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  #1  
Old 05-15-2019, 06:31 PM
Latech15 Latech15 is offline
 
Join Date: Apr 2018
Location: louisiana
Posts: 74
Default Anti-splat cowl flaps popping fuses

Iíve had a couple of fuses blow in the cowl flaps. It happened today at 9kft when I went to close them. I pulled the fuse and put a new one in. The label on the wire was a 1 amp fuse. I had a 3 and stuck it in there and it popped immediately.

I quit sticking fuses in after that. I realized after the fact that the switch was in the closed position when I replaced the fuse and the flaps were obviously still open. I stuck a 5 amp fuse in once back on the ground (with the switch in the open position) and cycled them a few times and it was all good. I donít feel comfortable with a 5 amp fuse in there where a 1 amp fuse should be.

Any ideas on why I would be popping fuses?
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  #2  
Old 05-15-2019, 07:38 PM
sibriggs sibriggs is offline
 
Join Date: Nov 2014
Location: Concord, NH
Posts: 181
Default May be binding

Check to see if the flap is rubbing or binding while trying to extend or retract, that might overload the motor, and cause a spike in current?

Steve
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  #3  
Old 05-15-2019, 07:42 PM
alpinelakespilot2000 alpinelakespilot2000 is offline
 
Join Date: Jan 2005
Posts: 3,576
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Quote:
Originally Posted by sibriggs View Post
Check to see if the flap is rubbing or binding while trying to extend or retract, that might overload the motor, and cause a spike in current?

Steve
Ditto this. My first cowl flap came with signficant binding that I didn't realize mattered. After repeated blown fuses and even some attempts to file out the binding I contacted Alan at AntiSplat and he promptly replaced the cowl flap. That solved the problem.
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  #4  
Old 05-16-2019, 08:42 AM
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airguy airguy is offline
 
Join Date: Oct 2006
Location: Garden City, Tx
Posts: 4,724
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I've found that my cowl flap doesn't like airspeed over about 105-110 KIAS, there is too much air load on it for opening. Closing doesn't seem to be an issue. If you can put an ammeter in the circuit and check the actual loads in flight at various airspeeds you'll have the full story.
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  #5  
Old 05-16-2019, 01:56 PM
Latech15 Latech15 is offline
 
Join Date: Apr 2018
Location: louisiana
Posts: 74
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I pulled the cowl today and immediately found the issue. The wires between the cowl flaps was taped with foil tape to the lower cowl. That tape had peeled back a bit too close to the exhaust. The insulation had melted and the wires were touching.

I managed to break one of the tiny wires off AT the actuator with nothing sticking out, so I guess Iíll need to order another actuator.

The bigger issue was that there was a good amount of oil on the bottom cowl that appeared to be coming from somewhere around the #1 cyl. On the starter, alternator, and cowl up in the front corner. This engine has never leaked like that and it is down about a quart over the last 2 hr flight.

Knowing that my flaps were open on my way back I took a very shallow decent with power left in to keep the chtís in the 325-330 range all the way until short final so I donít think I had a shock cooling issue.

Iím going to replace the actuator and do a runup after cleaning everything to see if I can tell where the oil is coming from.
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  #6  
Old 05-16-2019, 02:49 PM
svyolo svyolo is offline
 
Join Date: Oct 2017
Location: bellingham, wa
Posts: 146
Default

It is standard convention in the higher levels of aviation to never reset a popped CB in flight. Same with swapping a fuse. This being a good example of why not.

As someone once asked, "would you rather be flying in a glider,or a Roman Candle?"

Troubleshoot blown fuses and CB's on the ground.
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