For those of you who asked, I used McMaster-Carr (www.mcmastercarr.com) part number 1042K11, on page 983 of their current catalogue, to slow my flap retraction.

Although their catalogue doesn’t show it, this valve is equipped with a one-way check valve that allows it to free-flow in one direction, and moderate the flow via the adjustment knob in the other direction. I plumbed this into the base of the flap control cylinder (the port nearest the cylinder mounting flange; not the end with the operating rod) so it permits unrestricted flow out the cylinder, but regulates the inflow. Note that the Lancair-provided valve controls flow into (and out of) the other side of the cylinder- and thereby still controls flap extension speed. (Haven’t thought about why it doesn’t slow the flap travel in both directions; I suppose it does, but not sufficiently to suit me). With this set up, I was able to adjust the flap travel to approximately 4 seconds in each direction—on the ground—which seems comfortable in flight, although I have not timed the flaps in flight operation. This is a fairly easy mod, without any adverse effects I can determine. I’ve been very pleased with its operation in the  approximately 100 hours now on N437RP.

I suspect there are other ways to control flap retraction, but this has the advantage of giving full control in both directions. BTW, although the locking devices are different, the settings on both valves can be locked once you are satisfied.

Bob