From: "Dennis Havarlah" To: "samuelhodges" References: <750508.57015.qm@web180316.mail.gq1.yahoo.com> In-Reply-To: <750508.57015.qm@web180316.mail.gq1.yahoo.com> Subject: Re: Intake Date: Fri, 23 Jul 2010 23:16:40 -0500 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0033_01CB2ABD.1D3773B0" X-Priority: 3 X-MSMail-Priority: Normal X-Unsent: 1 X-MimeOLE: Produced By Microsoft MimeOLE V6.0.6002.18197 This is a multi-part message in MIME format. ------=_NextPart_000_0033_01CB2ABD.1D3773B0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Sam,=20 Things are a bit busy here - 2 funerals, and now out-of-state company = coupled with next week's vacation. =20 I believe Tracy's design works because his bells are within 3/4 inch of = the plenum box wall. I believe he is getting a reflected compression = wave off the wall that reenters the intake pipe it came out of. I have = not done the math but I believe the total intake lenght from rotor face = to wall and back should be the same as the length sound would travel = during the time period starting when the rotor closes the intake port = and ending when the next intake cycle is about 3/4 closed. An example would be as follows: Shaft rpm =3D 6300 rpm Rotor rpm =3D 2100 rpm, 360 deg/rev X 2100 =3D 756000deg/minute.or = 75600/60 =3D 12600 deg/sec. The rotor turnes 1/3 of a rotation going from intake closed to next = intake closed. ( on the same rotor). 1/3 X360 =3D 120 deg of rotation. 120 deg/12600deg/sec =3D 0.0095238sec. But I want the reflected wave to get there about 3/4 thurough the intake = cycle. We need to back up the intake angel 1/4 of the total time the = intake is open. I don't have the intake degrees here but assume it is 60 deg.=20 1/4 X 60 deg =3D 15 deg. =20 120 deg - 15 deg =3D 105 deg of rotation for the wave to leave the rotor = face, go through the tube, bounce off the far wall and return to the = rotor arriving when the intake is 3/4 through the intake cycle. Using 105 deg/12600deg/sec =3D 0.00833 sec. Using 1100 fps as the speed of sound - 1100fps X 12 in/ft =3D 13200 = in/sec. The total intake length would be 13200 X .00833 / 2 =3D 55 inches. If you use the 3 rd. bounce of the compression wave off the plenum wall = the intake would need to be 1/3 X 54 or 13.74 inches long.(most of the = car engines that used tuned intakes used the 3 rd. bounce from what I've = read) If the speed of sound is 1100 f/sec. ----- Original Message -----=20 From: samuelhodges=20 To: Dennis Haverlah=20 Sent: Tuesday, July 20, 2010 11:03 AM Subject: Intake I have been up in Michigan for awhile on vacation and the sad = thing is I had to drive. Last weekend I spent hours staring at the plane = and taking measurements trying to figure out how to duplicate Tracy's = Intake design and how to fit it in our cowling. Tracy mentioned that he = has a total runner length of 11.25 including what's in the block. Block = length is close to 3", am I reading this correctly? What is driving this = design is the lack of space in the forward most intake port. To reach = the length of 11.25 we're looking at 8.25" of tubing from the block. I = have tried various radius tubing only to find out that it will hit the = cowling somewhere in the design. If I end up with a straight tube design = I can fit a 7.5" tube and leave enough room for a .75 distance between = the bell mouth and plenum box. This will leave a total of .75" to 1" = short of 11.25", what effect it will have? I don't know. Had you had a = chance to verify Tracy's design yet? I plan on machining the intake = plate this weekend and fitting the tubing. I appreciate you trying to = reach me but it seems we can never get in touch with one another, I'll = try to call you later to see what you have come up with, take care. Sam=20 ------=_NextPart_000_0033_01CB2ABD.1D3773B0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Sam,
 
Things are a bit busy here - 2 = funerals, and now=20 out-of-state company coupled with next week's vacation.  =
 
I believe Tracy's design works because = his bells=20 are within 3/4 inch of the plenum box wall.  I believe he is = getting a=20 reflected compression wave off the wall = that reenters=20 the intake pipe it came out of.  I have not done the math but I = believe the=20 total intake lenght from rotor face to wall and = back=20 should be the same as the length sound would travel during the time = period=20 starting when the rotor closes the intake port and ending when the next = intake=20 cycle is about 3/4 closed.
 
An example would be  as follows:
 
Shaft rpm =3D 6300 rpm
Rotor rpm =3D 2100 rpm,  360 = deg/rev X 2100 =3D=20 756000deg/minute.or 75600/60 =3D 12600 deg/sec.
The rotor turnes 1/3 of a rotation = going from=20 intake closed to next intake closed. ( on the same rotor).
1/3 X360 =3D 120 deg of = rotation.
 
120 deg/12600deg/sec =3D = 0.0095238sec.
But I want the reflected wave to get = there about=20 3/4 thurough the intake cycle.  We need to back up the intake angel = 1/4 of=20 the total time the intake is open.
I don't have the intake degrees here = but assume it=20 is 60 deg.
 
1/4 X 60 deg =3D 15 deg.  =
120 deg - 15 deg =3D 105 deg of = rotation for the wave=20 to leave the rotor face, go through the tube, bounce off the far wall = and return=20 to the rotor arriving when the intake is 3/4 through the = intake=20 cycle.
 
Using 105 deg/12600deg/sec =3D 0.00833=20 sec.
 
Using 1100 fps as the speed of sound = - =20 1100fps X 12 in/ft =3D 13200 in/sec.
The total intake length would be 13200 = X=20 .00833 / 2 =3D 55 inches.
 
If you use the 3 rd. bounce of the = compression wave=20 off the plenum wall the intake would need to be 1/3 X 54 or 13.74 = inches=20 long.(most of the car engines that used tuned intakes used the 3 rd. = bounce from=20 what I've read)
 
 
If the speed of sound is 1100 = f/sec.
 
 
 
----- Original Message -----
From:=20 samuelhodges
To: Dennis Haverlah
Sent: Tuesday, July 20, 2010 = 11:03=20 AM
Subject: Intake

I have been up in Michigan for awhile on vacation and the = sad thing=20 is I had to drive. Last weekend I spent hours staring at the = plane and=20 taking measurements trying to figure out how to = duplicate Tracy's=20 Intake design and how to fit it in our cowling. Tracy mentioned = that he=20 has a total runner length of 11.25 including what's in the = block. Block=20 length is close to 3", am I reading this correctly? What is = driving this=20 design is the lack of space in the forward most intake port. To = reach=20 the length of 11.25 we're looking at 8.25" of tubing from the = block. I=20 have tried various radius tubing only to find out = that it=20 will hit the cowling somewhere in the design. If I end up with a = straight tube design I can fit a 7.5" tube and leave enough room = for a=20 .75 distance between the bell mouth and plenum box. This will = leave a=20 total of .75" to 1" short of 11.25", what effect it will have? I = don't=20 know. Had you had a chance to verify Tracy's design yet? I = plan on=20 machining the intake plate this weekend and fitting the tubing. = I=20 appreciate you trying to reach me but it seems we can never get = in touch=20 with one another, I'll try to call you later to see what you = have come=20 up with, take care.
 
=
Sam
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