X-Virus-Scanned: clean according to Sophos on Logan.com X-PolluStop: No license found, only first 5 messages were scanned Return-Path: Received: from [216.211.128.10] (HELO mail-in03.adhost.com) by logan.com (CommuniGate Pro SMTP 4.3.6) with ESMTP id 1059676 for flyrotary@lancaironline.net; Mon, 18 Jul 2005 15:00:01 -0400 Received-SPF: none receiver=logan.com; client-ip=216.211.128.10; envelope-from=joeh@PilgrimTech.com Received: from pilgrim9 (tide40.microsoft.com [131.107.0.83]) by mail-in03.adhost.com (Postfix) with ESMTP id D9DA22A8592 for ; Mon, 18 Jul 2005 11:59:03 -0700 (PDT) (envelope-from joeh@PilgrimTech.com) Reply-To: From: "Joe Hull" To: "'Rotary motors in aircraft'" Subject: RE: [FlyRotary] Re: Startic Timing / TDC Date: Mon, 18 Jul 2005 11:59:09 -0700 Organization: Pilgrim Technologies MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0105_01C58B90.1C146FA0" X-Mailer: Microsoft Office Outlook, Build 11.0.6353 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.2180 In-Reply-To: Thread-Index: AcWK34ADJWARBHfCR/mLZ94xPiIYFQA6qzJA Message-Id: <20050718185903.D9DA22A8592@mail-in03.adhost.com> This is a multi-part message in MIME format. ------=_NextPart_000_0105_01C58B90.1C146FA0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit Thanx for everyone's (especially Lynn's) response on startup procedures and static timing! Unfortunately for the plane project I'm in the middle of moving between two homes. I got the plane project moved yesterday in the weeeeeeee hours of the morning (since the wing spar is almost 12ft wide and the legal street limit without permit and "guide car" is only 9ft). But the plane made it safe and sound. In another couple of weeks I'll try to start it again (I'm going to OSH next week too - wife's real happy 'bout that:-) ) Thanxagain! Joe Hull Bellevue (Seattle), Washington Cozy MkIV #991 (working on Engine & Electrical & Finishing) http://www.maddyhome.com/canardpages/pages/JoeHull/index.html _____ From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Lehanover@aol.com Sent: Sunday, July 17, 2005 7:54 AM To: Rotary motors in aircraft Subject: [FlyRotary] Re: Startic Timing / TDC In a message dated 7/17/2005 5:50:54 AM Pacific Daylight Time, finn.lassen@verizon.net writes: Hi Mark, I have read this a dozen times; I cannot make sense of it! What do I do after I count the teeth? And what tooth do I place the mark on? Once you have marked the two teeth, the TDC mark should be added half way between those two marked teeth. So, mark the two teeth that correspond to the apex seal in the center of the spark plug hole. Count the teeth between the two marked teeth. Divide that number by 2. For example, say there are 17 teeth between the marked teeth. Half way will be the full tooth 8 teeth from each of the marked teeth. If the number is even, say 16 teeth, half way will be the throat between two teeth. It does not matter. Just put a paint mark there in the throat. Make the TDC paint mark a different color from the first two marks. With the TDC mark under the pointer, at the flywheel or flexplate, sight along one of the water pump mounting studs and across the timing pointer on the front case to the pulley. Move your head back and forth so that when looking past the correct stud (like sighting a rifle) half of the pulley will appear on each side of the pointer on the front case. Make a paint mark on the pulley. ( I file a groove in the pulley flange and fill it with paint ). That takes care of the TDC mark. Now the good part. Count the total number of teeth on the flywheel/flexplate. For example, let us say that there are 110 teeth. Divide 360 (degrees in a circle) by 110 teeth to get 3.27 degrees per tooth. So, now determine what total advance you want to use. Tracy has the most time on a 13B in aircraft so check his site for the number. In a racing, 12A NA engine 20 degrees is fine up to 9,000 RPM. In a racing 13B NA engine 25 degrees is plenty up to 9,000 RPM is plenty. These numbers may sound conservative, but the rotor (piston) is moving at 1/3 crank speed, so there is ample time to get a full burn and develop the highest cylinder pressure at the ideal crank angle, which is the whole idea behind correct ignition timing. For example, let us say that you want 25 degrees of total advance. Divide 360 degrees by 3.27 to get 7.64 teeth. Count off 7.64 teeth from your TDC mark on the flexplate/flywheel, in the direction of rotation. You may have to turn the engine backwards slightly (top of the flywheel moving toward the intake side) to get to this tooth. In this case, the total advance mark with nearly be identical to one of your first apex seal marks. (8 teeth). Your actual tooth count may be different. Make that tooth red and white to stand out as your total advance mark. Leave this mark in front of the pointer. Go back to the front pulley. Sight along the pointer/ mounting stud combination and again mark the pulley with the full advance mark. Using the same color as on the flywheel full advance mark would be good clear thinking. Timing from the flywheel end marks will be a bit more accurate. Timing from the pulley marks will be further from the prop. In the event you want more distance there. Lynn E. Hanover ------=_NextPart_000_0105_01C58B90.1C146FA0 Content-Type: text/html; charset="US-ASCII" Content-Transfer-Encoding: quoted-printable

Thanx for everyone’s (especially Lynn’s) response on = startup procedures and static timing!

 

Unfortunately for the plane project = I’m in the middle of moving between two homes. I got the plane project moved yesterday in the weeeeeeee hours of the = morning (since the wing spar is almost 12ft wide and the legal street limit = without permit and “guide car” is only 9ft).  But the plane made it safe and = sound. In another couple of weeks I’ll try to start it again (I’m = going to OSH next week too – wife’s real happy ‘bout = that<= span style=3D'mso-char-type:symbol;mso-symbol-font-family:Wingdings'>J<= /span> )

 

Thanxagain= !

Joe = Hull

Bellevue = (Seattle), Washington

Cozy MkIV #991 = (working on Engine & Electrical & Finishing)

http://www.maddyhome.com/canardpages/pages/JoeHull/index.html

 

From: = Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Lehanover@aol.com
Sent: Sunday, July 17, = 2005 7:54 AM
To: Rotary motors in = aircraft
Subject: [FlyRotary] Re: = Startic Timing / TDC

 

In a message dated 7/17/2005 = 5:50:54 AM Pacific Daylight Time, finn.lassen@verizon.net = writes:

Hi Mark,
I have read this a dozen times; I cannot make sense of it!
What do I do after I count the teeth? And what tooth do I place the mark = on?

 

=

 

=

 

=

 

=


 

Once you have marked the two = teeth, the TDC mark should be added half way between those two marked teeth. =

 

=

So, mark the two teeth that = correspond to the apex seal in the center of the spark plug hole. Count the teeth = between the two marked teeth. Divide that number by 2.

 

=

For example, say there are 17 = teeth between the marked teeth.

 

=

Half way will be the full = tooth 8 teeth from each of the marked teeth. 

 

=

If the number is even, say 16 = teeth, half way will be the throat between two teeth. =

 

=

It does not = matter.

 

=

Just put a paint mark there in the throat.

 

=

Make the TDC paint mark a = different color from the first two marks.

 

=

With the TDC mark under the = pointer, at the flywheel or flexplate, sight along one of the water pump mounting = studs and across the timing pointer on the front case to the pulley. =

 

=

Move your head back and forth so = that when looking past the correct stud (like sighting a rifle) half of the = pulley will appear on each side of the pointer on the front case. =

 

=

Make a paint mark on the pulley. ( = I file a groove in the pulley flange and fill it with paint = ).

 

=

That takes care of the TDC = mark.

 

=

Now the good = part.

 

=

Count the total number of teeth on = the flywheel/flexplate.

 

=

For example, let us say that there = are 110 teeth.

 

=

Divide 360 (degrees in a circle) = by 110 teeth to get 3.27 degrees per tooth.

 

=

So, now determine what total = advance you want to use.

 

=

Tracy has the most time on a 13B = in aircraft so check his site for the number.

 

=

In a racing, 12A NA engine 20 = degrees is fine up to 9,000 RPM. In a racing 13B NA engine 25 degrees is = plenty up to 9,000 RPM is plenty.

 

=

These numbers may sound = conservative, but the rotor (piston) is moving at 1/3 crank speed, so there is ample time = to get a full burn and develop the highest cylinder pressure at the ideal = crank angle, which is the whole idea behind correct = ignition timing. 

 

=

For example, let us say that you = want 25 degrees of total advance.

 

=

Divide 360 degrees by 3.27 to get = 7.64 teeth.

 

=

Count off 7.64 teeth from your TDC = mark on the flexplate/flywheel, in the direction of rotation. =

 

=

You may have to turn the engine = backwards slightly (top of the flywheel moving toward the intake side) to get to = this tooth.

 

=

In this case, the total advance = mark with nearly be identical to one of your first apex seal marks. (8 teeth). = Your actual tooth count may be different.

 

=

Make that tooth red and white to = stand out as your total advance mark. Leave this mark in front of the = pointer.

 

=

Go back to the front pulley. Sight = along the pointer/ mounting stud combination and again mark the pulley with = the full advance mark. Using the same color as on the flywheel full advance mark = would be good clear thinking. 

 

=

Timing from the flywheel end marks = will be a bit more accurate. Timing from the pulley marks will be further = from the prop. In the event you want more distance = there.

 

=

 

=

Lynn E. = Hanover 

 

=

 

=

 

=

 

=

 

=

 

=

 

=

 

=

 

=
------=_NextPart_000_0105_01C58B90.1C146FA0--