X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from mail-wy0-f180.google.com ([74.125.82.180] verified) by logan.com (CommuniGate Pro SMTP 5.4c2) with ESMTPS id 4903759 for flyrotary@lancaironline.net; Fri, 11 Mar 2011 20:10:45 -0500 Received-SPF: pass receiver=logan.com; client-ip=74.125.82.180; envelope-from=fluffysheap@gmail.com Received: by wyj26 with SMTP id 26so3037747wyj.25 for ; Fri, 11 Mar 2011 17:10:08 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:mime-version:in-reply-to:references:date :message-id:subject:from:to:cc:content-type; bh=qKS771WlGoCgkKsUaw2FK3Zae2nV8yShOLpCrZwWHbA=; b=CbVHwr0grLonko3fWCkz4Hx+khEgI2F77lULHp3Pewerws4bW0nzHRM6Hw8rBOIG2C C+kMaDgLs9OajjFykO/9xDHxmW1M0csrvFAAGrPgZegRHYDGXJiM/QEQlU/FjCBBrbHV LtvOFBrEPOtGVE6qAH8q3OoSJx2rlql7HKs04= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type; b=ZOPt+18MKxJw5K63CAxUz1rr6JZJVU5bc6TGu2erpdDMDE5gApFeodPek8CFVDNjG9 6caSZkbJkE72PIPnlaTITghO9HICNODQxhPkL65qGDqjS+x6KAC7wvVmLDkye+/3+SrM BWSpQuGXCiiowJMBZ4ew/IIS/qa87wvIu+7Gs= MIME-Version: 1.0 Received: by 10.227.162.197 with SMTP id w5mr8939531wbx.191.1299892208401; Fri, 11 Mar 2011 17:10:08 -0800 (PST) Received: by 10.227.142.202 with HTTP; Fri, 11 Mar 2011 17:10:08 -0800 (PST) In-Reply-To: References: Date: Fri, 11 Mar 2011 18:10:08 -0700 Message-ID: Subject: Re: [FlyRotary] Re: Crankcase ventilation From: William Wilson To: Rotary motors in aircraft Cc: Marc Wiese Content-Type: multipart/alternative; boundary=20cf3001b81353ff6f049e3ebd06 --20cf3001b81353ff6f049e3ebd06 Content-Type: text/plain; charset=ISO-8859-1 The fasteners and turbo impeller are Inconel because steel will deform at those temperatures, but I think the manifold itself is still cast iron. Inconel would just be too expensive for the whole manifold, not to mention the manufacturing difficulty of trying to form it into the necessary shape. I assume the 20B is the same way, but Idon't really know. On Fri, Mar 11, 2011 at 3:25 PM, Marc Wiese wrote: > And the 3rd gen tubo manifolds, bolts, studs, and nuts are Inconel as > well! (Is the 20B like that?) > > Marc Wiese > > > > *From:* Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] *On > Behalf Of *William Wilson > *Sent:* Friday, March 11, 2011 7:22 AM > > *To:* Rotary motors in aircraft > *Subject:* [FlyRotary] Re: Crankcase ventilation > > > > Rotary engines crack exhaust manifolds fairly often. The 3rd gen RX-7 has > it worse (IMO, because of the complex shape of the manifold), but it happens > to the 2nd gen motors too on occasion. The key factor is whether it is > cracked far enough to cause an exhaust leak or not. The car guys usually > don't fix the crack until it starts to leak. A crack that doesn't cause a > leak probably doesn't present a safety issue. I wouldn't at all be > surprised if a worn exhaust gasket accelerates the cracking process as it > may change the temperature distribution over the manifold, increasing the > stress on it. > > If you are using a custom manifold, there is a balance between the mass of > the manifold, and the resistance to cracking. Cast iron is heavy. Mazda's > manifolds are as heavy as the engine block, or at least it seems that way. > Aftermarket manifolds, which are usually lighter weight, crack more often. > You have to think Mazda knew what they were doing, since the RX-7 is a very > light car with a very light engine and yet Mazda put these enormously heavy > duty manifolds on it, which still crack sometimes. For whatever reason, > quality headers on naturally aspirated cars never seem to have problems, > it's only with turbos. More air going through the manifold maybe, or maybe > having the turbo attached causes more stress. Maybe Racing Beat would know. > > It turns out they are talking about this exact issue on one of the car > forums right now, with pictures: > http://rotarycarclub.com/rotary_forum/showthread.php?t=13552 > > My gut says that oxidation won't significantly affect the cracking > situation. It's cast iron, after all, it's always oxidizing. I believe the > cracking process is entirely physical in nature. RX-7s always have oxygen > in their exhaust but only the thermally and mechanically stressed ones > crack. > > On Fri, Mar 11, 2011 at 5:15 AM, David Leonard > wrote: > > Kelly, > > > > My single EGT probe is just down stream of the turbo. I do my measurements > in Celsius. Peak is about 915 or so. I usually climb out ROP and with the > reduced RPMs, EGT are in the mid 700's to low 800's. MP on take off is > anywhere between 30 and 45" depending on my mood and who I am trying to > impress - though I usually try to keep it under 40". Even then it is for > only the first 1000' or so, then I usually maintain about 28-30" through > most of climb, and cruse at 22-30" depending on my mood. ROP cruse EGTs are > 750 to 900 depending on power, RPM and how rich I make things. I usually > lean it out just enough to keep EGT's around 870. (that is appx 100 deg > ROP). If I am using a lot of boost or flying formation (when I cant keep an > eye on the EGT) I will richen it up and keep the EGT's in the low 800's. > > > > I have done a lot of LOP flying. In cruse it is difficult to get the temps > much below about 890 without the engine running a little rough (occasional > misfire). Climbing LOP is actually better because the lower RPM's really > help keep those EGT's down. Descending is the opposite, the EGTs really > climb with the higher RPM. That is how I lost turbo #2, a long high-power > descent at essentially peak EGT (about 920 or so) (Hey, I was late and > didn't know any better - you guys can thank me for doing the testing :-) > > > > I have been on a kick lately to keep my EGT's down so I have been running > mostly ROP. At the last annual I was getting some leaking around the stock > exhaust manifold. Turns out that the gasket had worn out and that the > manifold itself was getting some of the typical cracks that those cast iron > manifolds are known to get. It looked to me as though at least part of the > problem was oxidation. I replaced the manifold with one I had sitting > around, but they have suddenly become harder to find. So my current plan > was to eliminate the oxygen in the exhaust and keep the temps lower by > running ROP. > > > > The problem is, that ROP flying really uses up a lot more fuel. Yesterday, > flying home from Mammoth. I was hitting a headwind and would have maybe had > to stop for fuel if I didn't lean it out (ASOS on departure was reporting > wiinds 25 gusting 38mph - tough to get the plane loaded and untied in those > winds). Anyway, 9 gal/hr LOP will get me about the same power and EGT as 11 > gal/hr ROP (different MAP setting). Add more fuel and get lower EGT's but > power starts dropping a little while the cost goes up fast. So, I have > decided to go back to running LOP during cruse on my longer trips, > especially if I fly at lower MAP settings. > > > > -- > David Leonard > > Turbo Rotary RV-6 N4VY > http://N4VY.RotaryRoster.net > http://RotaryRoster.net > > On Thu, Mar 10, 2011 at 11:05 AM, Kelly Troyer wrote: > > David, > > Glad to hear from you..........Reminded me to ask you the same questions > about your > > turboed 13B as I did John Slade.......... > Would like to know your typical EGT's and MP (boost) at takeoff , > climb and cruise > > and if you lean "lean of peak" (or lean at all)........... > > > > Kelly Troyer > *"DYKE DELTA JD2"** **(Eventually)* > > "13B ROTARY"_ Engine > "RWS"_RD1C/EC2/EM2 > "MISTRAL"_Backplate/Oil Manifold > > "TURBONETICS"_TO4E50 Turbo > > > > > ------------------------------ > > *From:* David Leonard > *To:* Rotary motors in aircraft > *Sent:* Thu, March 10, 2011 12:26:56 PM > *Subject:* [FlyRotary] Re: Crankcase ventilation > > > Interesting Idea, though you still probably want some other crankcase vent > functional in case the injection ports don't suck enough. BTW, VERY little > oil, if any, comes out the vent unless there is something wrong with one of > the side seals. probably best to just plug the oil injection and vent the > crank case. > > -- > David Leonard > > Turbo Rotary RV-6 N4VY > http://N4VY.RotaryRoster.net > http://RotaryRoster.net > > On Thu, Mar 10, 2011 at 8:36 AM, Ernest Christley > wrote: > > I've not provided for clean way to vent the crankcase, yet. And I'm also > not going to use the oil injection ports. As I understand it, the injection > ports should always be at a negative pressure. Would it be a crazy idea to > have the ports pull the dirty air out of the crankcase and not spread it > across my airplane's belly? > > -- > > Homepage: http://www.flyrotary.com/ > Archive and UnSub: > http://mail.lancaironline.net:81/lists/flyrotary/List.html > > > > > > > --20cf3001b81353ff6f049e3ebd06 Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable The fasteners and turbo impeller are Inconel because steel will deform at t= hose temperatures, but I think the manifold itself is still cast iron.=A0 I= nconel would just be too expensive for the whole manifold, not to mention t= he manufacturing difficulty of trying to form it into the necessary shape.= =A0 I assume the 20B is the same way, but Idon't really know.

On Fri, Mar 11, 2011 at 3:25 PM, Marc Wiese <cardmarc@charter.net> wrot= e:

And the 3rd gen tub= o manifolds, bolts, studs, and nuts are Inconel as well! (Is the 20B like t= hat?)

Marc Wiese<= /span>

= =A0

Fr= om: Rotary motors in aircraft [= mailto:fly= rotary@lancaironline.net] On Behalf Of William Wilson
Sent: Friday, March 11, 2011 7:22 AM


To:= Rotary motors in aircraft
Subject: [FlyRotary] Re: Crankca= se ventilation

=A0

Rotary engines= crack exhaust manifolds fairly often.=A0 The 3rd gen RX-7 has it worse (IM= O, because of the complex shape of the manifold), but it happens to the 2nd= gen motors too on occasion.=A0 The key factor is whether it is cracked far= enough to cause an exhaust leak or not.=A0 The car guys usually don't = fix the crack until it starts to leak.=A0 A crack that doesn't cause a = leak probably doesn't present a safety issue.=A0 I wouldn't at all = be surprised if a worn exhaust gasket accelerates the cracking process as i= t may change the temperature distribution over the manifold, increasing the= stress on it.

If you are using a custom manifold, there is a balance between the mass= of the manifold, and the resistance to cracking.=A0 Cast iron is heavy.=A0= Mazda's manifolds are as heavy as the engine block, or at least it see= ms that way.=A0 Aftermarket manifolds, which are usually lighter weight, cr= ack more often.=A0 You have to think Mazda knew what they were doing, since= the RX-7 is a very light car with a very light engine and yet Mazda put th= ese enormously heavy duty manifolds on it, which still crack sometimes.=A0 = For whatever reason, quality headers on naturally aspirated cars never seem= to have problems, it's only with turbos.=A0 More air going through the= manifold maybe, or maybe having the turbo attached causes more stress.=A0 = Maybe Racing Beat would know.

It turns out they are talking about this exact issue on one of the car = forums right now, with pictures:
http://rotarycarclub.= com/rotary_forum/showthread.php?t=3D13552

My gut says that oxidation won't significantly affect the cracking = situation.=A0 It's cast iron, after all, it's always oxidizing.=A0 = I believe the cracking process is entirely physical in nature.=A0 RX-7s alw= ays have oxygen in their exhaust but only the thermally and mechanically st= ressed ones crack.

O= n Fri, Mar 11, 2011 at 5:15 AM, David Leonard <wdleonard@gmail.com> wrote:

=

Kelly,

=A0

My single EGT probe is just down stream of the turbo. I do my mea= surements in Celsius.=A0 Peak is about 915 or so.=A0 I usually climb out RO= P and with the reduced RPMs, EGT are in the mid 700's to low 800's.= =A0 MP on take off is anywhere between 30 and 45" depending on my mood= and who I am trying to impress - though I usually try to keep it=A0under 4= 0".=A0=A0Even then it is for only the first 1000' or so, then I=A0= usually=A0maintain about 28-30" through most of climb, and cruse at 22= -30" depending on my mood.=A0ROP cruse EGTs are 750 to 900 depending o= n power, RPM and how rich I make things.=A0 I usually lean it out=A0just en= ough to=A0keep EGT's around 870. (that is appx 100 deg ROP).=A0 If I am= using a lot of boost or flying formation (when I cant keep an eye on the E= GT)=A0I will richen it up and keep the EGT's in the low 800's.

=A0

= I have done a lot of LOP flying.=A0 In cruse it is difficult to get the tem= ps much below about 890 without the engine running a little rough (occasion= al misfire).=A0 Climbing LOP is actually better because the lower RPM's= really help keep those EGT's down.=A0 Descending is the opposite, the = EGTs really climb with the higher RPM.=A0 That is how I lost turbo #2, a lo= ng high-power descent at essentially peak EGT (about 920 or so) (Hey, I was= late and didn't know any better - you guys can thank me for doing the = testing :-)

=A0

= I have been on a kick lately to keep my EGT's down so I have been runni= ng mostly ROP.=A0 At the last annual I was getting some leaking around the = stock exhaust manifold.=A0 Turns out that the gasket had worn out and that = the manifold itself was getting some of the typical cracks that those cast = iron manifolds=A0are known=A0to get.=A0 It looked to me as though at least = part of the problem was oxidation.=A0 I replaced the manifold with one I ha= d sitting around, but they have suddenly become=A0harder to find.=A0 So my = current plan was to eliminate the oxygen in the exhaust and keep the temps = lower by running ROP.

=A0

= The problem is, that ROP flying really uses up a lot more fuel.=A0 Yesterda= y, flying home from Mammoth. I was hitting a headwind and would have maybe= =A0had to stop for fuel if I didn't lean it out (ASOS on departure was = reporting wiinds=A025 gusting 38mph - tough to get the plane loaded and unt= ied in those winds).=A0 Anyway, 9 gal/hr LOP will get me about the same pow= er and EGT=A0as 11 gal/hr ROP (different MAP setting).=A0 Add more fuel and= get lower EGT's but power starts dropping a little while the cost goes= up fast.=A0 So, I have decided to go back to running LOP during cruse on m= y longer trips, especially if I fly at lower MAP settings.



--
David Leonard

Turbo Rotar= y RV-6 N4VY
h= ttp://N4VY.RotaryRoster.net
http://RotaryRoster.net

On Thu, Mar 10, 2011 at 11:05 AM, Kelly Troyer <keltro@att.net> wro= te:

David,

=A0=A0 Glad to hear from= you..........Reminded me to ask you the same questions about your

turboed = 13B as=A0I did John Slade..........
=A0=A0 Would like to know your typic= al EGT's and MP (boost)=A0at takeoff , climb=A0and cruise=A0

=

and if you lean "lean of peak" (= or lean at all)...........

=A0

Kelly Troyer
"DYKE DELTA JD2" (Eventually)

"13B ROTARY"_ Engine
"= ;RWS"_RD1C/EC2/EM2
"MISTRAL"_Backplate/Oil Manifold

"TURBONETICS"_TO4E50 Tur= bo

=A0

=

=A0

David Leonard <wdleonard@gmail.com= >
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Se= nt: Thu, March 10, 2011 12:26:56 PM
Subject: [FlyRotary] Re: = Crankcase ventilation


Interesting Idea, though you still p= robably want some other crankcase vent functional in case the injection por= ts don't suck enough.=A0 BTW, VERY little oil, if any, comes out the ve= nt unless there is something wrong with one of the side seals.=A0 probably = best to just plug the oil injection and vent the crank case.

--
David Leonard

Turbo Rotary RV-6 N4VY
http://N4VY.RotaryRoster.net=
http://RotaryRos= ter.net

O= n Thu, Mar 10, 2011 at 8:36 AM, Ernest Christley <echristley@att.net> wrote:

I've not provided for clea= n way to vent the crankcase, yet. =A0And I'm also not going to use the = oil injection ports. =A0As I understand it, the injection ports should alwa= ys be at a negative pressure. =A0Would it be a crazy idea to have the ports= pull the dirty air out of the crankcase and not spread it across my airpla= ne's belly?

--
Homepage: =A0http= ://www.flyrotary.com/
Archive and UnSub: =A0 http://ma= il.lancaironline.net:81/lists/flyrotary/List.html



<= /div>



<= /p>

=A0


--20cf3001b81353ff6f049e3ebd06--