Ragsf15e Posted February 24 Report Posted February 24 4 hours ago, PeytonM said: It did not fix the issue. It takes about 3 minutes to move from fully closed to 1/4 open and I lose 2-3 knots. Yep, that’s what mine still does. I can’t wait for you to find a solution! I was pulling my hair out for a while but I have moved on… happy to circle back if we find out what’s causing it. If I close it all the way on the ground and lay under the nose, I can pull very hard on the cowl flap and not budge it. Weird.
PeytonM Posted February 27 Author Report Posted February 27 After David tightened the cowl flap motor screws, I paid more attention to the cowl flap behavior. Yesterday during a long flight in smooth air, it took almost 4 minutes for the cowl flaps to settle 1/4 open. Before it was closer to 2 minutes, so I wonder if vibration is contributing. It’s a new engine installation, so maybe prop misbalance or vibration contributes. We tried pulling the cowl flap open manually and the motor did not budge. 1
EricJ Posted February 27 Report Posted February 27 I haven't looked at the schematics, but if one of the relays is vibrating "on" at a low duty cycle it may be powering the flaps open to a point that it stops vibrating. Low probability, I think, but it looks like you're looking for oddball things like that. You might make sure that the switches/relays are secure and nothing is near the terminals or the terminals are insulated. Otherwise you may be right that it's just the gears vibrating and allowing some back driving.
Bolter Posted February 27 Report Posted February 27 23 minutes ago, EricJ said: I haven't looked at the schematics, but if one of the relays is vibrating "on" at a low duty cycle it may be powering the flaps open to a point that it stops vibrating. Low probability, I think, but it looks like you're looking for oddball things like that. You might make sure that the switches/relays are secure and nothing is near the terminals or the terminals are insulated. Otherwise you may be right that it's just the gears vibrating and allowing some back driving. If this is occurring, a quick test of closing fully, then pulling the breaker for 10 minutes would confirm this. If the switch is in the "off" position, it should have no power anyway, but maybe that is making momentary contact due to vibration (per the theory) 2
Ragsf15e Posted February 27 Report Posted February 27 5 hours ago, PeytonM said: After David tightened the cowl flap motor screws, I paid more attention to the cowl flap behavior. Yesterday during a long flight in smooth air, it took almost 4 minutes for the cowl flaps to settle 1/4 open. Before it was closer to 2 minutes, so I wonder if vibration is contributing. It’s a new engine installation, so maybe prop misbalance or vibration contributes. We tried pulling the cowl flap open manually and the motor did not budge. I checked mine today. It was bumpy. It took 1:30 to open 1/4 tgen pretty much stops. Here’s a picture of the indication where it stopped. Disregard the red dots. Previous owner put those there.
jetdriven Posted March 4 Report Posted March 4 There is a one Rpm version in a two Rpm version. The two Rpm version has a smaller gear ratio, and the air flow through the cowling, actually pushes on the cowl flap and turns the motor and opens the cowl flaps somewhat. The one Rpm version has enough gear ratio to prevent this. It’s like parking your manual transmission car on a hill and putting it in either first gear or third with no parking brake. 1
Ragsf15e Posted March 4 Report Posted March 4 8 minutes ago, jetdriven said: There is a one Rpm version in a two Rpm version. The two Rpm version has a smaller gear ratio, and the air flow through the cowling, actually pushes on the cowl flap and turns the motor and opens the cowl flaps somewhat. The one Rpm version has enough gear ratio to prevent this. It’s like parking your manual transmission car on a hill and putting it in either first gear or third with no parking brake. Too bad Globe is out of business. I think allied motors bought them, but I think it’ll be tough to get these things fixed or oh in the future. Or probably even to get spare parts.
jetdriven Posted March 4 Report Posted March 4 It was hard getting the cowl flap motor and gearbox out of them four years ago, and it’s not possible at all anymore. I have a brand new motor from that other assembly, but not the gearbox so if somebody needs a cowl flap motor, I’ve got it.
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