X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from mta31.charter.net ([216.33.127.82] verified) by logan.com (CommuniGate Pro SMTP 5.4c2) with ESMTP id 4903623 for flyrotary@lancaironline.net; Fri, 11 Mar 2011 17:25:43 -0500 Received-SPF: pass receiver=logan.com; client-ip=216.33.127.82; envelope-from=cardmarc@charter.net Received: from imp11 ([10.20.200.11]) by mta31.charter.net (InterMail vM.7.09.02.04 201-2219-117-106-20090629) with ESMTP id <20110311222507.LUDV12685.mta31.charter.net@imp11> for ; Fri, 11 Mar 2011 17:25:07 -0500 Received: from HomeDesktop ([97.94.193.28]) by imp11 with smtp.charter.net id HyR71g00A0dDVdd05yR70F; Fri, 11 Mar 2011 17:25:07 -0500 X-Authority-Analysis: v=1.1 cv=e/jNQBkeaj4K45mAC4i6wbaTgYPJ6USEUtAk45WPcGY= c=1 sm=1 a=xz5Wbyv1AAMA:10 a=4sash9Gc6afUAQh1p1CCVg==:17 a=Ia-xEzejAAAA:8 a=utgO0FMuAAAA:8 a=pGLkceISAAAA:8 a=N8B9JuSIAAAA:8 a=HZJGGiqLAAAA:8 a=7g1VtSJxAAAA:8 a=W2jFcxtSLKi1TZVjcdUA:9 a=sEZXJ58r23e3rrtqDBgA:7 a=4HFk-M2FG93_s4gUjEvJQKB51hEA:4 a=CjuIK1q_8ugA:10 a=Qa1je4BO31QA:10 a=5C9b1urg-XMA:10 a=EzXvWhQp4_cA:10 a=MSl-tDqOz04A:10 a=HeoGohOdMD0A:10 a=ZvXsVci378HXnSGP:21 a=_zGL1dw8bNuZoq-I:21 a=yMhMjlubAAAA:8 a=SSmOFEACAAAA:8 a=xf7mk66g9kHWGuTfsXAA:9 a=bhRHtW8VW4w6YI_tHuMA:7 a=qcdT9xFBTqm1MDA_m0-dj_ufZJEA:4 a=Xm8690tLmAGVJUi2:21 a=cZewsxI-zMSkLsOf:21 a=4sash9Gc6afUAQh1p1CCVg==:117 From: "Marc Wiese" To: "'Rotary motors in aircraft'" References: In-Reply-To: Subject: RE: [FlyRotary] Re: Crankcase ventilation Date: Fri, 11 Mar 2011 16:25:07 -0600 Message-ID: <002b01cbe03b$2d893490$889b9db0$@charter.net> MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_002C_01CBE008.E2F10E80" X-Mailer: Microsoft Outlook 14.0 Thread-Index: AQGj7oyQJrD8TP1jSn2/SES0Ikp7fpR4mPpA Content-Language: en-us This is a multipart message in MIME format. ------=_NextPart_000_002C_01CBE008.E2F10E80 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit 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 ------=_NextPart_000_002C_01CBE008.E2F10E80 Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable

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:
h= ttp://rotarycarclub.com/rotary_forum/showthread.php?t=3D13552

= 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 <wdleonard@gmail.com> = 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

<= div>

On Thu, Mar 10, 2011 at 11:05 AM, = Kelly Troyer <keltro@att.net> = 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/O= il Manifold

"TURBONE= TICS"_TO4E50 Turbo

 

 

From:= = David Leonard <wdleonard@gmail.com>
To: Rotary = motors in aircraft <flyrotary@lancaironline.net>
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 = <echristley@att.net> 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.h= tml





 

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