X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from mail-ww0-f50.google.com ([74.125.82.50] verified) by logan.com (CommuniGate Pro SMTP 5.4c2) with ESMTPS id 4903023 for flyrotary@lancaironline.net; Fri, 11 Mar 2011 08:22:24 -0500 Received-SPF: pass receiver=logan.com; client-ip=74.125.82.50; envelope-from=fluffysheap@gmail.com Received: by wwc33 with SMTP id 33so2450963wwc.7 for ; Fri, 11 Mar 2011 05:21:46 -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=Pte1JLZO1MTBxqj2A6BzVHv0swg0r6DZ/adbSNIvI+o=; b=KVMl1S/6LVIL/1UP/37blXi3N8OkaNrjvi3UgWmOR+8HWTq/ws3bMiMQf4MJmgdgcd MG4m18dOsAHRIYiO0Z+tIcYbdvDzDbcVXG3oD4NqCqKq86pkLiUBa0kQi05HKu9K5BNN 6a7oveVwKET5CV3Zyy7jVmaRB5qRDwLqpqTCs= 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=NgdfnUd8BAjS1aUfEbrCqMf7e2bpDMCBHQ7+HcygdaaKam9VtCCcPPrI+ex1e7k/dy kISjNywNM+7m9xAgVjIs2hYws3TSd+4pDo07JpgGIxAsEhqzQiaRahftHAHEClhEhdZ+ R65BXpFdwH0/aBg3NKoLZWsmtTIABcxcbHV9Y= MIME-Version: 1.0 Received: by 10.227.37.28 with SMTP id v28mr1611414wbd.75.1299849706295; Fri, 11 Mar 2011 05:21:46 -0800 (PST) Received: by 10.227.142.202 with HTTP; Fri, 11 Mar 2011 05:21:46 -0800 (PST) In-Reply-To: References: Date: Fri, 11 Mar 2011 06:21:46 -0700 Message-ID: Subject: Re: [FlyRotary] Re: Crankcase ventilation From: William Wilson To: Rotary motors in aircraft Cc: David Leonard Content-Type: multipart/alternative; boundary=0022159f03c20153dd049e34d8a1 --0022159f03c20153dd049e34d8a1 Content-Type: text/plain; charset=ISO-8859-1 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 >>> >> >> >> >> > > > --0022159f03c20153dd049e34d8a1 Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Rotary engines crack exhaust manifolds fairly often.=A0 The 3rd gen RX-7 ha= s it worse (IMO, because of the complex shape of the manifold), but it happ= ens 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 usua= lly don't fix the crack until it starts to leak.=A0 A crack that doesn&= #39;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 crackin= g 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.=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/s= howthread.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.

On Fri, Mar 11, 2011 at 5:15 AM, David Leona= rd <wdleonard@g= mail.com> wrote:
Kelly,
=A0
My single EGT probe is just down stream of the turbo. I do my measurem= ents in Celsius.=A0 Peak is about 915 or so.=A0 I usually climb out ROP and= with the reduced RPMs, EGT are in the mid 700's to low 800's.=A0 M= P 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 40&quo= t;.=A0=A0Even then it is for only the first 1000' or so, then I=A0usual= ly=A0maintain about 28-30" through most of climb, and cruse at 22-30&q= uot; depending on my mood.=A0ROP cruse EGTs are 750 to 900 depending on pow= er, RPM and how rich I make things.=A0 I usually lean it out=A0just enough = to=A0keep EGT's around 870. (that is appx 100 deg ROP).=A0 If I am usin= g a lot of boost or flying formation (when I cant keep an eye on the EGT)= =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 th= e temps much below about 890 without the engine running a little rough (occ= asional misfire).=A0 Climbing LOP is actually better because the lower RPM&= #39;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 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 :-)
=A0
I have been on a kick lately to keep my EGT's down so I have been = running 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 l= east part of the problem was oxidation.=A0 I replaced the manifold with one= I had sitting around, but they have suddenly become=A0harder to find.=A0 S= o my current plan was to eliminate the oxygen in the exhaust and keep the t= emps lower by running ROP.
=A0
The problem is, that ROP flying really uses up a lot more fuel.=A0 Yes= terday, flying home from Mammoth. I was hitting a headwind and would have m= aybe=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= untied in those winds).=A0 Anyway, 9 gal/hr LOP will get me about the same= power 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 my longer trips, especially if I fly at lower MAP settings.


--
David Leonard

Turbo Rotary RV-6 N4VY
http://N4VY.RotaryRoster.net<= br>http://RotaryRoste= r.net
On Thu, Mar 10, 2011 at 11:05 AM, Kelly Troyer <= span dir=3D"ltr"><ke= ltro@att.net> wrote:
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 kn= ow your typical 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 Turbo


From: David Leonard <wdleonard@gmail.com<= /a>>
To: Rotary moto= rs in aircraft <flyrotary@lancaironline.net>
Sent: Thu, March 10, 2011 = 12:26:56 PM
Subject: [F= lyRotary] Re: Crankcase ventilation

Interesting Idea, though you still probably want some other crankc= ase vent functional in case the injection ports don't suck enough.=A0 B= TW, VERY little oil, if any, comes out the vent unless there is something w= rong with one of the side seals.=A0 probably best to just plug the oil inje= ction and vent the crank case.

--
David Leonard

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

On Thu, Mar 10, 2011 at 8:36 AM, Ernest Christle= y <echristley@att.net> wrote:
I've not prov= ided for clean way to vent the crankcase, yet. =A0And I'm also not goin= g to use the oil injection ports. =A0As I understand it, the injection port= s should always be at a negative pressure. =A0Would it be a crazy idea to h= ave the ports pull the dirty air out of the crankcase and not spread it acr= oss my airplane's belly?

--
Homepage: =A0http://www.flyrotary.com/
Archive and Un= Sub: =A0 http://mail.lancaironline.net:81/lists/flyrotary/Lis= t.html







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