From: "lehanover lehanover@aol.com" <flyrotary@lancaironline.net>
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Date: Sun, 1 Nov 2020 13:01:25 +0000 (UTC)
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To: flyrotary@lancaironline.net
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Subject: Re: [FlyRotary] Sump Breather?
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Crank case pressure is a function of the volume of combustion gasses escapi=
ng past the side seals and through the end gaps at the side seal ends and c=
orner seal fitments.=C2=A0=C2=A0There will always be some flow even on a ne=
w engine. So the trick is to keep the outbound flow speed low so as to keep=
 escaping oil droplets falling back into the engine rather than being expel=
led. In racing we are required to have a catch bottle with a minimum volume=
 of 1 quart. A well done rotary has a remarkable low flow rate and can get =
along fine with a small diameter vent tube. Not a big problem on the street=
.=C2=A0In the aircraft the flow will be higher as the engine is usually run=
 at or near full throttle for long periods.=C2=A0So run it hard and look in=
to a catch bottle to see how much oil is being lost. A few drops to nothing=
 is ideal.=C2=A0Most can be vented into the intake flow but that will not s=
how up any problems. Every landing needs a oil level check. If the breathin=
g is restricted, pressure may push out a seal or turn a seal lip over backw=
ards. Followed by much oil loss. I shorten the seal springs and build seal =
retainers on each engine. You can also buy doublelip seals with one lip fac=
ing in and out. Keeps dust out of the seal lips.=C2=A0=C2=A0This is seldom =
a problem and did not occur on showroom stock Mazda rotaries that were turn=
ed up to high RPM. So probably not a factor.Lynn E. Hanover=C2=A0 =C2=A0=C2=
=A0=C2=A0In a message dated 11/1/2020 4:57:53 AM Atlantic Standard Time, fl=
yrotary@lancaironline.net writes:=C2=A0
Hi Lynn EH and all=C2=A0What size breather from the sump is required?Is thi=
s the same for all the various models (particularly the Renesis)?We have th=
e OEM sump but removed the plastic manifold and put a filler cap with small=
 breather on the top of the steel vertical tube that runs down into the pan=
.What would happen if this breather was too small?=C2=A0Thanks=C2=A0Steve I=
zettPerth Western Australia.=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0--Homepage:=C2=A0=
 http://www.flyrotary.com/Archive and UnSub:=C2=A0 http://mail.lancaironlin=
e.net:81/lists/flyrotary/List.html

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<div>
<div class="userEdit" style="font-family: arial, helvetica, sans-serif; font-size: 10pt; color: #000000;">
<div><span style="font-family: arial, helvetica, sans-serif; font-size: 10pt; color: #000000;">Crank case pressure is a function of the volume of combustion gasses escaping past the side seals and through the end gaps at the side seal ends and corner seal fitments.&nbsp;</span></div>
<div>&nbsp;</div>
<div><span style="font-family: arial, helvetica, sans-serif; font-size: 10pt; color: #000000;">There will always be some flow even on a new engine. So the trick is to keep the outbound flow speed low so as to keep escaping oil droplets falling back into the engine rather than being expelled. In racing we are required to have a catch bottle with a minimum volume of 1 quart. A well done rotary has a remarkable low flow rate and can get along fine with a small diameter vent tube. Not a big problem on the street.&nbsp;</span></div>
<div><span style="font-family: arial, helvetica, sans-serif; font-size: 10pt; color: #000000;">In the aircraft the flow will be higher as the engine is usually run at or near full throttle for long periods.&nbsp;</span></div>
<div><span style="font-family: arial, helvetica, sans-serif; font-size: 10pt; color: #000000;">So run it hard and look into a catch bottle to see how much oil is being lost. A few drops to nothing is ideal.&nbsp;</span></div>
<div><span style="font-family: arial, helvetica, sans-serif; font-size: 10pt; color: #000000;">Most can be vented into the intake flow but that will not show up any problems. Every landing needs a oil level check. If the breathing is restricted, pressure may push out a seal or turn a seal lip over backwards. Followed by much oil loss. I shorten the seal springs and build seal retainers on each engine. You can also buy double</span></div>
<div><span style="font-family: arial, helvetica, sans-serif; font-size: 10pt; color: #000000;">lip seals with one lip facing in and out. Keeps dust out of the seal lips.&nbsp;</span></div>
<div>&nbsp;</div>
<div><span style="font-family: arial, helvetica, sans-serif; font-size: 10pt; color: #000000;">This is seldom a problem and did not occur on showroom stock Mazda rotaries that were turned up to high RPM. So probably not a factor.</span></div>
<div><span style="font-family: arial, helvetica, sans-serif; font-size: 10pt; color: #000000;">Lynn E. Hanover&nbsp; &nbsp;&nbsp;</span></div>
<div><span style="font-family: arial, helvetica, sans-serif; font-size: 10pt; color: #000000;">&nbsp;</span></div>
</div>
In a message dated 11/1/2020 4:57:53 AM Atlantic Standard Time, flyrotary@lancaironline.net writes:
<div>&nbsp;</div>
<div class="quotedReply">
<blockquote style="padding-left: 5px; margin-left: 5px; border-left: blue 2px solid;">
<div dir="ltr">Hi Lynn EH and all</div>
<div dir="ltr">&nbsp;</div>
<div dir="ltr">What size breather from the sump is required?</div>
<div dir="ltr">Is this the same for all the various models (particularly the Renesis)?</div>
<div dir="ltr">We have the OEM sump but removed the plastic manifold and put a filler cap with small breather on the top of the steel vertical tube that runs down into the pan.</div>
<div dir="ltr">What would happen if this breather was too small?</div>
<div dir="ltr">&nbsp;</div>
<div dir="ltr">Thanks</div>
<div dir="ltr">&nbsp;</div>
<div dir="ltr">Steve Izett</div>
<div dir="ltr">Perth Western Australia.</div>
<div dir="ltr">&nbsp;</div>
<div dir="ltr">&nbsp;</div>
<div dir="ltr">&nbsp;</div>
<div dir="ltr">&nbsp;</div>
<div dir="ltr">&nbsp;</div>
<div dir="ltr">--</div>
<div dir="ltr">Homepage:&nbsp; <a href="http://www.flyrotary.com/" target="_blank" rel="noopener">http://www.flyrotary.com/</a></div>
<div dir="ltr">Archive and UnSub:&nbsp; <a href="http://mail.lancaironline.net:81/lists/flyrotary/List.html" target="_blank" rel="noopener">http://mail.lancaironline.net:81/lists/flyrotary/List.html</a></div>
</blockquote>
</div>
</div>
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