"Dave Butler" wrote in message
...
Mike Rapoport wrote:
wrote in message
...

Mike Rapoport wrote:
: Keep in mind that the short field settings shorten the ground run but
: generally increase the distance to clear a 50' obstical.

Isn't that the *point* of short field technique... to get off and over in
the
shortest distance? There would appear to be a logical flaw to that
statement.

I would agree that it will take more *time* to get to a given altitude at
(e.g. 50' obstacle clearance)... Short field performance is defined to
give the best
obstacle clearance per *distance*. I would agree that soft-field
technique will
increase distance, but short is short.

Am I missing something?


Maybe :-) If the short field takoff is using a higher drag, higher lift
configuration (more flaps) to get off the ground at a lower speed
(shorter roll) it then takes longer (in both time and distance) to make
the climb over the obstacle because of the higher drag configuration. I
hope this makes sense.

Yes, it makes sense, but I don't think it always holds up in practice. For
example, in my Mooney, the recommended obstacle clearance technique is to
not retract the gear until the obstacle is cleared. More drag gives a
greater -angle- of climb.


In the Helio, the shortest ground roll is with 40 degrees of flaps but
the shortest distance over a 50' obstacle is with 30 degrees of flaps.

It seems the configuration for best angle is model-specific.


More drag, by itself, can't improve angle of climb. They must have had
another reason.

Mike
MU-2