X-Virus-Scanned: clean according to Sophos on Logan.com From: "Neil Unger" Received: from nskntmtas05p.mx.bigpond.com ([61.9.168.149] verified) by logan.com (CommuniGate Pro SMTP 6.1.5) with ESMTPS id 7998433 for flyrotary@lancaironline.net; Fri, 18 Sep 2015 00:18:29 -0400 Received-SPF: pass receiver=logan.com; client-ip=61.9.168.149; envelope-from=neil.unger@bigpond.com Received: from nskntcmgw08p ([61.9.169.168]) by nskntmtas05p.mx.bigpond.com with ESMTP id <20150918041753.JMEY25105.nskntmtas05p.mx.bigpond.com@nskntcmgw08p> for ; Fri, 18 Sep 2015 04:17:53 +0000 Received: from UserPC ([58.168.127.99]) by nskntcmgw08p with BigPond Outbound id JUHp1r00e28oHN201UHqbG; Fri, 18 Sep 2015 04:17:53 +0000 X-Authority-Analysis: v=2.0 cv=D6DF24tj c=1 sm=1 a=FFFx9FrFIolsJRnwuFKMHQ==:17 a=1IlZJK9HAAAA:8 a=Ia-xEzejAAAA:8 a=7g1VtSJxAAAA:8 a=IFKksG_vjLOOqtFWreIA:9 a=QEXdDO2ut3YA:10 a=Qa1je4BO31QA:10 a=lFwCsGX5rX4yqreL:21 a=c0nmv7Vli6V4oqjz:21 a=Ex239LpgqSOgWyaqz2wA:9 a=_W_S_7VecoQA:10 a=FFFx9FrFIolsJRnwuFKMHQ==:117 Message-ID: To: "Rotary motors in aircraft" References: In-Reply-To: Subject: Re: [FlyRotary] Re: New psru Date: Fri, 18 Sep 2015 14:17:39 +1000 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_002C_01D0F21C.C66D1CB0" X-Priority: 3 X-MSMail-Priority: Normal Importance: Normal X-Mailer: Microsoft Windows Live Mail 15.4.3555.308 X-MimeOLE: Produced By Microsoft MimeOLE V15.4.3555.308 This is a multi-part message in MIME format. ------=_NextPart_000_002C_01D0F21C.C66D1CB0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Charlie, As usual anything is possible. The 2.85 ratio is easier to = alter the gear set , but by the time the =E2=80=9Clittle=E2=80=9D mods = are done the cost climbs yet again. May look at the possibility as all = the drawings are done and alterations are now much simpler. Will get = the bugs out of this one first. Most prop makers that I went to just do = not want to hear =E2=80=9Crotary=E2=80=9D. The revs are there but the = torque is not compared to a lyc. Much to learn in this area. Regards, = neil. From: Charlie England=20 Sent: Friday, September 18, 2015 12:44 AM To: Rotary motors in aircraft=20 Subject: [FlyRotary] Re: New psru Hi Neil,=20 Congrats on your progress; it looks nice. I like the idea of being able = to source some of the parts locally, given that international shipping = can cost more than a lot of parts.=20 The damper issue is a real bummer. IIRC, Tracy's been running a later = version of his 2.85 directly coupled to an aluminum racing flywheel. One = or two others have used light weight steel flywheels, but I think they = were still using Tracy's damper mechanism, which doesn't look too = complicated to build with precision machine tools that you obviously = have access to. I know you'll hate to hear this question, but....are there provisions to = use the 2.85 ratio in your design? The reason I ask is that many of us = have no desire to turn the engine beyond 7500 rpm, and that wide ratio = means cruise rpm at the prop of well below 2000 rpm. Most of us are = flying planes that can't swing the 7-8 foot diameter prop needed to = maintain efficiency at those low prop rpms. It also complicates getting = a prop made that will perform correctly, since it's outside the area = where most prop makers have worked. It's confused some reputable prop = makers here in the USA, even with the 2.85 ratio.=20 Again, congrats on the new design, Charlie On Wed, Sep 16, 2015 at 11:28 PM, Neil Unger = wrote: Gents, Finally the first PSRU with a reduction of 3.12 to 1. = Pictured is the basic box which is heavily based on Tracy=E2=80=99s PSRU = but with the larger reduction and 2 oil lubricated thrust bearings on = the prop shaft instead of a single sealed roller bearing in = Tracy=E2=80=99s. This psru will mount directly in place of Tracy's 2.85 = reduction PSRU with no modification. Now to put to test to see if the practice matches the theory. = Already found one fault. The =E2=80=9CO=E2=80=9D ring seal that seals = the main body of the PSRU to the base that attaches to the mounting = plate is outside all the attachment bolts, which means that the oil can = wick down the bolts and make a lovely mess of your pride and joy. Now = looking for more faults as this is easily fixed. Unlike Tracy's , this = PSRU is totally sealed with O rings to ease dismantling with no clean up = of whatever gasket sealer you have had to use. Now the terrible part and still undecided as I am yet to cost a = damper on the drive. Sadly it also is not cheap and may yet cost near = $500 for a =E2=80=9Dbit of rubber=E2=80=9D. Then comes a mounting plate = as made by Geoff Doddridge which he sells for around $400 USD. There is = no point in me trying to compete with Geoff as he does a magnificent job = at a cheap price. Freight is always a horrible price so he makes the = plate and there is no freight from Aust to be added. The total cost in Aust dollars (including Geoff=E2=80=99s plate) = will be around the $5000 which equates to $3500 USD. Then freight of = possibly $200. Currently looking at further reduction in price if you = source the gear set locally saving on freight both ways to Aust and = back. I will have to alter the way it is constructed so that all the = mods can be done by you the builder. Still looking! So far the progress. Neil. -- Homepage: http://www.flyrotary.com/ Archive and UnSub: = http://mail.lancaironline.net:81/lists/flyrotary/List.html ------=_NextPart_000_002C_01D0F21C.C66D1CB0 Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable
Charlie,  As usual anything is possible.  The 2.85 ratio = is=20 easier to alter the gear set , but by the time the = =E2=80=9Clittle=E2=80=9D mods are done the=20 cost climbs yet again.  May look at the possibility as all the = drawings are=20 done and alterations are now much simpler.  Will get the bugs out = of this=20 one first.  Most prop makers that I went to just do not want to = hear=20 =E2=80=9Crotary=E2=80=9D.  The revs are there but the torque is not = compared to a=20 lyc.  Much to learn in this area.  Regards,  neil.
 
Sent: Friday, September 18, 2015 12:44 AM
Subject: [FlyRotary] Re: New psru
 
Hi Neil,=20
 
Congrats on your progress; it looks nice.  I like the idea of = being=20 able to source some of the parts locally, given that international = shipping can=20 cost more than a lot of parts.
 
The damper issue is a real bummer. IIRC, Tracy's been running a = later=20 version of his 2.85 directly coupled to an aluminum racing flywheel. One = or two=20 others have used light weight steel flywheels, but I think they were = still using=20 Tracy's damper mechanism, which doesn't look too complicated to build = with=20 precision machine tools that you obviously have access to.
 
I know you'll hate to hear this question, but....are there = provisions to=20 use the 2.85 ratio in your design? The reason I ask is that many of us = have no=20 desire to turn the engine beyond 7500 rpm, and that wide ratio means = cruise rpm=20 at the prop of well below 2000 rpm. Most of us are flying planes that = can't=20 swing the 7-8 foot diameter prop needed to maintain efficiency at those = low prop=20 rpms. It also complicates getting a prop made that will perform = correctly, since=20 it's outside the area where most prop makers have worked. It's confused = some=20 reputable prop makers here in the USA, even with the 2.85 ratio.
 
Again, congrats on the new design,
 
Charlie
 
On Wed, Sep 16, 2015 at 11:28 PM, Neil Unger = <flyrotary@lancaironline.net> wrote:
Gents,
=
           &n= bsp; =20 Finally the first PSRU with a reduction of 3.12  to 1.  = Pictured is=20 the basic box which is heavily based on Tracy=E2=80=99s PSRU but with = the larger=20 reduction and 2 oil lubricated thrust   bearings on the prop = shaft=20 instead of a single sealed roller bearing in Tracy=E2=80=99s.  = This psru will=20 mount directly in place of Tracy's 2.85 reduction PSRU with no=20 modification.
    Now to put to test to see if the practice = matches the=20 theory.  Already found one fault. The =E2=80=9CO=E2=80=9D ring = seal that seals the main=20 body of the PSRU to the base that attaches to the mounting plate is = outside=20 all the attachment bolts, which means that the oil can wick down the = bolts and=20 make a lovely mess of your pride and joy.  Now looking for more = faults as=20 this is easily fixed.  Unlike Tracy's , this PSRU is totally = sealed with=20 O rings to ease dismantling with no clean up of whatever gasket sealer = you=20 have had to use.
    Now the terrible part and still undecided as I = am yet=20 to cost a damper on the drive.  Sadly it also is not cheap and = may yet=20 cost near $500 for a =E2=80=9Dbit of rubber=E2=80=9D.  Then comes = a mounting plate as=20 made by Geoff Doddridge which he sells for around $400 USD.  = There is no=20 point in me trying to compete with Geoff as he does a magnificent job = at a=20 cheap price.  Freight is always a horrible price so he makes the = plate=20 and there is  no freight from Aust to be added.
    The total cost in Aust dollars (including = Geoff=E2=80=99s=20 plate) will be around the $5000 which equates to $3500 USD.  Then = freight=20 of possibly $200.  Currently looking at further reduction in = price if you=20 source the gear set locally saving on freight both ways to Aust and=20 back.  I will have to alter the way it is constructed so that all = the=20 mods can be done by you the builder.  Still looking!
    So far the progress. =20 Neil.

--
Homepage:  http://www.flyrotary.com/
Archive and = UnSub:  =20 http://mail.lancaironline.net:81/lists/flyrotary/List.htm= l

 
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