Hi,
I must confess that a couple of years ago, it happened to me to do some fancy flying. For example I did not care about cowl flaps.
Today I care. The Bonanza deserves it. So I made various readings on the web and abstracted this:
What
Cowl flaps are small doors located in the bottom of the engine cowling that allow for greater cylinder cooling during takeoff and climb.
Where
Cowl flaps are found on high-performance aircrafts where larger engines with more horsepower generate lots of heat.
When
Cowl flaps are used during the take off and climb phases. Their use comes at the cost of increasing drag. Cowl flaps should be closed during cruise, descent, and landing.
How
The pilot operates the cow flaps via a control within the cockpit.
Now my question
Ok the 2D panel ("post-it") checklist "says": 1) Open cowl flaps after engine start. 2) Check cowl flaps are open before take off. 3) Cruise: cowl flaps closed. 4) Approach-Landing: cowl flaps closed.
I can see that the cowl flaps control is a lever going from 0% to 100%. For take off and climb, how much (%) do I have to open the cowl flaps?
Using cowl flaps
Using cowl flaps
P3Dv4.5 - V35B - C172 - Cherokee
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Microsoft Force Feedback 2 modded with CH Fighterstick - VKB Sim T-Rudder Mk.IV Pedals
Re: Using cowl flaps
Open them all the way for takeoff and climb, you want that heat out of there and CHTs below 400.
Close them up in cruise as required to keep CHTs below 400. It can take some time for CHTs to stabilize, so always include those engine instruments in your instrument scan. A good scan is good practice as you'll catch faults early.
Close them up in cruise as required to keep CHTs below 400. It can take some time for CHTs to stabilize, so always include those engine instruments in your instrument scan. A good scan is good practice as you'll catch faults early.
Flight Simmer since 1983. PP ASEL IR Tailwheel
N28021 1979 Super Viking 17-30A
N28021 1979 Super Viking 17-30A
Re: Using cowl flaps
I close them in cool/cold weather during warm up on the ground. Is that normal or effective?
Chris J.
Asus Maximus VII Hero motherboard | Intel i7 4790k CPU | MSI GTX 970 4 GB video card | Corsair DDR3 2133 32GB SDRAM | Corsair H50 water cooler | Samsung 850 EVO 250GB SSD (2) | EVGA 1000 watt PSU | Windows & Pro 64 bit | FSX:SE
Asus Maximus VII Hero motherboard | Intel i7 4790k CPU | MSI GTX 970 4 GB video card | Corsair DDR3 2133 32GB SDRAM | Corsair H50 water cooler | Samsung 850 EVO 250GB SSD (2) | EVGA 1000 watt PSU | Windows & Pro 64 bit | FSX:SE
Re: Using cowl flaps
Roger that Chief Master Sergeant!Oracle427 wrote:Open them all the way for takeoff and climb, you want that heat out of there and CHTs below 400.
Close them up in cruise as required to keep CHTs below 400. It can take some time for CHTs to stabilize, so always include those engine instruments in your instrument scan. A good scan is good practice as you'll catch faults early.
Accurate and crystal clear.
Many thanks Oracle427.
P3Dv4.5 - V35B - C172 - Cherokee
i5 4670K @4.3 Ghz - 32 Gb DDR3 - GTX 1080 8 Gb - 2K @165 Hz G-Sync - Win 7 x64
Microsoft Force Feedback 2 modded with CH Fighterstick - VKB Sim T-Rudder Mk.IV Pedals
i5 4670K @4.3 Ghz - 32 Gb DDR3 - GTX 1080 8 Gb - 2K @165 Hz G-Sync - Win 7 x64
Microsoft Force Feedback 2 modded with CH Fighterstick - VKB Sim T-Rudder Mk.IV Pedals
Re: Using cowl flaps
Hi, this is not recommended by engine manufacturer or POH. Perhaps it may lead to unequal heating of upper and lower cylinder/head parts.Orlaam wrote:I close them in cool/cold weather during warm up on the ground. Is that normal or effective?
Re: Using cowl flaps
Ok okay. Was thinking it would speed up warm up.Jarek wrote:Hi, this is not recommended by engine manufacturer or POH. Perhaps it may lead to unequal heating of upper and lower cylinder/head parts.Orlaam wrote:I close them in cool/cold weather during warm up on the ground. Is that normal or effective?
Chris J.
Asus Maximus VII Hero motherboard | Intel i7 4790k CPU | MSI GTX 970 4 GB video card | Corsair DDR3 2133 32GB SDRAM | Corsair H50 water cooler | Samsung 850 EVO 250GB SSD (2) | EVGA 1000 watt PSU | Windows & Pro 64 bit | FSX:SE
Asus Maximus VII Hero motherboard | Intel i7 4790k CPU | MSI GTX 970 4 GB video card | Corsair DDR3 2133 32GB SDRAM | Corsair H50 water cooler | Samsung 850 EVO 250GB SSD (2) | EVGA 1000 watt PSU | Windows & Pro 64 bit | FSX:SE
- DHenriques_
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Re: Using cowl flaps
I usually opened cowls post roll out on landings and kept them open for all ground operation especially run-ups.Orlaam wrote:I close them in cool/cold weather during warm up on the ground. Is that normal or effective?
I'd open them for starts and keep them open during taxi but watching the CHT in the process.
Dudley Henriques
Re: Using cowl flaps
Yes it is not generally recommended because of uneven heating and hot spots getting too hot quickly without cooling airflow. In cold conditions, I understand some folks start the engines with cowl flaps closed but open them as soon as the engine idles on its own. I don't comment, because I don't know, about how easy it would be to forget them closed.Orlaam wrote:Ok okay. Was thinking it would speed up warm up.Jarek wrote:Hi, this is not recommended by engine manufacturer or POH. Perhaps it may lead to unequal heating of upper and lower cylinder/head parts.Orlaam wrote:I close them in cool/cold weather during warm up on the ground. Is that normal or effective?
-Esa
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