X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from cdptpa-omtalb.mail.rr.com ([75.180.132.121] verified) by logan.com (CommuniGate Pro SMTP 5.3.8) with ESMTP id 4365883 for flyrotary@lancaironline.net; Mon, 21 Jun 2010 22:03:05 -0400 Received-SPF: pass receiver=logan.com; client-ip=75.180.132.121; envelope-from=eanderson@carolina.rr.com Return-Path: X-Authority-Analysis: v=1.1 cv=8MuG1bpxLlSbaYWWtODGdBCK7StbFcRsMXhWm1NVx/I= c=1 sm=0 a=-FrGwpZH45sA:10 a=0qYQvVkOOIcA:10 a=Er6hwA6a1l4K/FyzC6NN7w==:17 a=Ia-xEzejAAAA:8 a=pedpZTtsAAAA:8 a=3oc9M9_CAAAA:8 a=Hl1Gy0H5AAAA:8 a=kviXuzpPAAAA:8 a=L1-6v2vwPHT9pwpO4DMA:9 a=nUnWSNVLBW1IjT0ysKUA:7 a=4TOOmVE7gRW0I4Jtm_Aw0qufCeMA:4 a=wPNLvfGTeEIA:10 a=EzXvWhQp4_cA:10 a=eJojReuL3h0A:10 a=U8Ie8EnqySEA:10 a=4vB-4DCPJfMA:10 a=vsxrO9tUcVkjbonH:21 a=-KO89MxRuNU-mDwm:21 a=SSmOFEACAAAA:8 a=20xdH2NtCjBUnOZ4pQQA:9 a=Z5jpR7EtiAUhll7U298A:7 a=Xt8Sa6Ped8IFjqZeB2vrs_mqDtwA:4 a=Er6hwA6a1l4K/FyzC6NN7w==:117 X-Cloudmark-Score: 0 X-Originating-IP: 75.181.123.159 Received: from [75.181.123.159] ([75.181.123.159:1512] helo=edsnewcomputer1) by cdptpa-oedge03.mail.rr.com (envelope-from ) (ecelerity 2.2.2.39 r()) with ESMTP id FB/45-00502-4B9102C4; Tue, 22 Jun 2010 02:02:30 +0000 Message-ID: <001001cb11ae$fa9ebd80$0902a8c0@edsnewcomputer1> From: "Ed Anderson" To: "Rotary motors in aircraft" References: Subject: Pulse Tuning [FlyRotary] Re: 13B rotary engines Date: Mon, 21 Jun 2010 22:02:33 -0400 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_000D_01CB118D.735D8200" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.3664 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.3664 This is a multi-part message in MIME format. ------=_NextPart_000_000D_01CB118D.735D8200 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable BW, as best I recall (don't have a Renesis) that small chamber is simply = a "transfer chamber" to get the pulse from one intake tube to another.=20 The DIE effect that Tracy mentions relies on a type of pulse called a = "Finite Amplitude Wave (FAW)" - this wave behaves different from = traditional sound waves and makes a 125 db sound wave seem lik a very = tiny soundin comparison. These wave shatter metal not to mention ear = drums. There are several "tuning" techniques which attempt to make use of these = Finite Amplitude waves in induction systems. Mazda has been one of the = most successful attempts in part due to its unique construction (no = valves) and the rapid generation of these waves in the intake. In the = older 13B anytime the intake port opened, the still present exhaust = gases would burst forth and produce a shock wave ( FAW pulse). If the = intakes were tied together and of the proper length - at a specific rpm = the pulse generated by the opening of the intake of one rotor would = travel through the intake to the intake of the 2nd rotor. It was = designed to arrive just as the intake port was closing. When an engine (piston or rotary) starts its compression stroke, the = intake remains open for a period - during this period the compressiing = piston/rotor pushes out some of the mixture its already "sucked" into = the chamber. Typically the value for this mixture pushed out during = this "Reversion of flow" amounts to around 15% of the amount already = "sucked" in. =20 So if the FAW Pulse arrives at the right time most of its dynamic energy = is converted from kinetic energy to a localized increase in pressure = right beside the closing intake port. If all goes well it prevents most = of this reversion. In fact, Mazda found a 15% increase in HP at 6000 = rpm using this knowledge. However, it is generally only significant for one rpm - or if you do = like Mazda and have a valve to change the length of the intake for this = pulse, you may get two sweet spots at a lower and a higher rpm. Since PP are not interconnected the approach Mazda used on the N/A 13B = side ports won't work as is. However, due to the properties of the FAW pulse when it encounters a = change in cross sectional area, the pulse tuning technique could = theoretically be used on a PP. Since you want a increase in pressure as = the port closes, and since the FAW pulse will reflect from an opening = into the atmosphere (Plenumn box also) - if you made your PP tube a = specific length then at some rpm (which can be calculated) the pulse = will bounce back from the plenumn and reach the intake port at exactly = the correct time. That said when one makes the calculations (as best I recall from a few = years ago - so don't hold me to exact figures), you would find that say = for the peak to occur at 6000 rpm - your PP tube would need to be around = 48" long. High target rpm would result in smaller lengths required. Then again, that length (whatever it is) is only good at one RPM to get = the effect. In my case, I spent 3 months just doing the analysis to derive the = equations for the old 13B. Since my primary objective was power on take = off - (I really don't care about top speed as I don't fly there - too = expensive {:>)), I did not mind the restriction to one rpm. So my DIE intake is tuned to give maximum power at around 6000 rpm (My = static for take off swinging a 74x88 prop). I may get up to 6200 rpm = static on a colder day as the sweet spot is a function of the speed of = sound (among other things) which changes with OAT temperture. In my opinion (and that is all it is), if I were going PP, I would = probably not spend much time considering DIE (or Dynamic Chamber -- = which is not quite what most people think it is). FWIW Ed ----- Original Message -----=20 From: Bryan Winberry=20 To: Rotary motors in aircraft=20 Sent: Monday, June 21, 2010 8:38 PM Subject: [FlyRotary] Re: 13B rotary engines Thanks Tracy, I didn't realize the plenum would have that effect. =20 The stock Renesis seems to have a chamber prior to the valves that = create the DIE, but I guess it is too small to be called a plenum = chamber. BW =20 -------------------------------------------------------------------------= ----- From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] = On Behalf Of Tracy Crook Sent: Monday, June 21, 2010 8:12 PM To: Rotary motors in aircraft Subject: [FlyRotary] Re: 13B rotary engines =20 I hate to ask, but what about the Dynamic Intake effect in the PP with = a traditional log-type manifold? If you think about the meaning and function of the Dynamic effect, you = will see that it is mutually exclusive with the traditional log-type = manifold. the 'log' is a plenum chamber which inherently damps out the = dynamic waves and reflections in a DIE intake system. The timing, length, etc would be different than for the sideport DIE = setup that Ed Anderson did so much work on. I won't even pretend to = have any idea what the proper parameters are for a PP DIE setup. Tracy On Mon, Jun 21, 2010 at 7:44 PM, Bryan Winberry = wrote: Yeah, I just saw those MP taps for the oil injection on another site. I'm = no expert, but that seems like an odd place to gather MP data. =20 I only asked about the slide throttle, I certainly had not decided = that it was the answer. =20 Sounds like you recommend the traditional TB - manifold - runners = setup for the PP as well. =20 I hate to ask, but what about the Dynamic Intake effect in the PP with = a traditional log-type manifold? =20 Bryan =20 -------------------------------------------------------------------------= ----- From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] = On Behalf Of Tracy Crook Sent: Monday, June 21, 2010 7:29 PM To: Rotary motors in aircraft Subject: [FlyRotary] Re: 13B rotary engines =20 Bill, I have purchased the EC-3. Will this make any difference in the = difficulty of tuning? Is it a good choice for a PP setup? I'd imagine I should aim for around 7500 rpm for a RD-1C. Bryan =20 Bryan, Mark (the Mustang II w/ pp 13B) used an EC2 on his engine and = eventually got it running pretty well but it was a MAJOR pain getting it = to work with that slide throttle since getting manifold pressure was = hard to do since there IS NO MANIFOLD when using that slide right at the = port. No one seems to consider these 'details' when planning their = installation. I'm of the same opinion as Bill on the slide throttle- = Why the hell do it? Mark eventually got a usable MP signal by taping = into the oil injection ports in the rotor housing but that's not ideal. = BTW, several people referd to Mark's PP 13B as a Renesis PP but I = thought it was a 2nd gen 13B. I could be wrong. Pity that the airplane = was lost in that ground accident, I had not heard about that. Tracy On Mon, Jun 21, 2010 at 7:13 PM, wrote: Bryan, The importance of any system that you use will be, DO YOU UNDERSTAND = IT? Have you ever tuned an engine using a carb, or FI yourself? Tracy's = system seems like a good one for the price. I have not used Tracy's EMS = but it has been effective for the guys that keep at it. A good fuel flow = and mixture meter are top tools for determining where you are. I believe = those are built into the EC-3. Remember, while it won't be changing = while you run the engine, the intake and exhaust are just as "active" = parts as ignition and injection. My advise would be to be sure that you = triple check all your wiring before you install it. Too many of the guys = have run into problems in their wiring. Be sure you are dealing with a = genuine tuning problem and you will be miles ahead. Bill, I have purchased the EC-3. Will this make any difference in the = difficulty of tuning? Is it a good choice for a PP setup? I'd imagine I should aim for around 7500 rpm for a RD-1C. Bryan =20 =20 =20 -----Original Message----- From: Bryan Winberry To: Rotary motors in aircraft Sent: Mon, Jun 21, 2010 3:50 pm Subject: [FlyRotary] Re: 13B rotary engines Bill, I have purchased the EC-3. Will this make any difference in the = difficulty of tuning? Is it a good choice for a PP setup? I'd imagine I should aim for around 7500 rpm for a RD-1C. Bryan =20 =20 -------------------------------------------------------------------------= ----- From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] = On Behalf Of wrjjrs@aol.com Sent: Monday, June 21, 2010 6:41 PM To: Rotary motors in aircraft Subject: [FlyRotary] Re: 13B rotary engines =20 Bryan, As a reference the original Powersport 13B P-port is rated at 210 HP = normally aspirated. The fuel flows are very similar to any other engine = producing that level of power. Steve tells me that they were seeing FF = very comparable to an angle valve IO-360 producing identical power. This = engine was dynoed with butterfly valves in the housing. These p-ports = were 1-5/8' diameter optimized for 6000 RPM. The engine would rev higher = but you were already at peak power anyway. Larger ports will make more = power at higher RPM. Tuning will become more critical with the larger = ports. A personal anecdote here. I built a high reving motorcycle engine = in 1978 with all the "best" parts at the time. The engine was unreal at = high revs, but if you transitioned to anything below 4000 RPM by = shutting the throttle off and quickly opening it again the engine would = "catch" or hit an RPM plateau and would rev no higher. In fact the = engine would die if not returned to idle! This horrible malfunction was = TUNED OUT later, and the solution was surprisingly simple, however = difficult to find. The key here is that many people underestimate the = job of installing and tuning p-ports. There are two aspects, first the = initial install being sure there are no leaks . Then second, and most = overlooked is that the system must tolerate the heat cycles of a high = power engine without DEVELOPING NEW LEAKS for a long time. Powersport = used an insert with o-rings sealing the port. O-rings or other = elastomers work much better than epoxy on long-term sealing because = there are different expansion rates between the port and the epoxy. On a = car you can usually get away with epoxy for a while. An aircraft is a = different animal. The aircraft engine needs to tolerate 80-100% power = for long periods and then long cold-soaks on the ground. The rotary is = mechanically tough enough but you need to design your subsystems like a = race car that will see a 500 mile long straight-away! When Paul Lamar = ran one of the newsletter guys P-port Renesis at MazdaTrix, They got = great numbers, but only after changing to an intake that MazdaTrix had = spent lots of time tuning. P-ports will run great, and even idle well if = not too oversized, but don't expect the tuning to be real easy. Remember = you are designing a new intake, exhaust, and the equivilent of a new cam = timing all at once. The rotary is very much like a two-cycle in that = respect. The results can be very worth while if you understand the = difficulty involved. Bill Jepson =20 -----Original Message----- From: George Lendich To: Rotary motors in aircraft Sent: Mon, Jun 21, 2010 2:36 pm Subject: [FlyRotary] Re: 13B rotary engines Bryan, Not all P-ports are equal. More power =3D more fuel. Talk to Bill Jepson ( on here) about availability of new P-ports. George ( down under). All this talk of additional power coupled with an easier intake = design has me thinking I should probably go this direction with my = Renesis. It's still on the stand after rebuild. I haven't constructed the manifold yet anyway. =20 I assume fuel flow will be higher than normal? =20 Is slide throttle best option? =20 Need to search archives I guess. =20 Good info Lynn, Thanks =20 Bryan =20 =20 =20 =20 -------------------------------------------------------------------------= --- From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] = On Behalf Of Lynn Hanover Sent: Monday, June 21, 2010 12:15 PM To: Rotary motors in aircraft Subject: [FlyRotary] Re: 13B rotary engines =20 In a message dated 6/21/2010 11:03:01 A.M. Eastern Standard Time, = rv-4mike@cox.net writes: Thanks for the feedback Lynn. Unusual to see a "poor port design" = actually aid performance. =20 Mike Wills =20 =20 It is not obvious until you start graphing the open and close = events, but the side port which uses the side of the rotor as a shutter = to open and close the port, offers Mazda great latitude in port timing. = In the periphery ported engine (both ports) it is impossible to arrive = at zero overlap, and have an engine that will produce any power at all. = The apex seal does not close off either port at all, it just valves = gasses in one direction or another.=20 =20 In addition, the overlap of the periphery ported engine is far more = effective flow wise than overlap in the side ported engine. One apex = seal is above the intake port when the opposing apex seal is below the = exhaust port. Flow between the two is unobstructed. =20 So, at low RPM you get fresh mixture leaving through the exhaust = port, and combinations of burned and unburned fuel and exhaust gasses = flowing partway back into the intake runners. =20 This reduces the low RPM output to the point that the engine seems = quit docile, and is easy to drive around in the car, slowly, or possibly = taxi in an aircraft. This would make off idle tuning data useless as = there will be fuel burning right on top of the EGT probes, and unburned = fuel reaching the F/A sensor. =20 =20 The engine will act along the lines of a piston engine with a long = duration cam. When the engine reaches its happy RPM where all of the = mixture is burning inside the engine, it will step up on the "CAM" and = you will see what a good idea this was. Use slow throttle inputs until = you find the "WOW" RPM, and be ready with all available rudder.=20 =20 When we first ran a factory periphery port engine, we found that = there were places on the track that would not allow full throttle. This = with 11" wide slicks. Thank Heaven for rev limiters. The driver reported = the rear end getting real loose cresting hills and bumps. =20 Why yes it was.......... =20 Lynn E. Hanover=20 =20 =20 ------=_NextPart_000_000D_01CB118D.735D8200 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
BW, as best I recall (don't have a = Renesis) that=20 small chamber is simply a "transfer chamber" to get the pulse from one = intake=20 tube to another.
 
The DIE effect that Tracy mentions = relies on a type=20 of pulse called a "Finite Amplitude Wave (FAW)" - this wave behaves = different=20 from traditional sound waves and makes a 125 db sound wave seem lik a = very tiny=20 soundin comparison.  These wave shatter metal not to mention ear=20 drums.
 
There are several "tuning" techniques = which attempt=20 to make use of these Finite Amplitude waves in induction systems.  = Mazda=20 has been one of the most successful attempts in part due to its unique=20 construction (no valves) and the rapid generation of these waves in the=20 intake.  In the older 13B anytime the intake port opened, the still = present=20 exhaust gases would burst forth and produce a shock wave ( FAW=20 pulse).  If the intakes were tied together and of the proper length = - at a=20 specific rpm the pulse generated by the opening of the intake of one = rotor would=20 travel through the intake to the intake of the 2nd rotor.  It was = designed=20 to arrive just as the intake port was closing.
 
When an engine (piston or rotary) = starts its=20 compression stroke, the intake remains open for a period - during this = period=20 the compressiing piston/rotor pushes out some of the mixture its already = "sucked" into the chamber.  Typically the value for this mixture = pushed out=20 during this "Reversion of flow" amounts to around 15% of the amount = already=20 "sucked" in. 
 
So if the FAW Pulse arrives at the = right time most=20 of its dynamic energy is converted from kinetic energy to a localized = increase=20 in pressure right beside the closing intake port.  If all goes well = it=20 prevents most of this reversion.  In fact, Mazda found a 15% = increase in HP=20 at 6000 rpm using this knowledge.
 
However, it is generally only = significant for one=20 rpm - or if you do like Mazda and have a valve to change the length of = the=20 intake for this pulse, you may get two sweet spots at a lower and a = higher=20 rpm.
 
Since PP are not interconnected the = approach Mazda=20 used on the N/A 13B side ports won't work as is.
 
However, due to the properties of the = FAW pulse=20 when it encounters a change in cross sectional area, the pulse tuning = technique=20 could theoretically be used on a PP.  Since you want a increase in = pressure=20 as the port closes, and since the FAW pulse will reflect from an opening = into=20 the atmosphere (Plenumn box also) - if you made your PP tube a specific = length=20 then at some rpm (which can be calculated) the pulse will bounce back = from the=20 plenumn and reach the intake port at exactly the correct = time.
 
That said when one makes the = calculations (as best=20 I recall from a few years ago - so don't hold me to exact figures), you = would=20 find that say for the peak to occur at 6000 rpm - your PP tube would = need to be=20 around 48" long.  High target rpm would result in smaller lengths=20 required.
 
Then again, that length (whatever it = is) is only=20 good at one RPM to get the effect.
 
In my case, I spent 3 months just doing = the=20 analysis to derive the equations for the old 13B.  Since my primary = objective was power on take off - (I really don't care about top speed = as I=20 don't fly there - too expensive {:>)), I did not mind the restriction = to one=20 rpm.
 
So my DIE intake is tuned to give = maximum power at=20 around 6000 rpm (My static for take off swinging a 74x88 prop).  I = may get=20 up to 6200 rpm static on a colder day as the sweet spot is a function of = the=20 speed of sound (among other things) which changes with  OAT=20 temperture.
 
In my opinion (and that is all it is), = if I were=20 going PP, I would probably not spend much time considering DIE (or = Dynamic=20 Chamber -- which is not quite what most people think it = is).
 
FWIW
 
Ed
----- Original Message -----
From:=20 Bryan Winberry
Sent: Monday, June 21, 2010 = 8:38 PM
Subject: [FlyRotary] Re: 13B = rotary=20 engines

Thanks = Tracy,

I didn=92t = realize the=20 plenum would have that effect.  

The stock = Renesis=20 seems to have a chamber prior to the valves that create the DIE, but I = guess=20 it is too small to be called a plenum = chamber.

BW

 

From:=20 Rotary motors in aircraft = [mailto:flyrotary@lancaironline.net] On=20 Behalf Of Tracy Crook
Sent: Monday, June 21, 2010 = 8:12=20 PM
To: = Rotary motors in aircraft
Subject: [FlyRotary] Re: 13B = rotary=20 engines

 

I=20 hate to ask, but what about the Dynamic Intake effect in the PP with a = traditional log-type manifold?

If = you think=20 about the meaning and function of the Dynamic effect, you will see = that it is=20 mutually exclusive with the traditional log-type manifold.   = the=20 'log' is a plenum chamber which inherently damps out the dynamic waves = and=20 reflections in a DIE intake system.

The timing, length, etc = would be=20 different than for the sideport DIE setup that Ed Anderson did so much = work=20 on.  I won't even pretend to have any idea what the proper = parameters are=20 for a PP DIE setup.

Tracy

On Mon, Jun 21, 2010 at 7:44 PM, Bryan = Winberry <bryanwinberry@bellsouth.net>=20 wrote:

Yeah,

I just saw = those MP=20 taps for the oil injection on another site.  I=92m no expert, but = that=20 seems like an odd place to gather MP = data.

 

I only = asked about=20 the slide throttle, I certainly had not decided that it was the=20 answer.

 

Sounds like = you=20 recommend the traditional TB =96 manifold =96 runners setup for the PP = as=20 well.

 

I hate to = ask, but=20 what about the Dynamic Intake effect in the PP with a traditional = log-type=20 manifold?

 

Bryan

 

From:=20 Rotary motors in aircraft = [mailto:flyrotary@lancaironline.net] On Behalf Of Tracy = Crook
Sent: Monday, June 21, 2010 = 7:29=20 PM


To: Rotary=20 motors in aircraft
Subject: [FlyRotary] Re: 13B = rotary=20 engines

 

Bill,

I have = purchased=20 the EC-3.  Will this make any difference in the difficulty of=20 tuning?  Is it a good choice for a PP=20 setup?

I=92d = imagine I=20 should aim for around 7500 rpm for a=20 RD-1C.

Bryan =20

Bryan,
  =20 Mark (the Mustang II w/ pp 13B) used an EC2 on his engine and = eventually got=20 it running pretty well but it was a MAJOR pain getting it to work with = that=20 slide throttle since getting manifold pressure was hard to do since = there IS=20 NO MANIFOLD when using that slide right at the port.  No one = seems to=20 consider these 'details' when planning their installation.  I'm = of the=20 same opinion as Bill on the slide throttle-  Why the hell do = it? =20 Mark eventually got a usable MP signal by taping into the oil = injection ports=20 in the rotor housing but that's not ideal. 

BTW, several = people=20 referd to Mark's PP 13B as a Renesis PP but I thought it was a 2nd gen = 13B.  I could be wrong.  Pity that the airplane was lost in = that=20 ground accident, I had not heard about that.
Tracy

On Mon, Jun 21, 2010 at 7:13 PM, <wrjjrs@aol.com>=20 wrote:

Bryan,

The = importance of=20 any system that you use will be, DO YOU UNDERSTAND IT? Have you ever=20 tuned an engine using a carb, or FI yourself? Tracy's = system seems=20 like a good one for the price. I have not used Tracy's EMS = but it has=20 been effective for the guys that keep at it. A good fuel flow and = mixture=20 meter are top tools for determining where you are. I believe those are = built=20 into the EC-3. Remember, while it won't be changing while you run the = engine,=20 the intake and exhaust are just as "active" parts as ignition and = injection.=20 My advise would be to be sure that you triple check all your wiring = before you=20 install it. Too many of the guys have run into problems in their = wiring. Be=20 sure you are dealing with a genuine tuning problem and you will be = miles=20 ahead.

Bill,

I have = purchased=20 the EC-3.  Will this make any difference in the difficulty of=20 tuning?  Is it a good choice for a PP=20 setup?

I=92d = imagine I=20 should aim for around 7500 rpm for a=20 RD-1C.

Bryan=20  

 

 

-----Original=20 Message-----
From: Bryan Winberry <bryanwinberry@bellsouth.net>
To: = Rotary motors in aircraft <flyrotary@lancaironline.net>
Sent: Mon, Jun = 21, 2010=20 3:50 pm
Subject: [FlyRotary] Re: 13B rotary=20 engines

Bill,

I have = purchased the=20 EC-3.  Will this make any difference in the difficulty of = tuning? =20 Is it a good choice for a PP setup?

I=92d = imagine I should=20 aim for around 7500 rpm for a = RD-1C.

Bryan=20  

 

From: = Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of wrjjrs@aol.com
Sent: Monday, June 21, 2010 = 6:41=20 PM
To: = Rotary motors in aircraft
Subject: [FlyRotary] Re: 13B = rotary=20 engines

 

Bryan,

As a = reference the=20 original Powersport 13B P-port is rated at 210 HP normally aspirated. = The fuel=20 flows are very similar to any other engine producing that level of = power.=20 Steve tells me that they were seeing FF very comparable to an angle = valve=20 IO-360 producing identical power. This engine was dynoed with = butterfly valves=20 in the housing. These p-ports were 1-5/8' diameter optimized for = 6000=20 RPM. The engine would rev higher but you were already at peak power = anyway.=20 Larger ports will make more power at higher RPM. Tuning will become=20 more critical with the larger ports. A personal anecdote here. I = built a=20 high reving motorcycle engine in 1978 with all the "best" parts at the = time.=20 The engine was unreal at high revs, but if you transitioned to = anything below=20 4000 RPM by shutting the throttle off and quickly opening it again the = engine=20 would "catch" or hit an RPM plateau and would rev no higher. = In fact=20 the engine would die if not returned to idle! This horrible = malfunction was=20 TUNED OUT later, and the solution was surprisingly simple, however = difficult=20 to find. The key here is that many people underestimate the job = of=20 installing and tuning p-ports. There are two aspects, first the = initial=20 install being sure there are no leaks . Then second, and most = overlooked is=20 that the system must tolerate the heat cycles of a high power engine = without=20 DEVELOPING NEW LEAKS for a long time. Powersport used an insert with = o-rings=20 sealing the port. O-rings or other elastomers work much better than = epoxy on=20 long-term sealing because there are different expansion rates between = the port=20 and the epoxy. On a car you can usually get away with epoxy for a = while.=20 An aircraft is a different animal. The aircraft engine needs to = tolerate=20 80-100% power for long periods and then long cold-soaks on the = ground.=20 The rotary is mechanically tough enough but you need to design your = subsystems=20 like a race car that will see a 500 mile long straight-away! =  When=20 Paul Lamar ran one of the newsletter guys P-port Renesis at MazdaTrix, = They=20 got great numbers, but only after changing to an intake that MazdaTrix = had=20 spent lots of time tuning. P-ports will run great, and even idle well = if not=20 too oversized, but don't expect the tuning to be real easy. Remember = you are=20 designing a new intake, exhaust, and the equivilent of a new cam = timing all at=20 once. The rotary is very much like a two-cycle in that respect. The = results=20 can be very worth while if you understand the difficulty=20 involved.

Bill=20 Jepson

 

-----Original=20 Message-----
From: George Lendich <lendich@aanet.com.au>
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Sent: Mon, Jun = 21, 2010=20 2:36 pm
Subject: [FlyRotary] Re: 13B rotary=20 engines

 Bryan,

Not all = P-ports are=20 equal.

More power = =3D more=20 fuel.

Talk to = Bill Jepson=20 ( on here) about availability of new=20 P-ports.

George ( = down=20 under).

All this = talk of=20 additional power coupled with an easier intake design has me = thinking I=20 should probably go this direction with my Renesis.  It=92s = still on the=20 stand after rebuild.

I = haven=92t=20 constructed the manifold yet=20 anyway.

 

I assume = fuel flow=20 will be higher than normal?

 

Is slide = throttle=20 best option?

 

Need to = search=20 archives I guess.

 

Good info = Lynn,=20 Thanks

 

Bryan

 

 

 

 

From: = Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Lynn = Hanover
Sent: Monday, June 21, 2010 = 12:15=20 PM
To: = Rotary motors in aircraft
Subject: [FlyRotary] Re: 13B = rotary=20 engines

 

In a message dated 6/21/2010 = 11:03:01=20 A.M. Eastern Standard Time, rv-4mike@cox.net=20 writes:

Thanks for the=20 feedback Lynn. Unusual to see a "poor = port design"=20 actually aid = performance.

 

Mike = Wills

 

 

It is not obvious until you = start=20 graphing the open and close events, but the side port which uses the = side of=20 the rotor as a shutter to open and close the port, offers Mazda = great=20 latitude in port timing.  In the periphery ported engine (both = ports)=20 it is impossible to arrive at zero overlap, and have an engine that = will=20 produce any power at all. The apex seal does not close off either = port at=20 all, it just valves gasses in one direction or another.=20

 

In addition, the overlap of = the=20 periphery ported engine is far more effective flow wise than overlap = in the=20 side ported engine. One apex seal is above the intake port when the = opposing=20 apex seal is below the exhaust port. Flow between the two is=20 unobstructed.

 

So, at low RPM you get fresh = mixture=20 leaving through the exhaust port, and combinations of burned and = unburned=20 fuel and exhaust gasses flowing partway back into the intake=20 runners.

 

This reduces the low RPM = output to the=20 point that the engine seems quit docile, and is easy to drive around = in the=20 car, slowly, or possibly taxi in an aircraft.  This would make = off idle=20 tuning data useless as there will be fuel burning right on top of = the EGT=20 probes, and unburned fuel reaching the F/A sensor. =20

 

The engine will = act along the=20 lines of a piston engine with a long duration cam. When the engine = reaches=20 its happy RPM where all of the mixture is burning inside the engine, = it will=20 step up on the "CAM" and you will = see what=20 a good idea this was. Use slow throttle inputs until you find the = "WOW" RPM,=20 and be ready with all available rudder.=20

 

When we first ran a factory = periphery=20 port engine, we found that there were places on the track that would = not=20 allow full throttle. This with 11" wide slicks. Thank Heaven for rev = limiters. The driver reported the rear end getting real loose = cresting hills=20 and bumps.

 

Why yes it=20 was..........

 

Lynn E.=20 = Hanover 

 

 

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