Re: An 24 V

Date:         03 Aug 97 02:50:15 
From:         Steve Lacker <CAN_SPAM@arlut.utexas.eedu>
Organization: applied research laboratories
References:   1
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Marc Schaeffer wrote:
> This post is related to the high performance version of the Antonov 24
> called 24V. I read that it has an auxilary turbojet engine in the right
> engine nacelle rated at 8kN. The same engine is also used on the An26.

Yup...very odd! just looked it up in Janes World Aircraft Recognition
Handbook, and the single starbord jet it indeed mentioned. Its also used
on the AN 30.

> - Is this a unique way to enhance performance of a turboprop ?

Unique in using an "add-on" jet to boost performance? Not unique but
rare. I guess the best example I can think of is the B-36, which was
piston-powered but did use 4 podded jets to boost takeoff/climb
performance (and increase top speed in certain situations). The recent
discussion on the Trident also pointed out its use of a booster jet. I
think the Antonov use of a *single* jet on one side of the A/C is
probably unique though. Probably made takeoff procedures interesting...

> - Was this choice caused by a lack of more powerful engines ?

Probably, but just a guess. The later AN-32 which had more powerful
turboprops does not appear to have had the booster jet as did the AN 24,
26, and 30.

> - Is there a picture and/or technical description of this particular
> feature on the WWW ?

Don't know about the web... the pictures in Janes make it apparent that
the jet is well-concealed in the nacelle. About the only distinguishing
feature is that teh starbor nacelle has a blunt trailing edge profile,
while the port nacelle is rounded.

As a side note, Janes refers to this auxiliary jet being used "for
engine starting..." (like an APU, I suppose) and "... to boost
takeoff/climb performance in event of engine failure..."

Stephen Lacker
Applied Research Laboratories, The University of Texas at Austin
PO Box 8029, Austin TX 78713-8029