Unable to close cowl flaps during cruise

[Houman]

Hi,

On today's flight, my instructor and I noticed that we can't close the cowl flaps completely during flight, specially in cruise, the handel is always about 1/4 open, as such CHT is lower than normal. On ground, we are able to close them fully.

It seemed during flight, we could'nt push hard enough to close the cowl flaps, although I would have tought that the air pressure against it in flight would make it easier to close.

Am I missing something, maybe it's someting simple that we are missing.

Thanks !!!

[Bob_Belville]

Did you try to close CF at a lower speed, say in the landing pattern? If the issue is air pressure that should tell you something. (My M20E would be quite different but I have a tough time getting the flaps to stay put in a partial open position due to air pressure on the cflaps.

[Andy95W]

Mine's the same way. The faster I go, the harder they are to close. Makes me feel good knowing they're doing their job. Seems to work good if I close them just after level off as the airspeed just starts to increase.

[carusoam]

I would think there is air pressure on both sides, no?

Did you try cleaning the controls?

Best regards,

-a-

[N201MKTurbo]

Ok, so you need to re-rig the cowl flaps. Adjust the cable so the mechanism goes all the way then adjust the rods so they are closed a little tight. Make sure the pivot bushings are not falling apart too bad.

[cbarry]

If I'm not mistaken, there's more pressure coming from air flowing through the cowling than from around the cowling--especially as it pertains to where the cowl flaps are located. Thus, closing the cowl flaps is harder than opening them. The next time you're in cruise, watch the oil filler access door when you close the cowl flaps and you'll see the door rise/bulge ever so slightly. This indicates a rise in pressure inside of the cowling caused by closing off most if the exiting air.

[drake15d]

Did you try to close CF at a lower speed, say in the landing pattern? If the issue is air pressure that should tell you something. (My M20E would be quite different but I have a tough time getting the flaps to stay put in a partial open position due to air pressure on the cflaps.

 

Agreed. My J's cowl flaps are a bear to close if I don't do it right at level off. If I wait even 1 minute I find myself struggling.