Andy Blackburn wrote:
At 16:18 06 June 2006, Shawn wrote:

Seems like a preflight run-up of the engine would reveal/mitigate
many
starting problems in flight.


My thought exactly.

There have been some comments here that sustainers
generally are not run up prior to flights (presumably
including flights where use of the engine is a distinct
possibility) AND that periods of inactivity significantly
up the odds of the engine failing to start.

If both of these statements are true it seems that
flying a sustainer-equipped sailplane cross-country
without a preflight engine runup is a bit of a roll
of the dice. It also raises in my mind two somewhat
related questions:

1) Is there a good reason why one shouldn't do a runup
prior to every (cross-country) flight?

2) Do many pilots flying sustainer-equipped sailplanes
presume that the engine is unlikely to start and not
care, do they presume that the engine IS likely to
start (correctly or incorrectly), or do they believe
a preflight runup doesn't help the odds anyway.

Besides the issue of the engine readiness, there is the issue of pilot
readiness: if the pilot hasn't started the engine in the air recently,
isn't he more likely to bungle the start when he getting low and under
pressure? Even better than a preflight, on-the-ground start, would be to
do it after releasing from the launch. You could even take lower
aerotow, and save a bunch on the tow fee.

--
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Eric Greenwell - Washington State, USA

www.motorglider.org - Download "A Guide to Self-launching Sailplane
Operation"