rear cowl flap motor

[Richard]

Any ideas why these things cost so much? Cessna (if they have any in stock) are asking over 3k for these. I've owned 4 Skymasters and all of them have had one or both fail. Only when I started researching, carefully, what partnumbers they were using did I discover why the rear is failing more frequently than the front.

The motor in the rear is a different motor than the front. Early Skymasters had the same motor, but I'm sure they quickly figured out the rear needed a higher gear ratio and brake. It's all too common though that I check out other peoples craft and see they are using the smaller motor in the rear. Could this be a reason for common failures?

Anyone found tips for extending the life of these units?

[Ernie Martin]

My rear cowl flap motor recently failed and I've spent the past few days researching the matter, so let me update some of the information you just posted.

A new Cessna motor now lists for $6095 and Yingling will give you a bit of a discount and sell it for $5409. Although the price seems high, it's not out of line with other aerospace itmes when you consider the size and complexity of the elements (especially the planetary gears) inside the motor and the small production number.

I have all the parts catalogs dating back to 1965 and a) the rear motor part number hasn't changed, and b) it's different from the front part number for all years. That suggests that early models did not use the same motor in the front and the rear. Perhaps the cases you have seen using the smaller motor in the rear are the result of erroneous replacement. Or perhaps the same motor was indeed used for a short while and the catalogs were later changed to reflect that they should be different.

Don Nieser at Commodore (405-503-4686) had as of this afternoon a new Cessna rear motor that he will sell for considerably less than $6000 -- in the $3,000 to $4,000 range.

Owen Bell at Aviation Enterprises (615-865-1802) has a new PMA rear motor for around $1,500 to $2,000 exchange, and an STC that replaces the motor and actuates the cowl flaps mechanically with a cable system.

Both of these gentlemen sometimes have rebuilt used motors.

Ernie

[RRossner]

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]

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]

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]

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]

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