Turboprop de-ice: Why not like a jet instead of boots?

[md-100]

Why all turboprops have boots?
Is there any reason not to install leading edge hot air heating ?

[Cardinal]

Long wings + Small engines = Tremendous bleed air demand.

[Livesinafield]

Yep generally too much bleed air required for it unless lost of engines with lots of power.. for example the Lockheed electra has a "hot" wing and no boots

[Pugilistic Animus]

besides the tremendous bleed demand...turboprops look good in Pradas:}

[V1... Ooops]

Some types of turboprop engines, such as the Pratt & Whitney PT6 series, cannot supply sufficient (or hot enough) bleed air at low engine speeds to support hot-leading-edge de-icing systems.

At cruise power, no problem, but at the lower power settings frequently used during approach - there's just not enough air to spare. Hence boots are used instead.

[MarkerInbound]

Not all turboprops have boots. As said above the L-188 has enough bleed air. The CV-580 also uses bleed air, the CV-600/640 has a set of combustion heaters just to heat the leading edge.

[Love_joy]

Its not simply a matter of bleed air availability either.

The temperature of the bleed air tapped off on some turbo-prop aircraft is simply not hot enough to do the job.

Its much simpler to use the cool air to run a pneumatic system.

That said, give me back my hot wing any day! I've never had a hot wing go wrong on me yet.

[barit1]

The Allison T56/501-D (http://en.wikipedia.org/wiki/Allison_T56) engine has a relatively huge "core", thus its ability to bleed sufficient compressor air for hot-wing anti-icing on CV580 and L-188. More modern engines - PT6, PW1xx, CT7 etc. have much lower core airflow, and thus sip the petrol. The tradeoff is less bleed air available for airframe use.

[Daysleeper]

On the Allison 501 opening the bleed for de-icing is akin to a 25% reduction in eSHP, so if you open all 4 then you are running 1 engine purely to de-ice the aircraft, oh and the wing glows a bit. :E

[proxus]

If I remember correctly, the Dornier 328 Jet has also boots although it's a Turbofan. They're just silver colored instead of black so it wouln't look like a pneumatic boot.