X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from mail-qy0-f182.google.com ([209.85.221.182] verified) by logan.com (CommuniGate Pro SMTP 5.2.15) with ESMTP id 3791879 for flyrotary@lancaironline.net; Sat, 01 Aug 2009 21:53:11 -0400 Received-SPF: pass receiver=logan.com; client-ip=209.85.221.182; envelope-from=rwstracy@gmail.com Received: by qyk12 with SMTP id 12so3363618qyk.7 for ; Sat, 01 Aug 2009 18:52:36 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:mime-version:sender:received:in-reply-to :references:date:x-google-sender-auth:message-id:subject:from:to :content-type; bh=oOHO6wMB321Pmunjj6GuZ4uxsExtD9QysoIeu+RkCss=; b=gygENF1BMhGZpgl7Ta6UYAdjKlJfXLLzJ6AMsvBpk+pl+S2z5YtzKUicNm6lOu20XI DEqGK/0luZCVfF6ncVLOv2SCd75JcKHW3w5RRJdqAebjK2d8AEywsmOFr+mYJri8ndDy t7V1ZovAYOuHzkiyIi+/tzReP3q7FsPYRTKqk= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:sender:in-reply-to:references:date :x-google-sender-auth:message-id:subject:from:to:content-type; b=idl+pmajxAH4/B0IQCXe17iM8gYR6TbQvXHP+piOvQp5NVIACaM+TL0JIT5tskXmwU 8+ElU5eV9jls1iD0Kg5Qp2ZT8WzmVuhib/+osYqiraociSVOb7zUPUBR5ENv1eyf+qyK TtfrHA6ocnrXnXjhDL/3eugFiNy9mT0y1z5Ww= MIME-Version: 1.0 Sender: rwstracy@gmail.com Received: by 10.224.54.70 with SMTP id p6mr3478081qag.171.1249177956543; Sat, 01 Aug 2009 18:52:36 -0700 (PDT) In-Reply-To: References: Date: Sat, 1 Aug 2009 21:52:36 -0400 X-Google-Sender-Auth: ef56587ab6732194 Message-ID: <1b4b137c0908011852j55e71b9du68330d7d879c67c7@mail.gmail.com> Subject: Re: [FlyRotary] Re: EC2 and Ed's EFISM - a great combination From: Tracy Crook To: Rotary motors in aircraft Content-Type: multipart/alternative; boundary=0015175cd5ca5c6f6004701ee8e5 --0015175cd5ca5c6f6004701ee8e5 Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: quoted-printable Hi Al, No argument about the desirability of empirical testing results. I don't think anyone has said the Ross did not have a prop thrust bearing. It was the lack of an input shaft thrust bearing that was the concern. It may not be intuitive but if my calculations were correct, the thrust o= n the helical sun gear (which is transferred to the engine's thrust bearing with a Ross drive) is about four times what the prop thrust is in a typical application. I agree that the slamming back & forth of the input shaft on the Ross was a problem too. That is hydraulically damped with oil pressure in the RWS drive. Same way the lash on valves is controlled by hydraulic lifters in many engines. Tracy Crook On Sat, Aug 1, 2009 at 11:13 AM, Al Wick wrote: > I flew 5 years with a Ross. I've disassembled and inspected 5 or so, jus= t > to help out other builders. Just want to offer a different viewpoint base= d > on my findings: > > 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 importan= t > 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 p= rop > 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 sha= ft > that goes between flywheel and gears. Low rpm torsionals caused that shaf= t > to slam back and forth between flywheel and gears. This caused pilot bear= ing > damage, fatigue failures on the drive plate. I changed the design by > controlling thrust at the sun gear. All of those failures then disappear. > > Second, Ross decision to restrict oil flow to redrive is very sound desig= n. > 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. > > > 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 quic= kly > disassemble and measure temperature of various components. A friend slapp= ed > 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 fin= d > tons of things you believe in, that just aren't significant. > > I am in agreement that Tracy version of the Ross design is looking prett= y > good. When asked by builders which redrive to consider, his gets high mar= ks. > I don't have rose colored glasses. There have been a couple design > oversights that resulted in failures. I like the solutions. > > -al wick > > > ----- Original Message ----- > > *From:* Ed Anderson > *To:* Rotary motors in aircraft > *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. > > > > 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. > > > > 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, t= he > internals are considerably ahead of anything Ross had. Pressure lubricat= ion > 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 =96 otherwise the thing leaked like crazy =96 e= ven > with the restrictor, the rear seal frequently was a leaky mess. But, > reducing the oil pressure was one reason the Ross had marginal lubricatio= n > in my opinion. Even then, the oil distribution inside the Ross was also n= ot > well designed. > > > > Don=92t get me wrong, I was glad to get a Ross =96 because it was the onl= y > thing around at the time. Had old man, Lou Ross, lived longer he may hav= e > eventually fixed a lot of these issues, but unfortunately he did not and = I > won=92t go into the situation with his son, Chris. But, we are fortunate= that > Tracy took on this challenge and did it right. > > > > One thing I really appreciate about the RWS design is that it has a > considerably different internal set up with easily replaceable parts =96 = 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. > > > > 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. > > > > 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] *O= n > 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 > > > > > > 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. > > > > 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). > > > > Steve, > > I went with the RD-1B PSRU from RWS. > > > > 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 > > --0015175cd5ca5c6f6004701ee8e5 Content-Type: text/html; charset=windows-1252 Content-Transfer-Encoding: quoted-printable Hi Al,
=A0No argument about the desirability of empirical testing result= s.

I don't think anyone has said the Ross did not have a prop th= rust bearing.=A0 It was the lack of an input shaft thrust bearing that was = the concern.

=A0 It may not be intuitive but if my calculations were correct, the th= rust on the helical sun gear (which is transferred to the engine's thru= st bearing with a Ross drive) is about four times what the prop thrust is i= n a typical application.

I agree that the slamming back & forth of the input shaft on the Ro= ss was a problem too.=A0 That is hydraulically damped with oil pressure in = the RWS drive.=A0 Same way the lash on valves is controlled by hydraulic li= fters in many engines.

Tracy Crook

On Sat, Aug 1, 2009 at 11= :13 AM, Al Wick <al= wick@juno.com> wrote:
I flew 5 years with a Ross. I've d= isassembled and=20 inspected 5 or so, just to help out other builders. Just want to offer a=20 different viewpoint based on my findings:
=A0
First, all of the Ross's have larg= e bearing that=20 absorbs the prop thrust forces. I'm quite puzzled your statement that t= hey=20 don't. A very important part of the installation is to verify you have = clearance=20 to flywheel. I'm wondering if you are just confusing the pilot bearing = damage=20 issue with prop thrust? Ross redrive had one significant design oversight. = This=20 oversight caused around 80% of their field failures. Basically Ross picked = a=20 poor method of controlling input shaft clearance. Input shaft is the short = shaft=20 that goes between flywheel and gears. Low rpm torsionals caused that shaft = to=20 slam back and forth between flywheel and gears. This caused pilot bearing= =20 damage, fatigue failures on the drive plate. I changed the design by contro= lling=20 thrust at the sun gear. All of those failures then disappear.
=A0
Second, Ross decision to restrict oil = flow to=20 redrive is very sound design. It limits flow because excess oil flow to red= rive=20 has significant effect on hp loss. A friend actually measured hp loss relat= ed to=20 oil volume. I verified flow on my redrive gears &=A0bearings, absolutel= y=20 no issues. I do believe there were lube issues on some Ross applications, b= ut=20 definitely not true on mine. I don't understand why the difference.=20
=A0
=A0
There is a method of proving design ch= anges that=20 Tracy doesn't use often enough. Basically you measure how close the des= ign is to=20 failure. You don't rely on theory. For example, I verified oil flow jus= t 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 f= riend=20 slapped a plastic cover on his redrive, then watched the oil flow. These=20 methods=A0let you predict future=A0failures. Too much design theory, not=20 enough actual measurements. If you can force yourself to test your theories= ,=20 you'll find tons of things you believe in, that just aren't signifi= cant.=20
=A0
I am in agreement that Tracy version o= f the Ross=20 design is looking pretty good. When asked by builders which redrive to cons= ider,=20 his gets high marks. I don't have rose colored glasses. There have been= a couple=20 design oversights that resulted in failures. I like the solutions. <= /div>
=A0
-al=A0 wick
=A0
=A0
----- Original Message -----
From:=20 Ed=20 Anderson
Sent: Friday, July 31, 2009 3:46 P= M
Subject: [FlyRotary] Re: EC2 and E= d's=20 EFISM - a great combination

Actually, George, The=20 RWS drive was not just a redevelopment of the Ross drive.=20 =A0

=A0

Tracy basically started=20 from scratch and engineered a redrive that was designed to meet certain= =20 objectives while achieving a reasonable cost. =A0=A0There is no other=20 redrive I am familiar with that has anywhere near the number of flying ho= urs=20 that the RWS redrive has with none of the problems associated with the=20 Ross.

=A0

While there is a=20 superficial similarly to the Ross (Prop on one end and rotary on the othe= r,=20 planetary gears in the middle {:>)) in appearance, the internals are= =20 considerably ahead of anything Ross had.=A0 Pressure lubrication of the= =20 prop shaft for one thing, an integral thrust bearing for another, a remov= able=20 propeller shaft for yet another, full oil pressure lubrication.=A0 The Ro= ss=20 drive required a restrictor in the oil line to (can you believe this) red= uce=20 oil pressure =96 otherwise the thing leaked like crazy =96 even with the= =20 restrictor, the rear seal frequently was a leaky mess.=A0 But, reducing t= he=20 oil pressure was one reason the Ross had marginal lubrication in my opini= on.=20 Even then, the oil distribution inside the Ross was also not well designe= d.=20

=A0

Don=92t get me wrong, I=20 was glad to get a Ross =96 because it was the only thing around at the=20 time.=A0 Had old man, Lou Ross, lived longer he may have eventually fixed= a=20 lot of these issues, but unfortunately he did not and I won=92t go into t= he=20 situation with his son, Chris.=A0 But, we are fortunate that Tracy took o= n this=20 challenge and did it right.=A0=A0

=A0

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.=A0 If you wanted to completely disassembly a Ross unit you most= =20 likely had to take it to a machine shop.

=A0

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

=A0

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: [F= lyRotary] Re: EC2 and Ed's=20 EFISM - a great combination

=A0

=A0

Steve,

The Ross drive was redeveloped=20 by Tracy Crook of Real World Solutions (RWS). Tracy now uses the 6 plan= et planetary (Ford=20 Unit) and is about the best you will get=A0 weight wise and value for= =20 money.

=A0

There are other similar units=20 -=A0all have slightly different construction, however Tracy's is we= ll=20 proven. I will probably make my own, but only because of the tyranny of= =20 distance and associated costs.

George (down=20 under).

=A0

Steve,

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

=A0<= /font>

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<= /span>


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