X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from mail-vb0-f43.google.com ([209.85.212.43] verified) by logan.com (CommuniGate Pro SMTP 6.0.5) with ESMTPS id 6398892 for flyrotary@lancaironline.net; Wed, 31 Jul 2013 20:11:08 -0400 Received-SPF: pass receiver=logan.com; client-ip=209.85.212.43; envelope-from=rwstracy@gmail.com Received: by mail-vb0-f43.google.com with SMTP id h11so1446517vbh.30 for ; Wed, 31 Jul 2013 17:10:32 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=subject:references:from:content-type:x-mailer:in-reply-to :message-id:date:to:content-transfer-encoding:mime-version; bh=iJfNnjzy+0N2kZC5N/wH0Ysx+FTlyvVcS1Us3Ax2ZzQ=; b=GKCOtjp40EbCRnsUH3O0kYj8qnxP15N/lxRIQOo2dDy0qI7VjWDVmIBJOIrkQUuVZY P86iIJSjII39pgR3Ldshg4cQvi5dBYIMFOVXWyViZFGtliyUhe93YwpV5ySURShpE+89 npaLLJ+F7TCGlTi73ivMAd1uE5De6Dlq6aJ8Q0qBIqp0JG0k4ExviYkmut3s+62zlsHt 1cfwSh7UFUKIjcY0EmOcuC7imiz4YslZ53MbLuH+cxyTuolGtYHstesXAPP/ttr1lfx/ oD1q2NaupvHW/bhTUuuJ8ClgvTASIoYpQ5FE+LiM5HWvXEjOyvbqLoZuggTsYlWa/DfR Sk8A== X-Received: by 10.59.9.69 with SMTP id dq5mr28736337ved.87.1375315832834; Wed, 31 Jul 2013 17:10:32 -0700 (PDT) Return-Path: Received: from [75.202.83.107] (107.sub-75-202-83.myvzw.com. [75.202.83.107]) by mx.google.com with ESMTPSA id ir5sm197473veb.6.2013.07.31.17.10.29 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Wed, 31 Jul 2013 17:10:32 -0700 (PDT) Subject: Re: [FlyRotary] Re: Fwd: [FlyRotary] Re: : Misfire References: From: Tracy Content-Type: multipart/alternative; boundary=Apple-Mail-4B91455F-1633-4D70-8F5B-A2186D8F9995 X-Mailer: iPad Mail (10B329) In-Reply-To: Message-Id: <7717F446-E39B-49EA-8853-1139E66C8BD6@gmail.com> Date: Wed, 31 Jul 2013 20:10:26 -0400 To: Rotary motors in aircraft Content-Transfer-Encoding: 7bit Mime-Version: 1.0 (1.0) --Apple-Mail-4B91455F-1633-4D70-8F5B-A2186D8F9995 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: quoted-printable Scott, are you saying the trailing spark plug hole WAS opened up? =20 Turbocharged or not, don't EVER do that! And don't let your engine builder d= o,that. If the engine could be improved simply with a bigger hole there, Mazda would= have certainly done it. =20 Yes, that could promote detonation. Tracy Sent from my iPad On Jul 31, 2013, at 20:03, Scott Emery wrote: > So my engine may have detonated simply because the engine builder opened u= p the upper (trailing) spark plug holes to improve the redundant dual igniti= on idea of an aircraft engine? > As rpm and boost increased the compression of the intake charge? The fire c= ould jump the apex seal at the big hole and light the leading edge of the in= take charge just as the intake ports are closing?! >=20 > Sent from my iPhone >=20 > On Jul 30, 2013, at 11:16 AM, Lehanover@aol.com wrote: >=20 >> In a message dated 7/30/2013 1:36:12 P.M. Eastern Daylight Time, Lehanove= r@aol.com writes: >> The rotary has three features that make for a poor idle compared to a pis= ton engine. >> =20 >> Heat of compression. >> The rise in chamber temperature caused by compressing the fuel/air mixtur= e. >> The rotary has poor heat of compression because of the large surface are o= f the chamber, and much of the chamber surface is cooled. Low heat of compre= ssion allows fuel droplets to condense on the chamber surfaces and the engin= e sees this as a mixture that is too lean to light. >> =20 >> Compression leakage: >> The rotor face has many end gaps through which it leaks compression. >> =20 >> For example, on NA rotaries I gap the side seal to corner seal at zero. S= o long as the combination of two side seals and the joining corner seal pop b= ack up when depressed and released, that is sufficient. The zero gap will be= come a measurable gap shortly after break in. Overly wide end gaps lead to l= eakage of compression, and that leads to lowered heat of compression as abov= e. >> =20 >> Effective compression ratio: >> =20 >> At idle and near idle, the amount of air allowed into the engine is minim= al. So the computer limits the injection pulse width accordingly.So the cyli= nder filling is minimal, and so heat of compression is minimal. >> =20 >> So, if the same amount of cylinder filling is used. The rotor with the hi= gher compression ratio will generate fewer misses and a smoother idle. Becau= se for a fixed cylinder filling number, the higher compression rotor produce= s the highest heat of compression.=20 >> =20 >> Higher heat of compression means better fuel vaporization and a more thor= ough burn. >> =20 >> A misfire is an event wherein a dose or part of a dose of mixture was not= lighted at or near the correct time during the cycle. >> A misfire that involves no burned mixture is a noticeable event, in that t= he engine will be out of balance for that cycle. The engine will wiggle in i= ts mount. A misfire that involves a trailing plug will not be noticed at or n= ear idle. A misfire that involves the leading plug can be noticed by the ver= y attentive. >> =20 >> A popping sound in the headers or exhaust in general with no engine wiggl= e is more likely a small air leak in the header, that allows oxygen to mix i= n the header with some as yet unburned fuel. The popping is this mixture ign= iting. Very likely to be experienced on long closed throttle descents. >> =20 >> A misfire at higher throttle settings and full power, will be very notice= able, as an unlighted charge between two lighted charges will produce quite a= n imbalance jerk in the engine, and the mixture from the misfire will light i= n the header right outside the engine. So you get a jerk and a loud change i= n engine tone. >> This does not damage the engine, but can damage the exhaust system and, o= r, ruin a muffler. As has been seen, a damaged muffler can stop an engine or= reduce it's power out put to useless levels. >> =20 >> Lynn E. Hanover >> =20 >> =20 >> >> -- >> Homepage: http://www.flyrotary.com/ >> Archive and UnSub: http://mail.lancaironline.net:81/lists/flyrotary/Lis= t.html --Apple-Mail-4B91455F-1633-4D70-8F5B-A2186D8F9995 Content-Type: text/html; charset=utf-8 Content-Transfer-Encoding: quoted-printable
Scott, are you saying the trailing spa= rk plug hole WAS opened up?  
Turbocharged or not, don't EVER= do that!  And don't let your engine builder do,that.
If the e= ngine could be improved simply with a bigger hole there, Mazda would have ce= rtainly done it.   

Yes, that could promo= te detonation.

Tracy

Sent from my iPa= d

On Jul 31, 2013, at 20:03, Scott Emery <shipchief@aol.com> wrote:

So my engine may have detonated simply because the= engine builder opened up the upper (trailing) spark plug holes to improve t= he redundant dual ignition idea of an aircraft engine?
As rpm and b= oost increased the compression of the intake charge? The fire could jump the= apex seal at the big hole and light the leading edge of the intake charge j= ust as the intake ports are closing?!

Sent from my iPhone
<= br>On Jul 30, 2013, at 11:16 AM, Lehano= ver@aol.com wrote:

In a message dated 7/30/2013 1:36:12 P.M. Eastern Daylight Time,=20 Lehanover@aol.com writes:
The rotary has three features that make for a poor idle=20 compared to a piston engine.
 
Heat of compression.
The ris= e in chamber temperature=20 caused by compressing the fuel/air mixture.
=
The rotary has poor heat of compression because of the large surface a= re=20 of the chamber, and much of the chamber surface is cooled. Low heat of=20 compression allows fuel droplets to condense on the chamber surfaces and t= he=20 engine sees this as a mixture that is too lean to light.
 
Compression leakage:
The rot= or face has many end=20 gaps through which it leaks compression.
=  
For exa= mple, on NA rotaries I=20 gap the side seal to corner seal at zero. So long as the combination of two s= ide=20 seals and the joining corner seal pop back up when depressed and released, t= hat=20 is sufficient. The zero gap will become a measurable gap shortly after break= in.=20 Overly wide end gaps lead to leakage of compression, and that leads to lower= ed=20 heat of compression as above.
 
Effective compression ratio:
 
At idle and near idle, the amount of air allowed into the engine is=20 minimal. So the computer limits the injection pulse width accordingly.So the= =20 cylinder filling is minimal, and so heat of compression is minimal.
 
So, if the same amount of cylinder filling is used. The rotor with the=20= higher compression ratio will generate fewer misses and a smoother idle. Bec= ause=20 for a fixed cylinder filling number, the higher compression rotor produ= ces=20 the highest heat of compression. 
 
Higher heat of compression means better fuel vaporization and a more=20= thorough burn.
 
A misfire is an event wherein a dose or part of a dose of mixture was n= ot=20 lighted at or near the correct time during the cycle.
A misfire that involves no burned mixture is a noticeable event, in tha= t=20 the engine will be out of balance for that cycle. The engine will wiggle in i= ts=20 mount. A misfire that involves a trailing plug will not be noticed at or nea= r=20 idle. A misfire that involves the leading plug can be noticed by the very=20= attentive.
 
A popping sound in the headers or exhaust in general with no engine wig= gle=20 is more likely a small air leak in the header, that allows oxygen to mix in t= he=20 header with some as yet unburned fuel. The popping is this mixture igniting.= =20 Very likely to be experienced on long closed throttle descents.
 
A misfire at higher throttle settings and full power, will be very=20 noticeable, as an unlighted charge between two lighted charges will produce=20= quite an imbalance jerk in the engine, and the mixture from the misfire= =20 will light in the header right outside the engine. So you get a jerk and a l= oud=20 change in engine tone.
This does not damage the engine, but can damage the exhaust system and,= =20 or, ruin a muffler. As has been seen, a damaged muffler can stop an eng= ine=20 or reduce it's power out put to useless levels.
 
Lynn E. Hanover
 <= /font>
 
&l= t;mime-attachment>
= --Apple-Mail-4B91455F-1633-4D70-8F5B-A2186D8F9995--