rear cowl flap motor

RRossner · #1 06-05-08, 06:38 PM

Yeah we've found them out there for around $3-4K but be careful with Owen Bells rear flap motor. We tried them in the past as well as others and they do not work! In fact we've seen them burn up on the first flight and Owen refuses to replace them.

Hank · #2 06-06-08, 11:55 AM

I had the Owen Bell mechanical conversion kit for the rear cowl flaps installed in my 1965 Skymaster. The system was installed by an experienced A&P and works fine. It did take some work to install properly. The T-handle can be be a little difficult to push in (close the rear cowl flaps) while in flight, sometimes I put on the autopilot and have to use both hands. I went this way because I had replaced the follow up cable twice in the past few years. The locking mechanism failed after a few months and Owen replaced it under warranty. I would recommend this system.

Richard · #3 06-07-08, 03:29 AM

This is going to be my next step. Fortunately, I've found a source that has a few used / functional units. We are negotiating on price right now. They are front motors and require me to take all they have. The asking price is going to be less than $1000 each. I'm seriously thinking about it since Cessna wants either your house or both kidneys for one.

Ernie Martin · #4 06-07-08, 04:10 PM

Richard:

I believe, as stated earlier, that the rear motor is a very different unit and that use of the front motor in the rear is a recipe for trouble. If I'm right, and if most of the failures are in the rear, is having a bunch of front motors a good idea? It would be an asset for Skymaster owners if you acquired such inventory, but I'd hate for you to be burned financially.

Ernie

Pete Somers · #5 06-08-08, 12:51 PM

I have just spent a couple of days just lookiing into the difference in the part numbers and why there is a a difference between the two and I have not found one yet.
A motor is a motor and to control these motors you have micro switches to limit the open and close limits. So any ideas?

Pete

Ernie Martin · #6 06-08-08, 01:03 PM

The rear one has a brake, the front one may not. Gearing and motor torque may be different, in part due to different aerodynamic forces that the device must overcome.

Ernie

Richard · #7 06-08-08, 08:23 PM

The front and rear are both a MIL SPEC 8609- motor, the 24 10,000 rpm motor is still the same, but that is the end of the similarities. (unless you are talking about early 337s and 336s, they have the same motor)

The front one is a 524.6:1 planetary gear motor which gives you 215 oz/in force.

The rear one is a 11??:1 planetary gear motor that gives you almost 500 oz/in of force as well as having an electric brake on the back. It is about 1.5"-2" longer than the front motor.

I've stayed up lots of nights counting all the gear teeth and figuring out the DC motor side.

One thing I have learned is how important that 2 amp inline fuse is to the system. There is enough force from the motors to cause some real damage before it overheats and burns out. The 2 amp fuse is there to protect both your skin and the motor windings.