[kevin]

Just to clarify, in case anybody else misreads Mark's post, as I did at first, when Mark says you "lose 100 FPM" he means "your climb rate is reduced by 100 FPM". So if you had 375 FPM with the gear up, it would be 275 FPM with the gear down.

I have experimented some with this, and I am not sure the penalty for having the gear remain down is as high as 100 FPM, but there is some penalty. The airplane does climb amazingly well with the gear down though. I experimented with this to determine if, during a best angle, short field departure, I was better off raising the gear, or leaving it down until I had cleared the obstacles. I decided that I was better off leaving the gear down and continuing to climb at 75 MPH (RSTOL) until the obstacles are cleared, then pushing the nose over and raising the gear when I got a bit more speed. If I remember right, this is the Robertson recommended procedure as well.

On the other hand, I am even more pessimistic than Mark about gear doors stuck in transit. I would be very suprised if an airplane with the gear doors stuck in transit (and an engine out) would maintain level flight. My copy of the O-2 flight manual says that the doors extract a 240 FPM climb penalty during transit, at least after a rear engine failure. If you take the performance numbers from a '67 337, the best single engine rate of climb, rear engine feathered, is 335 FPM at sea level on a standard day. I suspect real world performance is 100 FPM less than that, meaning that having the doors stuck open would result in a gradual descent.

This leads to my strong belief that Skymasters built before 1973 which have the hydraulic pump on one engine and have not had the gear door removable mod done should be flown with the gear down during takeoff until a comfortable altitude is reached, maybe 800' or so. Why? If the "wrong" engine (the one with the pump) fails at exactly the wrong time during the gear retraction, I would not want to be trying to hand pump the gear to finish the retraction cycle at the same time I was feathering an engine and dealing with the rest of the emergency. I know, supposedly if you leave the engine unfeathered until the gear comes up the rest of the way, you can deal with it that way. But that would induce a real "sinking feeling" as well, with the prop windmilling and the gear slowly retracting. And I am not completely convinced that the prop would keep windmilling, depending on the situation and the type of engine failure...

Post '72 Skymasters should use positive rate, gear up in my opinion. With the electric hydralic pump, the gear will continue to retract no matter which engine fails.

My opinion only, each pilot should look at the data and make his own decision. Cessna's recommendation is to retract the gear immediately (positive rate, gear up) on all models of 337.

Kevin