Re: Status of Maine 1649 Connies?

From:         Steve Lacker <>
Organization: applied research laboratories
Date:         21 Jul 96 13:29:35 
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  or MIME structure ( 0 Falke_Charlie phone dist ) wrote:
>The answer to "why bother?" is specific fuel consumption.  The
>recovered energy in the exhaust put the fuel efficiency of turbo
>compounds in a class by themselves among aircraft engines. They were
>almost as good as diesels!
>   As far as why there weren't more American large turboprops, the
>main answer is the same, the poor SFC of the early turboprops wasn't
>offset by their lighter weight, in comparison to recips, nor were they
>that much faster than the best recip powered airliners.

I agree that SFC of turbo-compounds was astounding... but was that really the
motivation?? After all, the TC's had to burn >>100 octane aviation gasoline,
while a turboprop could burn bargain-basement kerosene. On top of that, this
was the '50s and '60s, when fuel costs were less of a factor (although still
admittedly a large factor) in expense management. Add in the cost of
maintaining a turbo compound, and then it seems to me that even a pig of an
inefficient turboprop looks pretty good.

Now, to hop to your side of the argument... I suppose its true that the
airlines would opt for the low SFC of the TC engines initially, then back down
*later* when maintenance problems actually begin to hit home. By then, jets
were taking over, and the turboprop finally made inroads in the US (principally
on the Electra).

And since you mentioned it... why aren't we overrun with diesel engined
aircraft? Poor power-to-weight ratio?

Steve Lacker	/	Applied Research Laboratories, The University of Texas
512-835-3286	/	PO Box 8029, Austin TX 78713-8029