of the aileron, the two masses b alance around the hinge bracket. When you apply a vertical gust, the inertia load on both sides of the hinge is the same, and in the same direction, so t he hinge bracket gets wacked with combined load of the aileron mass + the co unter weight mass X the vertical gust factor. This means the aileron wouldn' t rotate, but there would be a large bending moment at the junction of the w eight to tube welded joint. With rust and continuous fatigue loading it coul d break. Since no aileron rotation occurs, the rod would not hit the stop. > An estimate of the Max load and rod stress seen can be found by determinin g the ultimate capability of the hinge bracket. Since I gather it did not fa il, the bending moment applied to the rod would be 1/2 the bracket ultimate load capability X the length of the rod to the CG of the mass. The gust fa ctor would be 1/2 the bracket ultimate load divided by the weight of the cou nter weight upamGrumman-List" target="_blank">http://www.matronics.com/Nav igator?TeamGrumman-List<================== ===== > > > > > > ========================== ========= ========================== ========= ========================== ========= ========================== ========= > ------------------------------------------------------------------------------------- Other Matronics Email List Services ------------------------------------------------------------------------------------- Post A New Message teamgrumman-list@matronics.com UN/SUBSCRIBE http://www.matronics.com/subscription List FAQ http://www.matronics.com/FAQ/TeamGrumman-List.htm Web Forum Interface To Lists http://forums.matronics.com Matronics List Wiki http://wiki.matronics.com Full Archive Search Engine http://www.matronics.com/search 7-Day List Browse http://www.matronics.com/browse/teamgrumman-list Browse Digests http://www.matronics.com/digest/teamgrumman-list Browse Other Lists http://www.matronics.com/browse Live Online Chat! http://www.matronics.com/chat Archive Downloading http://www.matronics.com/archives Photo Share http://www.matronics.com/photoshare Other Email Lists http://www.matronics.com/emaillists Contributions http://www.matronics.com/contribution ------------------------------------------------------------------------------------- These Email List Services are sponsored solely by Matronics and through the generous Contributions of its members.