Opinions on BP& Wing (Looking to Upgrade)

[ams511]

I find these discussions rather fruitless. The small wing proponents cite performance benefits for using a small wing as opposed to a large one, however I have yet to see a quantification as to the amount of the performance difference. I am not an engineer but I suspect that it can not be quantified because the difference in drag would vary depending on the shape of the wing, the shape of the diver, dimensions of the tank, exposure protection, type of diving, current, etc. For example, I would expect the performance loss of using a larger wing to be larger when diving against a current than with a current.

Also if you cut the buoyancy too close then you limit the amount of future accessories a diver can carry, items such as cameras, lights, reels, fins, etc. add up too.

 

[cool_hardware52]

My body: say it's ~1lb negative
Aluminum backplate: ~2lb negative
Steel 120, full: ~9lb negative
The human head: I prefer every bit of this to be out of the water, which means it's not displacing any water, so the whole weight pushes down, ~10lb
The head being out of the water also means some of the tank is out of the water, and it happens to be the heavy end with the neck, valve, and regulator.

I'm not 25 lbs negative. I'm still a little bit positive in this situation, enough so that I could fully exhale and my mouth would still be just barely out of the water. It's not the most comfortable thing though. I would be able to swim this rig up to a boat ladder if the wing exploded somehow, or if it were in the lake here I'd have a couple of hours if I felt like crawling to shore along the bottom. A few more pounds of lift would make floating on the surface relaxing, rather than something that takes a little bit of work. A few less pounds of lift would make it stressful. I see absolutely no point in that, there is just nothing about an ultra-small wing that I'm in love with, I have no compulsion to spoil my fun just to shave off every last bit of extra lift.

Do you think diving intentionally overweighted is a good thing? Is it responsible to advocate doing so on a public forum?

Tobin

 

[halocline]

The small wing proponents cite performance benefits for using a small wing as opposed to a large one, however I have yet to see a quantification as to the amount of the performance difference.

Here it is: small wings are more fun to dive with.

 

[ams511]

Here it is: small wings are more fun to dive with.

But how much more fun?

 

[victorzamora]

I find these discussions rather fruitless. The small wing proponents cite performance benefits for using a small wing as opposed to a large one, however I have yet to see a quantification as to the amount of the performance difference. I am not an engineer but I suspect that it can not be quantified because the difference in drag would vary depending on the shape of the wing, the shape of the diver, dimensions of the tank, exposure protection, type of diving, current, etc. For example, I would expect the performance loss of using a larger wing to be larger when diving against a current than with a current.

Also if you cut the buoyancy too close then you limit the amount of future accessories a diver can carry, items such as cameras, lights, reels, fins, etc. add up too.

I agree with you in that a slightly oversized wing is better than a wing with marginal lift. I like having the extra lift as a backup for a buddy. My wife's bcd failed (torn corrugated hose) and my extra lift allowed me to save her.

However, I disagree with literally every word you said about fluid dynamics and engineering. I feel confident disagreeing with you, as an Aerospace Engineer specializing in fluid dynamics. With or without a current, that doesn't matter. Drag is dependant upon the relative velocity of the body and the fluid in which is submerged, not the absolute velocity or the "ground speed"

Sent from my SCH-I545 using Tapatalk 4

 

[ams511]

Perhaps I should have been more precise in my wording. If you are drift diving (diving with the current) then the additional drag of a larger wing will not impact your performance as much as diving into the current. You are going with the flow than against the flow. Also isn't drag also dependent upon whether the fluid is disrupted or not before it meets the object? However being you are an engineer can you quantify the differences in performance between the wings?

 

[NAM001]

Im no engineer. can only speek from experience. If a 20 is needed a 30 is ok and a 50 is bad juju. 15# air lift in a small wing does not move much head to tail movement when using a small wing. perhaps a 3" movement. a large wing allows the same air to move drastically from one end to the other., a 12" movement perhaps. the wing taco ing minimizes the movement in a small wing and it enhances it is a too large wing. i had a dr transpac with a 50# wing on it. worked great till i took off the bungy cords then i was upright or feet up. i then got a dss wing 27# i think and all was well in the world. my doubles 47 is nice but i will probably never use my dr 68 ever again same problem. too much room for a bubble to run head to tail. i am now using oxytheq 30 or 32# single wings. no more dss (cant change bladders, and hose location) i put 10# lift of air and the bubble with the tacoing disperses it 2/3 to 3/4 the length of the wings sides. thats not much room for the bubble's center to move in responce to small trim changes. 3-4 inches perhaps. I am probably neg 15>-18 in my shorty wet suit. -10 tank -10 bp/w +9 wet suit -5 regs and stuff. so i might be able to use a 20-25# wing but i have a 32 for use with my ds and the 32 is not that much over sized for single diving and the reserve i can use for a buddy lift if needed. I seriously doubt that a 40 could work for me at all unless i was in doubles.

---------- Post added September 28th, 2013 at 01:28 PM ----------

pls help me understand your being light. -1 -2 -9 -10 is -23 and that is no regs or other crap you are carrying.ias it that you have a wet suit that comps for it. if so what are you at depth when the suit squeezes and looses its bouyancy. Then numbers are not adding up or subtracting down. When you are at the surface i would have to assume that you have a 25# lift to keep your head minimally above the water which is ok as you normally go right down and when you come up you have 5-10 less gass on you.

My body: say it's ~1lb negative
Aluminum backplate: ~2lb negative
Steel 120, full: ~9lb negative
The human head: I prefer every bit of this to be out of the water, which means it's not displacing any water, so the whole weight pushes down, ~10lb
The head being out of the water also means some of the tank is out of the water, and it happens to be the heavy end with the neck, valve, and regulator.

I'm not 25 lbs negative. I'm still a little bit positive in this situation, enough so that I could fully exhale and my mouth would still be just barely out of the water. It's not the most comfortable thing though. I would be able to swim this rig up to a boat ladder if the wing exploded somehow, or if it were in the lake here I'd have a couple of hours if I felt like crawling to shore along the bottom. A few more pounds of lift would make floating on the surface relaxing, rather than something that takes a little bit of work. A few less pounds of lift would make it stressful. I see absolutely no point in that, there is just nothing about an ultra-small wing that I'm in love with, I have no compulsion to spoil my fun just to shave off every last bit of extra lift.

 

[eelnoraa]

I think the point Tobin or others are trying to make is NOT to have the smallest wing, so that lift exactly = change in buoyance. But rather, an over size wing is NOT the answer to a over weighted rig. I do want a few lb of extra lift so that I can be more comfortable on surface, but I will never want to dive rig where if my wing fail, I will sink like a stone with empty tank

I find these discussions rather fruitless. The small wing proponents cite performance benefits for using a small wing as opposed to a large one, however I have yet to see a quantification as to the amount of the performance difference. I am not an engineer but I suspect that it can not be quantified because the difference in drag would vary depending on the shape of the wing, the shape of the diver, dimensions of the tank, exposure protection, type of diving, current, etc. For example, I would expect the performance loss of using a larger wing to be larger when diving against a current than with a current.

Also if you cut the buoyancy too close then you limit the amount of future accessories a diver can carry, items such as cameras, lights, reels, fins, etc. add up too.

 

[halocline]

But how much more fun?

Exactly this much.

 

[cool_hardware52]

I think the point Tobin or others are trying to make is NOT to have the smallest wing, so that lift exactly = change in buoyance. But rather, an over size wing is NOT the answer to a over weighted rig. I do want a few lb of extra lift so that I can be more comfortable on surface, but I will never want to dive rig where if my wing fail, I will sink like a stone with empty tank

Ding, ding, ding.....