X-Junk-Score: 0 [] X-Cloudmark-Score: 0 [] X-Cloudmark-Analysis: v=2.3 cv=cpHlbGwi c=1 sm=1 tr=0 a=bhq3n9Va5qLdRPODfS1a7Q==:117 a=x7bEGLp0ZPQA:10 a=A-0mRrAPPO4A:10 a=3JhidrIBZZsA:10 a=Ia-xEzejAAAA:8 a=_6GpL_ENAAAA:8 a=QoHPSLBpZtMfbgT4B5MA:9 a=QEXdDO2ut3YA:10 a=wn4LMc2zVwpUsDT-LrYA:9 a=Go0hFlmqg_uDGifI:21 a=Urk15JJjZg1Xo0ryW_k8:22 From: "Charlie England ceengland7@gmail.com" Received: from mail-pl1-f171.google.com ([209.85.214.171] verified) by logan.com (CommuniGate Pro SMTP 6.2.10) with ESMTPS id 12098619 for flyrotary@lancaironline.net; Sun, 13 Jan 2019 12:48:26 -0500 Received-SPF: pass receiver=logan.com; client-ip=209.85.214.171; envelope-from=ceengland7@gmail.com Received: by mail-pl1-f171.google.com with SMTP id u6so9051225plm.8 for ; Sun, 13 Jan 2019 09:48:26 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to; bh=DkwU9iUGTFAHMvMOx+iet1U7xTKcxUQM5et3EhJywQQ=; b=mdsN+YLFnD6WPs109WuiKhRp9mlkzm3X1i0v/haK/2ss4pMotZgKrZV9MSAjrBoNSJ LMBG4Z3X/SJEBWaE5aQvlQWA8V9LvZ9VDdzN48PG0WZVeyQq+P1RvyMS4EDWjx88HacP EAkoT3G+bGzPSu05M0mrbUKw/QfySsVnFaM2n5Pu9oSFGbiLGsZHUHBFT4/RrVbsSUsO O0g/ywfdn6VbhriqorbY8/J/OuWB+Bv1qmwpveZ37Iik2aP+yVwp7y40kz7MOfairLpn V7Bd3gT3PclHA36y9FsdGxvjILSSRTJSKojw8IHwXy04zIPjBzyZ61iKTE0VeNi7KRr3 BX9w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to; bh=DkwU9iUGTFAHMvMOx+iet1U7xTKcxUQM5et3EhJywQQ=; b=WnzAifaPFh+nMjRziYbSpWUYq82dRmHLMwvHeve6aRIStwUKCoAJy2oW+WlmQ3sD7T aEldPRNnBmnk78mh8EP4CYDIM5qCf7XCz5E0xjoZJfXhBaQzu6LiCBIT2TN3CYXKM4Bk a3c3jwRKcu0WAUH3Z3HbqNsQUgRM/YMoYXi7KjhY6b735nZdWSHhfh0u9KFKR5dqMFAM TWeIHl5PwPRVZgopVsu9ETWl4wgvi08omB094VzAM1uc37WQHhVDLBdo7EASMnPeeuWs vhlUAkrQ8rlKIpWXhQvMfAXtycfPI/K+6FZGCKyuzNHq3pqNmD4OoB0Lna5Cu3gOJTHT CxUQ== X-Gm-Message-State: AJcUukfzmYR7WblHVN7fJXWSa59mLZbgA/JV+ALskxW8qiEXZP7HM41b mbkyeNJGqPzi/DPNthH2/CnPPPjN2cCZuo3vbA4Mbg== X-Google-Smtp-Source: ALg8bN6nvWGgUcF0GEO/gTYA5/NXtl3iOUGjX3Ekn3ytaCKoNvR53bmAx+Zg35t3ENlTgaqT1gJZxS9QnVWkeJV6BWk= X-Received: by 2002:a17:902:5a86:: with SMTP id r6mr5839694pli.301.1547401688452; Sun, 13 Jan 2019 09:48:08 -0800 (PST) MIME-Version: 1.0 References: In-Reply-To: Date: Sun, 13 Jan 2019 11:47:01 -0600 Message-ID: Subject: Re: [FlyRotary] gearbox drain To: Rotary motors in aircraft Content-Type: multipart/alternative; boundary="000000000000f710e9057f5a87cd" --000000000000f710e9057f5a87cd Content-Type: text/plain; charset="UTF-8" On Sun, Jan 13, 2019 at 10:58 AM Steven W. Boese SBoese@uwyo.edu < flyrotary@lancaironline.net> wrote: > Tracy and Neil, > > > I installed a -4 fitting at the top of both the -C drive and also the -A > drive that I converted to 3.17 to one ratio. At idle with oil at about 50 > degrees, a gauge connected to that top fitting read about 4 psi inside the > gearbox. With oil at about 180 degrees, the gauge read about 2 psi. The 2 > psi was unchanged when the engine rpm was increased to 5000. Both > gearboxes behaved the same. > > > I also installed a ball valve in the -6 drain line that I could close > immediately after shutting the engine off. Then I could disconnect the > drain line and collect the oil that was inside the gearbox. The converted > -A drive with a 3 pinion planetary contained 22 oz of oil after shutdown > while the -C drive with the 6 pinion planetary contained 18 oz of oil. > This was with the top fitting dead ended to the gauge and not venting > anything during operation. > > > The oil flow rate from the prop end of the gearbox was found to be about > 1/4 oz per minute while the total oil flow rate through the gearbox was > found to be about 90 oz per minute. This explains why installing separate > -6 drain lines to the engine did not change the behavior. During the flow > rate measurement, the oil draining from the gearbox just after starting the > engine had a lot of entrained air for a short time. > > > So the conclusion is that the gearboxes are completely filled with oil > during operation and any air initially inside them is entrained in the oil > and forced out the drain by the incoming oil. The gearbox recommendations > that I could find do not recommend running with the components completely > submerged due to the power consumed by churning the oil and resultant > generation of heat. Those sources also say that if the gearbox is > partially filled with oil but the level is too high, the oil will foam and > lubrication will be degraded if the system circulates the oil using an > external pump. In our case, it may be better to accept the power loss and > extra heat as opposed to returning a lot of aerated oil to the engine. > > > An impeller was added to the planet carrier of the converted -A drive but > that gearbox still operated completely filled with oil. > > > The gearbox drain and the engine drain connection were increased to 1/2" > NPT and fittings drilled out to 21/32" ID were installed. 3/4" ID hose was > installed as the drain line. The drain line was close to level but > slightly down hill in operation. This reduced the gearbox internal > pressure to a value not measurable with a normal gauge. The amount of oil > inside the gearbox was measured by clamping off the drain hose immediately > after shutting down the engine, disconnecting the hose from the engine, and > then recovering the oil remaining inside the gearbox. The gearbox was > found to be completely filled with oil just as before. > > > When the -4 fitting in the top of the gearbox was connected to the engine > crankcase as a vent, the amount of oil recovered from the gearbox after > operation was now found to be about 5 to 6 oz. The recovered oil did not > appear to be foamed and its volume changed very little upon standing for > several hours. > > Steve Boese > > - > Well, I just had one of those 'Duh!' moments. It should have been obvious to me, but if the oil is foaming in the box (logical, given the thrashing by the gears) and carrying air out the drain, it's got to be replaced with something, and the only thing available is oil. The vent back to the crankcase lets the entrained air get replaced by air, instead of oil. Now, if the drain is the original -6 line, but the vent is added back to the crankcase, would it still keep up with the pressurized feed from the engine? Charlie Virus-free. www.avast.com <#DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2> --000000000000f710e9057f5a87cd Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable


On Sun, Jan 13, 2019 at 10:58 AM Steven W. Boese SBoese@uwyo.edu <flyrotary@lancaironline.net> wrote:

Tracy and Neil,<= /p>


I installed a -4 fitting at the top of both the -C drive and also the= -A drive that I converted to 3.17 to one ratio.=C2=A0 At idle with oil at = about 50 degrees, a gauge connected to that top fitting read about 4 psi in= side the gearbox.=C2=A0 With oil at about 180 degrees, the gauge read about 2 psi.=C2=A0 The 2 psi was unchanged whe= n the engine rpm was increased to 5000.=C2=A0 Both gearboxes behaved the sa= me.


I also installed a ball valve in the -6 drain line that I could close= immediately after shutting the engine off.=C2=A0 Then I could disconnect t= he drain line and collect the oil that was inside the gearbox.=C2=A0 The co= nverted -A drive with a 3 pinion planetary contained 22 oz of oil after shutdown while the -C drive with the 6 pinion= planetary contained 18 oz of oil.=C2=A0 This was with the top fitting dead= ended to the gauge and not venting anything during operation.


The oil flow rate from the prop end of the gearbox was found to be ab= out 1/4 oz per minute while the total oil flow rate through the gearbox was= found to be about 90 oz per minute.=C2=A0 This explains why installing sep= arate -6 drain lines to the engine did not change the behavior.=C2=A0 During the flow rate measurement, the oil d= raining from the gearbox just after starting the engine had a lot of entrai= ned air for a short time.


So the conclusion is that the gearboxes are completely filled with oi= l during operation and any air initially inside them is entrained in the oi= l and forced out the drain by the incoming oil. =C2=A0 The gearbox recommen= dations that I could find do not recommend running with the components completely submerged due to the power consumed= by churning the oil and resultant generation of heat.=C2=A0 Those sources = also say that if the gearbox is partially filled with oil but the level is = too high, the oil will foam and lubrication will be degraded if the system circulates the oil using an external pump.= =C2=A0 In our case, it may be better to accept the power loss and extra hea= t as opposed to returning a lot of aerated oil to the engine.


An impeller was added to the planet carrier of the converted -A drive but tha= t gearbox still operated completely filled with oil.


The gearbox drain and the engine drain connection were increased to 1= /2" NPT and fittings drilled out to 21/32" ID were installed. =C2= =A03/4" ID hose was installed as the drain line.=C2=A0 The drain line = was close to level but slightly down hill in operation.=C2=A0 This reduced=C2=A0the gearbox internal pressure to a value not mea= surable with a normal gauge.=C2=A0 The amount of oil inside the gearbox was= measured by clamping off the drain hose immediately after shutting down th= e engine, disconnecting the hose from the engine, and then recovering the oil remaining inside the gearbox.=C2=A0 Th= e gearbox was found to be completely filled with oil just as before.=


When the -4 fitting in the top of the gearbox was connected to the en= gine crankcase as a vent, =C2=A0the amount of oil recovered from the gearbo= x after operation was now found to be about 5 to 6 oz.=C2=A0 The recovered = oil did not appear to be foamed and its volume changed very little upon standing for several hours.

Steve Boese

-
Well, I just had one of those 'Duh!' moments. It should have be= en obvious to me, but if the oil is foaming in the box (logical, given the = thrashing by the gears) and carrying air out the drain, it's got to be = replaced with something, and the only thing available is oil. The vent back= to the crankcase lets the entrained air get replaced by air, instead of oi= l.

Now, if the drain is the original -6 line, but the vent is added back t= o the crankcase, would it still keep up with the pressurized feed from the = engine?

Charlie

=C2=A0

3D"" Virus-free. www.avast.com
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