X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from smtp103.sbc.mail.mud.yahoo.com ([68.142.198.202] verified) by logan.com (CommuniGate Pro SMTP 5.0.9) with SMTP id 1129873 for flyrotary@lancaironline.net; Sat, 27 May 2006 00:20:42 -0400 Received-SPF: none receiver=logan.com; client-ip=68.142.198.202; envelope-from=dcarter11@sbcglobal.net Received: (qmail 91259 invoked from network); 27 May 2006 04:19:56 -0000 Received: from unknown (HELO davidsdell8200) (dcarter11@sbcglobal.net@67.41.226.150 with login) by smtp103.sbc.mail.mud.yahoo.com with SMTP; 27 May 2006 04:19:55 -0000 Message-ID: <25a601c68145$114467a0$6401a8c0@davidsdell8200> From: "David Carter" To: "Rotary motors in aircraft" References: Subject: Ignition tutorial [was Re: [FlyRotary] Re: Another case of heat-soaked coils? Date: Fri, 26 May 2006 22:21:45 -0600 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_25A3_01C68112.C5E19E90" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.2869 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.2869 This is a multi-part message in MIME format. ------=_NextPart_000_25A3_01C68112.C5E19E90 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Lynn, that is a masterful and understandable explanation to carry an old = guy from 1940's ignition systems to "high energy" systems. I knew the = term "high energy" but had never heard/read a thing about what it = consisted of. You gave me exactly what I was hoping for. Thank you = very much, as always, for taking the time to share your knowledge with = us. Let's see if I've learned anything: Ques: If I have a "high energy = ignition system, do I want to continue using my old method to trouble = shoot a steady miss at idle by "holding" the spark plug boot close = enough for the plug to fire, then pull it away from the plug to see if = the miss gets worse?=20 . . . Answer: Only if I want a "mini-nap on the way to the ground where = I will sit dazed struggling to remember my name". David Carter ----- Original Message -----=20 From: Lehanover@aol.com=20 To: Rotary motors in aircraft=20 Sent: Friday, May 26, 2006 7:44 AM Subject: [FlyRotary] Re: Another case of heat-soaked coils? In a message dated 5/24/2006 11:58:50 P.M. Eastern Daylight Time, = dcarter11@sbcglobal.net writes: I just sent a post asking Lynn to explain the .010 gap. I still had = his original e-mail in the in-basket and have just re-read it - I don't = understand the reference to "secondary ignition breakdown" and = "secondary breakdown" in the 2nd paragraph, "One quick check for = secondary ignition breakdown, is to quickly install two new plugs in the = leading holes, gapped at .010". If the problem is still there, it is = less likely the secondary output. If the problem is gone, it is likely = the secondary output." Please help an old timer used to "coil and distributor ignition = systems" who is a "first time owner" (and VERY HAPPY user) of a modern = (1993 & 1995 Ford Escort) ignition system: . . . Are these new "igniter blocks" still using the = "primary"/"secondary" coil principle of the old round coils? If so, = what makes these 1990's and later "high energy" systems "higher = voltage"? Higher ratio of primary to secondary coil windings? (or vice = versa?) and/or the totally mysterious "ignition modules" that go along = with the coil packs? I.e., are the square coil/igniter coil blocks = doing the same thing, only better, than the old coils? . . . If so, then is Lynn's ref to "secondary ignition breakdown" a = ref to some kind of failure or degradation of the secondary coil = windings? (such as internal shorting of sec coil windings to each other, = so as to reduce "effective" number of coils in secondary; or, arcing of = secondary to engine mount/block) so voltage to plugs is significantly = down?) Also, why put the .010 plugs only in the leading holes, as opposed = to trailing, or both holes? David The first ignition systems I saw were points systems using a capacitor = across the open points to prevent arcing and short points life. This is = a great system with 30 billion or so installations working just fine. = Cars, tractors, airplanes, lawn mowers, everything. Then we want to go faster and make more power with higher compression = and more revs and the trusty Kettering system starts to have problems.=20 The time it takes to build a full flux field in the coil is a function = of a number of built in features, and some outside stuff such as battery = voltage. One trouble shooting item that you learn early is that = secondary ignition breakdown (anything that reduces high voltage = performance) is greatly affected by battery voltage.=20 When the generator on the 40 Ford dies at night and things start to = get dim on the way home, you jump out and pull off a headlight wire and = down the road a bit the engine will no longer take full throttle, but = will run OK at a lower throttle setting. Sometimes you make it home and = sometimes you don't.=20 So you cannot get full voltage (energy) from the coil if you don't put = in enough voltage (energy). You know now that higher cylinder pressure = requires more secondary voltage, and full throttle means higher cylinder = pressure. So when you back off of the throttle a bit and lower the = cylinder pressure, the engine runs fine again.=20 So supply voltage and cylinder pressure affect secondary voltage = performance. Cylinder pressure would include higher compression ratios, = turbo or supercharging, adding more carbs, wilder cam profile, and all = of that other stuff you did. Voltage is obvious, less in =3D less out. = Too simple maybe? Rise time (time to full field saturation) is a function of = construction, core volume, lamination count and permeability, wire = diameter (resistance) inductive reactance, turns ratio, container = material and shape and hundreds of other features that a coil engineer = would talk your ears off for hours telling you about. Rise time in coils = and capacitors function in accordance with the 62% rule. However long it = takes the coil to charge up to 62% of it's full field capacity, is one = time period. So when you establish that period of time, the coil will = require another of those time periods to charge to 62% of the 28% of = remaining capacity. This rather sluggish performance is the same for all = coils, and capacitors everywhere, all of the time, even in California. So if you want more performance from an ignition system you have to = come up with a way to cheat the system. Thicker primary wire for the 40 = Ford? Yes. A coil with a higher turns ratio and thicker low voltage = wire? Yes. A laminated coil core instead of a solid slug. Yes, and on it = goes. An 8 volt battery? yes to everything. But the rise time may be faster but it is still subject to the same = rule. So if you want more revs and the rise time of the coil is starting = to limit secondary voltage, you keep at it and then you come up with = dual point distributors. So more time is spent with power supplied to = the coil. Simple. You may also have noticed that no coil or capacitor = ever gets to be fully charged. No matter how long you work on it, even = forever. One problem is the points themselves. Noisy, bouncing, high = resistance, attracting dirt and oil, requires a capacitor to stay alive, = wear out and need adjustment and so on. So, the Transistor is invented (by my friends at Western Electric = (Bell labs)) And then the SCR Silicone Controlled Rectifier (big high = current Transistor) and somebody says look at this. If we figure out a = way to tell this thing when to do it, we could switch off the coil = primary and eliminate the points. And they did. And then the points = system was relegated to the lawnmower. =20 The electronic switch does wonders for a Kettering system. Allows = longer power on time to the primary, ( like the dual point distributor) = so coil saturation is always higher before field collapse. No point = noise broadcast into the radio. And in the early days they switched it = with the same old points. The points just carried just a few volts and little current so they = didn't wear out quickly and so on.=20 Then came induced triggering from an optical source and shutter wheel, = or a magnetic trigger. No no parts touched any other parts, so nothing = could wear out, and a tune up was limited to plugs and wires. But the coil is still limited to the 62% rule. And if you want to = scream a multi cylinder engine rise time still limits high voltage = output. But at low speeds, you can use bigger plug gaps and get better = mileage. The piston engine drives the fuel air mixture toward the spark plug(s) = and the possibility of some of it not lighting is slim. The rotary moves = the fuel air mixture past the plugs at 150 miles an hour, and the = possibility that some of it won't burn is excellent. The rotary also has = virtually no squish area and a large cold low compression combustion = chamber. All bad mojo. =20 So anything that adds fire (energy) to the combustion process is a big = help in a rotary.=20 So, you know the coil rules now, so how do you add energy at the spark = plug? The 8 volt battery (The cheater battery from the Ford tractor for cold = weather starting) helped the 40 Ford street racer. Wow, 24 volts really makes a great high out put coil and cuts the rise = time way down.=20 How about 400 volts? What would that do? Where could we get that much? = Well, in the lab, 400 volts to the primary windings cuts rise time to = nearly nothing, so you could have great high voltage performance in a = V-12 engine turning 10,000 RPM. Unlikely to be needed, but you could do = it. =20 So, through electronic trickery a free running mono-stable = multi-vibrator circuit (two transistors) generates sort of a fake square = wave AC that drives a transformer that steps the 12 volts up to 400+ = volts, that is fed to a rectifier (to turn it back into DC) to charge a = large high value capacitor, in a very short (rise time). When ignition = is called for by whatever triggering device, A large SCR connects the = output of the capacitor to the coil primary. This 400 volts surprises = the hell out of the 12 volt coil and the coil delivers about three times = it's rated output to the plug, and anyone standing too close. There you = go. A high energy system. The very short rise times aid in firing dirty or fouled plugs before = leakage paths are found to short the plug by establishing a path around = the gap. The leading plugs in the rotary deliver the spark that does most of = the work. So loosing the leading system makes about a 25% loss of power. = The trailing system helps out a bit on power, and helps with emissions, = so loosing that system makes about a 5% loss in power. So many trailing = systems fail and go unnoticed for years.=20 If an engine stumbles and reducing throttle slightly, returns smooth = running, the first thing I think about is voltage to the ignition = system. Lynn E. Hanover =20 ------=_NextPart_000_25A3_01C68112.C5E19E90 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Lynn, that is a masterful and understandable explanation to carry = an old=20 guy from 1940's ignition systems to "high energy" systems.  I knew = the term=20 "high energy" but had never heard/read a thing about what it consisted=20 of.  You gave me exactly what I was hoping for.  Thank = you very=20 much, as always, for taking the time to share your knowledge with = us.
 
Let's see if I've learned anything: Ques:  If I have a = "high=20 energy ignition system, do I want to continue using my old method to = trouble=20 shoot a steady miss at idle by "holding" the spark plug boot close = enough=20 for the plug to fire, then pull it away from the plug to see if=20 the miss gets worse? 
. . . Answer:  Only if I want a "mini-nap on the way to the = ground=20 where I will sit dazed struggling to remember my name".
 
David Carter
----- Original Message -----
From:=20 Lehanover@aol.com
Sent: Friday, May 26, 2006 7:44 = AM
Subject: [FlyRotary] Re: = Another case of=20 heat-soaked coils?

In a message dated 5/24/2006 11:58:50 P.M. Eastern Daylight Time, = dcarter11@sbcglobal.net=20 writes:
I just sent a post asking Lynn to explain the .010 gap.  I = still=20 had his original e-mail in the in-basket and have just re-read it - = I don't=20 understand the reference to "secondary ignition breakdown" and = "secondary=20 breakdown" in the 2nd paragraph, "One quick check for secondary = ignition breakdown, is to quickly install two new plugs in the = leading=20 holes, gapped at .010". If the problem is still there, it is less = likely the=20 secondary output. If the problem is gone, it is likely the secondary = output."
 
Please help an old timer used to "coil and distributor ignition = systems" who is a "first time owner" (and VERY HAPPY user) of a = modern (1993=20 & 1995 Ford Escort) ignition system:
. . .  Are these new "igniter blocks" still using the=20 "primary"/"secondary" coil principle of the old round coils?  = If so,=20 what makes these 1990's and later "high energy" systems "higher=20 voltage"?  Higher ratio of primary to secondary coil windings? = (or vice=20 versa?) and/or the totally mysterious "ignition modules" that go = along with=20 the coil packs?  I.e., are the square coil/igniter coil blocks = doing=20 the same thing, only better, than the old coils?
. . . If so, then is Lynn's ref to "secondary ignition = breakdown"=20 a ref to some kind of failure or degradation of the secondary coil = windings?=20 (such as internal shorting of sec coil windings to each other, so as = to=20 reduce "effective" number of coils in secondary; or, arcing of = secondary to=20 engine mount/block) so voltage to plugs is significantly = down?)
 
Also, why put the .010 plugs only in the leading holes, as = opposed to=20 trailing, or both holes?
 
David
The first ignition systems I saw were points systems using a = capacitor=20 across the open points to prevent arcing and short points life. This = is a=20 great system with 30 billion or so installations working just = fine. Cars,=20 tractors, airplanes, lawn mowers, everything.
 
Then we want to go faster and make more power with higher = compression and=20 more revs and the trusty Kettering system starts to have problems. =
 
The time it takes to build a full flux field in the coil is a = function of=20 a number of built in features, and some outside stuff such as battery = voltage.=20 One trouble shooting item that you learn early is that secondary = ignition=20 breakdown (anything that reduces high voltage performance) is greatly = affected=20 by battery voltage.
 
When the generator on the 40 Ford dies at night and things start = to get=20 dim on the way home, you jump out and pull off a headlight wire and = down the=20 road a bit the engine will no longer take full throttle, but will run = OK at a=20 lower throttle setting. Sometimes you make it home and sometimes = you=20 don't.
 
So you cannot get full voltage (energy) from the coil if you = don't put in=20 enough voltage (energy). You know now that higher cylinder pressure = requires=20 more secondary voltage, and full throttle means higher cylinder = pressure. So=20 when you back off of the throttle a bit and lower the cylinder = pressure, the=20 engine runs fine again.
 
So supply voltage and cylinder pressure affect secondary voltage=20 performance. Cylinder pressure would include higher compression = ratios, turbo=20 or supercharging, adding more carbs, wilder cam profile, and all of = that other=20 stuff you did. Voltage is obvious, less in =3D less out. Too simple = maybe?
 
Rise time (time to full field saturation) is a function of = construction,=20 core volume, lamination count and permeability, wire diameter = (resistance)=20 inductive reactance, turns ratio, container material and shape and = hundreds of=20 other features that a coil engineer would talk your ears off for hours = telling=20 you about. Rise time in coils and capacitors function in accordance = with the=20 62% rule. However long it takes the coil to charge up to 62% of it's = full=20 field capacity, is one time period. So when you establish that period = of time,=20 the coil will require another of those time periods to charge to 62% = of the=20 28% of remaining capacity. This rather sluggish performance is the = same for=20 all coils, and capacitors everywhere, all of the time, even in=20 California.
 
So if you want more performance from an ignition system you have = to come=20 up with a way to cheat the system. Thicker primary wire for the 40 = Ford? Yes.=20 A coil with a higher turns ratio and thicker low voltage = wire? Yes. A=20 laminated coil core instead of a solid slug. Yes, and on it goes. An 8 = volt=20 battery? yes to everything.
 
But the rise time may be faster but it is still subject to = the same=20 rule. So if you want more revs and the rise time of the coil is = starting to=20 limit secondary voltage, you keep at it and then you come up with dual = point=20 distributors. So more time is spent with power supplied to the coil. = Simple.=20 You may also have noticed that no coil or capacitor ever gets to be = fully=20 charged. No matter how long you work on it, even forever.
 
One problem is the points themselves. Noisy, bouncing, high = resistance,=20 attracting dirt and oil, requires a capacitor to stay alive, wear out = and need=20 adjustment and so on.
 
So, the Transistor is invented (by my friends at Western Electric = (Bell=20 labs)) And then the SCR Silicone Controlled Rectifier (big = high=20 current Transistor) and somebody says look at this. If we figure out a = way to=20 tell this thing when to do it, we could switch off the coil primary = and=20 eliminate the points. And they did. And then the points system was = relegated=20 to the lawnmower.   
 
The electronic switch does wonders for a Kettering system. Allows = longer=20 power on time to the primary, ( like the dual point distributor) so = coil=20 saturation is always higher before field collapse. No point noise = broadcast=20 into the radio. And in the early days they switched it with the same = old=20 points.
The points just carried just a few volts and little current so = they=20 didn't wear out quickly and so on.
 
Then came induced triggering from an optical source and shutter = wheel, or=20 a magnetic trigger. No no parts touched any other parts, so nothing = could wear=20 out, and a tune up was limited to plugs and wires.
But the coil is still limited to the 62% rule. And if you want to = scream=20 a multi cylinder engine rise time still limits high voltage output. = But at low=20 speeds, you can use bigger plug gaps and get better mileage.
 
The piston engine drives the fuel air mixture toward the spark = plug(s)=20 and the possibility of some of it not lighting is slim. The rotary = moves the=20 fuel air mixture past the plugs at 150 miles an hour, and the = possibility that=20 some of it won't burn is excellent. The rotary also has virtually no = squish=20 area and a large cold low compression combustion chamber. All bad=20 mojo.  
 
So anything that adds fire (energy) to the combustion process is = a big=20 help in a rotary.
 
So, you know the coil rules now, so how do you add energy at the = spark=20 plug?
 
The 8 volt battery (The cheater battery from the Ford tractor for = cold=20 weather starting) helped the 40 Ford street racer.
 
Wow, 24 volts really makes a great high out put coil and cuts the = rise=20 time way down.
How about 400 volts? What would that do? Where could we get that = much?=20 Well, in the lab, 400 volts to the primary windings cuts rise time to = nearly=20 nothing, so you could have great high voltage performance in a V-12 = engine=20 turning 10,000 RPM. Unlikely to be needed, but you could do it. =  
 
So, through electronic trickery a free running mono-stable = multi-vibrator=20 circuit (two transistors) generates sort of a fake square wave AC that = drives=20 a transformer that steps the 12 volts up to 400+ volts, that is fed to = a=20 rectifier (to turn it back into DC) to charge a large high value=20 capacitor, in a very short (rise time). When ignition is called for by = whatever triggering device, A large SCR connects the output of the = capacitor=20 to the coil primary. This 400 volts surprises the hell out of the 12 = volt=20 coil and the coil delivers about three times it's rated output to = the=20 plug, and anyone standing too close. There you go. A high energy = system.
 
The very short rise times aid in firing dirty or fouled plugs = before=20 leakage paths are found to short the plug by establishing a path = around the=20 gap.
 
The leading plugs in the rotary deliver the spark that does most = of the=20 work. So loosing the leading system makes about a 25% loss of power. = The=20 trailing system helps out a bit on power, and helps with emissions, so = loosing=20 that system makes about a 5% loss in power. So many trailing systems = fail and=20 go unnoticed for years. 
 
If an engine stumbles and reducing throttle slightly, returns = smooth=20 running, the first thing I think about is voltage to the ignition=20 system.
 
Lynn E. Hanover    
 
 
 
 
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