X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Tue, 10 Jan 2006 00:20:30 -0500 Message-ID: X-Original-Return-Path: Received: from imo-m25.mx.aol.com ([64.12.137.6] verified) by logan.com (CommuniGate Pro SMTP 5.0.6) with ESMTP id 918767 for lml@lancaironline.net; Mon, 09 Jan 2006 12:41:16 -0500 Received-SPF: pass receiver=logan.com; client-ip=64.12.137.6; envelope-from=Sky2high@aol.com Received: from Sky2high@aol.com by imo-m25.mx.aol.com (mail_out_v38_r6.3.) id q.19a.4393c264 (58550) for ; Mon, 9 Jan 2006 12:40:28 -0500 (EST) From: Sky2high@aol.com X-Original-Message-ID: <19a.4393c264.30f3fa0c@aol.com> X-Original-Date: Mon, 9 Jan 2006 12:40:28 EST Subject: Re: [LML] Re: Idle power descent? X-Original-To: lml@lancaironline.net MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="-----------------------------1136828428" X-Mailer: 9.0 Security Edition for Windows sub 5300 X-Spam-Flag: NO -------------------------------1136828428 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit George, et al, Finally, on Sunday I was able fly after some unexpected maintenance on my nose gear. Because of time limitations and other conflicts, I was able to only do a short run although simulating the altitudes used by the pilot with the "failed" engine. In preparation for the test, I obtained a digital tape-less voice activated recorder and plugged it into the intercom headphone output - Voila! A cockpit voice recorder. I don't have to write anymore, just talk to myself - something I am used to doing. Remember my engine is an I/O 320 with a 9:1 CR and a ram air recovery system. I climbed to 8500 MSL and leveled out (7C OAT, 29.44 Hg Baro) operating at WOT, 22" MAP, 2500 RPM. Cyl #1 leaned to peak @1390 EGT and 7.6 GPH. Adjusting the mixture LOP to 1370 EGT and 7.4 GPH, The cruise looked like this: 167 KIAS, 193 KTAS, 22.6" MAP, 2490 RPM and 27 DBTDC with a temp spread: CHT EGT 1 350 1370 2 360 1400 3 360 1400 4 370 1400 From here on out only Cyl #1 is monitored with the RPM at 2500. The throttle was closed to 17" MAP and a spiral descent was begun near an airport at a rate of 1500 to 1000 FPM (timing to 32 DBTDC). At 5500 MSL and 188 KIAS, 18.5" MAP, 290 CHT, 1280 EGT, 4.9 GPH and 31 DBTDC. Throttle to 17" MAP At 4000 MSL and 196 KIAS, 17.5" MAP, 280 CHT, 1290 EGT, 5.0 GPH, and 31 DBTDC. Throttle later moved to 17" MAP. At 3000 MSL and 185 KIAS 17" MAP, 270 CHT, 1310 EGT, 5.2 GPH. At 2000 MSL, slowed to 150 KIAS, 17"MAP, 270 CHT, 1340 EGT, 4.7 GPH, Oil Temp 155F. Then, throttle moved to 27" MAP. At 2000 MSL, Aircraft speeding up, 27" MAP, CHT?, 1370 EGT, 8.3 GPH, 25 DBTDC. The throttle was moved back to 25" MAP and the mixture adjusted to 10.4 GPH, about 182 KIAS, CHT 350-360, EGT 1300-1310. There was no stumbling or engine difficulty indicated at all when the power was applied. This still leaves us with the question of "Why did that fellow's engine stop running?" I will repeat this test several times including ROP. I must, because most of my flying is done ROP and I could probably descend differently than I do now. Currently, I reduce power by MAP reduction rather than RPM reduction because I get vibration below 2300 RPM. This power regime is probably not good for the engine. I continue to reduce MAP because the power increase (natural MAP increase from higher speed and descent) changes the speed and pitch too much. I tweak up the mixture to stop the EGTs from climbing. At low power, this may not be necessary. Just remember the usual rule for increasing power is to work the knobs from right to left - Increase mixture, prop and throttle in that order. Anyway, I waited 'til after testing to re-read Deakin's 2003 AVWEB article (.....Part 4 -- Descent). Below is the summary from that article followed by the URL. Summary Use full power on all takeoffs, with a "rich enough" mixture. FORCE your mechanic to set that fuel flow high enough to get roughly 1300 degrees EGT or a bit less, and CHTs in the low to middle 300s. If you have that full-power mixture set properly, determine your "target" EGT right after takeoff, and lean in the climb to keep that same absolute value on the digital EGT. As you climb, that EGT will drop a little. Lean until it comes back up. Drops a little, lean and bring it back up. For cruise, first determine your range needs, and set a power setting to maintain the AIRSPEED that will do the job you want. Set WOT, then the RPM and mixture you need to maintain that. LOP is much better, if it will do the job, but use ROP if needed. Cruise outside the red box, or at worst, on the fringes of it. For descent, use mixture control and RPM to get the desired descent, switching to slightly rich of peak EGT, if you wish to keep the CHTs up. (Remember, 50 ROP on the EGT may be the same absolute value of EGT as 50 LOP, but the CHT will be much hotter when 50 ROP!) ......... _http://www.avweb.com/cgi-bin/udt/im.display.printable?client.id=avweb&story.i d=183094_ (http://www.avweb.com/cgi-bin/udt/im.display.printable?client.id=avweb&story.id=183094) It would be wise to read all four. OK, give me a break.. I'm working on it. Some day I'll get it all together. At least I climb in the manner he indicates. Scott Krueger AKA Grayhawk Lancair N92EX IO320 SB 89/96 Aurora, IL (KARR) -------------------------------1136828428 Content-Type: text/html; charset="US-ASCII" Content-Transfer-Encoding: quoted-printable
 
George, et al,
 
Finally, on Sunday I was able fly after some unexpected maintenance on=20= my=20 nose gear.  Because of time limitations and other conflicts, I was able= to=20 only do a short run although simulating the altitudes used by the pilot with= the=20 "failed" engine.  In preparation for the test, I obtained a digital=20 tape-less voice activated recorder and plugged it into the intercom headphon= e=20 output - Voila!  A cockpit voice recorder. I don't have to wr= ite=20 anymore, just talk to myself - something I am used to doing.
 
Remember my engine is an I/O 320 with a 9:1 CR and a ram air recovery=20 system.  I climbed to 8500 MSL and leveled out (7C OAT, 29.44 Hg Baro)=20 operating at WOT, 22" MAP, 2500 RPM.  Cyl #1 leaned to peak @1390=20= EGT=20 and 7.6 GPH.  Adjusting the mixture LOP to 1370 EGT and 7.4 GPH, T= he=20 cruise looked like this:
 
167 KIAS, 193 KTAS, 22.6" MAP, 2490 RPM and 27 DBTDC with a temp=20 spread:
 
  CHT  EGT
1 350  1370
2 360  1400
3 360  1400
4 370  1400
 
From here on out only Cyl #1 is monitored with the RPM at 2500.  T= he=20 throttle was closed to 17" MAP and a spiral descent was begun near an airpor= t at=20 a rate of 1500 to 1000 FPM (timing  to 32 DBTDC). 
 
At 5500 MSL and 188 KIAS, 18.5" MAP, 290 CHT, 1280 EGT, 4.9 GPH an= d 31=20 DBTDC.  Throttle to 17" MAP
 
At 4000 MSL and 196 KIAS, 17.5" MAP, 280 CHT, 1290 EGT, 5.0 GPH, a= nd=20 31 DBTDC.  Throttle later moved to 17" MAP.
 
At 3000 MSL and 185 KIAS 17" MAP, 270 CHT, 1310 EGT, 5.2 GPH.
 
At 2000 MSL, slowed to 150 KIAS, 17"MAP, 270 CHT, 1340 EGT, 4.7 GPH, Oi= l=20 Temp 155F.  Then, throttle moved to 27" MAP.
 
At 2000 MSL, Aircraft speeding up, 27" MAP, CHT?, 1370 EGT, 8.3 GPH, 25= =20 DBTDC.
 
The throttle was moved back to 25" MAP and the mixture adjusted to 10.4= =20 GPH, about 182 KIAS, CHT 350-360, EGT 1300-1310.
 
There was no stumbling or engine difficulty indicated at all when the p= ower=20 was applied. 
 
This still leaves us with the question of "Why did that fellow's=20 engine stop running?"
 
I will repeat this test several times including ROP.  I must, beca= use=20 most of my flying is done ROP and I could probably descend differently than=20= I do=20 now.  Currently, I reduce power  by MAP reduction rather than RPM=20 reduction because I get vibration below 2300 RPM.  This power=20 regime is probably not good for the engine.  I continue to reduce=20= MAP=20 because the power increase (natural MAP increase from higher speed and desce= nt)=20 changes the speed and pitch too much.  I tweak up the mixture to=20 stop the EGTs from climbing.  At low power, this may not be=20 necessary.  Just remember the usual rule for increasing power is to wor= k=20 the knobs from right to left - Increase mixture, prop and throttle in that=20 order.
 
Anyway, I waited 'til after testing to re-read Deakin's 2003 AVWEB= =20 article (.....Part 4 -- Descent).  Below is the summary from that artic= le=20 followed by the URL.
 

Summary

Use full power on all takeoffs, with a "rich enough" mixture. FORCE your=20 mechanic to set that fuel flow high enough to get roughly 1300 degrees EGT o= r a=20 bit less, and CHTs in the low to middle 300s.

If you have that full-power mixture set properly, determine your "target"= EGT=20 right after takeoff, and lean in the climb to keep that same absolute value=20= on=20 the digital EGT. As you climb, that EGT will drop a little. Lean until it co= mes=20 back up. Drops a little, lean and bring it back up.

For cruise, first determine your range needs, and set a power setting to=20 maintain the AIRSPEED that will do the job you want. Set WOT, then the RPM a= nd=20 mixture you need to maintain that. LOP is much better, if it will do the job= ,=20 but use ROP if needed. Cruise outside the red box, or at worst, on the fring= es=20 of it.

For descent, use mixture control and RPM to get the desired descent,=20 switching to slightly rich of peak EGT, if you wish to keep the CHTs up.=20 (Remember, 50 ROP on the EGT may be the same absolute value of EGT as 50 LOP= ,=20 but the CHT will be much hotter when 50 ROP!) .........

 
http://www.avweb.com/cgi-bin/udt/im.display.print= able?client.id=3Davweb&story.id=3D183094
 
It would be wise to read all four. 
 
OK, give me a break..  I'm working on it.  Some day I'll get=20= it=20 all together.  At least I climb in the manner he indicates.=20
 
Scott Krueger=20 AKA Grayhawk
Lancair N92EX IO320 SB 89/96
Aurora, IL=20 (KARR)
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