Engine quit today

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CharlieTango
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Re: Engine quit today

Postby CharlieTango » Fri Jan 20, 2017 11:51 pm

MrMorden wrote:
CharlieTango wrote:
drseti wrote:You are confusing minimum sink and best glide. They are not 2 versions of the same thing. Best glide is best l/d ratio and min sink is min vert speed.


What I am talking about is maximum distance over the ground before running out of altitude to make a landing, regardless of sink rate. In an engine out situation, that is all I care about. The low inertia of the CT seems to work better with higher speeds in the glide. At lower speed and higher flaps the airplane just seems to sink faster with less progress over the ground. This is also the reason the standard PAPI/VASI glideslopes are too shallow for a normal approach with flaps in most LSA.


Andy, max glide can be primary but just as likely it will be time you need. Take the current exampe, 4,000' above pattern and just 6 miles out, in a light sport in 30kt winds amongst 13,000' peaks. Point is without power I would have arrived at the airport with several thousand feet to loose.

This probably happens most of the time, nearest airport is only a short glide. When I arrive without power I might want all the time I can get by using minimum sink speed. If my judgement isn't working out I might want more time to adjust my approach.

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drseti
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Re: Engine quit today

Postby drseti » Sat Jan 21, 2017 12:22 am

As a generalization, I'd think if I were dead-stick from directly above the airport, I'd want maximum time aloft to figure out my pattern (and triple-check my checklists). Otherwise, I'd probably want maximum glide distance. But, of course, all generalizations are untrue! :wink:
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CharlieTango
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Re: Engine quit today

Postby CharlieTango » Sat Jan 21, 2017 10:34 am

eyeflygps wrote:Unless you're right above the airport, maximum time may be worthless. Suppose your maximum "dwell" time is at 35 knots and you're facing a 35 knot headwind to the airport? Good luck.


Descending above the field is only one place I might choose minimum sink speed.

Here's a scenario: Its a summer day with convective activity, you are flying 3,000' below cloud base and there is a cumulous cloud street crossing your flight path to the field at a 45* angle. On one portion of your glide you can track the cloud street. If your min sink speed gives you zero vertical speed then you can track that street as long and as far as you want all the while getting closer without losing altitude. This might work well with a partial power loss.


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