matrobw Posted July 30, 2015 Report Posted July 30, 2015 We've been having some pretty consistent flap issues the last 6 months or so. We thought we had it fixed but it came back this morning. Here is the scenario. On taxi out the flaps worked fine. After takeoff they retracted normal as did it on approach and landing at out station airport. On taxi out they worked fine but after takeoff they failed to retract. It took about 10 minutes for them to retract and the left one retracted fully and the right one seemed to not come up all the way. Return flight and on arrival no flaps at all. Handle felt very spongy and did nothing. Had to make a flaps up landing. This is not the first time this has happened. It is a recurring thing. Anyone have any ideas? Where is the resevoir for the flap system fluid? We are baffled. Thanks
carusoam Posted July 30, 2015 Report Posted July 30, 2015 The flap system is quite simple. My 65 C either worked or didn't work. Not much in between. The flap control operates a valve. Wear of the bits and pieces along with adjustments can be a small challenge. The cherry juice flap/brake fluid gets old, thickens and is a small hassle to get fully flushed out. The return rate of the flap is adjustable, following the maintenance procedure. Under real flight conditions, what is set on the ground is a lot faster with air pressure. Other than flushing the system, check with your mechanic for the adjustments... The reservoir is on the backside of the firewall. Spilling any excess fluid ends up on the carpet. Nice to have the access panels in front of the windshield.... As fluid leaks out of the system... The flaps stop operating just before the brakes run out of fluid. Spongy flaps comes before spongy brakes... Check the age of the hoses returning to the reservoir. Chances are they are coming up on 50 years old. If they don't look new they may be crumbly old leaky hoses. If the belly panels have a light sticky dry coating that looks like something pooling in them... How does that sound? Keep in mind, I am a PP not a mechanic. Best regards, -a-
Shadrach Posted July 30, 2015 Report Posted July 30, 2015 Flap retraction is effected by a cam that depresses a pin the opens a valve allowing the hydraulic fluid to flow out of the actuator through the pump assembly and back to the reservoir. The cam is controlled by a simple cable. If the cable moves are is loose, the cam does not fully depress the relief valve and the flaps will bleed up very slowly. the unevenness has me baffled. The flaps are tied together by a common shaft and actuated by a single lever. I have done a lot of work to these systems under the supervision of an I/A and on occasion help out non Mooney Mechanics who need to trouble shoot. Anthony is correct, the system is very simple. it is almost infinitely repairable/rebuildable. When is the last time it was opened? I believe the flaps and brakes share a reservoir on your bird.
carusoam Posted July 30, 2015 Report Posted July 30, 2015 Asymmetric flap deployment....? I have no experience with that. That would need immediate attention of the do not fly variety... Fighting the power of ailerons vs. asymmetric flaps is best done on the ground... Best regards, -a- 1
Shadrach Posted July 30, 2015 Report Posted July 30, 2015 I don't think it's true asymmetric flap retraction. However, there could be damage to the sub-spar causing a "twisted" appearance. It goes without saying this is something to troubleshoot on the ground!
Alhall Posted July 30, 2015 Report Posted July 30, 2015 It sounds to me that one of your flap retract springs may have broken. Drop the panel that covers flap shaft area and you can see the actuator shaft springs,shaft, and the whole mechanism.
M20F Posted July 30, 2015 Report Posted July 30, 2015 It sounds to me that one of your flap retract springs may have broken. Drop the panel that covers flap shaft area and you can see the actuator shaft springs,shaft, and the whole mechanism. Doubtful given the inconsistency of problem and issue with both flaps going up and down.
Shadrach Posted July 30, 2015 Report Posted July 30, 2015 It sounds to me that one of your flap retract springs may have broken. Drop the panel that covers flap shaft area and you can see the actuator shaft springs,shaft, and the whole mechanism. If it's hanging down in flight, something is tweaked. Retraction spring is only needed for ground ops. Flaps will not hang in trail unless jammed.
M20F-1968 Posted July 30, 2015 Report Posted July 30, 2015 This sounds very strang: 1) the flaps when not connected to the hydraulic actuator should move up/down symmetrically as they are attached and in flight operated by one actuator. If they do not move together and symmetrically stop everything and first figure own what is mechanically wrong - meaning bent. 2) If you have not serviced the system in a very long time - just drain the system and change the hoses. The cost is cheap v. your time spent. While the system is apart, test the hydraulic pump for its action and retraction speed. LASAR can do this for you if you send them the flap pump. Also rebuild the seals in the flap hydraulic pump and actuator. Not very expensive. 3) put it all together and fill with hydraulic fluid. Bleed as necessary. 4) You should then be pretty close to working normally. John Breda 1
Alhall Posted July 30, 2015 Report Posted July 30, 2015 Retention springs are used for more than ground operation. There what retracts your flaps by pushing the flap up and forcing the hydraulic fluid back thru the system. They are what holds your flaps up. If one was to break or come loose it would have half the force when retracting and also be In a bind. One flap may hang slightly down but both are fastened to the same actuator.
Shadrach Posted July 30, 2015 Report Posted July 30, 2015 Retention springs are used for more than ground operation. There what retracts your flaps by pushing the flap up and forcing the hydraulic fluid back thru the system. They are what holds your flaps up. If one was to break or come loose it would have half the force when retracting and also be In a bind. One flap may hang slightly down but both are fastened to the same actuator. I should not have said they were for ground ops only. It's just that I am pretty sure that the flaps would come up on their own in flight. I could be wrong, I just assume so because if I set for 10 sec retraction speed on the ground they come up in about 6 secs while in flight. I could see a flap hanging on the ground, but it seems unlikely in flight unless something is jammed or bent.
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