I have to get there next year. Still stuck in Taiwan on an extended business trip (darn day job).
I was talking with Tim Van Milligan prior to the event and he was planning a presentation on a drag study done on the airfoil rail guides. Anything happen on that subject? Maybe I will ask his permission to post it here.
Yeah, that one was really interesting. He examined drag on 1/4 inch launch lugs vs. rail buttons vs. rail guides, and included the airfoiled buttons. It had some interesting and surprising results.
Nutshell: Rail buttons had the highest drag by far (in a computer simulation), followed by rail guides and airfoil buttons (though I don't remember exactly the order or the figures), followed by launch lugs. Long lugs have
less drag than short ones, and angling the leading edge at 45 degrees reduces drag, but angling the trailing edge
forward by 45 degrees actually increases it, while angling it
back (i.e. to match the angle of the forward swept end) reduces it further. A fillet appears to reduce drag on a lug. An internal chamfer increases drag, while rounding the outside forward edge decreases it.
Ideal looks like a longer lug, both ends swept back by 45 degrees, with the leading outside edge rounded and the whole thing filletted.
Of course, this is based on a computer airflow simulation, and may or may not really apply to real life. Also, to get good numbers, he increased the size of the simulated model by (I think) about 10X. Really, wind tunnel tests and flight tests may be necessary to determine if the simulations are correct, and how much if at all actual flight would be affected.
Oh, and rounding the top edge of the airfoiled buttons also seems to help.
The whole report will likely be the topic of a forthcoming Apogee newsletter. I thought it was great, because I've seen people claim that rail buttons have lower drag several times, but to my knowledge that had never actually been put to the test. I'd like to see more.