X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from mail03.syd.optusnet.com.au ([211.29.132.184] verified) by logan.com (CommuniGate Pro SMTP 5.2c1) with ESMTPS id 2604787 for flyrotary@lancaironline.net; Wed, 19 Dec 2007 01:55:02 -0500 Received-SPF: pass receiver=logan.com; client-ip=211.29.132.184; envelope-from=lendich@optusnet.com.au Received: from george (d220-236-79-144.dsl.nsw.optusnet.com.au [220.236.79.144]) by mail03.syd.optusnet.com.au (8.13.1/8.13.1) with SMTP id lBJ6sDiw010710 for ; Wed, 19 Dec 2007 17:54:15 +1100 Message-ID: <003801c8420b$fb4166e0$904fecdc@george> From: "George Lendich" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Re: Degrees overlap Date: Wed, 19 Dec 2007 16:54:18 +1000 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0035_01C8425F.CBA6C610" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.2180 X-MIMEOLE: Produced By Microsoft MimeOLE V6.00.2900.2180 X-Antivirus: avast! (VPS 0657-0, 12/12/2006), Outbound message X-Antivirus-Status: Clean This is a multi-part message in MIME format. ------=_NextPart_000_0035_01C8425F.CBA6C610 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Lynn, Just found it interesting that's all. While playing with the degree wheel and ports I was wondering what = exactly happens in the inlet manifold when the apex seal goes over the = ports - as you say their open 24-7. No need to answer Lynn, I stopped thinking about as there's too many = things going on and it's not there for long anyway. BTW the overlap in a PP RX8 is 40 degrees - interesting!! George ( down under) Lynn, I was all over the shop before, but now I think I've got it all = sorted. I was trying to see the differences the PP gave in overlap and = open ( intake) time. I was confusing myself yet again, until I realized I was looking at = the degrees of crank, when I should have been looking at the degrees of = the rotor. With IO @ 32 degrees ATDC and IC @ 40 degrees ABDC (12A engine) or IC @ 310 degrees ATDC =3D 278 degrees/3 =3D 93 degrees of the = rotor I did the same for Exhaust =3D 415 degrees/3 =3D131 degrees. Overlap ( standard) =3D25 degrees/3 =3D 8 degrees. Overlap PP =3D 144 degrees/3 =3D 48 degrees. PP inlet =3D 430/3 =3D143 degrees. Inlet time with the PP is an additional 50 degrees (very good) but = with a penalty of 40 extra degrees of overlap (bad) but only bad at low = RPM's. Interestingly the overlap is 6 times the original - this all varies = accordingly with the different models. While doing this exercise it is interesting to see the RX 8 port and = why it's placed where it is to eliminate overlap. While it might be nice = to have say 180 degree of rotor ( or more) for complete burn of the = fuel, realistically the power derived from this exercise would be = marginal at best. The power from combustion would (I believe) be totally = converted to mechanical power ( to the rotor) by the time it reaches the = existing exhaust opening. George ( down under) It is endlessly interesting to turn this thing around slowly and watch = the ports open and close. The published open and close events from (for = example) Paul Yaw's web page WWW.yawpower.com are at the crank.=20 So being so many (crankshaft degrees) ATDC or BTDC is looking at a = very small portion of a cycle that requires 1080 degrees (3 complete = revolutions) of crankshaft rotation to complete. One of the many = advantages of this engine is that everything is happening in slow = motion. In regard to most engine functions this is good news. Sadly this = exposes way too much iron and aluminum to the combustion process in each = cycle. So you get quenched out flame fronts and unburned hydrocarbons, = (HC) and a bit less efficiency compared to a piston engine of the same = displacement. It has no squish areas to drive mixture to the flame front = or spark plugs. In the Fiat I could run .040" clearance between the head = and the piston top and move all of the mixture into the plug and flame = ball. So long as the piston didn't touch the head too hard at TDC all = was well, and it would run with 14:1 compression ratio.=20 Of the two tube frame cars, the first gen with the factory Pport = engine was far easier to drive around in the paddock at below idle speed = in first gear. It was not required to declutch and add revs now and = again to keep it moving. The exhaust dilution was very bad and this = gives you a very slow burn, and a nice long push in each cycle. It was = just like a stock car. Very tractable. The third gen car has a bridge = port that opens at 110 degrees BTDC and the overlap is way more than the = Pport. It is just about not drivable without declutching and adding revs = to 4,000, then letting in some clutch (grabby 2 disc metallic) for a = lunge, then repeat. Very hard on the clutch. Engine stalls about 20 = times on the way to the false grid and so on. So we tow it there with a = little tractor.=20 The Pport is very friendly. It is soft in power output until it steps = up on the tune at about 5,500 RPM, where the exhaust port closes soon = enough to keep a good amount of mixture in the engine. While the porting = numbers suggest that the intake port is closing at thus and so degrees, = it never actually closes does it?=20 Where the side port gets the flat side of the rotor actually sealing = it off, the Pport gets the point of a rotor passing through, valving = mixture up or down but never closing the port. Never closed is a lot of = intake time. No matter how badly you design your inlet tract, the Pport will = provide outstanding power. Should do well from 3,000 RPM to about 14,000 = RPM.=20 The Pport intake is open for business 24-7. That is where the power = comes from. =20 While the gearing allows the rotor to turn (rotate) one time for three = rotations of the crank, the stress on the crank is monumental. At 10,000 = RPM the full centrifugal loads of two 9 pound rotors are on the crank = and rotor bearings. It happens that the bearing area is well up to the = job. Much confusion results from the gearing and speeds involved. The engine is far over-square. And the poor torque (from the short = lever arm of the short stroke) is exacerbated by the rotor/crank = gearing. So when you gear the reduction unit at 2.78:1 you have not even = got back to one to one looking at the rotors. But stick with the degree = wheel on the crank. Thinking about the rotor speed will damage your = mind. It did mine. Lynn E. Hanover =20 -------------------------------------------------------------------------= ----- See AOL's top rated recipes and easy ways to stay in shape for winter. -------------------------------------------------------------------------= ----- No virus found in this incoming message. Checked by AVG Free Edition.=20 Version: 7.5.503 / Virus Database: 269.17.2/1185 - Release Date: = 15/12/2007 12:00 PM ------=_NextPart_000_0035_01C8425F.CBA6C610 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Lynn,
Just found it interesting that's all.
While playing with the degree wheel and ports I was wondering what = exactly=20 happens in the inlet manifold when the apex seal goes over the ports - = as you=20 say their open 24-7.
No need to answer Lynn, I stopped thinking about = as there's=20 too many things going on and it's not there for long=20 anyway.
 
BTW the overlap in a PP RX8 is 40 degrees - interesting!!
George ( down under)
 
Lynn,
I was all over the shop before, but = now I think=20 I've got it all sorted. I was trying to see the differences the PP = gave in=20 overlap and open ( intake) time.
 
I was confusing myself yet again, = until I=20 realized I was looking at the degrees of  crank, when I should = have=20 been looking at the degrees of the rotor.
 
With IO @ 32 degrees = ATDC
and IC @ 40 degrees ABDC (12A=20 engine)
or IC @ 310 degrees ATDC =3D 278 = degrees/3 =3D 93=20 degrees of the rotor
 
I did the same for Exhaust =3D 415 = degrees/3 =3D131=20 degrees.
 
Overlap ( standard) =  =3D25 degrees/3 =3D=20 8 degrees.
Overlap PP =3D 144 degrees/3 =3D 48 = degrees.
 
PP inlet =3D 430/3 =3D143 = degrees.
 
Inlet time with the PP is an = additional 50=20 degrees (very good) but with a penalty of 40 extra degrees of = overlap (bad)=20 but only bad at low RPM's.
 
Interestingly the overlap is 6 = times the=20 original - this all varies accordingly with the different=20 models.
 
While doing this exercise it is = interesting to=20 see the RX 8 port and why it's placed where it is to eliminate = overlap.=20 While it might be nice to have say 180 degree of rotor ( or more) = for=20 complete burn of the fuel, realistically the power derived from this = exercise would be marginal at best. The power from combustion would = (I=20 believe) be totally converted to mechanical power ( to the = rotor) by=20 the time it reaches the existing exhaust opening.
 
George ( down=20 under)
 
It is endlessly interesting to turn this thing around slowly and = watch=20 the ports open and close. The published open and close events from = (for=20 example) Paul Yaw's web page WWW.yawpower.com are at the = crank.
So being so many (crankshaft degrees) ATDC or BTDC is looking at = a very=20 small portion of a cycle that requires 1080 degrees (3 complete = revolutions)=20 of crankshaft rotation to complete. One of the many advantages of = this=20 engine is that everything is happening in slow motion. In regard to = most=20 engine functions this is good news. Sadly this exposes way too much = iron and=20 aluminum to the combustion process in each cycle. So you get quenched = out=20 flame fronts and unburned hydrocarbons, (HC) and a bit less efficiency = compared to a piston engine of the same displacement. It has no squish = areas=20 to drive mixture to the flame front or spark plugs. In the Fiat I = could run=20 .040" clearance between the head and the piston top and move all of = the=20 mixture into the plug and flame ball. So long as the piston didn't = touch the=20 head too hard at TDC all was well, and it would run with 14:1 = compression=20 ratio.
 
Of the two tube frame cars, the first gen with the factory Pport = engine=20 was far easier to drive around in the paddock at below idle speed in = first=20 gear. It was not required to declutch and add revs now and again to = keep it=20 moving. The exhaust dilution was very bad and this gives you a very = slow burn,=20 and a nice long push in each cycle. It was just like a stock car. Very = tractable. The third gen car has a bridge port that opens at 110 = degrees BTDC=20 and the overlap is way more than the Pport. It is just about not = drivable=20 without declutching and adding revs to 4,000, then letting in some = clutch=20 (grabby 2 disc metallic) for a lunge, then repeat. Very hard on the = clutch.=20 Engine stalls about 20 times on the way to the false grid and so on. = So we tow=20 it there with a little tractor.
 
The Pport is very friendly. It is soft in power output until it = steps up=20 on the tune at about 5,500 RPM, where the exhaust port closes soon=20 enough to keep a good amount of mixture in the engine. While the = porting=20 numbers suggest that the intake port is closing at thus and so = degrees, it=20 never actually closes does it?
 
Where the side port gets the flat side of the rotor actually = sealing it=20 off, the Pport gets the point of a rotor passing through, valving = mixture up=20 or down but never closing the port. Never closed is a lot of intake=20 time.
 
No matter how badly you design your inlet tract, the Pport will = provide=20 outstanding power. Should do well from 3,000 RPM to about 14,000 RPM. =
 
The Pport intake is open for business 24-7. That is where the = power comes=20 from.   
 
While the gearing allows the rotor to turn (rotate) one time for = three=20 rotations of the crank, the stress on the crank is monumental. At = 10,000 RPM=20 the full centrifugal loads of two 9 pound rotors are on the crank and = rotor=20 bearings. It happens that the bearing area is well up to the job. Much = confusion results from the gearing and speeds involved.
 
The engine is far over-square. And the poor torque (from the = short lever=20 arm of the short stroke) is exacerbated by the rotor/crank gearing. So = when=20 you gear the reduction unit at 2.78:1 you have not even got back to = one to one=20 looking at the rotors. But stick with the degree wheel on the crank. = Thinking=20 about the rotor speed will damage your mind. It did mine.
 
Lynn E. Hanover  



See AOL's top rated recipes and easy ways to stay in shape for = winter.

No virus found in this incoming message.
Checked by AVG Free = Edition.
Version: 7.5.503 / Virus Database: 269.17.2/1185 - = Release Date:=20 15/12/2007 12:00 PM
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