X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from exchange.carey.wa.edu.au ([118.82.44.212] verified) by logan.com (CommuniGate Pro SMTP 5.3.10) with ESMTPS id 4551755 for flyrotary@lancaironline.net; Tue, 02 Nov 2010 07:33:57 -0400 Received-SPF: none receiver=logan.com; client-ip=118.82.44.212; envelope-from=stevei@carey.asn.au Received: from exchange.carey.local ([10.10.0.5]) by exchange.carey.local ([10.10.0.5]) with mapi; Tue, 2 Nov 2010 19:33:10 +0800 From: To: Date: Tue, 2 Nov 2010 19:33:09 +0800 Subject: Re: [FlyRotary] Fw: LeMann's Induction system II Re: EM2 Numbers Thread-Topic: [FlyRotary] Fw: LeMann's Induction system II Re: EM2 Numbers Thread-Index: Act6gbl6Tkre47KjR2aJ+guczepOaA== Message-ID: References: In-Reply-To: Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: acceptlanguage: en-US Content-Type: multipart/alternative; boundary="_000_AB03BF5355FC478E889729A2BE087B90careyasnau_" MIME-Version: 1.0 --_000_AB03BF5355FC478E889729A2BE087B90careyasnau_ Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Hi Ed I realise that a total length was being sought. However, I was observing th= e change in length and how that effected the peak torque. So if you want to= lift the peak torque approx 1000RPM in the 5500 to 6500 band on a system s= imilar to the 26B intake tube dimensions, it seems that 2" would be about r= ight. Steve On 01/11/2010, at 11:15 PM, Ed Anderson wrote: From: Ed Anderson Sent: Monday, November 01, 2010 11:04 AM To: Rotary motors in aircraft Subject: LeMann's Induction system II Re: EM2 Numbers Hi Steve, Thanks for the graph, in reading up on the R26B LeMann engine (yes, I final= ly located the SAE paper on the web) - the length in the graph appears to = refer ONLY the change in length of telescoping portion of the variable indu= ction on the LeManns. You can see from the photo graphs that fully extende= d the total induction length is over twice the maximum 175mm of the telesco= ping length. Also this assertion is supported by this quote from the Mazda SAE paper on = the R26b engine The TIMS pipe can slide a maximum of 175 mm. The paper can be found at: http://www.rotaryeng.net/Mazda_R26B_US.pdf So if the telescoping portion can slide a maximum of 175mm then the total i= nduction system is clearly longer as can be seen in the sketch of the engin= e below. Therefore if making calculations its crucial to understand that this 175MM = appears to be ONLY the max length of the telescoping portion of the total = induction length and not the total length. Makes a big difference! In this photo you can see the telescoping section extended to its full leng= th. I have attached a larger scale drawing of the total induction system for th= ose who want to make their own determination of the intake length. If the = telescoping portion is fully extended then it appears that the rest of the = length is approx 1.75 the length of the telescoping section as best as I co= uld determine by relative scaling. Example Calculation I measured the diameter of the rotor housing (smallest dimension) and found= it to be 7 1/8". I then took a circle and made it the same diameter and t= hen used that from one end of the extended intake to the combustion chambe= r entrance and came up with 3.5 diameters or 3.5 * 7.125 =3D 24.9 inches o= r say 25inches. That figure does not appear unreasonable just looking at th= e relative length of the extended tube length in the photo. So if the telescoping section is fully extended at 6000 rpm then the total = induction length is approx 25 inches. if 25 inches then a pulse generated by the opening of the intake port trave= ling to the entrance of the intake and reflected back to the intake port (t= o aid in stuffing the combustion chamber) would need to travel twice that d= istance or 50 inches. 50 inches is 4.167 ft which traveling at the veloci= ty of sound at sea level of 1100 ft/sec would need 41.6/ 1100 =3D 0.00378 s= econds to make the round trip. Assuming the pulse is generated by the open= ing of the intake port which causes the trapped remant exhaust gas to burst= forth into the intake thereby generating a shockwave/pulse and you want it= to arrive back as the port is closing. Here are the PP port timings as found on Paul Yaws excellent web site on t= he rotary engine. Mazda Factory Peripheral Port IO 86=B0 BTDC IC 75=B0 ABDC EO 73=B0 BBDC EC 65=B0 ATDC This site is meant to give information Don't know if this is the port opening on the R26B engine but the only thin= g I could find. So 86 BTDC opening (pulse goes out) and 75 ABDC (Pulse arrives back), so to= tal rotation from opening to closing is 86 + 75 =3D 181 deg, now it will be= somewhat less than this as it takes some finite time for the pulse to be f= ully generated and you want it to arrive back probably 15-20 deg before the= port closes. But for the moment lets ignore those realities and see what we get. So 180 / 0.00378 =3D 47520 deg/sec of rotation speed required. 47520 /360 = =3D 132 revs/sec *60 =3D 7920 rpm which is a bit high. If we now adjust from some realities such as time it takes to generate the= pulse and having it arrive back before closing. Somewhere I found some da= ta in an engine book that indicates it would probably take around 5-10 % of= open time to generate the pulse peak. So taking 7.5 % opening time =3D 13= .75 deg, so taking 14 Deg that and lets say 15 % of total open period arriv= al before port closes. 0.20 * 181 =3D 27.2 deg before closing, we have 18= 1 - (14+27.2) =3D 139.9 deg total rotation travel time for the pulse to t= ransverse the intake. 140/0.00378 =3D 36960 deg/sec rotation speed required. 36960/360 =3D 103 = rev/sec * 60 sec =3D 6180 rpm - not too far from 6000 rpm. A few deg error= in assumption of the time it takes to generate the pulse and the time its = suppose to arrive back at the port could easily account for the difference. So if my estimates of the time it takes to generate the pulse and when the= pulse arrives back are off then naturally the calculation will be off as w= ell. My point is that Mark is correct - the length of the induction systems (and= exhaust system) has a significant effect - probably more so for the PP tha= n the normal ported 13B. At the other end of the telescopic length =3D 0 leaves approx 27 - 6.88 =3D= say 20 inches of total induction length. With the same assumptions for the pulse - we have travel time for 20 inche= s induction length =3D 40 inches for the round trip. 40/12 =3D 3.33 ft. 3= .33/1100 =3D 0.00303 travel time. 140/0.0303 =3D 46200 deg /sec rotation speed required. 45200/360 =3D 128.3= revs/sec * 60 sec =3D 7700 rpm. A bit low compared to the chart below - = that could be because the pulse generation time and the pulse closing targe= t may not change linearly with higher rpm. But again, my point is that length does matter (no matter what the lady sai= d {:>) Back to my cave Ed Edward L. Anderson Anderson Electronic Enterprises LLC 305 Reefton Road Weddington, NC 28104 http://www.andersonee.com http://www.eicommander.com From: stevei@carey.asn.au Sent: Monday, November 01, 2010 5:09 AM To: Rotary motors in aircraft Subject: [FlyRotary] Re: EM2 Numbers Hi Mark I have attached the Leman intake dimensions from Paul L. Hope this is helpful. Can't remember whether this measurement was to the ro= tor face or manifold face. Steve Izett Perth Western Australia ________________________________ The contents of this email are confidential and intended only for the named= recipients of this e-mail. If you have received this e-mail in error, you = are hereby notified that any use, reproduction, disclosure or distribution = or the information contained in this e-mail is prohibited. Please notify th= e sender immediately and then delete/destroy the e-mail and any printed cop= ies. All liability for viruses is excluded to the fullest extent of the law= . --_000_AB03BF5355FC478E889729A2BE087B90careyasnau_ Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Hi Ed

I= realise that a total length was being sought. However, I was observing the= change in length and how that effected the peak torque. So if you want to = lift the peak torque approx 1000RPM in the 5500 to 6500 band on a system si= milar to the 26B intake tube dimensions, it seems that 2" would be about ri= ght.

Steve

On 01/11/2010, = at 11:15 PM, Ed Anderson wrote:

 

Sent: Monday, November 01, 2010 11:04 AM
Subject: LeMann's Induction system II Re: EM2=20 Numbers

Hi Steve,
 
Thanks for the graph, in reading up on the R26B LeMann=20 engine (yes, I finally located the SAE paper on the web)  - the l= ength=20 in the graph appears to refer ONLY the change in length of telescop= ing=20 portion of the variable induction on the LeManns.  You can se= e=20 from the photo graphs that fully extended the total induction length is ove= r=20 twice the maximum 175mm of the telescoping length. 
 
Also this assertion is supported by this quote from the Mazda SAE pape= r on=20 the R26b engine
 

The TIMS pipe can slide a maximum of 175=20 mm. 

The paper can be found at:

http://www.rotaryeng.net/Mazda_R26B_US.pdf

So if the telescoping portion = can=20 slide a maximum of 175mm then the total induction system is clearly longer = as=20 can be seen in the sketch of the engine=20 below.
Therefore if making calculations its crucial to= understand that this=20 175MM  appears to be ONLY the max length of the telescoping porti= on of=20 the total induction length and not the total length.  Makes a big=20 difference!
 
 
<B4C1.jpg>
&l= t;B4D1.jpg>
 
 
In this photo you can see the telescoping secti= on extended to its=20 full length.
 
I=20 have attached a larger scale drawing of the total induction system for thos= e who=20 want to make their own determination of the intake length.  If th= e=20 telescoping portion is fully extended then it appears that the rest of the= =20 length is approx 1.75 the length of the telescoping section as best as I co= uld=20 determine by relative scaling. 
 
E= xample=20 Calculation
 
 
I=20 measured the diameter of the rotor housing (smallest dimension) and found i= t to=20 be 7 1/8".  I then took a circle and made it the same diameter and the= n=20 used that from one end of the extended  intake to the combustion=20 chamber entrance and came up with 3.5 diameters or 3.5 * 7.125 =3D&nbs= p; 24.9=20 inches or say 25inches. That figure does not appear unreasonable just looki= ng at=20 the relative length of the extended tube length in the=20 photo.
 
So if the telescoping section is fully extended= at 6000 rpm then the=20 total induction length is approx  25  inches. =20
 
if 25 inches then a pulse generated by the open= ing of the intake port=20 traveling to the entrance of the intake and reflected back to the intake po= rt=20 (to aid in stuffing the combustion chamber) would need to travel twice that= =20 distance or 50 inches.  50  inches is 4.167 ft which traveli= ng at=20 the velocity of sound at sea level of 1100 ft/sec would need 41.6/ 1100 =3D= =20 0.00378 seconds to make the round trip.  Assuming the pulse is generat= ed by=20 the opening of the intake port which causes the trapped remant exhaust gas = to=20 burst forth into the intake thereby generating a shockwave/pulse and you wa= nt it=20 to arrive back as the port is closing.
 
 Here=20 are the PP port timings as found on Paul Yaws excellent web site on the rot= ary=20 engine.=20

Mazda Factory Peripheral Port

IO 86=B0 BTDC
IC 75=B0 ABDC
= EO 73=B0 BBDC
EC 65=B0 ATDC

This site i= s meant to give information
Don't know if this is the port opening on the R= 26B engine but the=20 only thing I could find.
 
So 86 BTDC opening (pulse goes out) and 75 ABDC= (Pulse arrives back),=20 so total rotation from opening to closing is 86 + 75 =3D 181 deg, now it wi= ll be=20 somewhat less than this as it takes some finite time for the pulse to be fu= lly=20 generated and you want it to arrive back probably 15-20 deg before the port= =20 closes.
 
But for the moment lets ignore those realities and see what we get.
 
So 180 / 0.00378 =3D 47520 deg/sec of= rotation speed=20 required.  47520 /360 =3D 132 revs/sec *60 =3D 7920 rpm which is = a bit=20 high. 
 
 If we now adjust from some realities such= as time it takes to=20 generate the pulse and having it arrive back before closing.  Somewher= e I=20 found some data in an engine book that indicates it would probably take=20 around 5-10 % of open time to generate the pulse peak.  So taking= 7.5=20 % opening time =3D 13.75 deg, so taking 14 Deg that and lets say 15 % = of=20 total open period arrival before port closes.  0.20 * 1= 81 =3D=20 27.2 deg before closing,  we have 181 - (14+27.2)=20  =3D 139.9  deg total rotation travel time for the puls= e to=20 transverse the intake.
 
140/0.00378  =3D 3696= 0 deg/sec rotation speed=20 required.  36960/360 =3D 103 rev/sec * 60 sec =3D 6180 rpm - not too f= ar from=20 6000 rpm.  A few deg error in assumption of the time it takes to gener= ate=20 the pulse and the time its suppose to arrive back at the port could easily= =20 account for the difference.
 
So  if my estimates o= f the time it takes to generate the=20 pulse and when the pulse arrives back are off then naturally the calculatio= n=20 will be off as well.
 
My point is that Mark is correct - the length of = the=20 induction systems (and exhaust system) has a significant effect - probably = more=20 so for the PP than the normal ported 13B.
 
At the other end of the telescopic length =3D 0 l= eaves=20 approx 27 - 6.88 =3D say 20 inches of total induction length.
 
With the same assumptions for the pulse  - w= e have=20 travel time for 20 inches induction length =3D 40 inches for the round trip= . =20 40/12 =3D 3.33 ft.  3.33/1100 =3D 0.00303 travel time.
 
140/0.0303 =3D 46200 deg /sec rotation speed requ= ired. =20 45200/360 =3D 128.3 revs/sec * 60 sec =3D 7700 rpm.  A bit low compare= d to the=20 chart  below - that could be because the pulse generation time and the= =20 pulse closing target may not change linearly with higher rpm.
 
But again, my point is that length does m= atter (no=20 matter what the lady said {:>)
 
Back to my cave
 
Ed
 
Edwa= rd L.=20 Anderson
Anderson Electronic Enterprises LLC
305 Reefton=20 Road
Weddington, NC 28104
http://www.andersonee.com
http:= //www.eicommander.com

From: stevei@carey.asn.au
Sent: Monday, November 01, 2010 5:09 AM
Subject: [FlyRotary] Re: EM2 Numbers

Hi Mark=20

I have attached the Leman intake dimensions from Paul L.
Hope this is helpful. Can't remember whether this measurement was to t= he=20 rotor face or manifold face.

Steve Izett
Perth Western Australia 
<Lemans-torque-curves3.jpg>
  =20
The contents of this email a= re confidential=20 and intended only for the named recipients of this e-mail. If you have rece= ived=20 this e-mail in error, you are hereby notified that any use, reproduction,=20 disclosure or distribution or the information contained in this e-mail is=20 prohibited. Please notify the sender immediately and then delete/destroy th= e=20 e-mail and any printed copies. All liability for viruses is excluded to the= =20 fullest extent of the law.

= --_000_AB03BF5355FC478E889729A2BE087B90careyasnau_--