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  #1  
Unread 01-23-03, 12:28 PM
Guy Paris's Avatar
Guy Paris Guy Paris is offline
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Location: Nashua NH. (near ASH)
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Cool The aft cowl flaps....

on my flying machine, a 77 G are intermittent, real intermittent they will not open... I had been leaving them about an inch or so open because of this problem. What I noticed the last flight was that the blue light in the open position was quite dim. Prior to that I noticed that the cowl flaps could be open and the blue light was slow to come on. The motor and (1) limit switch were changed last year. Any ideas?? Guy, old72driver....
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  #2  
Unread 01-23-03, 02:01 PM
Bob Cook Bob Cook is offline
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the old cowl flap problem

Guy

Try testing on the ground. Use voltmeter across motor and/or switches.

Not enough information to diagnose or provide any clues.
1)move in and not out ?
out and not in?
move at all ?
on the ground ?
in the air ?
can you see a current change on the ships ammeter?

more info required. The blue light staying on might be there is current to the motor and the motor is stalled.

Bob
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  #3  
Unread 01-23-03, 02:01 PM
Dale Campbell's Avatar
Dale Campbell Dale Campbell is offline
Owner 337H N337DC
 
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Location: Scranton, Pa.
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Smile Cowl Flap motor

Hi Guy,
The cowl motor needs a good cleaning. They are easy to do if you wish to do it your self. I had both front & rear out on my 337H on my last annual. Yours should be the same. It took me about 1 hour each to remove disassemble, & clean. Remove the total motor & shaft assembly that is the easiest. Take the screws out of the support hanger on the fire wall that holds the long tub shaft . The far end away from cowl flap motor. Disconnect the links that go down to the cowl flaps & the link that go to the fire wall. Disconnect the quick disconnect wire harness. Remove the 2 screws in fire wall that hold the small sguare relay. Be very careful not to break these wires from relay they are very delicate.
No need to remove hanger on motor side of tub shaft. Move the whole assembly to the side & out. Look at it real good before removing, because it goes back in the same way. Put the whole assembly on work bench for disassembly & cleaning. Do not take motor out of assembly. That way you will not break any adjustments on motor travel or switches. Take the back end off motor, by remove 2 long screws that go through motor assembly.
There are 2 motor brushes in the motor that get gummy, hang up & cause the problem. Gently remove the back off the motor that house the brushes. Clean the brush assembly with a electrical cleaner or alcohol. Be careful not to break pig tails off brushes. Check lubrication on gear end of motor & replace. Reassemble motor and test. The motor can be tested on work bench by aplying 24 volts from battery or a 24 volt power supply to check motor travel & switch activation. Check all the wires before placing back on aircraft. Have your A&P inspect the proper installation & operation to make it legal. Have fun Dale Campbell
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  #4  
Unread 01-25-03, 08:31 PM
Guy Paris's Avatar
Guy Paris Guy Paris is offline
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Cool The aft cowl flaps.... Suggestions...

The aft cowl flap motor was changed out about a year ago with a new one from Cessna, many $$$$.00. Since this new problem I have been leaving them open about 2 inches and periodically trying them in the hangar to the open position. Recently they stoped opening, however they would go toward the closed position. Went flying today, watched cyl. temps closely. Placing the switch to the open position and after a while I could see the blue light very dimly lite. I could not see with my mirrors if they were open. Once on the ground I could see that they were open. I closed them to the 2 inch position then tried to open them. they would not open. Going into the shop next week and check it out. Well I went and had a $50.00 slice of pizza anyway... Parked along side N130Q a DC 3 on amphibious floats. Heard about it but I have never seen it and what a sight it was.. Should keep that darn throw away camera in the back... At 4500 feet, 2350/2400 with a +10 F the TAS was 160K, just me and not much gas... Guy, old72driver....

Last edited by Guy Paris : 01-25-03 at 08:36 PM.
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  #5  
Unread 01-25-03, 09:33 PM
Eustacio-Chachi Eustacio-Chachi is offline
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Guy, donīt fool with the rear cowl flap, some years ago I blew a cylinder on the rear engine because I kept fkying with a cowl flap motor that "sometimes" worked and let me tell you, besides the scare it was expensive. Chachi
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  #6  
Unread 01-25-03, 09:52 PM
Guy Paris's Avatar
Guy Paris Guy Paris is offline
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Cool Thanks, I am....

Going into the shop next week and check it out
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  #7  
Unread 01-26-03, 07:13 AM
Paul Sharp Paul Sharp is offline
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My model, a 1967 Turbo, may be different form yours. I had an intermittent problem with the rear cowl flap operation, and it turned out to be a loose wire going to the fuse assembly. I finally found it by taking off the cowling, turning on the master, and wiggling wires around the cowl flap motor system in the back until I saw them finally start to move (that was after setting the flap position to close after it was stuck open.

Turned out that a bad solder joint caused it, and airflow during flying would sometimes disturb it just enough to get it to where it wouldn't work. Then next time I flew it would be OK, etc. Was a pain to find but once re-soldered properly I didn't have any more trouble.
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  #8  
Unread 01-31-03, 10:08 PM
Guy Paris's Avatar
Guy Paris Guy Paris is offline
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Cool Aft cowl flaps update.....

Looking at the aft cowl flaps wireing we found a broken wire in the bundle. We could duplicate the problem very quickely. Repaired said problem. Looked like it was caused by the way it was ty-wrapped. While we were there noticed a small fuel leak at the Shaden fuel transducer, tightened fuel lines and have have been pressing on. Guy, old72driver....
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