fellis Posted March 22, 2020 Report Share Posted March 22, 2020 I have been chasing an issue on my 1980 M20J whereby the cowl flaps freely open and closed on ground but in the air will not fully close. Have investigated and flaps and various connections (rods and complete linkage going back to the cable) are very loose and sloppy which exacerbates the wear on the already worn components. Have ordered replacement parts and waiting for these to come in. While making the repairs I noticed that one of the threaded rods on right (exhaust side) has been modified as someone cut it, rewelded making it 1/2" longer. Thinking that this may have something to do with cowl flaps not closing but do not know for sure. Wanted to see if someone may know what the correct length of these rods may be. The opposite side is exactly 5 inches and length and appears to be original. Mooney parts catalog indicates that there are 3 possible rod combinations but does not provide any specifications on length. Any help on what length these should be and if they are supposed to be the same would be appreciated. Many thanks. Quote Link to comment Share on other sites More sharing options...
ArtVandelay Posted March 22, 2020 Report Share Posted March 22, 2020 Mine are the same, however, both my cowl flaps are the same and have the muffler bulge. I’ve seen some where the left side is just flat with no muffler opening and that might require different lengths. Quote Link to comment Share on other sites More sharing options...
carusoam Posted March 23, 2020 Report Share Posted March 23, 2020 Got a pic? -a- Quote Link to comment Share on other sites More sharing options...
fellis Posted March 29, 2020 Author Report Share Posted March 29, 2020 Quick update on the repair. All bushings and worn linkage replaced and reasembled. Virtually zero play in the cowl flaps now. Much better. Flaps open and close on the ground with no sticking and with ease. Took for test flight this morning and same problem. Flaps can be closed but will not stay shut. Simply push back to open position right after reaching closed postion. Any ideas? Quote Link to comment Share on other sites More sharing options...
Guest Posted March 29, 2020 Report Share Posted March 29, 2020 The cowl flap mechanism is meant to geometrically lock overcentre preventing them from opening. Clarence Quote Link to comment Share on other sites More sharing options...
N201MKTurbo Posted March 29, 2020 Report Share Posted March 29, 2020 You probably need to rig the cable a little shorter and the rods a little longer. Test on the ground by trying to pull them open. (The actual cowl flaps, not the handle). Undo the leakages from the cowl flaps. Close them with the knob. pull down on each linkage rod. if you can pull them open, re-rig the cable until you can't. Now rig the rods so they are closed just touching the cowl. Quote Link to comment Share on other sites More sharing options...
fellis Posted March 30, 2020 Author Report Share Posted March 30, 2020 Many thanks for the help. Went back to the hangar this evening and took a closer look after removing the top cowling. As it turns out the spring had little to no load on it when the cowl flaps were closed. I found a previous thread that had recommended to rotate the angled bracket slightly that allowed a little more load on the spring at the retracted position. I tried this and now the closed position has more load on the spring in this position. Put everything back together and cycled the cowl flaps. Appears to have much more positive load at closed but will still need to test to confirm. I will look at the positions of the flaps and adjust linkage as listed above my M201MKTurbo (many thanks for that). Also many thanks for the information above (M20Doc). Very much appreciate the help all. Hopefully will get a chance to take it up one day after work later this week and will report back. Have a great week and again thanks for the help. Quote Link to comment Share on other sites More sharing options...
carusoam Posted March 30, 2020 Report Share Posted March 30, 2020 Great follow-up, Fellis! Best regards, -a- Quote Link to comment Share on other sites More sharing options...
fellis Posted March 31, 2020 Author Report Share Posted March 31, 2020 21 hours ago, carusoam said: Great follow-up, Fellis! Best regards, -a- My pleasure and want to share the knowledge on the repair. 1 Quote Link to comment Share on other sites More sharing options...
Joe Larussa Posted March 31, 2020 Report Share Posted March 31, 2020 They may have added more rod so when trailing the flaps they would be more open for cooling? Quote Link to comment Share on other sites More sharing options...
fellis Posted April 1, 2020 Author Report Share Posted April 1, 2020 On 3/30/2020 at 9:59 PM, Joe Larussa said: They may have added more rod so when trailing the flaps they would be more open for cooling? Could very well be. Interestingly though it was only on one side (exhaust) Quote Link to comment Share on other sites More sharing options...
jaylw314 Posted April 1, 2020 Report Share Posted April 1, 2020 On 3/30/2020 at 7:59 PM, Joe Larussa said: They may have added more rod so when trailing the flaps they would be more open for cooling? Maybe they had a wonky muffler and that was their solution to make it fit? Quote Link to comment Share on other sites More sharing options...
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