X-Virus-Scanned: clean according to Sophos on Logan.com X-SpamCatcher-Score: 30 [X] Return-Path: Received: from mail35.syd.optusnet.com.au ([211.29.133.51] verified) by logan.com (CommuniGate Pro SMTP 5.1.8) with ESMTPS id 2041297 for flyrotary@lancaironline.net; Sun, 13 May 2007 02:13:11 -0400 Received-SPF: none receiver=logan.com; client-ip=211.29.133.51; envelope-from=lendich@optusnet.com.au Received: from george (d58-105-120-215.dsl.nsw.optusnet.com.au [58.105.120.215]) by mail35.syd.optusnet.com.au (8.13.1/8.13.1) with SMTP id l4D6CELT016141 for ; Sun, 13 May 2007 16:12:17 +1000 Message-ID: <001801c79525$aa6c47a0$d778693a@george> From: "George Lendich" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Re: EC2 smoke question Date: Sun, 13 May 2007 16:12:17 +1000 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0013_01C79579.7A2D2970" 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_0013_01C79579.7A2D2970 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Lynn Your saying what I want to hear P-port, high intake velocity = (smaller diameter tubes - I thinking about 1.6") and a after = considering Tracy's set-up and Talking to Ian Beadle ( Western = Australia) I'm also leaning toward the shorter inlet tube length. Of course nothing beats proof of testing. Speaking to Ian (he's into electronics) he suggested ( If I = understood him correctly) that the sine wave of the exhaust pulses are = shorter as the RPM goes higher (makes sense), so the intake length needs = to be shorter. I was always under the impression that the shorter manifold was for = torque and the longer for HP - but as they are inextricably linked = (HP=3DTxRPM/5252), what real difference is there, if any, in relation to = aviation needs. Perhaps pulling a few more RPM?? Mind you I'm still working on the single and to get a healthy HP out = of it. I'm hoping to achieve 125HP and maybe as much as 150 hp. I'm still debating the simplicity of a carby V fuel injection, after = riding the new bike around Australia I now understand the benefits of FI = in relation to economy. BTW I was hoping you would take a stab in the dark and say 6" to 8" = would be sufficient for the intake tube. After thinking about two TB's (as you suggested), it adds another = variable to the equation, I've got all sorts of things to consider. On another point, have you used the steel Bellhousings on the rotary = and are they very heavy!?=20 George ( down under) Lynn. What's your take on the runner length for 6,000? I believe you add = the plenum length to the tube length for the total length, So I guess = the longer/ bigger the plenum the shorter the tube has to be. George (Down under) I was hoping nobody would ask me that until I have tried a few on the = dyno. I need to go back to square one and get out some books, and have = my wife teach me Algebra and Trig again.=20 The problem in kind of a dumb way is that almost anything will work = well enough to power nearly anything you could want to fly in. Look at = the McCulloch Drone engines. 79 pounds, 72 HP. No inlet tract, no runner = length no air cleaner, no injection, carb a 4" tall length of pipe with = a needle valve stuck through one side and a gas hose through the other. = Bolted solid on the crankcase. Actually very well designed with a built = up crank in needle races needle bearing rods and wrist pins. Designed to last less than 10 minutes and get shot to pieces during = that time. The stud spacing for the intake tube was the same as an old 6 = cylinder Plymouth carb. So getting one running was no trick at all. So = is 4" just right for 5,500 or whatever those things ran? I know the props were not very long. Probably not. Maybe 8" or 10" = would have made a bit more HP. Was the square cut end of the tube a lack = of thinking? Or was the vena contracta so produced, there to make a = depression so the lack of a venturi would still get the carb to work. If = you put a nice bell shape on the top it would flow more air but have no = differential pressure to flow fuel. So the unhappy drag of a squared off = tube becomes a carb choke. The two rotor Mazda (It isn't really a Wankel) is two 4 stroke Otto = Cycle engines running on the same crank, and sharing a iron segment to = save weight. The piston controlled valving feature makes the intake tune = just like a piston port 2 cycle engine of the same displacement. About = 575 CC per engine. So for 5,000 to 7,000 it aught to look kind of like = a good running 500CC single dirt bike engine? And in airplanes we see = whopping big diameter tubes running over the engine and clamped to a big = plenum chamber with a big TB on one end or the other. Enough induction = system for over 500 HP. Just to wring out a paltry 160 (Maybe) HP?=20 The first good Chevy engine I built was a 302 for a CanAm car. It had = a Crane roller cam and gear drive. It made a wonderful gear howl when it = ran. The intake was Endrel manifold and tubes looking like a pipe organ. = Not very large in diameter, and shorter than others were using. It was a = dribble system like the Bendix systems on Continental engines but even = simpler. The engine driven pump metered fuel to a distribution block and = then into nozzles and into the intake all of the time. There was a line = back to the fuel tank that went through a selector block where a number = of return jet sizes could be selected by the driver to adjust gross = mixture. And I do mean gross. The real smart guys had other ways of tailoring = parts of the band but we didn't. We didn't have a clue. When the car was = sold, the new owner put that little cast iron Chevy on Jerry Mong's dyno = and got 575 HP. It was nothing like the big guys had, but in a 1300 = pound evil handling Lola, it was enough to keep the driver hysterical. = Waking up at night screaming, drinking too much. The usual stuff. But = those tubes were so small compared to what others were running. The = intake valves were only 2.02" so how big a diameter was correct. ??? I = never found out. Anyway the runners on our store bought (Daryl Drummond) race engines = are very nearly stock diameter. The very slightly modified stock = manifold gasket is used. The high mid range is important in a race car. = The closer you get to 2,000 RPM of power the better.=20 This is to have power when a gear change pulls RPM down further than = was expected. If you pull it down too far the time spent accelerating = again would have been saved with a downshift to the next lower gear.=20 So in an airplane, it is good to have power enough to at least stall = the prop a bit on power up from stopped. Rapid acceleration to lift off = with less time for gusts to upset you. Less time with poor aerodynamic = control, and so on. All the good stuff. So airplanes should have a good = mid range although lower than the race car, and the mid range should be = strong. With increasing power as the revs come up right through cruise = to top speed.=20 So what makes good mid range? runner velocity. More is better. Smaller = diameter is better than larger. Straight is better than curved. And if = injectors are closer to the port, slick and shiny is better than = anything else. The inlet end must be protected by a free flowing air = filter, and no vena contracta at the ends. Bell shapes only, always.=20 Other things to think about. Without a dyno and an adjustable length = runner system the chances of hitting the ideal length for best top power = and a good mid range, is zero.=20 But how about this. A log manifold is a convenience so you can run a = single TB and cable system. So two engines are miss tuned by = interconnection, for convenience. How about two smaller TBs? And it is = two engines, not 4 engines, why 4 tubes? How about two tubes? Either with a junction close to the engine or just bite the bullet and = go Pport with two tubes and 2 TBs. Much less space involved, and less = complex with much more power. You can get the length and diameter wrong = and still make more power than a side port engine. Notice Tracy's short = runner intake? Running real well. More later. Lynn E. Hanover -------------------------------------------------------------------------= ----- See what's free at AOL.com. ------=_NextPart_000_0013_01C79579.7A2D2970 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
 
Lynn
Your=20 saying what I want to hear P-port, high intake velocity (smaller = diameter=20 tubes - I thinking  about 1.6") and a after considering Tracy's = set-up=20 and Talking to Ian Beadle ( Western Australia) I'm also leaning = toward the=20 shorter inlet tube length.
Of course nothing beats proof of testing.
 
Speaking to Ian (he's into electronics) he suggested ( If I = understood=20 him correctly) that the sine wave of the exhaust pulses are shorter = as the=20 RPM goes higher (makes sense), so the intake length needs to be=20 shorter.
I was always under the impression that the shorter = manifold was=20 for torque and the longer for HP - but as they are=20 inextricably linked (HP=3DTxRPM/5252), what real difference is = there, if=20 any, in relation to aviation needs. Perhaps pulling a few more = RPM??
Mind you I'm still working on the single and to get a healthy = HP out of=20 it. I'm hoping to achieve 125HP and maybe as much as 150 hp.
I'm still debating the simplicity of a carby V fuel injection, = after=20 riding the new bike around Australia I now understand the benefits = of FI in=20 relation to economy.
BTW I was hoping you would take a stab in the dark and say 6" = to 8"=20 would be sufficient for the intake tube.
After thinking about two TB's (as you suggested), it adds = another=20 variable to the equation, I've got all sorts of things to = consider.
On another point, have you used the steel Bellhousings on the = rotary=20 and are they very heavy!? 
George ( down under)
 
 
Lynn.
What's your take on the runner length for 6,000? = I believe=20 you add the plenum length to the tube length for the total length, = So I=20 guess the longer/ bigger the plenum the shorter the tube has to = be.
George (Down = under)
I was hoping nobody would ask me that until I have tried a few on = the=20 dyno. I need to go back to square one and get out some books, and have = my wife=20 teach me Algebra and Trig again.
 
The problem in kind of a dumb way is that almost anything will = work well=20 enough to power nearly anything you could want to fly in. Look at the=20 McCulloch Drone engines. 79 pounds, 72 HP. No inlet tract, no runner = length no=20 air cleaner, no injection, carb a 4" tall length of pipe with a needle = valve=20 stuck through one side and a gas hose through the other. Bolted solid = on the=20 crankcase. Actually very well designed with a built up crank in needle = races=20 needle bearing rods and wrist pins.
 
Designed to last less than 10 minutes and get shot to pieces = during that=20 time. The stud spacing for the intake tube was the same as an old 6 = cylinder=20 Plymouth carb. So getting one running was no trick at all. So is 4" = just right=20 for 5,500 or whatever those things ran?
I know the props were not very long. Probably not. Maybe 8" or = 10" would=20 have made a bit more HP. Was the square cut end of the tube a lack of=20 thinking? Or was the vena contracta so produced, there to make a = depression so=20 the lack of a venturi would still get the carb to work. If you put a = nice bell=20 shape on the top it would flow more air but have no differential = pressure to=20 flow fuel. So the unhappy drag of a squared off tube becomes a carb=20 choke.
 
The two rotor Mazda (It isn't really a Wankel) is two 4 stroke = Otto Cycle=20 engines running on the same crank, and sharing a iron segment to save = weight.=20 The piston controlled valving feature makes the=20 intake tune just like a piston port 2 cycle engine of the same=20 displacement. About 575 CC per engine.  So for 5,000 to 7,000 it = aught to=20 look kind of like a good running 500CC single dirt bike engine? And in = airplanes we see whopping big diameter tubes running over the engine = and=20 clamped to a big plenum chamber with a big TB on one end or the other. = Enough=20 induction system for over 500 HP. Just to wring out a paltry 160 = (Maybe) HP?=20
 
The first good Chevy engine I built was a 302 for a CanAm car. It = had a=20 Crane roller cam and gear drive. It made a wonderful gear howl = when it=20 ran. The intake was Endrel manifold and tubes looking like a pipe = organ. Not=20 very large in diameter, and shorter than others were using. It was a = dribble=20 system like the Bendix systems on Continental engines but even = simpler. The=20 engine driven pump metered fuel to a distribution block and then into = nozzles=20 and into the intake all of the time. There was a line back to the fuel = tank=20 that went through a selector block where a number of return jet sizes = could be=20 selected by the driver to adjust gross mixture.
And I do mean gross. The real smart guys had other ways of = tailoring=20 parts of the band but we didn't. We didn't have a clue. When the car = was sold,=20 the new owner put that little cast iron Chevy on Jerry Mong's dyno and = got 575=20 HP. It was nothing like the big guys had, but in a 1300 pound evil = handling=20 Lola, it was enough to keep the driver hysterical. Waking up at = night=20 screaming, drinking too much. The usual stuff. But those tubes were so = small=20 compared to what others were running. The intake valves were only = 2.02" so how=20 big a diameter was correct. ??? I never found out.
 
Anyway the runners on our store bought (Daryl Drummond) race = engines are=20 very nearly stock diameter. The very slightly modified stock manifold = gasket=20 is used. The high mid range is important in a race car. The = closer you=20 get to 2,000 RPM of power the better.
 
This is to have power when a gear change pulls RPM down further = than was=20 expected. If you pull it down too far the time spent accelerating=20 again would have been saved with a downshift to the next lower = gear.=20
 
So in an airplane, it is good to have power enough to at least = stall the=20 prop a bit on power up from stopped. Rapid acceleration to lift off = with less=20 time for gusts to upset you. Less time with poor aerodynamic control, = and so=20 on. All the good stuff. So airplanes should have a good mid range = although=20 lower than the race car, and the mid range should be strong. With = increasing power as the revs come up right through cruise to top = speed.
 
So what makes good mid range? runner velocity. More is better. = Smaller=20 diameter is better than larger. Straight is better than curved. And if = injectors are closer to the port, slick and shiny is better than = anything=20 else. The inlet end must be protected by a free flowing air filter, = and no=20 vena contracta at the ends. Bell shapes only, always.
 
Other things to think about. Without a dyno and an adjustable = length=20 runner system the chances of hitting the ideal length for best top = power and a=20 good mid range, is zero.
 
But how about this. A log manifold is a convenience so you can = run a=20 single TB and cable system. So two engines are miss tuned by = interconnection,=20 for convenience. How about two smaller TBs? And it is two engines, not = 4=20 engines, why 4 tubes? How about two tubes?
 
Either with a junction close to the engine or just bite the = bullet and go=20 Pport with two tubes and 2 TBs. Much less space involved, and less = complex=20 with much more power. You can get the length and diameter wrong and = still make=20 more power than a side port engine. Notice Tracy's short runner = intake?=20 Running real well.
 
More later.
 
Lynn E. Hanover
 



See what's free at AOL.com.=20
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