zerotact Posted September 25, 2018 Report Share Posted September 25, 2018 So, Buttoning up the plane after a lot of work done, The cowl flaps aren't closing all the way. Looking at the mechanism it looks like the only adjustment I have is the rod length that connects to the flap itself. As the bar that the rods connect to are rotating to top dead center and then just a bit past. So the rod length that connects to the flaps is the only adjustment, I say this because the whole from of the plane has been apart and rebuilt and the cowl flaps look equally open but the rods only affect one side at a time. Quote Link to comment Share on other sites More sharing options...
Raptor05121 Posted September 25, 2018 Report Share Posted September 25, 2018 Is this per the maintenance manual? I believe my C manual calls for 3/4" opening at the fully-closed setting Quote Link to comment Share on other sites More sharing options...
jetdriven Posted September 25, 2018 Report Share Posted September 25, 2018 Shorten the rods up until they close flush or max open of 1/2”. If they’re 1-2” open they buffet and wear out the cowl flap hinges, and also pull the rivets they are attached to the cowl with. . On the early J models it’s a real job to repair those. I ended up replacing all the fiberglass in that area, the cowl flap frames, and hinges and added a replaceable bushing in the hinge. Probably 30 hours of work. 1 Quote Link to comment Share on other sites More sharing options...
zerotact Posted September 26, 2018 Author Report Share Posted September 26, 2018 The cowl flap itself was mostly original but the all the rest of the metal is new ... the whole cowling was a complete overhaul Quote Link to comment Share on other sites More sharing options...
INA201 Posted September 26, 2018 Report Share Posted September 26, 2018 On 9/25/2018 at 2:36 AM, jetdriven said: Shorten the rods up until they close flush or max open of 1/2”. If they’re 1-2” open they buffet and wear out the cowl flap hinges, and also pull the rivets they are attached to the cowl with. . On the early J models it’s a real job to repair those. I ended up replacing all the fiberglass in that area, the cowl flap frames, and hinges and added a replaceable bushing in the hinge. Probably 30 hours of work. How do you determine if you have buffeting, just 1/2” or less? Any merit to either 1/2” or fully closed? Thanks Quote Link to comment Share on other sites More sharing options...
jetdriven Posted September 27, 2018 Report Share Posted September 27, 2018 Between a half inch and fully closed the Cht is a few degrees, perhaps 20, than fully closed. I don’t know how to determine where it buffets, but do a run up with the cow flaps open fully and watch them. They move around quite a bit, and they flex the cowl and wear the hinges and flex the frames which cause cracking. Fully closed or nearly so, the cowl flaps are braced by more than the three pivot points. Quote Link to comment Share on other sites More sharing options...
zerotact Posted October 4, 2018 Author Report Share Posted October 4, 2018 I disconnected the rods and it was quickly evident when I tried to close them... the new metal was not notched out to clear the exhaust.... Quote Link to comment Share on other sites More sharing options...
Piloto Posted October 4, 2018 Report Share Posted October 4, 2018 (edited) The gap shown on the picture is about right. A fully closed cowl flap will increase the temps in cruise and climb. José Edited October 4, 2018 by Piloto 1 Quote Link to comment Share on other sites More sharing options...
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