Henry here. I used to subscribe to FF@ with Harry.
As I recall many years ago Harry and I had a discussion on FF@ on whether the hackle should be tied concave (dull side) down or convex (shiny side) down.
Unlike a standard dry, the hackle of a parachute is ABOVE the body of the fly. Therefore, the profile of the fly on the water differs from the standard palmered hackle dry fly.
Consider if the parachute hackle were straight. The hackle supports the fly so the body being UNDERNEATH the hackle would lie on or in the film. But the hackle is not straight. It is curved as Harry says and the amount of the curve depends on whether you are using neck or saddle hackle.
If you use oversized (longer by 2 hook sizes) neck hackle, tie with convex side down, tying off at the head; you get the tips below the body and the body sits high on the film. If you tie with saddle hackle, tie with the convex side down, and tie off on the post; you get a body that sits IN the film.
I used to tie concave side down and tie off on the head of the fly to get the highest float I could. Now I tie convex side down and tie off on the post to get the lowest profile and place the body of the fly IN the film. Why did I change?
Gary Borger changed my mind. Rather than a true dry fly, he believes the parachute adams is the universal emerger. With a body in the film, he believes that the parachute hackle simulates the the legs of the insect and the post, rather than an upright wing, actually simulates the emerging body of the insect.
For those of you that are familiar with the Klinkhammer by Hans van Klinken, it was designed to be a caddis emerger. It is a essentially a parachute adams type of fly tied on a curve hook without a tail so that the fly penetrates the film as it drops on the water. This type of fly falls into what are termed “suspender” patterns because they are suspended in the film. In fact you an turn a regular adams into a Klinkhammer by some simple modifications I wrote about on pg. 23 in Wisconsin Trout. The Klinkhammer pattern is mislabeled as a spinner but you will get the idea.
Another fly that sits low on/in the film is the sparkle dun of Craig Mathews. The zelon tail is critical in making this fly more effective than the comparadun of Al Caucci. Mathews says the zelon is the nymphal shuck. So Is it a dry or a late stage emerger? I believe it is late stage emerger. And I also believe if you use zelon or wood duck for the tail of a parachute, it makes for a better emerger pattern. Why are these two patterns so successful? As Gary says, it is because you can’t run with your pants down. An emerger is a fly with its pants down.
A version of the parachute is the paraloop or hackle stacker fly. Again I believe it is more a late stage emerger than a true dry because it sits low on/in the film. Tied on a curved hook with CDC like this fly, it definitely is an emerger. But how about the Quigley Hackle Stacker Dun tied with a zelon tail. Is it more a dun or a late stage emerger?
Harry has a tutorial on tying the paraloop/hackle stacker patterns.
http://www.troutflies.com/tutorials/stacker/index.shtml
I’ve believed from the early days on FF@ that naturals in the process of emergence are continuum of metamorphosis. We try to imitate this process of change with flies which are a single moment in this process. I believe that is one reason why there are soooo many emerger patterns. I happen to believe that parachutes are closer to emerger than the subimago immature adult, so I now tie them with saddle hackle with convex side down, tied off on the post to get the lowest profile I can.