X-Virus-Scanned: clean according to Sophos on Logan.com From: "Charlie England" Received: from mail-yk0-f173.google.com ([209.85.160.173] verified) by logan.com (CommuniGate Pro SMTP 6.1.5) with ESMTPS id 7996789 for flyrotary@lancaironline.net; Thu, 17 Sep 2015 10:44:34 -0400 Received-SPF: pass receiver=logan.com; client-ip=209.85.160.173; envelope-from=ceengland7@gmail.com Received: by ykdu9 with SMTP id u9so18737765ykd.2 for ; Thu, 17 Sep 2015 07:44:00 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :content-type; bh=1jq7/u2zW2/dKnNecTTastygb4hneP/PHFlhtymOwLk=; b=0V6vgk1dLCXDJni85WLIM677qfvV9BXpeSH0BNN5u18C+rxeyha4maRU7Zov+4/WCP uMym0khI2N4URzX7ijtQ/m6mSfsNYM5IWoMum2NDd193ZlNm+SSRUyXIVAnGPwMxuGM7 TKxXg91zl90J4618n54yYYLCYylUPiCb4aPi1UyB8+mTzfzTDBFmBrin0NZZErlUkPDb lhXl32qn69U7Wc3I5jDrvqrHDV/PFeRLeaeM0+ueKXHbJ9SLrgdBkgiDYcD1VV4x/ZOd W+XIi+d+64aBsUjmpF8qjVFQ7n8+UShtG0+I4XOADWa5+yQFRPmy4D+1erWW/oFDBTy5 yVZw== MIME-Version: 1.0 X-Received: by 10.129.157.145 with SMTP id u139mr34360646ywg.11.1442501040506; Thu, 17 Sep 2015 07:44:00 -0700 (PDT) Received: by 10.129.155.15 with HTTP; Thu, 17 Sep 2015 07:44:00 -0700 (PDT) In-Reply-To: References: Date: Thu, 17 Sep 2015 09:44:00 -0500 Message-ID: Subject: Re: [FlyRotary] New psru To: Rotary motors in aircraft Content-Type: multipart/alternative; boundary=94eb2c0b754c1b9367051ff27288 --94eb2c0b754c1b9367051ff27288 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Hi Neil, 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. 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. 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 modificati= on. > Now to put to test to see if the practice matches the theory. Alread= y > found one fault. The =E2=80=9CO=E2=80=9D ring seal that seals the main bo= dy of the PSRU to > the base that attaches to the mounting plate is outside all the attachmen= t > 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 easil= y > 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 us= e. > Now the terrible part and still undecided as I am yet to cost a dampe= r > 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. Freigh= t > 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 ha= ve > to alter the way it is constructed so that all the mods can be done by yo= u > 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 > > --94eb2c0b754c1b9367051ff27288 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable
Hi Neil,

Congrats on your progress; it = looks nice.=C2=A0=C2=A0I like the idea of being able to source some of the = parts locally, given that international shipping can cost more than a lot o= f parts.=C2=A0

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 s= teel flywheels, but I think they were still using Tracy's damper mechan= ism, which doesn't look too complicated to build with precision machine= tools that you obviously have access to.

I know y= ou'll hate to hear this question, but....are there provisions to use th= e 2.85 ratio in your design? The reason I ask is that many of us have no de= sire to turn the engine beyond 7500 rpm, and that wide ratio means cruise r= pm at the prop of well below 2000 rpm. Most of us are flying planes that ca= n't swing the 7-8 foot diameter prop needed to maintain efficiency at t= hose low prop rpms. It also complicates getting a prop made that will perfo= rm correctly, since it's outside the area where most prop makers have w= orked. It's confused some reputable prop makers here in the USA, even w= ith the 2.85 ratio.=C2=A0

Again, congrats on the n= ew design,

Charlie

On Wed, Sep 16, 2015 at 11:28 PM, Nei= l Unger <flyrotary@lancaironline.net> wrote:
Gents,
=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2= =A0=C2=A0=20 Finally the first PSRU with a reduction of 3.12=C2=A0 to 1.=C2=A0 Pictured = is=20 the basic box which is heavily based on Tracy=E2=80=99s PSRU but with the l= arger=20 reduction and 2 oil lubricated thrust=C2=A0=C2=A0 bearings on the prop shaf= t=20 instead of a single sealed roller bearing in Tracy=E2=80=99s.=C2=A0 This ps= ru will mount=20 directly in place of Tracy's 2.85 reduction PSRU with no modification.<= /div>
=C2=A0=C2=A0=C2=A0 Now to put to test to see if the practice matches t= he=20 theory.=C2=A0 Already found one fault. The =E2=80=9CO=E2=80=9D ring seal th= at seals the main=20 body of the PSRU to the base that attaches to the mounting plate is outside= all=20 the attachment bolts, which means that the oil can wick down the bolts and = make=20 a lovely mess of your pride and joy.=C2=A0 Now looking for more faults as t= his=20 is easily fixed.=C2=A0 Unlike Tracy's , this PSRU is totally sealed wit= h O rings=20 to ease dismantling with no clean up of whatever gasket sealer you have had= to=20 use.
=C2=A0=C2=A0=C2=A0 Now the terrible part and still undecided as I am y= et to=20 cost a damper on the drive.=C2=A0 Sadly it also is not cheap and may yet co= st=20 near $500 for a =E2=80=9Dbit of rubber=E2=80=9D.=C2=A0 Then comes a mountin= g plate as made by=20 Geoff Doddridge which he sells for around $400 USD.=C2=A0 There is no point= in=20 me trying to compete with Geoff as he does a magnificent job at a cheap=20 price.=C2=A0 Freight is always a horrible price so he makes the plate and t= here=20 is=C2=A0 no freight from Aust to be added.
=C2=A0=C2=A0=C2=A0 The total cost in Aust dollars (including Geoff=E2= =80=99s plate)=20 will be around the $5000 which equates to $3500 USD.=C2=A0 Then freight of= =20 possibly $200.=C2=A0 Currently looking at further reduction in price if you= =20 source the gear set locally saving on freight both ways to Aust and back.= =C2=A0=20 I will have to alter the way it is constructed so that all the mods can be = done=20 by you the builder.=C2=A0 Still looking!
=C2=A0=C2=A0=C2=A0 So far the progress.=C2=A0=20 Neil.

--
Homepage:=C2=A0 http://www.flyrotary.com/
Archive and UnSub:=C2=A0 =C2=A0http://mail= .lancaironline.net:81/lists/flyrotary/List.html


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