Okay, I know that some of you that read this are going to end up thinking "duh! It took you THIS long to figure that out?!?!?" But, well, yes, it did. In my defense, I have used my DR wing almost exclusively since I got it and I never had any trouble with it... So anyway, I'm posting this because I really wish somebody had told me this a year and a half ago when I started diving doubles.
I've had or have 4 doubles wings:
OMS 60 (horseshoe)
Dive Rite Rec EXP (45# donut)
Halcyon Explorer 55 (horseshoe)
Oxycheq Vertex Extreme 55 (donut)
I got the OMS wing and had no trouble getting good trim with it right off the bat. I never needed any weight beyond just my SS back plate. But, I bought it used and didn't realize until I had it that it is an older model with the inflator coming out of the front side of the wing instead of the back. That bothers my OCD, so I bought the DR.
The DR wing also gave me good trim right out of the box and has continued to do so, wet or dry, Kydex BP, SS BP, and SS BP with extra weight in V-weight pouch (which is mounted between the doubles band bolts, sandwiched between the tanks and BP). It just works.
I thought I might want more lift when diving cold water in a dry suit and carrying a deco bottle, so I bought the H wing. That wing only has one set of holes, so no way to adjust the wing position to affect trim. And it always wanted to put me head down/feet up. I tried a few quarry and pool sessions with it and couldn't get it to allow me good trim. And, at the time, I didn't want to hassle with adding a tail weight. So, I sold it.
More recently, I got the Oxy wing and just got to go try it out. With my dry suit but no undies, and no V-weight, I got good trim. Then I put on my undies and added my V-weight and it immediately started trying to stand me on my head. Very frustrating. Actually, it was more "interesting" than that. What it seemed to be doing was, if I got in a trim that was slightly head up, it was fine. But, as soon as I went truly horizontal, THEN as soon as I stopped moving my feet, I would quickly start to face plant.
I was just having a conversation about this subject and had an epiphany regarding my experience. I realized two things:
The DR wing side chambers are almost pure cylinders. In other words, they stay the same diameter from top to bottom (of the sides). In contrast, the H wing and the Oxy wing both get bigger towards the bottom (i.e. the end closer to the bottom of the tank).
I think this explains why they tend to make me go head down versus the DR which keeps me in proper trim. Putting more air in the H or Oxy wing puts more lift down by my waist (when I'm truly horizontal), instead of being evenly distributed along the length of my tank. If I'm slightly head up, the air would distribute more towards the top/front of the wing and I would be fine (as I experienced with the Oxy). Further, with the Oxy, it was less pronounced than the H. It only did it after I added the V-weight in the middle. But, that still seems to jibe with my theory. I added weight in the middle of the tanks, but adding more air to the Oxy to compensate would add the lift closer to the bottom of the tanks, thus promoting a forward roll.
So, the second part of my epiphany was that I don't necessarily have to add a tail weight in order to use the Oxy wing. I can use a weight belt and add weight there or move weight from the V-weight to my waist, in order to get it balanced.
It all seems so simple and obvious, now. But, the influence of the wing side chamber shape on my trim never really "clicked" in my head. Now that it has, I really wish somebody had explained all this to me a year and a half ago. Maybe my tech instructor should have, but he didn't and now it's all water under the bridge. Maybe he figured it was just obvious and didn't need explaining. Regardless, I'm just glad I feel like I finally figured something out, so I can (hopefully) get any wing to work for me now.
Comments to enhance my understanding further or correct me where I've come to a wrong conclusion would be VERY welcome!
I've had or have 4 doubles wings:
OMS 60 (horseshoe)
Dive Rite Rec EXP (45# donut)
Halcyon Explorer 55 (horseshoe)
Oxycheq Vertex Extreme 55 (donut)
I got the OMS wing and had no trouble getting good trim with it right off the bat. I never needed any weight beyond just my SS back plate. But, I bought it used and didn't realize until I had it that it is an older model with the inflator coming out of the front side of the wing instead of the back. That bothers my OCD, so I bought the DR.
The DR wing also gave me good trim right out of the box and has continued to do so, wet or dry, Kydex BP, SS BP, and SS BP with extra weight in V-weight pouch (which is mounted between the doubles band bolts, sandwiched between the tanks and BP). It just works.
I thought I might want more lift when diving cold water in a dry suit and carrying a deco bottle, so I bought the H wing. That wing only has one set of holes, so no way to adjust the wing position to affect trim. And it always wanted to put me head down/feet up. I tried a few quarry and pool sessions with it and couldn't get it to allow me good trim. And, at the time, I didn't want to hassle with adding a tail weight. So, I sold it.
More recently, I got the Oxy wing and just got to go try it out. With my dry suit but no undies, and no V-weight, I got good trim. Then I put on my undies and added my V-weight and it immediately started trying to stand me on my head. Very frustrating. Actually, it was more "interesting" than that. What it seemed to be doing was, if I got in a trim that was slightly head up, it was fine. But, as soon as I went truly horizontal, THEN as soon as I stopped moving my feet, I would quickly start to face plant.
I was just having a conversation about this subject and had an epiphany regarding my experience. I realized two things:
The DR wing side chambers are almost pure cylinders. In other words, they stay the same diameter from top to bottom (of the sides). In contrast, the H wing and the Oxy wing both get bigger towards the bottom (i.e. the end closer to the bottom of the tank).
I think this explains why they tend to make me go head down versus the DR which keeps me in proper trim. Putting more air in the H or Oxy wing puts more lift down by my waist (when I'm truly horizontal), instead of being evenly distributed along the length of my tank. If I'm slightly head up, the air would distribute more towards the top/front of the wing and I would be fine (as I experienced with the Oxy). Further, with the Oxy, it was less pronounced than the H. It only did it after I added the V-weight in the middle. But, that still seems to jibe with my theory. I added weight in the middle of the tanks, but adding more air to the Oxy to compensate would add the lift closer to the bottom of the tanks, thus promoting a forward roll.
So, the second part of my epiphany was that I don't necessarily have to add a tail weight in order to use the Oxy wing. I can use a weight belt and add weight there or move weight from the V-weight to my waist, in order to get it balanced.
It all seems so simple and obvious, now. But, the influence of the wing side chamber shape on my trim never really "clicked" in my head. Now that it has, I really wish somebody had explained all this to me a year and a half ago. Maybe my tech instructor should have, but he didn't and now it's all water under the bridge. Maybe he figured it was just obvious and didn't need explaining. Regardless, I'm just glad I feel like I finally figured something out, so I can (hopefully) get any wing to work for me now.
Comments to enhance my understanding further or correct me where I've come to a wrong conclusion would be VERY welcome!
