X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from access.aic-fl.com ([207.30.253.2] verified) by logan.com (CommuniGate Pro SMTP 5.1.10) with ESMTP id 2197215 for flyrotary@lancaironline.net; Tue, 24 Jul 2007 19:56:26 -0400 Received-SPF: softfail receiver=logan.com; client-ip=207.30.253.2; envelope-from=unicorn@gdsys.net Received: from main (gdsi-67.gdsys.net [207.30.255.67]) by access.aic-fl.com (Rockliffe SMTPRA 4.5.6) with SMTP id for ; Tue, 24 Jul 2007 18:52:11 -0500 Message-ID: <002301c7ce4e$2bf4e870$43ff1ecf@main> From: "Richard Sohn" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Re: carbs vs efi Date: Tue, 24 Jul 2007 18:55:49 -0500 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_001E_01C7CE24.40894170" 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 This is a multi-part message in MIME format. ------=_NextPart_000_001E_01C7CE24.40894170 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Hi Jerry, for your airplane, I don't think you have to worry about power, all you = have to worry about is weight. In order to meet 200lb FF, a bare engine, = say long block, should be under 100lb. My 12A based single is 90lb = giving a FF of 170lb. The 701 probabely will only require maybe 50hp at = cruise, and the utilization of every hp over and above that depends very = much on a proper prop dimensioning and setting. Especially on take off = distance, the heavier, stronger engine does not give you an advatage, = generally speaking. It mostly makes you climb better at higher airspeed. I have a friend with an AVID running a Rotax 582 with 65hp. His take off = distance is essentially the same as mine with 100hp, however, my = airplane is 15-20% heavier.=20 FWIW. Richard Sohn N2071U ----- Original Message -----=20 From: Jerry Hey=20 To: Rotary motors in aircraft=20 Sent: Tuesday, July 24, 2007 5:39 PM Subject: [FlyRotary] Re: carbs vs efi 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) -------------------------------------------------------------------------= ----- No virus found in this incoming message. Checked by AVG Free Edition.=20 Version: 7.5.476 / Virus Database: 269.10.17/915 - Release Date: = 7/24/2007 1:50 PM ------=_NextPart_000_001E_01C7CE24.40894170 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Hi Jerry,
 
for your airplane, I don't think you = have to worry=20 about power, all you have to worry about is weight. In order to meet = 200lb FF, a=20 bare engine, say long block, should be under 100lb. My 12A based single = is 90lb=20 giving a FF of 170lb. The 701 probabely will only require maybe = 50hp at=20 cruise, and the utilization of every hp over and above = that depends=20 very much on a proper prop dimensioning and setting. Especially on take = off=20 distance, the heavier, stronger engine does not give you an advatage, = generally=20 speaking. It mostly makes you climb better at higher = airspeed.
I have a friend with an AVID = running a Rotax=20 582 with 65hp. His take off distance is essentially the same as mine = with 100hp,=20 however, my airplane is 15-20% heavier.
FWIW.
 
Richard Sohn
N2071U
 
----- Original Message -----
From:=20 Jerry=20 Hey
Sent: Tuesday, July 24, 2007 = 5:39=20 PM
Subject: [FlyRotary] Re: carbs = vs=20 efi

George,  those hp claims seem=20 wildly exaggerated to me.  I have never heard anyone=20 claim  200 hp for a two rotor street port at 7500 rpm.  But = I hope=20 they do turn out to be true.  I accept the Power Sport numbers of = around=20 107.5 hp per rotor with a 1.5  i.d. p port.  Perhaps if they = had=20 turned 7500 rpm they might have made somewhat more hp.  According = to=20 calculations done for my original p port, a 1.5 i.d.port will flow = 8000 rpm=20 just fine.   Side ports are relatively terrible when = compared to a p=20 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=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)




No virus found in this incoming message.
Checked by AVG Free = Edition.
Version: 7.5.476 / Virus Database: 269.10.17/915 - = Release Date:=20 7/24/2007 1:50 PM
------=_NextPart_000_001E_01C7CE24.40894170--