X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from mail-gy0-f180.google.com ([209.85.160.180] verified) by logan.com (CommuniGate Pro SMTP 5.4.1) with ESMTPS id 5098921 for flyrotary@lancaironline.net; Sun, 21 Aug 2011 08:23:40 -0400 Received-SPF: pass receiver=logan.com; client-ip=209.85.160.180; envelope-from=rwstracy@gmail.com Received: by gyc15 with SMTP id 15so7209404gyc.25 for ; Sun, 21 Aug 2011 05:23:05 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=subject:references:from:content-type:x-mailer:in-reply-to :message-id:date:to:content-transfer-encoding:mime-version; bh=AYBvxM5JtF7Fb4XBD8/70fSzIKaqNTBo5RbE2pRHfO8=; b=CPY0vZnj+Rw608/DTU+mMKBn5WvNszN/ka4+k2hJ6oq2utAuMgzL7/8t73M94s20bT r3yDuMocL79dYXyDe0ocaxuX4L/Pie0uANzqxkG1Z3TcKv0ep3TRjPeJwcw5eYXUOxiN Imu/QuVjsCyp8WCz5dSr8xnyayf+i7uWeZkZU= Received: by 10.236.125.161 with SMTP id z21mr7352542yhh.58.1313929385250; Sun, 21 Aug 2011 05:23:05 -0700 (PDT) Return-Path: Received: from [10.0.1.2] (99-197-145-127.cust.wildblue.net [99.197.145.127]) by mx.google.com with ESMTPS id c63sm4885921yhe.46.2011.08.21.05.22.56 (version=TLSv1/SSLv3 cipher=OTHER); Sun, 21 Aug 2011 05:23:04 -0700 (PDT) Subject: Re: [FlyRotary] Re: Fwd: oil premix data; info request References: From: Tracy Content-Type: multipart/alternative; boundary=Apple-Mail-49-614728321 X-Mailer: iPad Mail (8F191) In-Reply-To: Message-Id: <393D6A3E-663D-4E8B-AD21-0911972341CC@gmail.com> Date: Sun, 21 Aug 2011 08:22:39 -0400 To: Rotary motors in aircraft Content-Transfer-Encoding: 7bit Mime-Version: 1.0 (iPad Mail 8F191) --Apple-Mail-49-614728321 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=us-ascii To give an actual example of what Lynn described, the 20B installation in my= RV-8 is plumbed with -8 oil lines. The oil requirements of the 20B is of c= ourse 50% more than the 13B and I still see full oil pressure at anything ov= er 3800 rpm and I'm measuring it at the far end of the oil galley in the eng= ine. The only measure I took to improve oil flow was to clean up the passa= ges in the front housing oil passages near the oil pump. I did some measurements of pressure drops through the system and did see tha= t the lines and fittings were dropping a significant amount of pressure so I= am pushing the lower limit of hose size and anything less would be a mistak= e. I had some space and routing issues that made -10 lines problematic, ot= herwise that's what I would have used. Tracy Sent from my iPad On Aug 21, 2011, at 1:37 AM, Lehanover@aol.com wrote: > The oil pump produces a fixed volume tied to RPM. The output is a function= of the total resistance to flow of the system which is just about fixed, pl= us the pop setting of the relief valve, also fixed. > =20 > So, if we do not include such things a viscosity changes, foaming, tempera= ture changes, suction side losses and all of the things that cloud the issue= , > and just look at the flow, we see that unless there has been a very small h= ose or gallery size selected, the hose or gallery diameter and volume has no= affect at all on pump output, total resistance, or temperature. So the bigg= er the hoses, in effect the closer you get to a static system where pressure= is uniform everywhere. The one effect of larger hoses we want is the lower v= elocity of the oil. Drag increases at the square of velocity, so a small inc= rease in diameter reduces the velocity and drag and also the amount of heat t= he pump puts into the oil. > =20 > We are also adding some length of hose in excess of the stock system, with= more remote filtering and ideal cooler locations and similar, so the larger= hose diameter is of some benefit there. > =20 > Suppose we have a 200 foot long oil hose in 12" diameter, and another in 1= /8" diameter. Both are pressurized with the same size pump turning the same R= PM. We have pressure gages at the opposite end next to the relief valve with= the pop pressure set at 80 PSI. We also have pressure gages at the pump end= . Assume both volumes remain as at rest, what happens when we fire the pumps= together? > =20 > The large diameter version, the pump builds to just above 80 PSI and the r= elieve valve pops at the far end about a second later holding the full 80 PS= I in the tube, and dumping excess oil with gusto. > =20 > In the small diameter version, the pump builds up 150 PSI, and 3 seconds l= ater the relief valve pops at 80 PSI, but just dribbles oil. > =20 > The larger system is a nearly static situation, while the smaller system i= s a very dynamic situation. > =20 > Lynn E. Hanover > =20 > No, I am not recommending 12" diameter oil hoses. > =20 > =20 > =20 > In a message dated 8/20/2011 1:25:20 P.M. Paraguay Standard Time, dale.rog= @gmail.com writes: > Kelly, >=20 > I know you asked Lynn, but ... >=20 > Things to think about: the original oil system for the 13B was designed to= support two 10mm (~3/8") oil paths - one to the main bearings and one to th= e pressure regulator in the rear (flywheel end) iron. Any volume of oil that= exceeds the capacities of those paths will result in excessive oil pressure= . Going to an external pressure regulator will solve that problem, but to w= hat purpose? For any given pressure, going from a 3/8" line to 1/2" adds 77= % to the volume being pumped; going to a -10 (5/8") nearly triples the oil f= low; -12 (3/4") more than quadruples it - you end up pumping a lot of oil - t= hereby adding heat to it - then cooling it and returning it directly to the s= ump.=20 >=20 > So, how much oil flow do you need for your turbo and re-drive? As much as= the engine itself? I rather suspect that having larger than -10 up to the p= oint where the oil supply splits to service the various components won't buy= you any advantage except lower oil temps, and that is actually doubtful. >=20 > Dale_R > COZY MkIV #0497 >=20 --Apple-Mail-49-614728321 Content-Transfer-Encoding: quoted-printable Content-Type: text/html; charset=utf-8
To give an actual example of what Lynn d= escribed, the 20B installation in my RV-8 is plumbed with -8 oil lines. &nbs= p; The oil requirements of the 20B is of course 50% more than the 13B and I s= till see full oil pressure at anything over 3800 rpm and I'm measuring it at= the far end of the oil galley in the engine.   The only measure I took= to improve oil flow was to clean up the passages in the front housing oil p= assages near the oil pump.

I did some measurements o= f pressure drops through the system and did see that the lines and fittings w= ere dropping a significant amount of pressure so I am pushing the lower limi= t of hose size and anything less would be a mistake.   I had some space= and routing issues that made -10 lines problematic, otherwise that's what I= would have used.

Tracy


Sent from= my iPad

On Aug 21, 2011, at 1:37 AM, Lehanover@aol.com wrote:

The oil pump produces a fixed volume tied to RPM. The output is a funct= ion=20 of the total resistance to flow of the system which is just about fixed, plu= s=20 the pop setting of the relief valve, also fixed.
 
So, if we do not include such things a viscosity changes, foaming,=20 temperature changes, suction side losses and all of the things that cloud th= e=20 issue,
and just look at the flow, we see that unless there has been a very sma= ll=20 hose or gallery size selected, the hose or gallery diameter and volume has n= o=20 affect at all on pump output, total resistance, or temperature. So the bigge= r=20 the hoses, in effect the closer you get to a static system where pressure is= =20 uniform everywhere. The one effect of larger hoses we want is the lower velo= city=20 of the oil. Drag increases at the square of velocity, so a small increase in= =20 diameter reduces the velocity and drag and also the amount of heat the pump p= uts=20 into the oil.
 
We are also adding some length of hose in excess of the stock=20 system, with more remote filtering and ideal cooler locations and simil= ar,=20 so the larger hose diameter is of some benefit there.
 
Suppose we have a 200 foot long oil hose in 12" diameter, and another i= n=20 1/8" diameter. Both are pressurized with the same size pump turning the same= =20 RPM. We have pressure gages at the opposite end next to the relief valve wit= h=20 the pop pressure set at 80 PSI. We also have pressure gages at the pump end.= =20 Assume both volumes remain as at rest, what happens when we fire the pumps=20= together?
 
The large diameter version, the pump builds to just above 80 PSI and th= e=20 relieve valve pops at the far end about a second later holding the full 80 P= SI=20 in the tube, and dumping excess oil with gusto.
 
In the small diameter version, the pump builds up 150 PSI, and 3 second= s=20 later the relief valve pops at 80 PSI, but just dribbles oil.
 
The larger system is a nearly static situation, while the smaller syste= m is=20 a very dynamic situation.
 
Lynn E. Hanover
 
No, I am not recommending 12" diameter oil hoses.
 
 
 
In a message dated 8/20/2011 1:25:20 P.M. Paraguay Standard Time,=20 dale.rog@gmail.com writes:
Kelly,

   I know you asked Lynn, b= ut=20 ...

Things to think about: the original oil system for the 13B was=20= designed to support two 10mm (~3/8") oil paths - one to the main bearings a= nd=20 one to the pressure regulator in the rear (flywheel end) iron. Any volume o= f=20 oil that exceeds the capacities of those paths will result in excessive oi= l=20 pressure.  Going to an external pressure regulator will solve that=20= problem, but to what purpose?  For any given pressure, going from a 3= /8"=20 line to 1/2" adds 77% to the volume being pumped; going to a -10 (5/8") ne= arly=20 triples the oil flow; -12 (3/4") more than quadruples it - you end up pump= ing=20 a lot of oil - thereby adding heat to it - then cooling it and returning i= t=20 directly to the sump.

So, how much oil flow do you need for your t= urbo=20 and re-drive?  As much as the engine itself?  I rather suspect t= hat=20 having larger than -10 up to the point where the oil supply splits to serv= ice=20 the various components won't buy you any advantage except lower oil temps,= =20 and  that is actually doubtful.

Dale_R
COZY MkIV=20 #0497

= --Apple-Mail-49-614728321--