Wing Drag

[rhincodon]

I've noticed that when diving with a wing completely or close to completely deflated, you end up with this sort of flat piece of material flapping behind you. I'm curious if this creates much drag? Probably not an issue in most situations, but say you have to swim against a strong current, will it create additional drag? I tried researching this, but couldn't find a whole lot of information, just a bungee vs non bungee debate that went south fast.

Regards
Jon

 

[tbone1004]

yes it creates drag, this is why it is important to have a wing only as large as you absolutely need.

 

[JamesDownUnder]

Adding bungee to wing to compress the excess when not fully inflated can help too. I don't have my wing set up that way but I know others who swear by it.


Posting from my iPad, please excuse unfortunate iCorrects.

 

[tbone1004]

and there are many more who swear against it. The danger of bungeeing a wing is that depending on the bungee you may or may not be able to orally inflate the wing in an emergency.... They also don't help to reduce drag significantly because they create turbulent spots on the wing. Best to have a wing sized appropriately.

 

[ams511]

I tried researching this, but couldn't find a whole lot of information, just a bungee vs non bungee debate that went south fast.

Jon, I don't think this was ever researched, because to do so properly a manufacturer would need access to a wave tank and testing equipment. I am sure it would be costly and provide little benefit.

Common sense would dictate that it would add additional drag, how much is the question. Your head and shoulders are displacing the water as well as the tank. I am not sure if the drag of the flapping wing would be noticeable. Just look at all the gear divers (especially tech divers) carry, when carry stages or wearing a dry suit I can't imagine a flopping wing adding much more drag.

---------- Post added May 17th, 2015 at 11:15 PM ----------

and there are many more who swear against it. The danger of bungeeing a wing is that depending on the bungee you may or may not be able to orally inflate the wing in an emergency.... They also don't help to reduce drag significantly because they create turbulent spots on the wing. Best to have a wing sized appropriately.

Many people may swear against it but many people just repeat the information they read and do not evaluate it. The whole bungie debate started when the DIR/GUE group rallied against the OMS "bondage" wing. OMS used to sell grossly oversized wings and then added bungies to control the shape of the wing. Wings like that haven't been sold for years. A modern bungie wing such as the Express Tech 24 or the new Hollis wings allow you to manually inflate the wing without any problem and have no turbulent spots. Next time you are at a dive shop that sells such equipment take a look at it. BTW, I have seem videos on YouTube of divers manually inflating the OMS bungie wings without any issues.

 

[eelnoraa]

The issue with bungee wing isn't so much about oral inflating, it is about if a wing fail in area except the most top portion like the elbow, you can still using the wing to make a proper ascent. With bungee wing, air will be force out of the wing. Personally, I have lost an OPV in a dive. And I have seen someone losing a inflator.

As for drag, I highly doubt a properly design wing will create much drag empty. A fully inflated wing creates far more drag. So get a properly design wing, and don't over weight

 

[ams511]

The issue with bungee wing isn't so much about oral inflating, it is about if a wing fail in area except the most top portion like the elbow, you can still using the wing to make a proper ascent. With bungee wing, air will be force out of the wing. Personally, I have lost an OPV in a dive. And I have seen someone losing a inflator.

As for drag, I highly doubt a properly design wing will create much drag empty. A fully inflated wing creates far more drag. So get a properly design wing, and don't over weight

I have seen inflators detach from BCs also. Usually the ones that incorporate a pull dump in the design. I never seen an OPV break but I guess it can happen. However in case of a total BC failure then the diver can ascend using muscle power if diving a balanced rig or drop the ditchable weight. If the diver is using doubles then the dry suit should provide redundant buoyancy. However, I do see the point that bungee wings are probably not ideal for an overhead environment.

 

[dumpsterDiver]

I've had BC's break in both locations. WATER PRESSURE will force the air out of a BC bladder.. don't be ridiculous..

 

[halocline]

The main issue with bungeed wings is that the bungees are often used to try to compensate for wings that are far too large, like a wing that tries to be a single/doubles hybrid. If you took the bungees off the wing and just used it, you'd still have the same problems of 'tacoing' and venting that a too-large wing presents. An additional problem with the bungees is that they might make the wing a bit harder to completely vent by creating some pockets for air bubbles to accumulate.

Lots of people talk about drag created by wings that are too large; I think this is a bit overstated. The big problem with too-large wings is venting and managing the air bubble. When a wing is compact and fits snugly around the tank, the bubble stays put. Making small adjustments in buoyancy and venting are much easier.

 

[lv2dive]

I've pulled an OPV off a wing too, and had no problem with the rest of the dive (couple of hours) - just got a little out of trim and the gas stayed in the top of the wing.

Was discussing this topic with friends who mentioned they saw same thing happen to diver wearing bungee'd wing and he ended up crawling out of cave creating hot mess. Ouch.

Mentioned both stories to another friend who dives a bungee'd wing and he said in that situation he would have cut the bungee ergo no issue.

Found both conversations enlightening.

---------- Post added May 18th, 2015 at 08:46 AM ----------

BTW my personal opinion is dive the right size wing for the tanks, period. In the case of my friend who dives a bungee'd wing, he is using bungees to manage *how* the gas is distributed for SM (not bc wing is too big) which sounds logical to me. I'm sure I didn't explain that perfectly but that was my understanding.