X-Virus-Scanned: clean according to Sophos on Logan.com From: "Tracy" Received: from mail-ob0-f174.google.com ([209.85.214.174] verified) by logan.com (CommuniGate Pro SMTP 6.1.5) with ESMTPS id 8001025 for flyrotary@lancaironline.net; Sat, 19 Sep 2015 08:10:00 -0400 Received-SPF: pass receiver=logan.com; client-ip=209.85.214.174; envelope-from=rwstracy@gmail.com Received: by obbda8 with SMTP id da8so54995660obb.1 for ; Sat, 19 Sep 2015 05:09:26 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=subject:references:from:content-type:in-reply-to:message-id:date:to :content-transfer-encoding:mime-version; bh=flImuqo41KZ9Ob1mf4dM8gmGC3tw42lwLuL8n0rbnJQ=; b=F9KDx7YeHUb6fLIIwQ6et6amq9jKbyLS9HoMEx/NKkV8IwLrqEt6vVVYlWY62Vhvg2 tchiC4ezicLhqf0clsgvbkHIlfMbsBmCq/etR5tHtn6oIHCcUhTeAJJp7Iq7Lh/gihs/ ibEog61dW97KGy5jib9fqaLMnVrNMNLhH92h0B63CN+1lKlhe3+St6rMDlEjZVTnWiFY 0Jz5TPPQxRh9hhU0lN6f1KF4bKBtD293/f1Ar2VjmoJvoB5XXU1PRz+GBwa0pbrpAvY6 RE8RfN5K/hzDeRmU+52sirQGKMiOt08rN0PKsMIaCgZuhVLHr+t5FeZzjDIb0Tmn7IZY CYqg== X-Received: by 10.60.155.198 with SMTP id vy6mr6855556oeb.27.1442664566202; Sat, 19 Sep 2015 05:09:26 -0700 (PDT) Return-Path: Received: from [192.168.1.3] (158.sub-70-196-192.myvzw.com. [70.196.192.158]) by smtp.gmail.com with ESMTPSA id k1sm6351687oet.3.2015.09.19.05.09.24 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Sat, 19 Sep 2015 05:09:25 -0700 (PDT) Subject: Re: [FlyRotary] Re: New psru References: Content-Type: multipart/alternative; boundary=Apple-Mail-0FBE804A-546D-4836-91DC-A7A33E54AEBF X-Mailer: iPad Mail (12H321) In-Reply-To: Message-Id: Date: Sat, 19 Sep 2015 06:09:19 -0600 To: Rotary motors in aircraft Content-Transfer-Encoding: 7bit Mime-Version: 1.0 (1.0) --Apple-Mail-0FBE804A-546D-4836-91DC-A7A33E54AEBF Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Looks like very nice work Neil, glad you picked up the ball and ran. I had= the same comment as Charlie but as long as you get a suitable prop the 3.12= will work. Only down side is I think the minimum BSFC 'sweet spot' of the r= otary (about 5000 - 5500 rpm) may be below the usable cruise settings if pro= pped for 8500 with a fixed pitch prop. Not a big deal though. When lookin= g at my flying expenses, fuel turns out to be about the cheapest item :-) I would urge you to investigate 'going naked' with the damper. My direct co= upler version is at least as smooth as the rubber coupled damper version. O= nly downside is it may not be suitable for metal props but I doubt you could= find a suitable metal one for 3.12 ratio anyway. Keep up the good work, Tracy Sent from my iPad > On Sep 18, 2015, at 09:15, Charlie England w= rote: >=20 > I understand about debugging what you've got, before going off in a new di= rection. That's why I hated to bring it up now. :-) >=20 > The prop doesn't know how fast the engine is turning; it just knows how fa= st *it* is turning, and how fast it's moving through the air. I think that t= he problems start when the prop carver gets out of his comfort zone, which i= s 2700 design rpm and around 72" maximum diameter (usually less). When diame= ter goes up to 74"-76" and design rpm starts to drop, they seem to get a bit= confused. For those of us who never expect to exceed 7500 rpm, with cruise= down around 5500-6000, a 3.12 ratio would mean prop at 2400 rpm max, and ar= ound 1900 at cruise. Nothing wrong with that if we could swing a 7 foot diam= eter prop, but with small, short legged a/c, you just can't do it.=20 >=20 > I couldn't find anything in my old emails about the prop you had problems w= ith. What were its specs & mfgr? Was the 6000 rpm static, or full throttle i= n flight at low altitude? Did you ever get your engine on a dyno? I know wha= t Lamar claimed for his p-port Renesis, but if those were 'corrected' dyno n= umbers, they are pretty useless for real world flying at higher than sea lev= el and anything above 'standard day' temperatures (which almost never happen= s). 250 HP seems pretty optimistic for a normally aspirated 2 rotor actually= flying in an a/c, but I hope you can get it working. I've been very tempted= to find another Renesis core & send the housings out to get them p-ported, &= if you're successful, you just might push me over the edge... >=20 > Charlie >=20 >=20 >=20 >> On 9/17/2015 11:17 PM, Neil Unger wrote: >> Charlie, As usual anything is possible. The 2.85 ratio is easier to alt= er 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 th= is 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 l= yc. Much to learn in this area. Regards, neil. >> =20 >> From: Charlie England >> Sent: Friday, September 18, 2015 12:44 AM >> To: Rotary motors in aircraft >> Subject: [FlyRotary] Re: New psru >> =20 >> Hi Neil, >> =20 >> Congrats on your progress; it looks nice. I like the idea of being able t= o source some of the parts locally, given that international shipping can co= st more than a lot of parts. >> =20 >> The damper issue is a real bummer. IIRC, Tracy's been running a later ver= sion 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 u= sing Tracy's damper mechanism, which doesn't look too complicated to build w= ith precision machine tools that you obviously have access to. >> =20 >> I know you'll hate to hear this question, but....are there provisions to u= se the 2.85 ratio in your design? The reason I ask is that many of us have n= o desire to turn the engine beyond 7500 rpm, and that wide ratio means cruis= e rpm at the prop of well below 2000 rpm. Most of us are flying planes that c= an't swing the 7-8 foot diameter prop needed to maintain eff= iciency 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 h= ave worked. It's confused some reputable prop makers here in the USA, even w= ith the 2.85 ratio. >> =20 >> Again, congrats on the new design, >> =20 >> Charlie >> =20 >>> 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. Pi= ctured is the basic box which is heavily based on Tracy=E2=80=99s PSRU but w= ith the larger reduction and 2 oil lubricated thrust bearings on the prop s= haft instead of a single sealed roller bearing in Tracy=E2=80=99s. This psr= u will mount directly in place of Tracy's 2.85 reduction PSRU with no modifi= cation. >>> Now to put to test to see if the practice matches the theory. Alrea= dy 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 al= l 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 t= his is easily fixed. Unlike Tracy's , this PSRU is totally sealed with O ri= ngs to ease dismantling with no clean up of whatever gasket sealer you have h= ad to use. >>> Now the terrible part and still undecided as I am yet to cost a damp= er 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 Ge= off Doddridge which he sells for around $400 USD. There is no point in me t= rying 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 fr= eight from Aust to be added. >>> The total cost in Aust dollars (including Geoff=E2=80=99s plate) wil= l 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 a= lter the way it is constructed so that all the mods can be done by you the b= uilder. Still looking! >>> So far the progress. Neil. >>>=20 >>> -- >>> Homepage: http://www.flyrotary.com/ >>> Archive and UnSub: http://mail.lancaironline.net:81/lists/flyrotary/Li= st.html >=20 --Apple-Mail-0FBE804A-546D-4836-91DC-A7A33E54AEBF Content-Type: text/html; charset=utf-8 Content-Transfer-Encoding: quoted-printable
Looks like very nice work Neil, glad y= ou picked up the ball and ran.   I had the same comment as Charlie but a= s long as you get a suitable prop the 3.12 will work.  Only down side i= s I think the minimum BSFC 'sweet spot' of the rotary (about 5000 - 5500 rpm= ) may be below the usable cruise settings if propped for 8500 with a fixed p= itch prop.  Not a big deal though.   When looking at my flying exp= enses, fuel turns out to be about the cheapest item  :-)

=
I would urge you to investigate 'going naked' with the damper. &n= bsp;My direct coupler version is at least as smooth as the rubber coupled da= mper version.  Only downside is it may not be suitable for metal props b= ut I doubt you could find a suitable metal one for 3.12 ratio anyway.
<= div>
Keep up the good work,
Tracy

Sent from m= y iPad

On Sep 18, 2015, at 09:15, Charlie England <flyrotary@lancaironline.net> wro= te:

=20 =20 =20
I understand about debugging what you've got, before going off in a new direction. That's why I hated to bring it up now. :-)

The prop doesn't know how fast the engine is turning; it just knows how fast *it* is turning, and how fast it's moving through the air. I think that the problems start when the prop carver gets out of his comfort zone, which is 2700 design rpm and around 72" maximum diameter (usually less). When diameter goes up to 74"-76" and design rpm starts to drop, they seem to get a bit confused.  For those of us who never expect to exceed 7500 rpm, with cruise down around 5500-6000, a 3.12 ratio would mean prop at 2400 rpm max, and around 1900 at cruise. Nothing wrong with that if we could swing a 7 foot diameter prop, but with small, short legged a/c, you just can't do it.

I couldn't find anything in my old emails about the prop you had problems with. What were its specs & mfgr? Was the 6000 rpm static, or full throttle in flight at low altitude? Did you ever get your engine on a dyno? I know what Lamar claimed for his p-port Renesis, but if those were 'corrected' dyno numbers, they are pretty useless for real world flying at higher than sea level and anything above 'standard day' temperatures (which almost never happens). 250 HP seems pretty optimistic for a normally aspirated 2 rotor actually flying in an a/c, but I hope you can get it working. I've been very tempted to find another Renesis core & send the housings out to get them p-ported, & if you're successful, you just might push me over the edge...

Charlie



On 9/17/2015 11:17 PM, Neil Unger wrote:
Charlie,  As usual anything is possible.  The 2.85 r= atio 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 no= t want to hear =E2=80=9Crotary=E2=80=9D.  The revs are there b= ut the torque is not compared to a lyc.  Much to learn in this area.  Regards,  neil.
 
Sent: Friday, September 18, 2015 12:44 AM
Subject: [FlyRotary] Re: New psru
 
Hi Neil,
 
Congrats on your progress; it looks nice.  I like th= e 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 <flyro= tary@lancaironline.net> wrote:
Gents,
        = ;      Finally the first PSRU with a reduction of 3.12  to 1.  Pictured is th= e basic box which is heavily based on Tracy=E2=80=99= s 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 direct= ly 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 s= eals 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 st= ill undecided as I am yet to cost a damper on the drive.  Sadly it also is not cheap and may ye= t 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 dolla= rs (including Geoff=E2=80=99s plate) will be around t= he $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.  N= eil.

--
Homepage:  http://www.flyrota= ry.com/
Archive and UnSub:   http://mail.lancaironline.net:81/lists/flyrota= ry/List.html

 

=20
= --Apple-Mail-0FBE804A-546D-4836-91DC-A7A33E54AEBF--