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Rotary Wing
Discuss helicopters and other rotary wing aircraft from any era.
Could this chopper float in case of emergency
ubisuck
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Quebec, Canada
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Posted: Tuesday, July 26, 2016 - 07:15 PM UTC
I've always wondered if the MH-53, with the big things on each sides (lack of the real word/names), they could float if landing in water in not too heavy weather. I know it's probably a dumb question but you do know (I am certain) what they (who?) say: there's no dumb questions, only..........( or whatever)!

I guess the question is mainly for HeavyArty, but anyone who knows the answer, feel free to help me go to sleep less dumb tonight, or, to be politically correct: go to bed more intelligent!

Here's what I mean by big things on each sides:

Jessie_C
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British Columbia, Canada
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Posted: Tuesday, July 26, 2016 - 07:45 PM UTC
Those side sponsons are fuel tanks, and the surrounding structure is not watertight, so it would not float well, nor for long. The problem with helicopters is that all the heavy parts (engines, transmissions, rotor head and rotors) are all above the centre of gravity, so when one winds up in the oggin, it almost immediately turns upside down and then behaves like a homesick flounder.

Even boat-hull helicopters such as the Sea Thing and the Mi-14 need to keep their rotors turning when they're on the water, which causes its own set of problems.
ubisuck
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Quebec, Canada
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Posted: Tuesday, July 26, 2016 - 07:55 PM UTC
Thank you Jessie

[EDIT] WoW, as soon as the blades touches water, the chopper disintegrate almost as fast as clicking your fingers.
Jessie_C
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British Columbia, Canada
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Posted: Tuesday, July 26, 2016 - 08:19 PM UTC
Rotor systems are very delicately balanced. The slightest thing to throw it out of balance causes the helicopter to beat itself to death in a heartbeat.
Kepler
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Genova, Italy
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Posted: Tuesday, July 26, 2016 - 08:20 PM UTC
I think they are oversize fuel tanks for long-range combat SAR operations. Also, I think a Sea Stallion should float, at least for some time, but not as a standard operational feature.
phantom_phanatic309
#372
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United Kingdom
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Posted: Tuesday, July 26, 2016 - 08:31 PM UTC

Quoted Text

Those side sponsons are fuel tanks, and the surrounding structure is not watertight, so it would not float well, nor for long. The problem with helicopters is that all the heavy parts (engines, transmissions, rotor head and rotors) are all above the centre of gravity, so when one winds up in the oggin, it almost immediately turns upside down and then behaves like a homesick flounder.

Even boat-hull helicopters such as the Sea Thing and the Mi-14 need to keep their rotors turning when they're on the water, which causes its own set of problems.



Any idea if the crew got out of that?
Jessie_C
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British Columbia, Canada
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Posted: Tuesday, July 26, 2016 - 08:57 PM UTC

Quoted Text


Any idea if the crew got out of that?



Apparently the pilot was killed, but everyone else escaped.
HeavyArty
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Florida, United States
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Posted: Tuesday, July 26, 2016 - 09:54 PM UTC
As Jessica already stated, the CH-53 does not float. The only non-boathull helo I know of that does float with its blades not turning is the CH-47 Chinook.




They are commonly used to retrieve special ops by landing in the water and driving the boat right up inside them.



Video of operation.

Even the Navy/Marine CH-46 needs additional floatation bags to keep afloat. You can see one just behind the gunners door below.

ubisuck
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Quebec, Canada
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Posted: Tuesday, July 26, 2016 - 10:22 PM UTC
Thank you everyone. Gino, great photos as always. Jessie, as I said earlier: nice clip.

Marc/ubi

[EDIT] Oh Mr Gino, just noticed you had a clip too. Thank you. Probably SEALS?
fhvn4d
#159
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Massachusetts, United States
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Posted: Tuesday, July 26, 2016 - 10:25 PM UTC
A study done in 1981 states that the CH-53 does in fact float under certain conditions....... Refer to page 17-19 of the study

http://www.dtic.mil/dtic/tr/fulltext/u2/a101640.pdf

Please not that this study was done to determine what if any additional floation would be needed to allow the 53 Echo model to sustain floation in sea state 5 and allow a full cabin of passengers time to evacuate the aircraft. Interesting reading and Im not at all saying it would float around like a ship for days... but worthy of note.
Jessie_C
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Posted: Tuesday, July 26, 2016 - 10:33 PM UTC

Quoted Text

Even the Navy/Marine CH-46 needs additional floatation bags to keep afloat.



The Vertol 107 could be made to float; the RCAF's rescue Labradors had the capacity, but I believe the USN/USMC didn't order theirs to the same standard. The Labradors had nice buoyant fuel tanks on the rear sponsons, for example
ubisuck
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Quebec, Canada
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Posted: Wednesday, July 27, 2016 - 12:20 AM UTC
Jessica, what happens if they stop the blades? I'm talking about the last photo you posted.
Jessie_C
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Posted: Wednesday, July 27, 2016 - 01:05 AM UTC
It would get a lot less stable, and be prone to rolling over. Remember that all the heavy parts are on top. It would be like balancing a balloon with a bolt taped to it and trying to keep the bolt on top of the balloon.

I think that a Lab would float for quite a while as long as the water is fairly calm, but if the waves get up it would roll over sooner or later.
ubisuck
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Quebec, Canada
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Posted: Wednesday, July 27, 2016 - 01:45 AM UTC
It's very logical Jessie. Thank you for the answer ;-)

Marc/ubi
Jessie_C
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British Columbia, Canada
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Posted: Wednesday, July 27, 2016 - 10:02 PM UTC
If they're going to do a lot of flying overwater, helicopters get equipped with inflatable emergency floatation systems. Here's an A 109 with its floats deployed.


The thread-starting MH-53 has such a system. Of course it will only be deployed in an emergency landing situation such as an engine or transmission failure scenario offshore. That's what the floatation study posted by Brian up the thread was based on. The emergency floats greatly increase the helicopter's "stability pyramid" and prevent it from rolling over for long enough for the crew and passengers to escape. They also will keep it from sinking even if it does roll over later on.

ubisuck
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Quebec, Canada
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Posted: Thursday, July 28, 2016 - 12:08 AM UTC
Jessie: Again, nice photos ;-)
CaptnTommy
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Connecticut, United States
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Posted: Sunday, January 08, 2017 - 10:53 PM UTC
Ubisuck

The MH-53e is a mine sweeping Helicopter and as another writer replied the large sponsons are gas tanks.

As to floating... YES BUT...Notice the height of the aircraft the weight of the rotor and gearbox would roll the helicopter on its Back. Capsize!!!

If the main rotor is under power, and a blade hits the water the action of 15000 horsepower stopping would instantly destroy the airframe and kill those aboard.

If the aircraft were going down at sea the engines would be shut down and the pilot would auto-rotate to the landing that way the freely rotating blades would not destroy the aircraft (though the tail might come off)

The thing is, it will sink, it is so heavy (34376 lbs empty) it will not float for more than 15 seconds (in the book), but that is enough time to evacuate. The crews are trained for this.

I worked on the aircraft and at Sikorsky for a while in the last century.

Captn Tommy
JClapp
#259
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Posted: Sunday, January 08, 2017 - 11:48 PM UTC

Quoted Text

Rotor systems are very delicately balanced. The slightest thing to throw it out of balance causes the helicopter to beat itself to death in a heartbeat.




oh dear...

RLlockie
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United Kingdom
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Posted: Monday, January 09, 2017 - 04:06 AM UTC
As I recall (wings things, whether fixed or rotary, are not my field), the Westland Wasp (Scout with wheels instead of skids) had its flotation aids mounted up high. While this ensured that everyone inside got wet while evacuating, in a ditching at least the aircraft had a reasonable chance of remaining upright for long enough to do so.
ubisuck
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Quebec, Canada
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Posted: Saturday, February 11, 2017 - 10:49 PM UTC

Quoted Text

Ubisuck

The MH-53e is a mine sweeping Helicopter and as another writer replied the large sponsons are gas tanks.

As to floating... YES BUT...Notice the height of the aircraft the weight of the rotor and gearbox would roll the helicopter on its Back. Capsize!!!

If the main rotor is under power, and a blade hits the water the action of 15000 horsepower stopping would instantly destroy the airframe and kill those aboard.

If the aircraft were going down at sea the engines would be shut down and the pilot would auto-rotate to the landing that way the freely rotating blades would not destroy the aircraft (though the tail might come off)

The thing is, it will sink, it is so heavy (34376 lbs empty) it will not float for more than 15 seconds (in the book), but that is enough time to evacuate. The crews are trained for this.

I worked on the aircraft and at Sikorsky for a while in the last century.

Captn Tommy



Thank you very much for this explanation

EDIT: RLlockie too ;-)