CHT again
Moderators: Rick, Lance Murray
-
- 3 Diamonds Member
- Posts: 101
- Joined: Sun Nov 20, 2016 12:43 am
- First Name: Sara
- Aircraft Type: DA62
- Aircraft Registration: N687DA
- Airports: KPAE
- Has thanked: 18 times
- Been thanked: 19 times
Re: CHT again
There are a few other clues that timing may be an issue -- one that's gotten worse since I replaced the prop a few months back. I've got the shop looking at that right now, in fact.
I've brought this to the shop's attention today, and will have them look into it. Thanks for the input, everybody. This has bugged me for the 2.5 years I've had this plane, and it would be good to make another run at getting some answers.
I'm running it pretty darn lean. There's a lot of room to back that off, but I'm going to be burning quite a bit more gas.
I've brought this to the shop's attention today, and will have them look into it. Thanks for the input, everybody. This has bugged me for the 2.5 years I've had this plane, and it would be good to make another run at getting some answers.
I'm running it pretty darn lean. There's a lot of room to back that off, but I'm going to be burning quite a bit more gas.
The highest art form of all is a human being in control of himself and his airplane in flight, urging the spirit of a machine to match his own. -- Richard Bach
- waynemcc999
- 5 Diamonds Member
- Posts: 568
- Joined: Sun Jun 08, 2014 3:38 pm
- First Name: Wayne
- Aircraft Type: DA40
- Aircraft Registration: N211WP
- Airports: KSBA
- Has thanked: 1517 times
- Been thanked: 411 times
Re: CHT again
Sara, if you go even leaner of peak you will SAVE gas.
Wayne McClelland
PPL/IR, 2008 Diamond Star DA40-XLS 40.922, KSBA
Photo logs of PilotsNPaws | Flying Doctors | Angel Flight | YouTube @GeezerGeekPilot
PPL/IR, 2008 Diamond Star DA40-XLS 40.922, KSBA
Photo logs of PilotsNPaws | Flying Doctors | Angel Flight | YouTube @GeezerGeekPilot
- astaib
- 5 Diamonds Member
- Posts: 617
- Joined: Mon Feb 26, 2018 9:00 pm
- First Name: Arnaud
- Aircraft Type: DA40
- Aircraft Registration: FGNJX
- Airports: LFPX
- Has thanked: 244 times
- Been thanked: 51 times
Re: CHT again
In my case I still have too hot CHT when I flight too low and too hot OAT. But it is not as hot CHT as you (400-415 max) in level flight.
Diamond Aircraft (Neil Grant) think that the Arizona Baffle will really help. I think that I will go for it.
When I fly higher or in winter time, my CHT are around 385.
Diamond Aircraft (Neil Grant) think that the Arizona Baffle will really help. I think that I will go for it.
When I fly higher or in winter time, my CHT are around 385.
Arnaud
DA40 Star 180 / 40.026 / 2001
Wingtip, landing and taxing LED (Whelen)
Skitube
GNS430 NON-WAAS
Steam gauges
Non certified ADS-b
DA40 Star 180 / 40.026 / 2001
Wingtip, landing and taxing LED (Whelen)
Skitube
GNS430 NON-WAAS
Steam gauges
Non certified ADS-b
- astaib
- 5 Diamonds Member
- Posts: 617
- Joined: Mon Feb 26, 2018 9:00 pm
- First Name: Arnaud
- Aircraft Type: DA40
- Aircraft Registration: FGNJX
- Airports: LFPX
- Has thanked: 244 times
- Been thanked: 51 times
Re: CHT again
If you lean too much the engine will vibrate (because not all 4 injectors have the same value, GAMI spread test) then each cylinder will shut down because to low fuel flow.
Arnaud
DA40 Star 180 / 40.026 / 2001
Wingtip, landing and taxing LED (Whelen)
Skitube
GNS430 NON-WAAS
Steam gauges
Non certified ADS-b
DA40 Star 180 / 40.026 / 2001
Wingtip, landing and taxing LED (Whelen)
Skitube
GNS430 NON-WAAS
Steam gauges
Non certified ADS-b
- perossichi
- 3 Diamonds Member
- Posts: 188
- Joined: Tue Sep 18, 2018 4:05 am
- First Name: Peter
- Aircraft Type: DA40
- Aircraft Registration: N925RH
- Airports: KVNY
- Has thanked: 31 times
- Been thanked: 75 times
Re: CHT again
Sara
Your plane already has the Arizona cyl 1 baffle as it is a 2007.
Your plane already has the Arizona cyl 1 baffle as it is a 2007.
Sold 2002. Powerflo, Hartzell composite two blade, 530W/430, 345 transponder.
-
- 3 Diamonds Member
- Posts: 101
- Joined: Sun Nov 20, 2016 12:43 am
- First Name: Sara
- Aircraft Type: DA62
- Aircraft Registration: N687DA
- Airports: KPAE
- Has thanked: 18 times
- Been thanked: 19 times
Re: CHT again
I meant "back that off" to mean "run richer," which, no, will not save me gas. The choice is either to run richer and cooler, or lean it out further, run hotter....and save gas right up to the point where the engine chokes itself off (a state that's not a far reach from where I'm leaning it out to -- usually, another quarter-inch movement on the lean lever will get me there.)
I had the baffles replaced by Clay Lacy at BFI shortly after I got this plane, in an attempt to address the problem. No idea if they replaced it with this "Arizona" baffle y'all are talking about.
The highest art form of all is a human being in control of himself and his airplane in flight, urging the spirit of a machine to match his own. -- Richard Bach
- waynemcc999
- 5 Diamonds Member
- Posts: 568
- Joined: Sun Jun 08, 2014 3:38 pm
- First Name: Wayne
- Aircraft Type: DA40
- Aircraft Registration: N211WP
- Airports: KSBA
- Has thanked: 1517 times
- Been thanked: 411 times
Re: CHT again
Sara, if you have decently tuned injectors (have you run and recorded the GAMI test, and sent to GAMI for evaluation??):
-- as you decrease fuel flow beyond peak EGTs (the cyan lines on the MFD with the Lean button activated)...
-- you will see the EGTs (and after a time delay, the CHTs) decrease
-- you should then (depending on %power) shoot for EGTs about 50 below peak value (cyan lines) -- this will be your fuel flow setting for LOP operation (for a given power setting and density altitude)
-- if you decrease fuel flow even more, yes, eventually you'll run rough
See Mike Busch https://youtu.be/_VfiPuheeGw
Again, my guess is that when you lean you are still at or very close to peak EGTs (and therefore unacceptably high CHTs)... if you lean further to say 50 degrees Lean-of-Peak (assuming decently tuned injectors)... you'll both SAVE fuel and have LOWER CHTs.
-- as you decrease fuel flow beyond peak EGTs (the cyan lines on the MFD with the Lean button activated)...
-- you will see the EGTs (and after a time delay, the CHTs) decrease
-- you should then (depending on %power) shoot for EGTs about 50 below peak value (cyan lines) -- this will be your fuel flow setting for LOP operation (for a given power setting and density altitude)
-- if you decrease fuel flow even more, yes, eventually you'll run rough
See Mike Busch https://youtu.be/_VfiPuheeGw
Again, my guess is that when you lean you are still at or very close to peak EGTs (and therefore unacceptably high CHTs)... if you lean further to say 50 degrees Lean-of-Peak (assuming decently tuned injectors)... you'll both SAVE fuel and have LOWER CHTs.
Wayne McClelland
PPL/IR, 2008 Diamond Star DA40-XLS 40.922, KSBA
Photo logs of PilotsNPaws | Flying Doctors | Angel Flight | YouTube @GeezerGeekPilot
PPL/IR, 2008 Diamond Star DA40-XLS 40.922, KSBA
Photo logs of PilotsNPaws | Flying Doctors | Angel Flight | YouTube @GeezerGeekPilot
- BRS
- 4 Diamonds Member
- Posts: 313
- Joined: Sun Mar 13, 2011 12:44 am
- First Name: Brock
- Aircraft Type: OTHER
- Aircraft Registration: N8QQ
- Airports: W52
- Has thanked: 31 times
- Been thanked: 94 times
Re: CHT again
Astaib, The only way that I have found in order to get precise adjustment of the mixture (while testing) is to put a band around the Mixture latch to hold it open all the time. Don't forget to remove it once done testing.
We had to do this when developing the SuperCharger STC.
40.649 Sold (Still miss the DA40 from time to time)
Fly and EAB Sportsman
Fly and EAB Sportsman
- Scottsware
- 3 Diamonds Member
- Posts: 66
- Joined: Tue Nov 27, 2018 12:59 am
- First Name: Scott
- Aircraft Type: DA40
- Aircraft Registration: N343SG
- Airports: KAPA
- Has thanked: 11 times
- Been thanked: 42 times
Re: CHT again
My engine has just over 500 hours and I recently had both magnetos IRAN. The CHT seems to be running 10-20 degrees cooler.
- DaveS1900
- 3 Diamonds Member
- Posts: 66
- Joined: Sun May 06, 2018 1:09 am
- First Name: Dave
- Aircraft Type: DA40
- Aircraft Registration: N521DD
- Airports: I74 Urbana Ohio
- Has thanked: 5 times
- Been thanked: 30 times
Re: CHT again
Sara,
I have fought a similar problem with another airplane, I feel your pain. Either there is no airflow to take the heat away (obstructions to airflow or airflow bypassing the cylinder baffles) or some thing is creating excessive heat (ie advanced timing or electronic ignition). You should do an experiment and post the results with the MP and mixture at various settings and record the CHT's.
Dave S.
I have fought a similar problem with another airplane, I feel your pain. Either there is no airflow to take the heat away (obstructions to airflow or airflow bypassing the cylinder baffles) or some thing is creating excessive heat (ie advanced timing or electronic ignition). You should do an experiment and post the results with the MP and mixture at various settings and record the CHT's.
Dave S.