Bill, the most common occurrence is that the main gear doors flex closed at the back due to air loads, and “trap” one or both mains, preventing them from fully retracting. Note that the retraction speed is lower than the extension speed--I suspect to compensate for the very strong prop blast under the airplane during takeoff? If the gear doesn’t retract because of this problem, reduce the power, slow down, extend the gear and try it again. If you suspect other gear problems, I’d put the gear down and if it extends normally, land and check it out. There are some malfunctions that can keep the gear from extending. This is not good…but having them hang up on retraction should be a minor issue; at most some chipped paint.

The gear actually tends to hang on the bolts holding the axle to the gear leg, or part of the brake assembly. You can usually tell after landing by the chipped paint on the inside of the gear door(s). In any case, the stiffness of the gear doors will have a lot of influence on whether the main(s) get hung up or not. Lancair modified their gear door build plans in about 2002 to significantly stiffen them. I incorporated this change and have had no trouble at all with mine. I tested retraction to 130 KIAS during my Phase I, but am probably lifting the gear more quickly than I should during normal operation, so I don’t think I get to 120 before the gear is secure during normal ops. By the way, I have only one (2 specified) springs on the back of each main gear door to close it.

You didn’t ask, but if you fail to re-connect the nose gear door operating linkage (after replacing the lower cowl?), the nose gear doors will swing shut a bit under air loads and trap the nose gear in a partially-retracted position (this one I know from personal experience!) It should extend normally by pushing the doors out of the way in the process. The only fix for this problem is to land and re-attach the linkage. I have not tried, but would bet money you’ll not get the nose gear past the doors, and even if you did, you’d have the doors flapping in the breeze.

By the way, I’m talking about mild exceedence of the published limits above. If you’re talking extending/retracting above 150 KIAS, then I’d think you could expect damage/loss of the gear doors, and possibly to other aircraft damage.

Bob Pastusek