The Melting Deck Plates Muddle - V-22 on LHD deck....

On Dec 9, 11:22*pm, Mike wrote:
StrategyPage.com
December 2, 2009

The Melting Deck Plates Muddle

by James Dunnigan

Earlier this year, the U.S. Navy discovered that the heat from the
MV-22's gas turbine engines, which blow their exhaust right on to the
deck of the LHD while waiting to take off, caused high enough
temperatures to the steel under the deck plates, to possibly warp the
understructure. This was already a known potential problem with the
new F-35B vertical takeoff jet fighter.
So now the Navy has two hot new aircraft that require an innovative
solution to the melting deck problem. The Navy also discovered that
the exhaust heat problem varied in intensity between different classes
of helicopter carriers (each with a different deck design.)

The Navy is looking for a solution that will not require extensive
modification of current carrier decks. This includes a lot of decks,
both the eleven large carriers, and the ten smaller LHAs and LHDs.
This is shaping up as another multi-billion dollar "oops" moment, as
the melting deck problem was never brought up during the long
development of either aircraft.

Previously, the Harrier was the only aircraft to put serious amounts
of heat on the carrier deck, but not enough to do damage. But when you
compare the Harrier engine with those on the V-22 and F-35B, you can
easily see that there is a lot more heat coming out of the two more
recent aircraft. Someone should have done the math before it became a
real problem.

How about false deck mobile deflectors that would be rolled into
place and exchanged between launches? The tractors exist.

On Dec 9, 11:22*pm, Mike wrote:
StrategyPage.com
December 2, 2009

The Melting Deck Plates Muddle

by James Dunnigan

Earlier this year, the U.S. Navy discovered that the heat from the
MV-22's gas turbine engines, which blow their exhaust right on to the
deck of the LHD while waiting to take off, caused high enough
temperatures to the steel under the deck plates, to possibly warp the
understructure. This was already a known potential problem with the
new F-35B vertical takeoff jet fighter.
So now the Navy has two hot new aircraft that require an innovative
solution to the melting deck problem. The Navy also discovered that
the exhaust heat problem varied in intensity between different classes
of helicopter carriers (each with a different deck design.)

The Navy is looking for a solution that will not require extensive
modification of current carrier decks. This includes a lot of decks,
both the eleven large carriers, and the ten smaller LHAs and LHDs.
This is shaping up as another multi-billion dollar "oops" moment, as
the melting deck problem was never brought up during the long
development of either aircraft.

Previously, the Harrier was the only aircraft to put serious amounts
of heat on the carrier deck, but not enough to do damage. But when you
compare the Harrier engine with those on the V-22 and F-35B, you can
easily see that there is a lot more heat coming out of the two more
recent aircraft. Someone should have done the math before it became a
real problem.

Here is the problem laid out in numbers


F-35 and V-22: Keeping it Cool on Deck
Posted by Graham Warwick at 6/24/2009 8:43 AM CDT

We've heard how the stealthy F-22 and F-35 are flying thermos bottles,
struggling under the huge heat loads imposed by their powerful engines
and systems. Well it seems the latest generation of vertical-lift
aircraft is turning the flight decks of US Navy amphibious assault
ships into frying pans.

blog post photo

Photo: US Navy

The initial culprit is the MV-22 tiltrotor, but the big concern is the
STOVL F-35B, which is due on deck after 2012. With nacelles tilted and
rotors turning, hot exhaust from the Osprey's engines is buckling the
decks, and Navy studies warn repeated buckling will cause deck failure
at 40% of planned ship life. F-35B exhaust plumes are expected to have
a "severe thermo-mechanical impact" on the structure and non-skid
surface of the flight deck.

That's according to a new solicitation from the Office of Naval
Research, which is looking for new ideas for flight deck thermal
management. The solicitation is looking for alternatives to a DARPA/
ONR program that is already looking at "cooled heat pipe technologies"
to overcome the thermal issues.

It's not a trivial problem. For the MV-22, where the exhausts are
close to the deck when the nacelles are vertical, buckling has been
observed after just 10min of sitting on the deck, rotors turning. The
F-35B will be in STOVL mode for a fraction of that time, but is
expected to cause even more heating of the deck.

ONR is looking for thermal management technologies that can keep the
deck surface temperature below 300ºF when exposed to MV-22 exhaust
plumes for 90 minutes before takeoff, and F-35B exhaust plumes for 2
minutes when landing. And cooling the deck is not enough - any
solution has to be compatible with the deck's non-skid coating. It
also has to be affordable and capable of being installed below deck or
retrofitted above deck. Tall order.

blog post photo
Photo: Lockheed Martin

Based on measurements taken during recent hover-pit tests, Lockheed
Martin does not believe there will be an issue with deck temperatures.
One acknowledged area of concern is the combined auxiliary/emergency
powerpack, or IPP, which exhausts downwards on the STOVL aircraft. (It
exhausts upwards on the F-35C carrier variant to protect deck crew,
but downwards on the F-35B and CTOL F-35A to save weight and gain fuel
volume.)

The IPP has two modes: bleed and bleed-and-burn. In bleed mode the
exhaust is relatively cool, Lockheed says. In bleed-and-burn, fuel is
burned in the IPP to generate more power, and exhaust temperature
rises. Because of operator concerns about surface heating, Lockheed
says the pilot will have the ability to switch the IPP back to bleed
mode if holding on the runway, or deck.

http://www.aviationweek.com/aw/blogs...6-08049291946b

On Dec 9, 9:22*pm, Mike wrote:
StrategyPage.com
December 2, 2009

The Melting Deck Plates Muddle

by James Dunnigan

Earlier this year, the U.S. Navy discovered that the heat from the
MV-22's gas turbine engines, which blow their exhaust right on to the
deck of the LHD while waiting to take off, caused high enough
temperatures to the steel under the deck plates, to possibly warp the
understructure. This was already a known potential problem with the
new F-35B vertical takeoff jet fighter.
So now the Navy has two hot new aircraft that require an innovative
solution to the melting deck problem. The Navy also discovered that
the exhaust heat problem varied in intensity between different classes
of helicopter carriers (each with a different deck design.)

The Navy is looking for a solution that will not require extensive
modification of current carrier decks. This includes a lot of decks,
both the eleven large carriers, and the ten smaller LHAs and LHDs.
This is shaping up as another multi-billion dollar "oops" moment, as
the melting deck problem was never brought up during the long
development of either aircraft.

Previously, the Harrier was the only aircraft to put serious amounts
of heat on the carrier deck, but not enough to do damage. But when you
compare the Harrier engine with those on the V-22 and F-35B, you can
easily see that there is a lot more heat coming out of the two more
recent aircraft. Someone should have done the math before it became a
real problem.



Distortion or warping of steel plating due to expansion from high
temperatures is a far cry from "melting".

On Dec 10, 3:44*pm, "Mr.Smartypants"
wrote:
On Dec 9, 9:22*pm, Mike wrote:



StrategyPage.com
December 2, 2009

The Melting Deck Plates Muddle

by James Dunnigan

Earlier this year, the U.S. Navy discovered that the heat from the
MV-22's gas turbine engines, which blow their exhaust right on to the
deck of the LHD while waiting to take off, caused high enough
temperatures to the steel under the deck plates, to possibly warp the
understructure. This was already a known potential problem with the
new F-35B vertical takeoff jet fighter.
So now the Navy has two hot new aircraft that require an innovative
solution to the melting deck problem. The Navy also discovered that
the exhaust heat problem varied in intensity between different classes
of helicopter carriers (each with a different deck design.)

The Navy is looking for a solution that will not require extensive
modification of current carrier decks. This includes a lot of decks,
both the eleven large carriers, and the ten smaller LHAs and LHDs.
This is shaping up as another multi-billion dollar "oops" moment, as
the melting deck problem was never brought up during the long
development of either aircraft.

Previously, the Harrier was the only aircraft to put serious amounts
of heat on the carrier deck, but not enough to do damage. But when you
compare the Harrier engine with those on the V-22 and F-35B, you can
easily see that there is a lot more heat coming out of the two more
recent aircraft. Someone should have done the math before it became a
real problem.

Distortion or warping of steel plating due to expansion from high
temperatures is a far cry from "melting".

1700 degrees was mentioned in one article.

Distortion or warping of steel plating due to expansion from high
temperatures is a far cry from "melting".

1700 degrees was mentioned in one article.

Hopefully, the airflow would be colder than what's required to start a
wildfire. Missing adequate structural expansion joints, the workaround
would be reflective coating and/or increasing thermal inertia with a
few tons of liquids trapped between the deck and a lining. Other
standard solutions include:

1) Jack in the box type helipads with an engine cold start while
ballistic
2) The ****ing match: Squad-Unbuckle-Ready-Aim-Pee!
3) Mk2 tractor towed movable through-deck holes
4) Frogwatch's spit buckets, a couple

On Dec 10, 2:21*pm, Jack Linthicum
wrote:
On Dec 10, 3:44*pm, "Mr.Smartypants"
wrote:





On Dec 9, 9:22*pm, Mike wrote:

StrategyPage.com
December 2, 2009

The Melting Deck Plates Muddle

by James Dunnigan

Earlier this year, the U.S. Navy discovered that the heat from the
MV-22's gas turbine engines, which blow their exhaust right on to the
deck of the LHD while waiting to take off, caused high enough
temperatures to the steel under the deck plates, to possibly warp the
understructure. This was already a known potential problem with the
new F-35B vertical takeoff jet fighter.
So now the Navy has two hot new aircraft that require an innovative
solution to the melting deck problem. The Navy also discovered that
the exhaust heat problem varied in intensity between different classes
of helicopter carriers (each with a different deck design.)

The Navy is looking for a solution that will not require extensive
modification of current carrier decks. This includes a lot of decks,
both the eleven large carriers, and the ten smaller LHAs and LHDs.
This is shaping up as another multi-billion dollar "oops" moment, as
the melting deck problem was never brought up during the long
development of either aircraft.

Previously, the Harrier was the only aircraft to put serious amounts
of heat on the carrier deck, but not enough to do damage. But when you
compare the Harrier engine with those on the V-22 and F-35B, you can
easily see that there is a lot more heat coming out of the two more
recent aircraft. Someone should have done the math before it became a
real problem.

Distortion or warping of steel plating due to expansion from high
temperatures is a far cry from "melting".

1700 degrees was mentioned in one article.-


That would still be "distortion" not "melting".

On Dec 11, 4:45*pm, "Mr.Smartypants"
wrote:
On Dec 10, 2:21*pm, Jack Linthicum
wrote:



On Dec 10, 3:44*pm, "Mr.Smartypants"
wrote:

On Dec 9, 9:22*pm, Mike wrote:

StrategyPage.com
December 2, 2009

The Melting Deck Plates Muddle

by James Dunnigan

Earlier this year, the U.S. Navy discovered that the heat from the
MV-22's gas turbine engines, which blow their exhaust right on to the
deck of the LHD while waiting to take off, caused high enough
temperatures to the steel under the deck plates, to possibly warp the
understructure. This was already a known potential problem with the
new F-35B vertical takeoff jet fighter.
So now the Navy has two hot new aircraft that require an innovative
solution to the melting deck problem. The Navy also discovered that
the exhaust heat problem varied in intensity between different classes
of helicopter carriers (each with a different deck design.)

The Navy is looking for a solution that will not require extensive
modification of current carrier decks. This includes a lot of decks,
both the eleven large carriers, and the ten smaller LHAs and LHDs.
This is shaping up as another multi-billion dollar "oops" moment, as
the melting deck problem was never brought up during the long
development of either aircraft.

Previously, the Harrier was the only aircraft to put serious amounts
of heat on the carrier deck, but not enough to do damage. But when you
compare the Harrier engine with those on the V-22 and F-35B, you can
easily see that there is a lot more heat coming out of the two more
recent aircraft. Someone should have done the math before it became a
real problem.

Distortion or warping of steel plating due to expansion from high
temperatures is a far cry from "melting".

1700 degrees was mentioned in one article.-

That would still be "distortion" not "melting".

Here are some numbers some from an amendment
BAA 09-031 Amendment 0001

Side note:
[Iron, out of the ground, melts at around 1510 degrees C (2750°F).
Steel often melts at around 1370 degrees C (2500°F).]

ONR is looking for thermal management technologies that can keep the
deck surface temperature below 300ºF when exposed to MV-22 exhaust
plumes for 90 minutes before takeoff, and F-35B exhaust plumes for 2
minutes when landing. And cooling the deck is not enough - any
solution has to be compatible with the deck's non-skid coating. It
also has to be affordable and capable of being installed below deck or
retrofitted above deck. Tall order.


“Structural Evaluation of an LHD-Class Amphibious
Ship Flight Deck Subjected to Exhaust Gas Heat from a MV-22 Osprey
Aircraft,” they note that deck buckling occurs at a temperature of
160oF to 170oF. Where does the 300oF limit originate?

Response: The 300 degree F is derived from the temperature limit of
the tires on aircraft.

How concentrated is the heat flux, how large an area is involved in
the 24,000BTU/min heating? I have had difficulty getting any numbers
and the information heat flux given in the BAA did not include an area
component.

Response: A range of 3-foot to 10-foot diameter is suggested.


Max exhaust temperature anticipated?
Response: This is tightly controlled. A range of max temperatures
could be 1000– 1700 deg. F.

http://www.onr.navy.mil/~/media/File...amend0001.ashx

ONR is looking for thermal management technologies that can keep the
deck surface temperature below 300ºF when exposed to MV-22 exhaust
plumes for 90 minutes before takeoff, and F-35B exhaust plumes for 2
minutes when landing. And cooling the deck is not enough - any
solution has to be compatible with the deck's non-skid coating. It
also has to be affordable and capable of being installed below deck or
retrofitted above deck. Tall order.


“Structural Evaluation of an LHD-Class Amphibious
Ship Flight Deck Subjected to Exhaust Gas Heat from a MV-22 Osprey
Aircraft,” they note that deck buckling occurs at a temperature of
160oF to 170oF. Where does the 300oF limit originate?

Response: The 300 degree F is derived from the temperature limit of
the tires on aircraft.

How concentrated is the heat flux, how large an area is involved in
the 24,000BTU/min heating? I have had difficulty getting any numbers
and the information heat flux given in the BAA did not include an area
component.

Response: A range of 3-foot to 10-foot diameter is suggested.


Max exhaust temperature anticipated?
Response: This is tightly controlled. A range of max temperatures
could be 1000– 1700 deg. F.

http://www.onr.navy.mil/~/media/File...amend0001.ashx

With hot aircraft tires being an additional concern, what about the
impact on the feet of the flight deck crew, refueling hoses, "mule"
tires, etc? It seems like this heat issue may take on the dimensions of
a "systemic" problem.

It's just the nature of naval air ops that once an aircraft (weapons
system) is established, it will become heaver, more powerful, and the
tempo of operations will increase.

On Dec 11, 5:06*pm, Jack Linthicum
wrote:
ONR is looking for thermal management technologies that can keep the
deck surface temperature below 300ºF when exposed to MV-22 exhaust
plumes for 90 minutes before takeoff, and F-35B exhaust plumes for 2
minutes when landing. And cooling the deck is not enough - any
solution has to be compatible with the deck's non-skid coating. It
also has to be affordable and capable of being installed below deck or
retrofitted above deck. Tall order.

I've got this conversation at ONR in my head...

"We've got a problem. Those Ospreys are ****ing up the decks."

"Define '****ing up.'"

"Well, here's the problem. [snip detailed description and analysis]"

"Are you serious? They never accounted for that?"

"No sir."

"Well...what do we have that can take that kind of heat?"

"Nothing that I know of, sir."

"Well...damn...look, SOMEONE's gotta have something. Put out an RFI
and keep your fingers crossed."

The Melting Deck Plates Muddle


The Navy is looking for a solution that will not require extensive
modification of current carrier decks. This includes a lot of decks,
both the eleven large carriers, and the ten smaller LHAs and LHDs.
This is shaping up as another multi-billion dollar "oops" moment, as
the melting deck problem was never brought up during the long
development of either aircraft.

What about clamshell deflectors for the hot exhausts?

During warmup before takeoff the clamshell halves deflect the hot
exhaust forward and rearward, away from the deck. At the moment of
takeoff the clamshell doors close partally to reduce the deflection
angle (which will provide some vertical thrust and side thrust) or
move out of the way altogether to allow the hot exhaust to shoot the
deck.

For landing, as the aircraft comes close to deck the clamshells are
partially closed, again to deflect the hot exhausts from blowing
directly on the deck. How this will affect controllability will need
to be tested for practicality. On landing the clamshell doors will be
in full deflection mode (Fwd and Rearwd) to keep the hot gasses awway
from the deck.