X-Junk-Score: 0 [] X-Cloudmark-Score: 0 [] X-Cloudmark-Analysis: v=2.3 cv=PbaBeRpd c=1 sm=1 tr=0 a=eM8eR9Kbi734Tvg/PCcf3Q==:117 a=_RQrkK6FrEwA:10 a=Jy3P6oOGoLoA:10 a=r77TgQKjGQsHNAKrUKIA:9 a=HZJGGiqLAAAA:8 a=pGLkceISAAAA:8 a=Ia-xEzejAAAA:8 a=7g1VtSJxAAAA:8 a=oyDQt2dSAAAA:8 a=_6GpL_ENAAAA:8 a=Pj2oY8TbS1Y4thqCs1oA:9 a=Sqhol26k20il6IZD:21 a=E9eLVfkMiEBh_lxL:21 a=QEXdDO2ut3YA:10 a=Qa1je4BO31QA:10 a=lrsIwZYKso8A:10 a=gvSQh4r-fQ0A:10 a=S0wkRrzPavQA:10 a=4PR2P7QzAAAA:8 a=jFy16rU9cfDEMdHgHgQA:9 a=z2KYCGRJlixmz7Z6:21 a=FWrGqcFhsyk1GQJJ:21 a=ujLmaYzchW8Gr7NQ:21 a=_W_S_7VecoQA:10 a=r1l34y2KONQA:10 a=Urk15JJjZg1Xo0ryW_k8:22 a=grOzbf7U_OpcSX4AJOnl:22 a=nY2paJTkNLOyQSZ-TCso:22 a=4dqwQCo7Po2mVW515mGf:22 a=pHzHmUro8NiASowvMSCR:22 a=Ew2E2A-JSTLzCXPT_086:22 From: "Finn Lassen finn.lassen@verizon.net" Received: from sonic306-21.consmr.mail.ne1.yahoo.com ([66.163.189.83] verified) by logan.com (CommuniGate Pro SMTP 6.2.14) with ESMTPS id 559680 for flyrotary@lancaironline.net; Thu, 23 Jul 2020 14:30:37 -0400 Received-SPF: pass receiver=logan.com; client-ip=66.163.189.83; envelope-from=finn.lassen@verizon.net DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=verizon.net; s=a2048; t=1595529020; bh=vqz3NDe4bfklDOAxLEU73XdzcDJnGRDqIHvsaKN41/k=; h=Subject:To:References:From:Date:In-Reply-To:From:Subject; b=CRcHMu9QxNftEKSMVmHXuJhtSjdiwJXbmg0M6X6yTKYYeRo+U51bVzQtEfzg/kIguCTG9m7LFbsuLplDbRzhl7pLqdEIo6yN6f6tf/p+LyicWwTD0PZYichiWjhvdBfbBzfOKlMiDWR5Yu4MvR7C0Re1P3d40PtV89rZDDhviK8try58Hsk7QVVGb0clWN8N/4zx8RP9XDM0QD+amHsic6ED3w6WMb+hRNLgKVkzBTXA5m80nA15X2TxOQe76/cmHE8G5p4flCmCc3BtDFGEgy89v7mloyjgpe32VvXhElKpvRXCOtahWawmB520h3LuQFscIBwlonWPVlL3IAAl0w== X-YMail-OSG: e4nB1HsVM1lB70lYqpn.gv_zmj6ZeskbMZeg0Kv4pSfI57Ho5SSoGUuWjsmb_TD FCOJNo89YrDvu_Y_CCx3mvjlURbIaoKrStg1s3.Mqp7_4jHbEUljWaSkxTaN8TRJo7tsf96Uds_6 TpFF4mHbGWHt02LJR2IIko5oq0kvYXlOrKIgOySMBl_0TgqX2zjVOHA8rJcnaBqq8IfSNhwyhGdd GSQ5heiuUmnUyoegCRnnvpb.ZqsyJpYNR.r6hINcT0axxtYE9EUut.SOqtHqI0Hh8g2ES2VQyZgD 783O55yPAI2IrZ95uq2M3XODJutfGizw8py9xFlTPQ6w9CO99no8VkTilCcOCDiyHdKGlvGXJkJO dQYibMqlpn02Lv1aGaBsLqkE0R0928S_b.JE7nRVGBcuHCTKyUKLjWjhiuJpv4yZmbq92.g3GTDc MDNrYY9g.PT4L_m.jjdIaAsqhckhH1XS.cAhasSAz.w8GQR2wPxcO7NQ6RL0hruuOv9eu3306xEa VPHuNzfHrh4a.qLRSTwrxILFTMqfWgADoVVDwU0TFx1lMQqY9i37Qe13CUfUQK85kOsFExb5g9g5 6U2B.cZgK6AK8GY5._TxLfKVKwKzZdIn_RbrioC9ehKMyaxo6DmuicL9KAZksR.fhSpa_IeUFpKc 0iBHoWPcKSZrnQbpRrtSExMcZaD76ITsB0TMUsDb_c.cxrWkX5ykpCkOAiWIXmOlzlmhH_fQ8uaG MB7lz0iQjX78bQa1CpZo9qfiHUKnLq5qximwFadX8KS1EufD_Z5OxFhG0KRNJMmNnVFvvjAPjlzY 1f5OXqJRdF9f_2gtpIg10CG1C.geq2PQqBlEdwxhcK0xg1nwhh.iqJG2vwq5CtlaOncBuAGYB8f4 bAg5ITi46woC7f4IzzTrXM8W5..wxNDiILgQzmTgFhOeSvAPkL_49ipWpO3rKecy4._7UbbzKnXc 0qHpbW7Qtys9igsP4StS9JIcM4kn7DBaNk_iwlMisFjFi0.s63_dqvvb2hZK1tGdJJ7YiNpY04.T Zp6.tSgInJwUwuVWCg_qx6.H2Aha9Fqyxu_bDcYhUFxgtIpcmKwBcF37mgqwb.0yeeBGrko3ldxB 6tuMvAXGBoEesX4HEr2mp3ExzS0zHMYRDWO2LceHaDBuE460TvEYAXwTvx3n0GRQmBFDiflP4i.Q RZrjjF0eLr1Gdg22EuGk01EnGjvLHfBTpBuMt3vkqCV6lFQdJEhz22e9tayrhJcr.7MqQ1NJd5hc dQ5Dp.tODHznsIL5S7CQOiBZDwkh7lpSh.kJCNt7aqimTz8sjcJIHKtuyXgfb_AK2P0xyfbTDUAO DUt5OBMX.APn9O8K4o0d4.KIR87vlAjqyQ9MPz37uS2QuYOUJfUwLR1Pe_4Lp2NrHSi2coKjHYHX Smeb6tlKbU5Va5TMqPfjoJhIhTPdOIEE4OUCrRABSKdpuRKsyNDXMqVrhykXOxGT3LBHqJEfNqFh x7RcCatwDlreM_O3SDGaphzv777M_ZEJ1Ll1qrE1RV3YyyFYdM.6dihTp6QfDY3nDTFucrvEYGzL 9Jn4CJqm3O8ZSWVLgWKgghV7oBkpHdMPmT5VARR7twfaldv_bBe5EJydDahoqSpaB2XDEfVgmI8b trcpuJZ.PsWixUXOon9Uwdc02SPqbOjYeES2XqzazHSAPDmeIR0AyN8yzVRcJY3EwlkcJGwVv1A- - Received: from sonic.gate.mail.ne1.yahoo.com by sonic306.consmr.mail.ne1.yahoo.com with HTTP; Thu, 23 Jul 2020 18:30:20 +0000 Received: by smtp402.mail.bf1.yahoo.com (VZM Hermes SMTP Server) with ESMTPA ID 7cc67cb6edb6da05478d1e7e7e173e96; Thu, 23 Jul 2020 18:30:14 +0000 (UTC) Subject: Re: [FlyRotary] Re: Engine Mount specs To: Rotary motors in aircraft References: Message-ID: <2bc7f8ee-360a-f1b0-c1a2-7d5436317360@verizon.net> Date: Thu, 23 Jul 2020 14:30:09 -0400 User-Agent: Mozilla/5.0 (Windows NT 5.1; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 MIME-Version: 1.0 In-Reply-To: Content-Type: multipart/alternative; boundary="------------2051B7E71EE3CA009EDC99B8" Content-Language: en-US X-Antivirus: Avast (VPS 200723-2, 07/23/2020), Outbound message X-Antivirus-Status: Clean X-Mailer: WebService/1.1.16271 hermes_aol Apache-HttpAsyncClient/4.1.4 (Java/11.0.7) Content-Length: 14242 This is a multi-part message in MIME format. --------------2051B7E71EE3CA009EDC99B8 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit I used Fusion360 (also free for hobby use) for my RV-4 Renesis engine mount. Finn On 7/23/2020 10:11 AM, Ernest Christley echristley@att.net wrote: > I was reading just last night in Sport Aviation that as a member of > the EAA, you can get a copy of Solidworks that will do stress > analysis.  Has anyone done this with a motor mount? > > > On Thursday, July 23, 2020, 9:32:33 AM EDT, Charlie England > ceengland7@gmail.com wrote: > > > > > On Wed, Jul 22, 2020 at 11:23 PM Le Roux Breytenbach > breytenbachleroux@gmail.com > > wrote: > > > Hi All members: > The 4130 chromemoly seamless pipe for the engine mount. > What is the appropriate size for building a engine frame, as the > included drawing of Paul L. ( copyright P.L ) > The outside diameter and wall thickness ? >  7/8  Inch OD x 0,069 “ Wall thickness ? > or 0.120 W > > 1 inch x OD ? > Cant find any specifications for such a design. > > > > Sent from my iPhone > Le Roux Breytenbach -- > Homepage: http://www.flyrotary.com/ > Archive and UnSub: > http://mail.lancaironline.net:81/lists/flyrotary/List.html > > > > For perspective, the RVs with up to an IO360 use 3/4" x 0.049" tubing. > But as Bobby & Andrew pointed out, crippling is the most critical > issue, and all of the RV's tubes that are loaded in compression are > much shorter than the bottom-most tube in that pic. I'd be most > concerned about that tube; the pair that are arrowed wouldn't concern > me that much. > > Those aren't the only issues; you need to look at the load paths > within welded joints, also. The strongest welds are the ones that are > stressed along their length. A tension load perpendicular to a weld > line is kinda 'worst case'. You obviously want to avoid loading tubes > in bending, but there are situations where it *might* be acceptable, > or even better. Ex: there are some 'bed mounts' (what that drawing > effectively shows) for some Continental 6cyl engines that use a > much larger horizontal member (left arrow in the pic), and attach the > compression member (bottom most tube in the pic) near the mid point of > the horizontal member. This loads the horizontal in bending (requiring > upsizing), but shortens the bottom compression member a lot, reducing > crippling loads on it 'Everything is a compromise.' ;-) Be sure that > your airframe's 'stock' motor mount doesn't include a horizontal > member between the two upper firewall attach points. RVs don't need > the tube, but some composite or wood designs might not have the > compression strength across the top of the fuselage that's needed  to > resist those two points trying to come together under positive G loading. > > Something I *wish* I could have done with my mount is to incorporate a > feature found on some radial engine mounts. They often have the 4 > firewall attach points being a U shaped bracket bolted through the > bottom of the U, to the firewall, and the motor mount termination a > vertical tube at each corner. By pulling the bolts on the top & bottom > of one side, the entire mount & engine can be swung to one side to > service stuff on the firewall or the back side of the engine. Trickier > to do with a mount like a taildragger RV, which has the gear leg > sockets incorporated in the mount. > >  I was fortunate enough to have two different engineers, both with > structural experience, critiquing my design attempts, and one of them > is also an excellent welder.... :-)  If you can find an engineer or > structures guy to look over your shoulder, it would be a good thing. > > Charlie --- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus --------------2051B7E71EE3CA009EDC99B8 Content-Type: text/html; charset=utf-8 Content-Transfer-Encoding: 8bit
I used Fusion360 (also free for hobby use) for my RV-4 Renesis engine mount.

Finn

On 7/23/2020 10:11 AM, Ernest Christley echristley@att.net wrote:
I was reading just last night in Sport Aviation that as a member of the EAA, you can get a copy of Solidworks that will do stress analysis.  Has anyone done this with a motor mount?


On Thursday, July 23, 2020, 9:32:33 AM EDT, Charlie England ceengland7@gmail.com <flyrotary@lancaironline.net> wrote:




On Wed, Jul 22, 2020 at 11:23 PM Le Roux Breytenbach breytenbachleroux@gmail.com <flyrotary@lancaironline.net> wrote:

Hi All members:
The 4130 chromemoly seamless pipe for the engine mount.
What is the appropriate size for building a engine frame, as the included drawing of Paul L. ( copyright P.L )
The outside diameter and wall thickness ?
 7/8  Inch OD x 0,069 “ Wall thickness ?
or 0.120 W

1 inch x OD ?
Cant find any specifications for such a design.



Sent from my iPhone
Le Roux Breytenbach --
Homepage:  http://www.flyrotary.com/
Archive and UnSub:   http://mail.lancaironline.net:81/lists/flyrotary/List.html

For perspective, the RVs with up to an IO360 use 3/4" x 0.049" tubing. But as Bobby & Andrew pointed out, crippling is the most critical issue, and all of the RV's tubes that are loaded in compression are much shorter than the bottom-most tube in that pic. I'd be most concerned about that tube; the pair that are arrowed wouldn't concern me that much.

Those aren't the only issues; you need to look at the load paths within welded joints, also. The strongest welds are the ones that are stressed along their length. A tension load perpendicular to a weld line is kinda 'worst case'. You obviously want to avoid loading tubes in bending, but there are situations where it *might* be acceptable, or even better. Ex: there are some 'bed mounts' (what that drawing effectively shows) for some Continental 6cyl engines that use a much larger horizontal member (left arrow in the pic), and attach the compression member (bottom most tube in the pic) near the mid point of the horizontal member. This loads the horizontal in bending (requiring upsizing), but shortens the bottom compression member a lot, reducing crippling loads on it 'Everything is a compromise.' ;-) Be sure that your airframe's 'stock' motor mount doesn't include a horizontal member between the two upper firewall attach points. RVs don't need the tube, but some composite or wood designs might not have the compression strength across the top of the fuselage that's needed  to resist those two points trying to come together under positive G loading.

Something I *wish* I could have done with my mount is to incorporate a feature found on some radial engine mounts. They often have the 4 firewall attach points being a U shaped bracket bolted through the bottom of the U, to the firewall, and the motor mount termination a vertical tube at each corner. By pulling the bolts on the top & bottom of one side, the entire mount & engine can be swung to one side to service stuff on the firewall or the back side of the engine. Trickier to do with a mount like a taildragger RV, which has the gear leg sockets incorporated in the mount.

 I was fortunate enough to have two different engineers, both with structural experience, critiquing my design attempts, and one of them is also an excellent welder.... :-)  If you can find an engineer or structures guy to look over your shoulder, it would be a good thing.

Charlie



Virus-free. www.avast.com
--------------2051B7E71EE3CA009EDC99B8--