Mailing List flyrotary@lancaironline.net Message #10174
From: marc <cardmarc@charter.net>
Subject: FW: RE: bsfc?
Date: Mon, 2 Aug 2004 18:27:52 -0500
To: <digest@cardinalflyers.com>, ACRE NL <rotaryeng@earthlink.net>, Flyrotary <flyrotary@lancaironline.net>
Gami's reply to my question. 300hp!
> ____________________Forward Header_____________________
> Subject:    RE: bsfc?
> Author: "George Braly" <SMTP:gwbraly@gami.com>
> Date:       8/2/2004 10:58 AM
>
> Marc,
>
> >> 17 hours of turbo-normalized operations in the last three days -
all
> lean of peak TIT.  Altitudes from 3000 MSL to 18,000 and everywhere in
> between.  ADH to ORL to PNE to ADH (55Kt headwind) ... headwinds on
two
> of three legs.  Average power? 92.5% of rated 300 HP continuous in
> cruise.
> Average torque? ~ 102% of rated torque; hottest CHT = ~ 378; TIT =~
1505
> to 1525F; and normal BSFC = ~ 0.385 lbs/hp/hr.<<
>
> That is the correct quote (note, 300 Hp, not 200).   I made the flight
> back in May.  The cylinders on that engine have been operated that way
> now for about 1400 hours.
>
> The BSFC of 0.385 is the normal BSFC for that engine when operating at
> high power and 50 to 80F  LOP, which is where the observed BSFC(min)
for
> that engine happens on a high power mixture sweep.
>
>  0.385 is pretty standard for a high compression (8.5:1)  big bore TCM
> engine, according to TCM's own published data which we have confirmed
on
> our test stand.
>
> And, yes,  0.385 is very good, and most people do not appreciate how
> excellent our aircraft engines are in this regard when properly
operated
> at high power while lean of peak.   For example,  the Porsche Mooney
> (geared) engine would only do about 0.42 to 0.425, even when LOP.  In
> that case, the overall smaller size of the engine,  the higher RPM,
and
> the gear box are what makes the difference.
>
> Regards,  George
>


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