CHT Temp Variations

Any DA40 related topics

Moderators: Rick, Lance Murray

User avatar
dwurfel
3 Diamonds Member
3 Diamonds Member
FIRST NAME: DAVID
Aircraft: DA40
Registration: N542GL
Airport: KTAD

Posts: 120
Joined: Sat Jun 06, 2015 1:54 pm
Has thanked: 1 time
Been thanked: 5 times

CHT Temp Variations

Post by dwurfel »

Have noticed that upon the first flight of the day and climb-out my CHT's can be as high as 410. I watch them pretty closely and do not let them get much above that especially 420. Upon cruise evrything settles down nicely. I will land maybe fuel or have breakfast. On my next leg with the same climb-out parameters my CHT's do not go above 380-390. That's great but curious as to why. Has anyone else had the same experience? :bow
User avatar
haykinson
3 Diamonds Member
3 Diamonds Member
FIRST NAME: ilya
Aircraft: DA40
Registration: N880BM
Airport: KSMO KHHR

Posts: 65
Joined: Thu Apr 19, 2018 8:32 am
Has thanked: 14 times
Been thanked: 16 times

Re: CHT Temp Variations

Post by haykinson »

I find that factors such as outside air temperature, humidity, climb airspeed, duration of climb, how hot the cylinders were before you took off, how quickly you dial back your RPM after take off — all those affect how easy it is to manage temps during climbing. For my airplane, I try to keep my cylinders below 400 — if they start going above by even a couple of degrees, I'll change something to drop the temperature. Practically speaking, airspeed and power (MP and RPM) are the only things you can change but some of these compete with each other so which you use might depend on the other factors that you can't change...

The weather seems to be the biggest factor — once I took a consistently-heavily-loaded airplane on a multi-day cross-country trip from LA to Toronto, and as I went further north and east my CHTs became easier and easier to manage.
User avatar
danno2000
3 Diamonds Member
3 Diamonds Member
FIRST NAME: Dan
Aircraft: DA40
Registration: N270DS
Airport: KAQW

Posts: 60
Joined: Thu Apr 06, 2017 4:26 pm
Has thanked: 30 times
Been thanked: 42 times

Re: CHT Temp Variations

Post by danno2000 »

dwurfel wrote:
Sun Nov 21, 2021 11:44 pm
Have noticed that upon the first flight of the day and climb-out my CHT's can be as high as 410. I watch them pretty closely and do not let them get much above that especially 420. Upon cruise evrything settles down nicely. I will land maybe fuel or have breakfast. On my next leg with the same climb-out parameters my CHT's do not go above 380-390. That's great but curious as to why. Has anyone else had the same experience? :bow
I have similar issues with my 2003 DA40-180 - I've found best practice has been to transition to a cruise climb at 100-110 knots as soon as practicable after takeoff. That usually gets the temps back below 400 pretty quickly.

In my early days on the forum, I found these threads on CHT management helpful. I'm sure there are others.

viewtopic.php?t=4356
viewtopic.php?t=6926

best,
dan
User avatar
dwurfel
3 Diamonds Member
3 Diamonds Member
FIRST NAME: DAVID
Aircraft: DA40
Registration: N542GL
Airport: KTAD

Posts: 120
Joined: Sat Jun 06, 2015 1:54 pm
Has thanked: 1 time
Been thanked: 5 times

Re: CHT Temp Variations

Post by dwurfel »

Thanks Dan and all. I will check those threads out. Mike Busch published a great article and webinar on the subject.
User avatar
Chris B
5 Diamonds Member
5 Diamonds Member
FIRST NAME: Chris
Aircraft: DA40
Registration: N171CB
Airport: KRHV

Posts: 822
Joined: Wed Sep 26, 2012 1:52 am
Has thanked: 197 times
Been thanked: 197 times

Re: CHT Temp Variations

Post by Chris B »

Maximizing fuel flow and carefully eliminating *all* baffle leaks are crucial steps to controlling CHT.
Enabling faster climb rates at relatively low IAS while keeping the cylinders attached. ;)

See: https://www.diamondaviators.net/forum/viewtopic.php?f=24&t=7409

Chris
User avatar
astaib
5 Diamonds Member
5 Diamonds Member
FIRST NAME: Arnaud
Aircraft: DA40
Registration: FGNJX
Airport: LFPX

Posts: 510
Joined: Mon Feb 26, 2018 9:00 pm
Has thanked: 174 times
Been thanked: 40 times

Re: CHT Temp Variations

Post by astaib »

Don't forget that Arizona kit will change a lot for the old planes.
Mine was with the very first front top left baffle (small inlet hole), I changed to the actual one with the "Arizona kit", and it was really a huge change in CHT.

Arnaud.
Arnaud
DA40 Star 180 / 40.026 / 2001
Wingtip, landing and taxing LED (Whelen)
Skitube
GNS430 NON-WAAS
Steam gauges
Non certified ADS-b
User avatar
dwurfel
3 Diamonds Member
3 Diamonds Member
FIRST NAME: DAVID
Aircraft: DA40
Registration: N542GL
Airport: KTAD

Posts: 120
Joined: Sat Jun 06, 2015 1:54 pm
Has thanked: 1 time
Been thanked: 5 times

Re: CHT Temp Variations

Post by dwurfel »

Arnaud, where can I get info on the Arizona kit. Google did not give me anything. Thanks
User avatar
astaib
5 Diamonds Member
5 Diamonds Member
FIRST NAME: Arnaud
Aircraft: DA40
Registration: FGNJX
Airport: LFPX

Posts: 510
Joined: Mon Feb 26, 2018 9:00 pm
Has thanked: 174 times
Been thanked: 40 times

Re: CHT Temp Variations

Post by astaib »

Hi,

Did you try the search engine of this Forum.
I can sent you part number and drawing yes.
Arnaud
DA40 Star 180 / 40.026 / 2001
Wingtip, landing and taxing LED (Whelen)
Skitube
GNS430 NON-WAAS
Steam gauges
Non certified ADS-b
User avatar
dwurfel
3 Diamonds Member
3 Diamonds Member
FIRST NAME: DAVID
Aircraft: DA40
Registration: N542GL
Airport: KTAD

Posts: 120
Joined: Sat Jun 06, 2015 1:54 pm
Has thanked: 1 time
Been thanked: 5 times

Re: CHT Temp Variations

Post by dwurfel »

Let me try that. Thanks Arnaud
User avatar
Rick
5 Diamonds Member
5 Diamonds Member
FIRST NAME: Rick
Aircraft: DA40
Registration: N171PS
Airport: KROA

Posts: 1516
Joined: Tue Jul 06, 2010 10:09 pm
Has thanked: 101 times
Been thanked: 260 times

Re: CHT Temp Variations

Post by Rick »

David,

There is this post with the part number and more information about the Arizona baffle in the rest of the thread.
2007 DA40 XL - Roanoke, VA (KROA)
Post Reply