X-Virus-Scanned: clean according to Sophos on Logan.com From: "Bruce Cosgrove" Received: from pecan.exetel.com.au ([220.233.0.8] verified) by logan.com (CommuniGate Pro SMTP 6.1.5) with ESMTP id 8000609 for flyrotary@lancaironline.net; Fri, 18 Sep 2015 22:29:59 -0400 Received-SPF: softfail receiver=logan.com; client-ip=220.233.0.8; envelope-from=bcosgrove@mac.com Received: from 231.65.70.115.static.exetel.com.au ([115.70.65.231] helo=[192.168.0.8]) by pecan.exetel.com.au with esmtp (Exim 4.84) (envelope-from ) id 1Zd7tz-00058Q-DB for flyrotary@lancaironline.net; Sat, 19 Sep 2015 12:29:23 +1000 Content-Type: multipart/alternative; boundary="Apple-Mail=_F206F01F-B103-4B8D-AF79-8FAA3E02FF15" Message-Id: Mime-Version: 1.0 (Mac OS X Mail 8.2 \(2098\)) Subject: Re: [FlyRotary] Re: New psru Date: Sat, 19 Sep 2015 12:29:23 +1000 References: To: Rotary motors in aircraft In-Reply-To: X-Mailer: Apple Mail (2.2098) --Apple-Mail=_F206F01F-B103-4B8D-AF79-8FAA3E02FF15 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=utf-8 Hi Christian, I am wondering what your psru ratio is? Bruce > On 19 Sep 2015, at 07:13, christamarmc = wrote: >=20 > Hi all > Just thought I'd pipe in with my results on my rv7 renises. >> I'm currently running a prince p tip prop at 68" and it has proven to = work extremely well with take of rpm around the 6400 rpm, I've compared = it to a 72" whirlwind ground adjustable and the prince was superior in = all ways on my install, I find if I could get more rpm and increase my = torque it would even be better with my prop, as we need revs to get = torque out of our machines I found that I had slightly less take off = ability at 3000 ft agl strip and still get better top end with the p tip = than the whirlwind. I max out at 175 k tas at strait and level at 8000 = ft, hope this helps. Spinning just 7400 rpm. >=20 >=20 > Cheers > Christian >=20 > Sent from my iPad >=20 > On 19 Sep 2015, at 1:15 am, Charlie England = > = wrote: >=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. :-) >>=20 >> 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.=20 >>=20 >> 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... >>=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 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. >>> =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 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. >>> =20 >>> 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, >>> =20 >>> Charlie >>> =20 >>> On Wed, Sep 16, 2015 at 11:28 PM, Neil Unger < = flyrotary@lancaironline.net = > 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. >>>=20 >>> -- >>> Homepage: http://www.flyrotary.com/ >>> Archive and UnSub: = http://mail.lancaironline.net:81/lists/flyrotary/List.html = >>>=20 >>> =20 >>=20 --Apple-Mail=_F206F01F-B103-4B8D-AF79-8FAA3E02FF15 Content-Transfer-Encoding: quoted-printable Content-Type: text/html; charset=utf-8 Hi Christian,

I am wondering what your psru ratio is?

Bruce


On = 19 Sep 2015, at 07:13, christamarmc <flyrotary@lancaironline.net> wrote:

Hi all
Just thought I'd pipe in with my results on my rv7 = renises.
I'm = currently running a prince p tip prop at 68" and it has proven to work = extremely well with take of rpm around the 6400 rpm, I've compared it to = a 72" whirlwind ground adjustable and the prince was superior in all = ways on my install, I find if I could get more rpm and increase my = torque it would even be better with my prop, as we need revs to get = torque out of our machines I found that I had slightly less take off = ability at 3000 ft agl strip and still get better top end with the p tip = than the whirlwind. I max out at 175 k tas at strait and level at 8000 = ft, hope this helps. Spinning just 7400 rpm.

Cheers
Christian

Sent from my = iPad

On 19 Sep 2015, at 1:15 am, = Charlie England <flyrotary@lancaironline.net> wrote:

=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 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
Sent: Friday, = September 18, 2015 12:44 AM
To: Rotary motors in aircraft
Subject: [FlyRotary] = Re: New psru
 
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 <flyrotary@lancaironline.net> wrote:
Gents,
          &nb= sp;   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=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 = 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<= br class=3D"">
 

=20

= --Apple-Mail=_F206F01F-B103-4B8D-AF79-8FAA3E02FF15--