JumboJim747 From Australia, joined Oct 2004, 2463 posts, RR: 46 Posted (8 years 8 months 3 weeks 6 days 5 hours ago) and read 2518 times:
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
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.
"Flying is more than a sport and more than a job; flying is pure passion and desire, which fill a lifetime"
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 From United States of America, joined Sep 2003, 3119 posts, RR: 11 Reply 4, posted (8 years 8 months 3 weeks 6 days 4 hours ago) and read 2468 times:
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.
Troubleshooter From Germany, joined Feb 2005, 423 posts, RR: 5 Reply 5, posted (8 years 8 months 3 weeks 6 days ago) and read 2413 times:
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.
JumboJim747 From Australia, joined Oct 2004, 2463 posts, RR: 46 Reply 8, posted (8 years 8 months 3 weeks 5 days 14 hours ago) and read 2328 times:
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.
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.