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jumbojim747
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Hot Wing Question?

Tue Mar 29, 2005 8:49 am

I heard that all large aircraft have hot wings where hot air is taken from the engines and fed into the wings to stop ice forming.
First from what stage of the engine does this air come from and why cant they use this system on the turbo props that have icing boots .?
Any help would be appreciated
On a wing and a prayer
 
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Starlionblue
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RE: Hot Wing Question?

Tue Mar 29, 2005 8:58 am

Quoting JumboJim747 (Thread starter):
why cant they use this system on the turbo props that have icing boots .?

They probably can, but I get the feeling icing boots are simpler and cheaper.
"There are no stupid questions, but there are a lot of inquisitive idiots." - John Ringo
 
B747FE
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RE: Hot Wing Question?

Tue Mar 29, 2005 9:25 am

Quoting JumboJim747 (Thread starter):
what stage of the engine does this air come from

In the B747 powered by JT9D the primary supply of pneumatic air is from the 8th compressor stage through a check valve. When 8th stage bleed air pressure is not high enough to supply system demands, 15th stage bleed air is used.
RB211 engines use the 14th stage as the source for high stage bleed air.


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B747FE.
"Flying is more than a sport and more than a job; flying is pure passion and desire, which fill a lifetime"
 
air2gxs
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RE: Hot Wing Question?

Tue Mar 29, 2005 9:28 am

Quoting JumboJim747 (Thread starter):
First from what stage of the engine does this air come from

The answer, of course, depends on the airframe and engine. Wing anti-ice normally comes through the PRSOV. The PRSOV normally receives air from 2 sources, a low pressure tap and a high pressure tap. Example: CF6 installed on a B767 has an 8th stage bleed and a 14th stage bleed. At low engine power settings and/or high pnuematic demands, the 14th stage supplies the aircraft. At high power settings, the 8th stage supplies the aircraft.

So, to answer your question: It depends on the aircraft, the engine and the power setting.
 
pilotpip
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RE: Hot Wing Question?

Tue Mar 29, 2005 9:42 am

The pneumatic boots are usually powered by bleed air as well. The reason that they are used on many smaller jets and turboprops is because hot wings take a lot more bleed air and as a result, power, from the engine.
DMI
 
troubleshooter
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RE: Hot Wing Question?

Tue Mar 29, 2005 1:49 pm

The BAe 146/RJ has INNER WING DE-ICE and OUTER WING ANTI ICE ducts. The inner wing de-ice uses a set of 3 piccolo ducts to heat up the wing leading edge. In the outer wing there is only one piccolo tube. Bleed air is extracted on the customer bleed duct. It uses bleed air from the compressor outlet. There is no bleed source switching depending on engine power setting.

The CRJ uses 14th stage bleed air for the airframe anti-ice system. There's no bleed source switching for anti-ice purposes, too. 10th stage bleed air is used to supply the cooling packs and the air turbine starter on the engines. 10th and 14th stage bleed can be selected individually as they use independent ducts and valves.

The ERJ uses 9th or 14th stage bleed air. 9th stage is used during higher power settings, 14th stage is used during lower power settings. But as soon as airframe anti-ice is selected, the high stage valve opens to supply the bleed air system with 14th stage air independent from engine power setting.
This job sucks!!! I love this job!!!
 
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jumbojim747
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RE: Hot Wing Question?

Tue Mar 29, 2005 6:04 pm

Thank you all for the replies .
Have learnt a lot from you guys .
Very much appreciated
On a wing and a prayer
 
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HAWK21M
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RE: Hot Wing Question?

Tue Mar 29, 2005 8:17 pm

Quoting JumboJim747 (Thread starter):
I heard that all large aircraft have hot wings where hot air is taken from the engines and fed into the wings to stop ice forming.

Its Reffered to as WTAI [Wing Thermal Antiicing].Bleed air from the Engines is ported through a WTAI Shut off Valve to heat the Leading Edges & prevent the Formation of Ice.

Quoting JumboJim747 (Thread starter):
and why cant they use this system on the turbo props that have icing boots .?

Deicing Boots is a Deicing system,it removes the Ice After its formed by Rubber Expander Boots.

Anticing & Deicing are the Main Differences.

regds
MEL
I may not win often, but I damn well never lose!!! ;)
 
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jumbojim747
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RE: Hot Wing Question?

Tue Mar 29, 2005 11:26 pm

Quoting HAWK21M (Reply 7):
it removes the Ice After its formed by Rubber Expander Boots.

MEL that's my point why wait till the ice is formed to remove it.? Why don't they make the same system that the big jets use instead.?
As Starlionblue already said they can use this system but costs are the issue and its a shame because these ATR are always flying in bad weather and are at a higher risk then the other jets but the dollar has shown its ugly face once more.
On a wing and a prayer
 
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HAWK21M
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RE: Hot Wing Question?

Wed Mar 30, 2005 12:56 am

Quoting JumboJim747 (Reply 8):
but the dollar has shown its ugly face once more.

It has a big Influence in Aviation,& cannot be disregarded.No point operating in a loss.
About the Deicing chosen version,I guess its the Choice of the Manufacturer.Although I'd def prefer the WTAI type.
regds
MEL
I may not win often, but I damn well never lose!!! ;)
 
411A
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RE: Hot Wing Question?

Wed Mar 30, 2005 9:21 am

Most turboPROP engines simply do not have a sufficient supply of hot bleed air to ANTIice wings and tail surfaces, without severe SHP penalties.

Even the Lockheed Electra was at a disadvantage here, in more than moderate icing

Hot wing anti-icing began long before turbine engines, of course.

Example...Douglas DC6 and DC7.
These aircraft used avgas fueled combustion heaters for wing and tail surface de-icing....and cabin heating.

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