X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from poplet2.per.eftel.com ([203.24.100.45] verified) by logan.com (CommuniGate Pro SMTP 5.3.2) with ESMTP id 4124254 for flyrotary@lancaironline.net; Sat, 13 Feb 2010 16:21:08 -0500 Received-SPF: none receiver=logan.com; client-ip=203.24.100.45; envelope-from=lendich@aanet.com.au Received: from sv1-1.aanet.com.au (mail.aanet.com.au [203.24.100.34]) by poplet2.per.eftel.com (Postfix) with ESMTP id AC1FA1738C7 for ; Sun, 14 Feb 2010 05:20:17 +0800 (WST) Received: from ownerf1fc517b8 (203.171.92.134.static.rev.aanet.com.au [203.171.92.134]) by sv1-1.aanet.com.au (Postfix) with SMTP id 4CD0DBEC027 for ; Sun, 14 Feb 2010 05:20:15 +0800 (WST) Message-ID: From: "George Lendich" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Re: Throttle limits was Re: N.A. Renesis to turbo Date: Sun, 14 Feb 2010 07:20:15 +1000 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0011_01CAAD46.27BD8C10" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.5843 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.5579 X-Antivirus: avast! (VPS 100213-1, 02/13/2010), Outbound message X-Antivirus-Status: Clean This is a multi-part message in MIME format. ------=_NextPart_000_0011_01CAAD46.27BD8C10 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Bill, I have stated this before and I will gain, my calculations indicate a = 44mm inlet ( per rotor) being the size needed to 7,500 rpm - giving max = inlet velocity ( of 100/120 mph). It wasn't until I seen that the = Powersport PP inlet tubes were 44mm that I was reassured I was on the = right track. Others that we know push for the 3" ( 75mm) TB, such as the = Renesis TB, nice that it is. Not many builders will go to 7,500 rpm so 44mm is slightly overkill. Probably could go as low as 38 to 40mm for lower RPM, but I would have = to crunch the numbers. At the time I was thinking I would have to go to = 7,500 RPM on the single rotor to get max take-off performance, so worked = with those numbers. Of course the lower the inlet diameter the higher = the velocity and the better the VE. Lynn spoke of 38mm and 44mm chokes, If I remember correctly and chokes = they are in his racing application of much higher rpm, but the trade-off = is inlet velocity. I know one of the ex-Powersport people are making ( machining) 44mm PP = with 2 piece inlet tubes and fitting them to housings with O rings. I = believe this service is available to anyone interested. Information = passed to me was that Powersport never had any sealing problems after = they went to this arrangement. Believe you me, they spent a fortune on = development. I'm just wondering how I'm going to get my housing over there to get it = done. George ( down under)=20 Ed, This throttle body size thing came as a surprise to me a couple of = years ago when I first started my engine. I selected the 75MM size = because that was what was in the RX-8 car. It pretty obviously is way = too large for our application. Apparently even the 65 MM that Dennis is = using appears to be too large. I suppose that is because in the car, = the engine can rev to 8K+ rpms. We are only revving in the 5-6K range = with an occasional outlier up in the low 7K range. The fact that the = car can rev so high, I suppose, is the reason that there are no = complaints about dead pedal in the car. Thanks to you, I feel I now understand what is causing the phenomenon. = I don't see that it is a problem that should be fixed, at least, not = yet. I just need to work on getting the engine to produce the most = power it can and then, maybe, resize my prop to get rpms in a good power = band for takeoff. =20 It seems that I remember someone on the list (probably Lynn) talking = about a couple of carb throats being 44MM that he uses. If so, they = (two of them) would have an area of about 3040 MM. A single 65 MM body = would have an area of 3317 MM.. an increase of over 9%. A 75 MM body = would have an area of 4415 MM.a whopping 45% increase! =20 Bill B =20 =20 -------------------------------------------------------------------------= ----- From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] = On Behalf Of Ed Anderson Sent: Friday, February 12, 2010 4:38 PM To: Rotary motors in aircraft Subject: [FlyRotary] Throttle limits was Re: N.A. Renesis to turbo Bill, if Dennis had a TB just big enough that it exactly provided = 100% power at sea level, then as he increases in altitude, he will find = more and more throttle travel that does nothing to increase power. This = is because it takes less and less throttle plate opening to provide = sufficient airflow for the pressure/air density in the manifold to reach = the ambient pressure/air density (ambient density is decreasing with = altitude). Since that air density is less than at sea level, it = requires less throttle opening to reach than at sea level. =20 The position of the throttle plate affects only the air flow volume = (not the density of that air airflow), but the amount of air flow volume = does determine the air density in the manifold. The external = atmospheric pressure is of course what is forcing the air through the = throttle body - The less air pressure at altitude means less air is = flowing through the TB as you gain altitude. Remember even though to = simply the verbiage - we often talk of the engine "sucking" but of = course it does not. The engine simply opens its ports and whatever = pressure is in the manifold forces that air into the essentially empty = combustion chamber.=20 =20 Think of it this way, there are two ways you can have ambient air = density in your intake manifold. Those two ways are with the throttle = open or the throttle closed - a contradiction? Not, so. You may have = ambient air pressure/density in the manifold when the engine is running = and TB open sufficiently to provide ambient pressure in the manifold OR = when the engine is not running. =20 When the engine is stopped - you also have ambient pressure in your = intake even with your throttle 99.99 % closed because the engine is not = "sucking" any air out of the manifold when stopped. So a small leak in = the throttle bottle is sufficient for the manifold pressure to reach and = maintain ambient when the engine is not running.=20 =20 What Dennis has done with his DIE intake does not change this factor, = but what the pulse in the intake does when it reaches the other end of = the intake manifold (note how his intakes are tied together so the pulse = can travel from one intake port of one rotor to the intake port of the = second rotor) is briefly create a localized pressure increase in the = intake manifold right at the intake port as it is open. This in effect = shoves more mixture into the combustion chamber - in effect it is a very = brief supercharger effect. It only lasts for milliseconds and therefore = you don't get the same power increase that you would if you had a = turbocharger pushing in denser air the entire time the intake is open. = On the other hand you don't have 30-50 lbs more weight and for basically = no more than fabricating your intake different - it's basically a free = lunch.=20 =20 But, as Dennis will tell you - doing the analysis to get the = equations so you get dimension correct for the effect - can give you a = headache {:>) - right Dennis??. =20 So, anyhow, back the throttle travel, if your TB is larger than needed = to reach 100% power at sea level, then you would also find "excess" = throttle travel sitting on the ground with the engine running at WOT. = Once the throttle is opened sufficient for manifold pressure to reach = ambient, then opening it further will provide no increase in power. You = have in the vernacular- "Maxed Out!" {:>) =20 Once the throttle plate is open sufficient to permit the manifold = pressure/air density to reach ambient conditions - no further opening = will produce any more power even though you may have 5" of throttle = travel and 50% more throttle plate opening to go. =20 =20 =20 Ed =20 =20 =20 Ed Anderson Rv-6A N494BW Rotary Powered Matthews, NC eanderson@carolina.rr.com http://www.andersonee.com http://www.dmack.net/mazda/index.html http://www.flyrotary.com/ http://members.cox.net/rogersda/rotary/configs.htm#N494BW http://www.rotaryaviation.com/Rotorhead%20Truth.htm -------------------------------------------------------------------------= ----- From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] = On Behalf Of Bill Bradburry Sent: Friday, February 12, 2010 3:33 PM To: Rotary motors in aircraft Subject: [FlyRotary] Re: rpm vs Power was : Throttle limits was Re: = N.A. Renesis to turbo =20 Thanks, Dennis, It sounds like you still have a little unused throttle travel even = with the new intake. Can you provide design measurements for your new intake? I ask only = if you have no plans to make and sell it. =20 Bill B=20 =20 -------------------------------------------------------------------------= ----- From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] = On Behalf Of Dennis Haverlah Sent: Friday, February 12, 2010 2:20 PM To: Rotary motors in aircraft Subject: [FlyRotary] Re: rpm vs Power was : Throttle limits was Re: = N.A. Renesis to turbo I used the same 65 mm Mustang throttle body on both my original and = new intakes. If I remember correctly, I believe I had a longer unused = throttle travel with the original intake but I never measured it. I = don't know the static rpm increase with the new intake - probably have = that in my notes some where but my max. rpm at high altitude (8,000 - = 10,000) increased 400-500 rpm. I estimated I went from 165 -170 HP with = the old intake to about 185 HP with the new intake. This in in line = with Ed Anderson's recent note that Mazda got about a 16% power increase = at 6000 rpm with the DIE effect. I felt much improved acceleration the = first time I took off with the new intake.=20 the new intake is based on dynamic intake effect (DIE) where the = closing of an intake valve caused the moving intake air to bounce off = the valve creating a pressure wave. The wave travels at the speed of = sound to the other intake valve and arrives there just before that valve = closes. This increases the amount of air and fuel that enters the = combustion chamber. (As we know the rotary has no valves but uses the = sides of the rotor for opening and closing the intakes.) I designed my = intake to give max. performance at 6300 rpm. If I had cut down my prop to 74" it would give me more clearance for = the prop on my RV-7A and increase my top end rpm. Max rpm is about = 6400 rpm with the new intake and the 76" prop. I'm really not needing = higher RPM now. Dennis Haverlah Bill Bradburry wrote: Dennis, Did your static rpm increase with the new manifold? How much? Did = you before and do you now have any unused throttle travel like Mike = describes? Are you using the same throttle body on the new manifold? = What is the MM opening of the Mustang body? My manifold is very similar to your old one. My tubes are cut just = above the injector bosses, which makes them a little (maybe an inch) = shorter than your old ones. I have a 76 X 88 Performance prop which I = am considering having cut down to 74" like Tracy and Ed when I send it = in for final finish. I am using an aftermarket throttle body that is = 75MM in throat diameter. This is the same size as the stock Renesis = throttle body which is why I picked it. I had intended to use the = Renesis body, but didn't wait for Tracy to get the fly by wire done. I = am not flying, but my static is 52-5300 rpm and I have a lot of throttle = left at that rpm. The last probably =BC of the travel is not used. Bill B =20 -------------------------------------------------------------------------= ----- =20 __________ Information from ESET NOD32 Antivirus, version of virus = signature database 3267 (20080714) __________ The message was checked by ESET NOD32 Antivirus. http://www.eset.com ------=_NextPart_000_0011_01CAAD46.27BD8C10 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Bill,
I have stated this before and I will = gain, my=20 calculations indicate a 44mm inlet ( per rotor) being the size needed to = 7,500=20 rpm - giving max inlet velocity ( of 100/120 mph). It wasn't until I = seen that=20 the Powersport PP inlet tubes were 44mm that I was reassured I was on = the right=20 track. Others that we know push for the 3" ( 75mm) TB, such as the = Renesis=20 TB, nice that it is.
 
Not many builders will go to 7,500 rpm = so 44mm is=20 slightly overkill.
Probably could go as low as 38 to 40mm = for lower=20 RPM, but I would have to crunch the numbers. At the time I was thinking = I would=20 have to go to 7,500 RPM on the single rotor to get max take-off = performance, so=20 worked with those numbers. Of course the lower the inlet diameter the = higher the=20 velocity and the better the VE.
 
Lynn spoke of 38mm and 44mm chokes, If = I remember=20 correctly and chokes they are in his racing application of = much higher=20 rpm, but the trade-off is inlet velocity.
 
I know one of the ex-Powersport people = are making (=20 machining) 44mm PP with 2 piece inlet tubes and fitting them to = housings=20 with O rings. I believe this service is available to anyone interested.=20 Information passed to me was that Powersport never had any sealing = problems=20 after they went to this arrangement. Believe you me, they spent a = fortune on=20 development.
 
I'm just wondering how I'm going to get = my housing=20 over there to get it done.
George ( down under) 

Ed,

This throttle body size = thing came=20 as a surprise to me a couple of years ago when I first started my=20 engine.  I selected the 75MM size because that was what was in = the RX-8=20 car.  It pretty obviously is way too large for our = application. =20 Apparently even the 65 MM that Dennis is using appears to be too = large. =20 I suppose that is because in the car, the engine can rev to 8K+ = rpms.  We=20 are only revving in the 5-6K range with an occasional outlier up in = the low 7K=20 range.  The fact that the car can rev so high, I suppose, is the = reason=20 that there are no complaints about dead pedal in the=20 car.

Thanks to you, I feel I = now=20 understand what is causing the phenomenon.  I don=92t see that it = is a=20 problem that should be fixed, at least, not yet.  I just need to = work on=20 getting the engine to produce the most power it can and then, maybe, = resize my=20 prop to get rpms in a good power band for=20 takeoff.

 

It seems that I remember = someone on=20 the list (probably Lynn) talking about a couple of = carb throats=20 being 44MM that he uses.  If so, they (two of them) would have an = area of=20 about 3040 MM.  A single 65 MM body would have an area of 3317 = MM.. an=20 increase of over 9%.  A 75 MM body would have an area of 4415 = MM=85a=20 whopping 45% increase!

 

Bill = B

 

 

From:=20 Rotary motors in aircraft = [mailto:flyrotary@lancaironline.net] On=20 Behalf Of Ed Anderson
Sent: Friday, February 12, 2010 = 4:38=20 PM
To: = Rotary motors in aircraft
Subject: [FlyRotary] Throttle = limits was=20 Re: N.A. Renesis to turbo

Bill, if = Dennis had a=20 TB just big enough =  that it=20 exactly provided 100% power at = sea=20 level, then as he increases in altitude, he will find more = and more=20 throttle travel that does nothing to increase power.  This is = because it=20 takes less and less throttle plate opening to provide sufficient = airflow for=20 the pressure/air density in the manifold to reach the ambient = pressure/air=20 density (ambient density is decreasing with altitude).  Since = that air=20 density is less than at sea level, it requires less throttle opening = to reach=20 than at sea level.

 

The = position of the=20 throttle plate affects only the air flow volume (not the density of = that air=20 airflow), but the amount of air flow volume does determine the air = density in=20 the manifold.  The external atmospheric pressure is of course = what is=20 forcing the air through the throttle body =96 The less air pressure at = altitude=20 means less air is flowing through the TB as you gain altitude.  = Remember=20 even though to simply the verbiage - we often talk of the engine = =93sucking=94 but=20 of course it does not.  The engine simply opens its ports and = whatever=20 pressure is in the manifold  forces that air into the essentially = empty=20 combustion chamber.

 

Think of it = this way,=20 there are two ways you can have ambient air density in your intake = manifold.=20 Those two ways are with the throttle open or the throttle closed =96 a = contradiction?  Not, so.  You may have ambient air = pressure/density=20 in the manifold when the engine is running and TB open sufficiently to = provide=20 ambient pressure in the manifold OR when the engine is not=20 running.

 

When the = engine is=20 stopped - you also have ambient pressure in your intake even with your = throttle 99.99 % closed because the engine is not =93sucking=94 any = air out of the=20 manifold when stopped.  So a small leak in the throttle bottle is = sufficient for the manifold pressure to reach and maintain ambient = when the=20 engine is not running.

 

What Dennis = has done=20 with his DIE intake does not change this factor, but what the pulse in = the=20 intake does when it reaches the other end of the intake manifold (note = how his=20 intakes are tied together so the pulse can travel from one intake port = of one=20 rotor to the intake port of the second rotor) is briefly create a = localized=20 pressure increase in the intake manifold right at the intake port as = it is=20 open.  This in effect shoves more mixture into the combustion = chamber =96=20 in effect it is a very brief supercharger effect.  It only lasts = for=20 milliseconds and therefore you don=92t get the same power increase = that you=20 would if you had a turbocharger pushing in denser air the entire time = the=20 intake is open.   On the other hand you don=92t have 30-50 = lbs more=20 weight and for basically no more than fabricating your intake = different =96 it=92s=20 basically a free lunch.

 

 But, = as Dennis=20 will tell you - doing the analysis to get the equations so you get = dimension=20 correct for the effect =96 can give you a headache {:>) =96 right=20 Dennis??.

 

So, anyhow, = back the=20 throttle travel, if your TB is larger than needed to reach = 100% power at sea level, then = you would=20 also find =93excess=94 throttle travel sitting on the ground with the = engine=20 running at WOT.  Once the throttle is opened sufficient for = manifold=20 pressure to reach ambient, then opening it further will provide no = increase in=20 power.  You have in the vernacular- =93Maxed Out!=94=20 {:>)

 

Once the = throttle=20 plate is open sufficient to permit the manifold pressure/air density = to reach=20 ambient conditions =96 no further opening will produce any more power = even=20 though you may have 5=94 of throttle travel and 50% more throttle = plate opening=20 to go.

 

 

 

Ed

 

 

 

Ed=20 Anderson

Rv-6A N494BW Rotary=20 Powered

Matthews,=20 NC

eanderson@carolina.rr.com

http://www.andersonee.com

http://www.dmack.net/mazda/index.html

http://www.flyrotary.com/

http://members.cox.net/rogersda/rotary/configs.htm#N494BW

http://www.r= otaryaviation.com/Rotorhead%20Truth.htm

From:=20 Rotary motors in aircraft = [mailto:flyrotary@lancaironline.net] On=20 Behalf Of Bill Bradburry
Sent: Friday, February 12, 2010 = 3:33=20 PM
To: = Rotary motors in aircraft
Subject: [FlyRotary] Re: rpm vs = Power was=20 : Throttle limits was Re: N.A. Renesis to turbo

 

Thanks, Dennis,

It sounds like you still have a little = unused throttle=20 travel even with the new intake.

Can you provide design measurements for your = new=20 intake?  I ask only if you have no plans to make and sell=20 it.

 

Bill = B 

 

From:=20 Rotary motors in aircraft = [mailto:flyrotary@lancaironline.net] On=20 Behalf Of Dennis Haverlah
Sent: Friday, February 12, 2010 = 2:20=20 PM
To: = Rotary motors in aircraft
Subject: [FlyRotary] Re: rpm vs = Power was=20 : Throttle limits was Re: N.A. Renesis to = turbo

I used the same = 65 mm Mustang=20 throttle body on both my original and new intakes.  If  I = remember=20 correctly, I believe I had a longer  unused throttle travel with = the=20 original intake but I never measured it.  I don't know the static = rpm=20 increase with the new intake - probably have that in my notes some = where but=20 my max. rpm at high altitude (8,000 - 10,000) increased 400-500 = rpm.  I=20 estimated I went from 165 -170 HP with the old intake to about 185 HP = with the=20 new intake.  This in in line with Ed Anderson's recent note that = Mazda=20 got about a 16% power increase at 6000 rpm with the DIE effect.  = I felt=20 much improved acceleration the first time I took off with the new = intake.=20

the new intake is based on dynamic=20 intake effect  (DIE) where the closing of an intake = valve=20 caused the moving intake air to bounce off the valve creating a = pressure=20 wave.  The wave travels at the speed of sound to the other intake = valve=20 and arrives there just before that valve closes.  This increases = the=20 amount of air and fuel that enters the combustion chamber.  (As = we know=20 the rotary has no valves but uses the sides of the rotor for opening = and=20 closing the intakes.)  I designed my intake to give max. = performance at=20 6300 rpm.

If I had cut down my prop to 74" it would give me = more=20 clearance for the prop on my RV-7A and increase my top end = rpm.  =20 Max rpm is about 6400 rpm with the new intake and the 76" prop.  = I'm=20 really not needing higher RPM now.

Dennis Haverlah

Bill=20 Bradburry wrote:

Dennis,<= /FONT>

Did your static rpm increase with the new=20 manifold?  How much?  Did you before and do you now have any = unused=20 throttle travel like Mike describes?   Are you using the = same=20 throttle body on the new manifold?  What is the MM opening of the = Mustang=20 body?

My manifold is very similar to your old = one.  My=20 tubes are cut just above the injector bosses, which makes them a = little (maybe=20 an inch) shorter than your old ones.  I have a 76 X 88 = Performance prop=20 which I am considering having cut down to 74=94 like Tracy and Ed when = I send it=20 in for final finish.  I am using an aftermarket throttle body = that is=20 75MM in throat diameter.  This is the same size as the stock = Renesis=20 throttle body which is why I picked it.  I had intended to use = the=20 Renesis body, but didn=92t wait for Tracy to get = the fly=20 by wire done.  I am not flying, but my static is 52-5300 rpm and = I have a=20 lot of throttle left at that rpm.  The last probably =BC of the = travel is=20 not used.

Bill B

 

 



__________ = Information from=20 ESET NOD32 Antivirus, version of virus signature database 3267 = (20080714)=20 __________

The message was checked by ESET NOD32 = Antivirus.

http://www.eset.com

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