X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from poplet2.per.eftel.com ([203.24.100.45] verified) by logan.com (CommuniGate Pro SMTP 5.2.15) with ESMTP id 3791861 for flyrotary@lancaironline.net; Sat, 01 Aug 2009 21:15:22 -0400 Received-SPF: none receiver=logan.com; client-ip=203.24.100.45; envelope-from=lendich@aanet.com.au Received: from sv1-1.aanet.com.au (sv1-1.per.aanet.com.au [203.24.100.68]) by poplet2.per.eftel.com (Postfix) with ESMTP id 5DDFD173BEC for ; Sun, 2 Aug 2009 09:14:45 +0800 (WST) Received: from ownerf1fc517b8 (203.171.92.134.static.rev.aanet.com.au [203.171.92.134]) by sv1-1.aanet.com.au (Postfix) with SMTP id 7CD96BEC01E for ; Sun, 2 Aug 2009 09:14:44 +0800 (WST) Message-ID: From: "George Lendich" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Re: EC2 and Ed's EFISM - a great combination Date: Sun, 2 Aug 2009 11:14:46 +1000 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0011_01CA1362.714E9AA0" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.5512 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.5579 X-Antivirus: avast! (VPS 090801-0, 08/01/2009), Outbound message X-Antivirus-Status: Clean This is a multi-part message in MIME format. ------=_NextPart_000_0011_01CA1362.714E9AA0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Al, Your approach is commendable, (as is your friends) but I don't think = everyone is up to those sorts of testing and modifications. I might copy = some of those approaches, I particularly like the plastic casing idea - = perhaps plastic windows would do just as well. However your also correct = about some early failures, but Tracy is quick to fix any problems. I can't remember the Ross bearings but I am also in favor of tapered = roller bearing, but they get heavy for the larger diameters (bloody = strong though). Probably the next best thing are the angular contact = ball bearings. Nothing wrong with the sleeve bearings Tracy uses but = they must be pressure fed. I will probably opt for the angular contact type. George ( down under) I flew 5 years with a Ross. I've disassembled and inspected 5 or so, = just to help out other builders. Just want to offer a different = viewpoint based on my findings:=20 First, all of the Ross's have large bearing that absorbs the prop = thrust forces. I'm quite puzzled your statement that they don't. A very = important part of the installation is to verify you have clearance to = flywheel. I'm wondering if you are just confusing the pilot bearing = damage issue with prop thrust? Ross redrive had one significant design = oversight. This oversight caused around 80% of their field failures. = Basically Ross picked a poor method of controlling input shaft = clearance. Input shaft is the short shaft that goes between flywheel and = gears. Low rpm torsionals caused that shaft to slam back and forth = between flywheel and gears. This caused pilot bearing damage, fatigue = failures on the drive plate. I changed the design by controlling thrust = at the sun gear. All of those failures then disappear.=20 Second, Ross decision to restrict oil flow to redrive is very sound = design. It limits flow because excess oil flow to redrive has = significant effect on hp loss. A friend actually measured hp loss = related to oil volume. I verified flow on my redrive gears & bearings, = absolutely no issues. I do believe there were lube issues on some Ross = applications, but definitely not true on mine. I don't understand why = the difference.=20 There is a method of proving design changes that Tracy doesn't use = often enough. Basically you measure how close the design is to failure. = You don't rely on theory. For example, I verified oil flow just by = placing aluminum slivers at key oil locations. Operate drive for a = minute, disassemble. Slivers were washed away by oil flow. Likewise, you = operate it, then quickly disassemble and measure temperature of various = components. A friend slapped a plastic cover on his redrive, then = watched the oil flow. These methods let you predict future failures. Too = much design theory, not enough actual measurements. If you can force = yourself to test your theories, you'll find tons of things you believe = in, that just aren't significant.=20 I am in agreement that Tracy version of the Ross design is looking = pretty good. When asked by builders which redrive to consider, his gets = high marks. I don't have rose colored glasses. There have been a couple = design oversights that resulted in failures. I like the solutions.=20 -al wick ----- Original Message -----=20 From: Ed Anderson=20 To: Rotary motors in aircraft=20 Sent: Friday, July 31, 2009 3:46 PM Subject: [FlyRotary] Re: EC2 and Ed's EFISM - a great combination Actually, George, The RWS drive was not just a redevelopment of the = Ross drive. =20 =20 Tracy basically started from scratch and engineered a redrive that = was designed to meet certain objectives while achieving a reasonable = cost. There is no other redrive I am familiar with that has anywhere = near the number of flying hours that the RWS redrive has with none of = the problems associated with the Ross. =20 While there is a superficial similarly to the Ross (Prop on one end = and rotary on the other, planetary gears in the middle {:>)) in = appearance, the internals are considerably ahead of anything Ross had. = Pressure lubrication of the prop shaft for one thing, an integral thrust = bearing for another, a removable propeller shaft for yet another, full = oil pressure lubrication. The Ross drive required a restrictor in the = oil line to (can you believe this) reduce oil pressure - otherwise the = thing leaked like crazy - even with the restrictor, the rear seal = frequently was a leaky mess. But, reducing the oil pressure was one = reason the Ross had marginal lubrication in my opinion. Even then, the = oil distribution inside the Ross was also not well designed.=20 =20 Don't get me wrong, I was glad to get a Ross - because it was the = only thing around at the time. Had old man, Lou Ross, lived longer he = may have eventually fixed a lot of these issues, but unfortunately he = did not and I won't go into the situation with his son, Chris. But, we = are fortunate that Tracy took on this challenge and did it right. =20 =20 One thing I really appreciate about the RWS design is that it has a = considerably different internal set up with easily replaceable parts - = which was not the case with the Ross. If you wanted to completely = disassembly a Ross unit you most likely had to take it to a machine = shop. =20 Just wanted to make it clear that in my opinion the RWS should not = be associated with the Ross unit which many have found shortcomings in. =20 Ed Anderson Rv-6A N494BW Rotary Powered Matthews, NC eanderson@carolina.rr.com http://www.andersonee.com http://www.dmack.net/mazda/index.html http://www.flyrotary.com/ http://members.cox.net/rogersda/rotary/configs.htm#N494BW http://www.rotaryaviation.com/Rotorhead%20Truth.htm -------------------------------------------------------------------------= --- From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] = On Behalf Of George Lendich Sent: Friday, July 31, 2009 5:20 PM To: Rotary motors in aircraft Subject: [FlyRotary] Re: EC2 and Ed's EFISM - a great combination =20 =20 Steve, The Ross drive was redeveloped by Tracy Crook of Real World = Solutions (RWS). Tracy now uses the 6 planet planetary (Ford Unit) and = is about the best you will get weight wise and value for money. =20 There are other similar units - all have slightly different = construction, however Tracy's is well proven. I will probably make my = own, but only because of the tyranny of distance and associated costs. George (down under). =20 Steve, I went with the RD-1B PSRU from RWS. =20 T Mann __________ Information from ESET NOD32 Antivirus, version of virus = signature database 3267 (20080714) __________ The message was checked by ESET NOD32 Antivirus. http://www.eset.com ------=_NextPart_000_0011_01CA1362.714E9AA0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Al,
Your approach is commendable, (as is = your friends)=20 but I don't think everyone is up to those sorts of testing and = modifications. I=20 might copy some of those approaches, I particularly like the plastic = casing idea=20 - perhaps plastic windows would do just as well. However your also = correct about=20 some early failures, but Tracy is quick to fix any = problems.
I can't remember the Ross bearings but = I am also in=20 favor of tapered roller bearing, but they get heavy for the larger = diameters=20 (bloody strong though). Probably the next best thing are the angular = contact=20 ball bearings. Nothing wrong with the sleeve bearings Tracy uses but = they must=20 be pressure fed.
I will probably opt for the angular = contact=20 type.
George ( down under)

I flew 5 years with a Ross. I've = disassembled and=20 inspected 5 or so, just to help out other builders. Just want to offer = a=20 different viewpoint based on my findings:
 
First, all of the Ross's have large = bearing that=20 absorbs the prop thrust forces. I'm quite puzzled your statement that = they=20 don't. A very important part of the installation is to verify you have = clearance to flywheel. I'm wondering if you are just confusing the = pilot=20 bearing damage issue with prop thrust? Ross redrive had one = significant design=20 oversight. This oversight caused around 80% of their field failures. = Basically=20 Ross picked a poor method of controlling input shaft clearance. Input = shaft is=20 the short shaft that goes between flywheel and gears. Low rpm = torsionals=20 caused that shaft to slam back and forth between flywheel and gears. = This=20 caused pilot bearing damage, fatigue failures on the drive plate. I = changed=20 the design by controlling thrust at the sun gear. All of those = failures then=20 disappear.
 
Second, Ross decision to restrict oil = flow to=20 redrive is very sound design. It limits flow because excess oil flow = to=20 redrive has significant effect on hp loss. A friend actually measured = hp loss=20 related to oil volume. I verified flow on my redrive gears=20 & bearings, absolutely no issues. I do believe there were = lube issues=20 on some Ross applications, but definitely not true on mine. I don't = understand=20 why the difference.
 
 
There is a method of proving design = changes that=20 Tracy doesn't use often enough. Basically you measure how close the = design is=20 to failure. You don't rely on theory. For example, I verified oil flow = just by=20 placing aluminum slivers at key oil locations. Operate drive for a = minute,=20 disassemble. Slivers were washed away by oil flow. Likewise, you = operate it,=20 then quickly disassemble and measure temperature of various = components. A=20 friend slapped a plastic cover on his redrive, then watched the oil = flow.=20 These methods let you predict future failures. Too much = design=20 theory, not enough actual measurements. If you can force yourself to = test your=20 theories, you'll find tons of things you believe in, that just aren't=20 significant.
 
I am in agreement that Tracy version = of the Ross=20 design is looking pretty good. When asked by builders which redrive to = consider, his gets high marks. I don't have rose colored glasses. = There have=20 been a couple design oversights that resulted in failures. I like the=20 solutions.
 
-al  wick
 
 
----- Original Message -----
From:=20 Ed Anderson
To: Rotary motors in = aircraft=20
Sent: Friday, July 31, 2009 = 3:46=20 PM
Subject: [FlyRotary] Re: EC2 = and Ed's=20 EFISM - a great combination

Actually, = George,=20 The RWS drive was not just a redevelopment of the Ross drive.=20  

 

Tracy = basically started=20 from scratch and engineered a redrive that was designed to meet = certain=20 objectives while achieving a reasonable cost.   There is = no other=20 redrive I am familiar with that has anywhere near the number of = flying hours=20 that the RWS redrive has with none of the problems associated with = the=20 Ross.

 

While = there is a=20 superficial similarly to the Ross (Prop on one end and rotary on the = other,=20 planetary gears in the middle {:>)) in appearance, the internals = are=20 considerably ahead of anything Ross had.  Pressure lubrication = of the=20 prop shaft for one thing, an integral thrust bearing for another, a=20 removable propeller shaft for yet another, full oil pressure=20 lubrication.  The Ross drive required a restrictor in the oil = line to=20 (can you believe this) reduce oil pressure =96 otherwise the thing = leaked like=20 crazy =96 even with the restrictor, the rear seal frequently was a = leaky=20 mess.  But, reducing the oil pressure was one reason the Ross = had=20 marginal lubrication in my opinion. Even then, the oil distribution = inside=20 the Ross was also not well designed.

 

Don=92t = get me wrong,=20 I was glad to get a Ross =96 because it was the only thing around at = the=20 time.  Had old man, Lou Ross, lived longer he may have = eventually fixed=20 a lot of these issues, but unfortunately he did not and I won=92t go = into the=20 situation with his son, Chris.  But, we are fortunate that = Tracy took = on this=20 challenge and did it right.   =

 

One thing = I really=20 appreciate about the RWS design is that it has a considerably = different=20 internal set up with easily replaceable parts =96 which was not the = case with=20 the Ross.  If you wanted to completely disassembly a Ross unit = you most=20 likely had to take it to a machine = shop.

 

Just = wanted to make=20 it clear that in my opinion the RWS should not be associated with = the Ross=20 unit which many have found shortcomings = in.

 

Ed=20 Anderson

Rv-6A = N494BW Rotary=20 Powered

Matthews, = NC

eanderson@carolina.rr.com

http://www.andersonee.com

http://www.dmack.net/mazda/index.html

http://www.flyrotary.com/

http://members.cox.net/rogersda/rotary/configs.htm#N494BW

http://www.r= otaryaviation.com/Rotorhead%20Truth.htm

From:=20 Rotary motors in = aircraft=20 [mailto:flyrotary@lancaironline.net] On=20 Behalf Of George Lendich
Sent: Friday, July 31, 2009 = 5:20=20 PM
To: = Rotary motors in aircraft
Subject: [FlyRotary] Re: EC2 = and Ed's=20 EFISM - a great combination

 

 

Steve,

The Ross drive was = redeveloped=20 by Tracy Crook of Real World Solutions (RWS). Tracy = now uses the 6=20 planet planetary (Ford Unit) and is about the best you will = get =20 weight wise and value for = money.

 

There are other = similar units=20 - all have slightly different construction, however Tracy's = is well=20 proven. I will probably make my own, but only because of the = tyranny of=20 distance and associated costs.

George (down=20 under).

 

Steve,

I = went with=20 the RD-1B PSRU from RWS.

 

T=20 Mann



__________ Information from ESET = NOD32=20 Antivirus, version of virus signature database 3267 (20080714)=20 __________

The message was checked by ESET NOD32 = Antivirus.

http://www.eset.com

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