---------------------------------------------------------- Stratus-List Digest Archive --- Total Messages Posted Fri 02/24/06: 4 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 07:08 AM - Re: Bings and EGTs (LarryMcFarland) 2. 08:36 AM - Re: Bings and EGTs (Don Walker) 3. 09:35 AM - Re: Bings and EGTs (Gary K) 4. 09:42 AM - Re: Bings and EGTs (LarryMcFarland) ________________________________ Message 1 _____________________________________ Time: 07:08:00 AM PST US From: LarryMcFarland Subject: Re: Stratus-List: Bings and EGTs --> Stratus-List message posted by: LarryMcFarland Don, I guess the cowl air flow would be reduced on descent and that might allow more heat to accrue at the sensor. I was thinking the altitude compensation built into the carbs was getting behind on enrichment. It could be either for the sake of only 50-60 degrees. Larry do not archive Don Walker wrote: >--> Stratus-List message posted by: "Don Walker" > >In that case your apparent wind may have something to do with it, which affects cowl pressure and air flow. do you suppose you are maintaining a constant cowl pressure though the descent? > > Don Walker wrote: > > No Don, > I reduce throttle to lose altitude, do tip the nose down a bit, but > found the reduction a little short of what was needed > to keep EGTs from climbing. > Maybe the difference of a 50 degree rise is just delayed cooling or heat > not flowing as fast out the pipes at a slight > reduction of rpm on a descent approach. > > Larry > do not archive > > >Larry, > > It seems that if you put your nose down to descend from an established cruise without pulling back, then your rpm has to increase...more heat? don > > > > > Nice for a good cross-country cruise, but as I > > descended to land, EGTs climbed back up to set limits on my EIS and the > > rpms had to be reduced to keep the EGTs at or below limits. Not > > something I'm worried about, but it seemed strange to see EGTs behind > > the curve while descending. > > > Larry McFarland - 601HDS at 85 hours and still testing. > > > > ________________________________ Message 2 _____________________________________ Time: 08:36:53 AM PST US From: "Don Walker" Subject: Re: Stratus-List: Bings and EGTs --> Stratus-List message posted by: "Don Walker" I dunno, just brainstorming with you. Looks like increased speed would increase cowl pressure to affect the mixture...and vice versa. Rate of descent may have something to do with it, too. I assume you are letting down at three to five hundred fpm? I am glad you are noting these things, Larry, Helps us all. don ----- Original Message ----- From: LarryMcFarland To: stratus-list@matronics.com Sent: Friday, February 24, 2006 9:07 AM Subject: Re: Stratus-List: Bings and EGTs --> Stratus-List message posted by: LarryMcFarland > Don, I guess the cowl air flow would be reduced on descent and that might allow more heat to accrue at the sensor. I was thinking the altitude compensation built into the carbs was getting behind on enrichment. It could be either for the sake of only 50-60 degrees. Larry do not archive Don Walker wrote: >--> Stratus-List message posted by: "Don Walker" > > >In that case your apparent wind may have something to do with it, which affects cowl pressure and air flow. do you suppose you are maintaining a constant cowl pressure though the descent? > > Don Walker wrote: > > No Don, > I reduce throttle to lose altitude, do tip the nose down a bit, but > found the reduction a little short of what was needed > to keep EGTs from climbing. > Maybe the difference of a 50 degree rise is just delayed cooling or heat > not flowing as fast out the pipes at a slight > reduction of rpm on a descent approach. > > Larry > do not archive > > >Larry, > > It seems that if you put your nose down to descend from an established cruise without pulling back, then your rpm has to increase...more heat? don > > > > > Nice for a good cross-country cruise, but as I > > descended to land, EGTs climbed back up to set limits on my EIS and the > > rpms had to be reduced to keep the EGTs at or below limits. Not > > something I'm worried about, but it seemed strange to see EGTs behind > > the curve while descending. > > > Larry McFarland - 601HDS at 85 hours and still testing. > > > > ________________________________ Message 3 _____________________________________ Time: 09:35:58 AM PST US From: "Gary K" Subject: Re: Stratus-List: Bings and EGTs --> Stratus-List message posted by: "Gary K" > really cool clear air. It would seem the carbs are still richer at > altitude and become lean during descent. > This would seem to be a reverse of what I'd expect. I agree Larry - they should get richer with descent, and maybe they are. I just read something that mentioned higher EGT with richer mixture because it is still burning when it's coming out of the exhaust (just found the article - Sport Aviation feb 06 p101). Sorry I can't help - no EGT's yet. I'm still trying to get my homemade engine monitor working. Right now I'm flying dumb and happy with just the basic temps and pressure. I'm sure I'll have lot's of questions when I'm monitoring and recording everything. gary ________________________________ Message 4 _____________________________________ Time: 09:42:25 AM PST US From: LarryMcFarland Subject: Re: Stratus-List: Bings and EGTs --> Stratus-List message posted by: LarryMcFarland Don, I spoke with technical support person at Bing and he said that on descent, sometimes cowl pressure under lowering throttle settings are still enough to lean out the mixture a bit and temps will go up. You were right. He also said that the enrichment (choke) cable could be pulled during the descent while rpms are reduced from 4500 rpm to 3500 rpm and the EGTs should return to normal. I'll have to try that on the next trip out. Larry McFarland - 601HDS Don Walker wrote: >--> Stratus-List message posted by: "Don Walker" > >I dunno, just brainstorming with you. Looks like increased speed would increase cowl pressure to affect the mixture...and vice versa. Rate of descent may have something to do with it, too. I assume you are letting down at three to five hundred fpm? > I am glad you are noting these things, Larry, Helps us all. don > > > --> Stratus-List message posted by: LarryMcFarland > > > Don, > I guess the cowl air flow would be reduced on descent and that might > allow more heat to accrue at the sensor. I was > thinking the altitude compensation built into the carbs was getting > behind on enrichment. It could be either for the sake > of only 50-60 degrees. > > Larry > > Don Walker wrote: > > >--> Stratus-List message posted by: "Don Walker" > > > > >In that case your apparent wind may have something to do with it, which affects cowl pressure and air flow. do you suppose you are maintaining a constant cowl pressure though the descent? > > > >