Airstart reliability

[Tom Nau]

A friend of mine recently was involved in an outlanding accident. It
seems as though having an engine on-board would help to avoid
outlandings and therefore outlanding accidents. If there are any
generalities to be made, which are generally more reliable for
airstarts - sustainer systems or self-launch systems? My question
refers to gasoline systems and not electrics. And yes I understand
that no system is completely reliable and one should always have a
safe-landing site available even with an on-board engine. Thanks.
Tom

[Eric Greenwell[_4_]]

On 7/8/2011 9:08 AM, Tom Nau wrote:
> A friend of mine recently was involved in an outlanding accident. It
> seems as though having an engine on-board would help to avoid
> outlandings and therefore outlanding accidents.

It does help avoid them; it doesn't eliminate them. Personally, I've
used my engine to avoid over 150 landouts in 16 years, with only one
landing, and that was on an airstrip.

> If there are any
> generalities to be made, which are generally more reliable for
> airstarts - sustainer systems or self-launch systems? My question
> refers to gasoline systems and not electrics. And yes I understand
> that no system is completely reliable and one should always have a
> safe-landing site available even with an on-board engine. Thanks.

I'm not aware of any statistics showing a reliability advantage of one
over the other for in-flight restarts to avoid landing. My observation
is it depends more on the pilot than the type: if the pilot keeps the
system well-maintained, practices with it regularly, keeps a safe field
in easy reach, and begins the restart high enough to avoid pilot stress,
either system will start reliably.

If your concern is primarily avoiding a landout, then a sustainer system
is probably the best choice. This assumes you can get sustainer with
adequate climb rate at the density altitudes of interest, which might
not be possible for high desert areas.

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to
email me)
- "A Guide to Self-launching Sailplane Operation Mar/2004" Much of what
you need to know tinyurl.com/yfs7tnz

[Tom Nau]

On Jul 9, 6:31*pm, Eric Greenwell > wrote:
> On 7/8/2011 9:08 AM, Tom Nau wrote:
>
> > A friend of mine recently was involved in an outlanding accident. *It
> > seems as though having an engine on-board would help to avoid
> > outlandings and therefore outlanding accidents.
>
> It does help avoid them; it doesn't eliminate them. Personally, I've
> used my engine to avoid over 150 landouts in 16 years, with only one
> landing, and that was on an airstrip.
>
> > *If there are any
> > generalities to be made, which are generally more reliable for
> > airstarts - sustainer systems or self-launch systems? *My question
> > refers to gasoline systems and not electrics. *And yes I understand
> > that no system is completely reliable and one should always have a
> > safe-landing site available even with an on-board engine. *Thanks.
>
> I'm not aware of any statistics showing a reliability advantage of one
> over the other for in-flight restarts to avoid landing. My observation
> is it depends more on the pilot than the type: if the pilot keeps the
> system well-maintained, practices with it regularly, keeps a safe field
> in easy reach, and begins the restart high enough to avoid pilot stress,
> either system will start reliably.
>
> If your concern is primarily avoiding a landout, then a sustainer system
> is probably the best choice. This assumes you can get sustainer with
> adequate climb rate at the density altitudes of interest, which might
> not be possible for high desert areas.
>
> --
> Eric Greenwell - Washington State, USA (change ".netto" to ".us" to
> email me)
> - "A Guide to Self-launching Sailplane Operation Mar/2004" Much of what
> you need to know tinyurl.com/yfs7tnz

Thank you to all who responded.
Tom