X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from mail07.syd.optusnet.com.au ([211.29.132.188] verified) by logan.com (CommuniGate Pro SMTP 5.1.10) with ESMTPS id 2197715 for flyrotary@lancaironline.net; Wed, 25 Jul 2007 03:07:15 -0400 Received-SPF: none receiver=logan.com; client-ip=211.29.132.188; envelope-from=lendich@optusnet.com.au Received: from george (d211-31-107-198.dsl.nsw.optusnet.com.au [211.31.107.198]) by mail07.syd.optusnet.com.au (8.13.1/8.13.1) with SMTP id l6P76NmP024649 for ; Wed, 25 Jul 2007 17:06:24 +1000 Message-ID: <006101c7ce8a$5088f4b0$c66b1fd3@george> From: "George Lendich" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Re: carbs vs efi Date: Wed, 25 Jul 2007 17:06:24 +1000 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_005E_01C7CEDE.215022F0" 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_005E_01C7CEDE.215022F0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Jerry, If you have time sit down and do the calculations in port areas, it's = surprising. All housings have two ports, usually one big and one small which add up = to approx 2 sq". The a proper street port area is 3 sq"( 1.5sq" ea). = Restrictions cause less HP so a inlet about the same size would be = appropriate. Although advice on the street ports is that the smaller port opening of = 1.18sq" feeding the 1.5 street port is adequate with smoothing, quite = obviously enlarging the port somewhat while doing the smoothing etc. = Let's say that is goes from 22% to 16 % less area. So 3 sq" (3 sq" is 50mm Dia), less 16% ( 3 sq" less 16% =3D 2.52 sq") = =3D 46mm. Now lest say the PP is 25% better than the Street port. We = take 41% (16%=3D25%) of 3 sq" =3D 1.8 Sq" that's still 38mm dia. I don't = think you can go below that without bogging down the HP=20 I think 1.5/1.6 will flow 8,000 just fine but not for the VE for higher = HP, I think 1.5 will give about 100hp - nothing startling, you can get = that out of a street port ( with perfect idle) but to get the extra I = need ( 115 to 125), I have to look further. The street port set up = perfectly, may give 116 hp at 7,500; then again it may not, so I am = convinced the PP has the advantage. I also agree that side ports don't flow as well as a P- port, one reason = may be is that the PP is open a lot longer ( longer duration I call it). I have confirmed in my own mind that the exhaust contamination with the = early opening P-port is the main contributor to the idle stumble. For = this reason I have selected a reasonably late P-port - strange thing it = equates almost exactly to the factory P-port timing. After measuring the = degree markings, this measures 44mm between IO/ IC. =20 That will do me, so I have opted for a 44mm inlet ( we are only arguing = a couple of mm here as the 1.6mm =3D 40.6mm) with a later opening = similar to the stock PP. I will feed that opening with a 44mm ID SS Tube = ( 44 =3D only 1.73" Dia) The thing to remember is that the calculations for the carbies are done = on piston engines which can create more velocity, where the rotary only = see restrictions - very important point, when looking at carbies. The stock PP seems to have a lot bigger D shaped opening, don't quite = understand that, but presume that the flat side of the D postpones the = IO and/or the larger area in the initial IO may override any residual = exhaust pressure, but I'm guessing. George (down under) =20 George, those hp claims seem wildly exaggerated to me. I have never = heard anyone claim 200 hp for a two rotor street port at 7500 rpm. But = I hope they do turn out to be true. I accept the Power Sport numbers of = around 107.5 hp per rotor with a 1.5 i.d. p port. Perhaps if they had = turned 7500 rpm they might have made somewhat more hp. According to = calculations done for my original p port, a 1.5 i.d.port will flow 8000 = rpm just fine. Side ports are relatively terrible when compared to a p = port. I don't think their comparable size has relevance. Jerry On Jul 24, 2007, at 6:10 PM, George Lendich wrote: Jerry, Sounds good! The Street port single will give about 116hp at 7,500, but you need = 1.18 x2 sq" minimum ( 2.36 sq") =3D 44 Dia inlet. David McCandles has found some old info, which I will forward under = separate cover, which confirms these numbers although I haven't read it = through myself as yet. The RX8 uses smaller runners but more of them, the inlet area is = massive in total, the smaller runner maintains the velocity. However = because the Rotary doesn't suck like a piston engine ( sucking creates = velocity) the advantages of velocity over area needed, are limited. The 12A and 13B are the same size P-port 43mm, the timing/position = are the same. We have to start to accept that they know the advantages of sizing = and position. George George,? I just got back from Oshkosh which would have been a = wasted trip except that I got to fly a CH 701 amphib off the water.? = This was a first for ?yours truly. ? ?What a lot of fun.? The airplane = handles perfectly and is the right one for me. ? ?It is limited by the = designer to 100 hp and 200 lbs for the engine installation. So I am in = the in enviable situation of not wanting to get too much out of my p = port. The plane was powered by a 100 hp Rotax.? ?It did very well.? ? Re your analysis comparing side ports with p ports, I wonder if = such an analysis is even possible as they are quite different.? Anyway, = I doubt that a standard port can deliver 100 hp or a street port 130 hp. = per rotor, certainly not when limited to 7500 rpm.? Of course I am only = guessing.? No real knowledge or experience.?? The only carb I saw at Oshkosh was the aero carb.? It is sized by = HP and they recommend the 38mm for? 125 to 160 hp.? This is too large = for my purposes.? I am considering going down to 35mm? (90 to 125 hp) ? = ?The problem is that I already have 38mm p ports.? Also, of interest is = that they do not recommend ram air. That simplifies the plumbing and the = cowl. ? ?The demo engine had rather long, small dia runners and an air = filter attached to the carb.? That is the "system." ((on an 80 hp = v.w.))? ?If I can get the drive figured out, ?I will build it with RB's = aluminum side plates and Atkins eccentric. ?BTW the 701 is a high wing. = ?The system will be strictly gravity. ? ?? ?Jerry <003501c7ce3f$7b719010$c66b1fd3> <003601c7ce3f$7b719010$c66b1fd3> On Jul 21, 2007, at 10:14 PM, George Lendich wrote: Jerry, I'm trying to compare the carb inlet area to port or P-port = areas. Standard Port area 32 deg ATDC to 50 degree ABDC =3D 1.18 sq " = each side (x2 =3D 2.36sq")- using the front and back housings only. ? A street port will be 1.5sq" x 2 =3D 3sq" . A 44mm P-port =3D 2.35sq" A?42mm p-port =3D 2.14sq" A 40mm P-port =3D 1.94sq" A 38mm P-port =3D 1.75sq" So you see a side port on a single has more port area than a = small P-port. Perhaps the velocity will make up for less area. The street port is bigger again at 3 sq" - this equates to 50mm = port. ? The standard port gives about 100 hp, the street port about = 130hp each rotor. I wouldn't want to choke down the port areas with too? = restrictive inlet carby?area. I can't see how a 38mm will cut the = mustard when your own calculations suggest 1.6 P-port =3D 42mm sq". ? In reality I'm only looking for 130HPat most, if I can get that. ? I can run a 41mm ID SS tube p-port with a 42mm Carby ( and hope = velocity makes up the difference) Or I can run with two 1.5 street = ported side ports 3 sq" with two smaller carbs, perhaps 2x32mm. ? BTW street ported 13B has been dynoed to 264hp can't remember = the RPM - it might have been higher than what we run. More confused than ever! ? Does anyone know the IO/IC and size and HP?of the factory = P-port. ? Lynn, does the timing given, calculated by the rotor uncovering = and covering the port, or the side seal uncovering/covering the port = opening? I was thinking the RX8 rotor will be slightly different (bigger) = with the harased edges. George ( down under) ? ? ? ? ----- Original Message ----- From: Jerry Hey To: Rotary motors in aircraft Sent: Sunday, July 22, 2007 9:17 AM Subject: [FlyRotary] Re: carbs vs efi George,? maybe I have the wrong idea, but I don't understand = why you need such a large bore carb for the single rotor.? No way you = are going to produce more than 150 hp.? I think 38mm would be enough.? = This is what Aero Carb recommends for the 0-320.? Jerry On Jul 21, 2007, at 5:56 PM, George Lendich wrote: Jerry, Looks like Pat was wrong about Revmaster having a 44mm, the = biggest they go to is 42mm ( at the present time)?and that costs $380. = If I remember the 32mm costs $320. Jerry I would be interested in feed back on what you thought = about the Aero Carb, especially how it's constructed - their all a = little different. I do like the Ellison but it's too bloody expensive. George ( down under) George,? the web site says $326.00.? You might want to = compare the aero carb which is similar.??http://www.aeroconversions.com I will be looking at both at Oshkosh on Tuesday and = Wednesday next week.? Jerry Jerry On Jul 20, 2007, at 10:06 PM, George Lendich wrote: ? I have been surprised at the recent flurry of carb = postings.? I assumed that everyone was doing EFI.? having experienced = total electrical failure in march on a trip to the Bahamas I was = thinking a lot about that Neanderthal carb bolted under my O320 and the = magnetos, all unaware of what was going on in the radio, GPS,?and nav = lights departments.??? the reality is that you don't want a reserve = battery to get you to the ground safely, you want to get to the Bahamas = and back and THEN look into what's wrong. my questions are "how much power/performance is lost = with a carb, and which carbs can do manual mixture?".? is it stupid to = ask if the Lycoming carb could run a 13B?? someone mentioned Harley = carbs?having a?good history of rough service.? what about = marvel/schebler?? is this question heresy? :-)? isn't efi a bit of = overkill for an engine that basically runs at 100% power, 75% power and = idle?? scanning thru the archives I see a lot of postings regarding = mixture, mapping, abrupt failures and such.? does this complexity buy us = 5%, 20%?? the question of turbo-charging seems to?beg similar line of = questioning.??? kevin ? Kevin, It's probably my fault, with a number of chaps helping = me out with information. My Buddy Bill Jepson will tell you nothing beats EFI = and when it's running well, he's absolutely right! Not only that it is the best for? fuel efficiency, = leaning reading fuel flow etc. etc. However I'm developing a single rotor and looking at = all sorts of issues including cost effectiveness of less elaborate = installations. I'm also not keen on high pressure fuel under the cowl. Most importantly I'm not?an electronics person and = seeing the problems experienced by others has me more than a little = nervous, in regard to EFI. Of course I know very little about carbies, so their = helping me with this as well. The Revmaster might be the choice for me, but I'm = awaiting the sticker shock! George ( down under) ------=_NextPart_000_005E_01C7CEDE.215022F0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Jerry,
If you have time sit down and do the = calculations=20 in port areas, it's surprising.
All housings have two ports, = usually one=20 big and one small which add up to approx 2 sq". The a proper street = port=20 area is 3 sq"( 1.5sq" ea). Restrictions cause less HP so a inlet about = the same=20 size would be appropriate.
 
Although advice on the street = ports is that=20 the smaller port opening of 1.18sq" feeding the 1.5 street port is = adequate=20 with smoothing, quite obviously enlarging the = port somewhat while=20 doing the smoothing etc. Let's say that is goes from 22% to 16 % = less=20 area.
 
So 3 sq" (3 sq" is 50mm Dia), = less=20 16% ( 3 sq" less 16% =3D 2.52 sq") =3D 46mm. Now lest say the PP is = 25% better=20 than the Street port. We  take 41% (16%=3D25%) of 3 sq" = =3D 1.8 Sq" that's=20 still 38mm dia. I don't think you can go below that without bogging down = the=20 HP 
 
I think 1.5/1.6 will flow 8,000 just = fine but not=20 for the VE for higher HP, I think 1.5 will give about 100hp - nothing = startling,=20 you can get that out of a street port ( with perfect idle) but to = get the=20 extra I need ( 115 to 125), I have to look further. The street port set = up=20 perfectly, may give 116 hp at 7,500; then again it may not, so I am = convinced=20 the PP has the advantage.
 
I also agree that side ports don't flow = as well as=20 a P- port, one reason may be is that the PP is open a lot = longer (=20 longer duration I call it).
 
I have confirmed in my own mind that = the exhaust=20 contamination with the early opening P-port is the main contributor to = the idle=20 stumble. For this reason I have selected a reasonably late P-port - = strange=20 thing it equates almost exactly to the factory P-port timing. After = measuring=20 the degree markings, this measures 44mm between IO/ IC.
 
That will do me, so I have opted for = a  44mm=20 inlet ( we are only arguing a couple of mm here as the 1.6mm =3D 40.6mm) = with a=20 later opening similar to the stock PP. I will feed that = opening with a=20 44mm ID SS Tube ( 44 =3D only 1.73" Dia)
 
The thing to remember is that the = calculations for=20 the carbies are done on piston engines which can create more velocity, = where the=20 rotary only see restrictions - very important point, when = looking at=20 carbies.
 
The stock PP seems to have a lot bigger = D shaped=20 opening, don't quite understand that, but presume that the flat side of = the D=20 postpones the IO and/or the larger area in the initial IO may = override any=20 residual exhaust pressure, but I'm guessing.
George (down under)
 
George, =20 those hp claims seem wildly exaggerated to me.  I have = never=20 heard anyone claim  200 hp for a two rotor street port at 7500 = rpm. =20 But I hope they do turn out to be true.  I accept the Power Sport = numbers=20 of around 107.5 hp per rotor with a 1.5  i.d. p port. =  Perhaps if=20 they had turned 7500 rpm they might have made somewhat more hp.=20  According to calculations done for my original p port, a 1.5 = i.d.port=20 will flow 8000 rpm just fine.   Side ports are relatively = terrible=20 when compared to a p port. I don't think their comparable size has=20 relevance.  Jerry


On Jul 24, 2007, at 6:10 PM, George Lendich wrote:
Jerry,
Sounds = good!
The Street port single = will give=20 about 116hp at 7,500, but you need 1.18  x2 sq" minimum ( = 2.36=20 sq") =3D 44 Dia inlet.
 
David McCandles has = found some=20 old info, which I will forward under separate cover, which confirms = these=20 numbers although I haven't read it through myself as=20 yet.
 
The RX8 uses smaller = runners but=20 more of them, the inlet area is massive in total, the smaller runner = maintains the velocity. However because the Rotary doesn't suck like = a=20 piston engine ( sucking creates velocity) the advantages of velocity = over area needed, are limited.
 
The 12A and 13B are = the same=20 size P-port 43mm, the timing/position are the = same.
We have to start to = accept that=20 they know the advantages of sizing and position.
George
George,?=20 I just got back from Oshkosh which would have been a wasted trip = except=20 that I got to fly a CH 701 amphib off the water.? This was a first = for=20 ?yours truly. ? ?What a lot of fun.? The airplane handles = perfectly and is=20 the right one for me. ? ?It is limited by the designer to 100 hp = and 200=20 lbs for the engine installation. So I am in the in enviable = situation of=20 not wanting to get too much out of my p port. The plane was = powered by a=20 100 hp Rotax.? ?It did very well.? ?

Re your analysis comparing side ports with p ports, I wonder = if such=20 an analysis is even possible as they are quite different.? Anyway, = I doubt=20 that a standard port can deliver 100 hp or a street port 130 hp. = per=20 rotor, certainly not when limited to 7500 rpm.? Of course I am = only=20 guessing.? No real knowledge or experience.??

The only carb I saw at Oshkosh was the aero carb.? It is = sized by HP=20 and they recommend the 38mm for? 125 to 160 hp.? This is too large = for my=20 purposes.? I am considering going down to 35mm? (90 to 125 hp) ? = ?The=20 problem is that I already have 38mm p ports.? Also, of interest is = that=20 they do not recommend ram air. That simplifies the plumbing and = the cowl.=20 ? ?The demo engine had rather long, small dia runners and an air = filter=20 attached to the carb.? That is the "system." ((on an 80 hp v.w.))? = ?If I=20 can get the drive figured out, ?I will build it with RB's aluminum = side=20 plates and Atkins eccentric. ?BTW the 701 is a high wing. ?The = system will=20 be strictly gravity. ? ?? ?Jerry


<003501c7ce3f$7b719010$c66b1fd3>

<003601c7ce3f$7b719010$c66b1fd3>

On Jul 21, 2007, at 10:14 PM, George Lendich wrote:
Jerry,
I'm trying to = compare the=20 carb inlet area to port or P-port = areas.
Standard Port area = 32 deg=20 ATDC to 50 degree ABDC =3D 1.18 sq " each side (x2 =3D = 2.36sq")-=20 using the front and back housings=20 only.
?
A street port will = be 1.5sq"=20 x 2 =3D 3sq"
.
A 44mm P-port=20 =3D=20 2.35sq"
A?42mm p-port =3D=20 2.14sq"
A 40mm P-port =3D=20 1.94sq"
A 38mm P-port =3D=20 1.75sq"
So you see a side = port on a=20 single has more port area than a small=20 P-port.
Perhaps the = velocity will=20 make up for less area.
The street port is = bigger=20 again at 3 sq" - this equates to 50mm = port.
?
The standard port = gives=20 about 100 hp, the street port about 130hp each=20 rotor.
I wouldn't want to = choke=20 down the port areas with too? restrictive inlet=20 carby?area.=20 I can't see how a 38mm will cut the mustard when your own = calculations=20 suggest 1.6 P-port =3D 42mm sq".
?
In reality I'm = only looking=20 for 130HPat most, if I can get that.
?
I can run a 41mm = ID SS tube=20 p-port with a 42mm Carby ( and hope velocity makes up the = difference) Or=20 I can run with two 1.5 street ported side ports 3 sq" with two = smaller=20 carbs, perhaps 2x32mm.
?
BTW street ported = 13B has=20 been dynoed to 264hp can't remember the RPM - it might have been = higher=20 than what we run.
More confused than = ever!
?
Does anyone know = the IO/IC=20 and size and HP?of the factory = P-port.
?
Lynn, does the = timing given,=20 calculated by the rotor uncovering and covering the port, or the = side=20 seal uncovering/covering the port = opening?
I was thinking the = RX8 rotor=20 will be slightly different (bigger) with the harased=20 edges.
George ( down=20 under)
?
?
?
?
----- Original Message -----
From:=20 Jerry=20 Hey
Sent:=20 Sunday, July 22, 2007 9:17 AM
Subject:=20 [FlyRotary] Re: carbs vs efi

George,? maybe I have the wrong idea, but I = don't=20 understand why you need such a large bore carb for the single = rotor.?=20 No way you are going to produce more than 150 hp.? I think = 38mm would=20 be enough.? This is what Aero Carb recommends for the 0-320.? = Jerry


On Jul 21, 2007, at 5:56 PM, George Lendich = wrote:
Jerry,
Looks like Pat = was wrong=20 about Revmaster having a 44mm, the biggest they go to is = 42mm ( at=20 the present time)?and that costs $380. If I remember the = 32mm costs=20 $320.
Jerry I would = be=20 interested in feed back on what you thought about the Aero = Carb,=20 especially how it's constructed - their all a little=20 different.
I=20 do like the Ellison but it's too bloody=20 expensive.
George ( down=20 under)
George,?=20 the web site says $326.00.? You might want to compare the = aero=20 carb which is similar.??http://www.aeroconversions.com
I will be looking at both at Oshkosh on Tuesday and = Wednesday=20 next week.? Jerry


Jerry






On Jul 20, 2007, at 10:06 PM, George Lendich = wrote:
?
I=20 have been surprised at the recent flurry of carb = postings.? I=20 assumed that everyone was doing EFI.? having = experienced total=20 electrical failure in march on a trip to the Bahamas I = was=20 thinking a lot about that Neanderthal carb bolted = under my=20 O320 and the magnetos, all unaware of what was going = on in the=20 radio, GPS,?and nav lights departments.??? the reality = is that=20 you don't want a reserve battery to get you to the = ground=20 safely, you want to get to the Bahamas and back and = THEN look=20 into what's = wrong.
my=20 questions are "how much power/performance is lost with = a carb,=20 and which carbs can do manual mixture?".? is it stupid = to ask=20 if the Lycoming carb could run a 13B?? someone = mentioned=20 Harley carbs?having a?good history of rough service.? = what=20 about marvel/schebler?? is this question heresy? :-)? = isn't=20 efi a bit of overkill for an engine that basically = runs at=20 100% power, 75% power and idle?? scanning thru the = archives I=20 see a lot of postings regarding mixture, mapping, = abrupt=20 failures and such.? does this complexity buy us 5%, = 20%?? the=20 question of turbo-charging seems to?beg similar line = of=20 questioning.??? = kevin
?
Kevin,
It's=20 probably my fault, with a number of chaps helping me = out with=20 information.
My=20 Buddy Bill Jepson will tell you nothing beats EFI and = when=20 it's running well, he's absolutely=20 right!
Not=20 only that it is the best for? fuel efficiency, leaning = reading=20 fuel flow etc. = etc.
However I'm = developing a=20 single rotor and looking at all sorts of issues = including cost=20 effectiveness of less elaborate installations. I'm = also not=20 keen on high = pressure
fuel=20 under the = cowl.
Most=20 importantly I'm not?an electronics person and seeing = the=20 problems experienced by others has me more than a = little=20 nervous, in regard to=20 EFI.
Of=20 course I know very little about carbies, so their = helping me=20 with this as = well.
The=20 Revmaster might be the choice for me, but I'm awaiting = the=20 sticker = shock!
George ( down=20 = under)




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