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From: Lehanover@aol.com
Message-ID: <760f4.507cf660.3a80514f@aol.com>
Date: Sun, 6 Feb 2011 14:32:31 EST
Subject: Re: [FlyRotary] Re: EGT Values and recovery.
To: flyrotary@lancaironline.net
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In a message dated 2/6/2011 10:27:50 A.M. Eastern Standard Time,  
keltro@att.net writes:

Lynn,
      Do I understand this  correctly.................You are saying that 
for maximum efficiency that we  need to fly
with full throttle at both climb and cruise and control "EGT"  with mixture 
control (and /or ECU map settings)
.............Slightly richer than best power for climb (to reduce EGT to  
less than 1650 F) then lean quickly 
(to lean stumble) then slightly richer.............The bottom line that  
being that trying to control "EGT" with the 
throttle will not help efficiency since it increases pumping losses  and 
only slightly reduces "EGT"..............

Kelly Troyer
"DYKE DELTA JD2" (Eventually) 
"13B ROTARY"_ Engine


Pulling off throttle is a good way to reduce total engine heat as in when  
you have an oil cooling problem and EGTs. 
 
From a climb setting at 1600 on the EGT you are fuel cooling the engine  to 
good extent. This is a costly way to cool any engine. But no damage will  
occur, and power will be good. So instead of fuel cooling.........
the over-lean mixture cools by removing BTUs. Smaller fire. Less  heat. 
Better more thorough burn due to excess oxygen. Lower oil temps.  And so-on. 
 
The rotor face is close to or in front of the spark plugs  longer than  a 
piston engine. More dwell. So less advance is needed, and there is more time  
for the over-lean mixture to burn. Thus more efficient than a piston 
engine? Not  quite but very close. Add a monster ignition system and lean even 
further.
 
That 1600 degrees is several hundred degrees from best power. That leaning  
to lean of peak EGT must be done very quickly. As you turn the leaning knob 
or  pull on the cable, you will pass right through the very point we are 
trying to  avoid, best power and peak EGT. Or, pull of just a bit of throttle, 
then go lean  and put the throttle back up. One must not diddle at or near 
peak EGT. Or,  tune "B" for lean of peak and just flip the switch. 
 
This is not some new idea. If your piston engine has enough compression to  
run lean of peak, it should be run so in cruise all of the time. All big 
radials  use fuel as fast as you can pour it out of a bucket. Were it not for 
lean of  peak operation they had very limited range, and poor payloads.
 
In the Fiat we never ran full throttle. I found on the dyno that more power 
 was available just short of full throttle. My guess was that the 
butterflies at  slightly less than straight up and down, helped turn the mixture a 
bit. An extra  3 HP every time.
 
Airplanes are dynamometers. 
Take advantage. Make one change at a time. Record everything. Use SAE  
tables to correct to sea level HP. 
 
Lynn E. Hanover

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<DIV>
<DIV>In a message dated 2/6/2011 10:27:50 A.M. Eastern Standard Time,=20
keltro@att.net writes:</DIV>
<BLOCKQUOTE  style=3D"BORDER-LEFT: blue 2px solid; PADDING-LEFT: 5px; MARG=
IN-LEFT: 5px"><FONT    style=3D"BACKGROUND-COLOR: transparent" color=3D#00=
0000 size=3D2 face=3DArial>
  <DIV>Lynn,</DIV>
  <DIV>&nbsp;&nbsp;&nbsp;&nbsp; &nbsp;Do I understand this=20
  correctly.................You are saying that for maximum efficiency tha=
t we=20
  need to fly</DIV>
  <DIV>with full throttle at&nbsp;both climb and cruise and control&nbsp;"=
EGT"=20
  with mixture control (and /or ECU map settings)</DIV>
  <DIV>.............Slightly richer than best power for climb (to reduce=
 EGT to=20
  less than 1650 F) then lean quickly </DIV>
  <DIV>(to lean stumble) then slightly richer.............The bottom line=
 that=20
  being that trying to control "EGT" with the </DIV>
  <DIV>throttle will not help efficiency since it&nbsp;increases pumping=
 losses=20
  and only slightly reduces "EGT"..............<BR>&nbsp;</DIV>
  <P>Kelly Troyer<BR><STRONG><FONT size=3D4>"DYKE DELTA JD2"</FONT> <FONT=
    size=3D1>(Eventually)</FONT></STRONG></P>
  <P>"13B ROTARY"_ Engine<BR></P></FONT></BLOCKQUOTE></DIV>
<DIV></DIV>
<DIV>Pulling off throttle is a good way to reduce total engine heat as in=
 when=20
you have an oil cooling problem and EGTs.&nbsp;</DIV>
<DIV>&nbsp;</DIV>
<DIV>From a climb setting at 1600 on the EGT you are fuel cooling the engi=
ne=20
to&nbsp;good extent. This is a costly way to cool any engine. But no damag=
e will=20
occur, and power will be good. So instead of fuel cooling.........</DIV>
<DIV>the over-lean mixture&nbsp;cools by removing&nbsp;BTUs. Smaller fire.=
 Less=20
heat. Better&nbsp;more thorough burn due to excess oxygen.&nbsp;Lower oil=
 temps.=20
And so-on. </DIV>
<DIV>&nbsp;</DIV>
<DIV>The rotor face is close to or in front of the spark plugs&nbsp; longe=
r than=20
a piston engine. More dwell. So less advance is needed, and there is more=
 time=20
for the over-lean mixture to burn. Thus more efficient than a piston engin=
e? Not=20
quite but very close. Add a monster ignition system and lean even further.=
</DIV>
<DIV>&nbsp;</DIV>
<DIV>That 1600 degrees is several hundred degrees from best power. That le=
aning=20
to lean of peak EGT must be done very quickly. As you turn the leaning kno=
b or=20
pull on the cable, you will pass right through the very point we are tryin=
g to=20
avoid, best power and peak EGT. Or, pull of just a bit of throttle, then=
 go lean=20
and put the throttle back up. One must not&nbsp;diddle at or near peak EGT=
. Or,=20
tune "B" for lean of peak and just flip the switch. </DIV>
<DIV>&nbsp;</DIV>
<DIV>This is not some new idea. If your piston engine has enough compressi=
on to=20
run lean of peak, it should be run so in cruise all of the time. All big=
 radials=20
use fuel as fast as you can pour it out of a bucket. Were it not for lean=
 of=20
peak operation they had very limited range, and poor payloads.</DIV>
<DIV>&nbsp;</DIV>
<DIV>In the Fiat we never ran full throttle. I found on the dyno that more=
 power=20
was available just short of full throttle. My guess was that the butterfli=
es at=20
slightly less than straight up and down, helped turn the mixture a bit. An=
 extra=20
3 HP every time.</DIV>
<DIV>&nbsp;</DIV>
<DIV>Airplanes are dynamometers. </DIV>
<DIV>Take advantage. Make one change at a time. Record everything. Use SAE=
=20
tables to correct to sea level HP. </DIV>
<DIV>&nbsp;</DIV>
<DIV>Lynn E. Hanover</DIV></FONT></BODY></HTML>

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