Steve Leonard
June 18th 07, 11:54 PM
One thing that you should be careful of is comparing
the Diana with the Diana 2 as far as wing location.
The leading edge at the wing root was moved forward
from the Diana to the Diana 2. This was most likely
due to the overall shift in the wing planform. On
the Diana, the leading edge is more nearly straight
out, and on the Diana 2, the trailing edge is more
nearly straight out. To keep the pilot position relative
to the aerodynamic center similar, the leading edge
of the wing at the root must be moved forward. They
changed from a slightly forward swept wing to a slightly
aft swept wing. This is very important as the Diana
is very light and the pilot is a significant portion
of the minimum flying weight.
This change would also show up in stability if you
used distances and datum lines from a Diana 1 manual
with a Diana 2, or vice versa. Gliders tend to be
flown with the CG very near the aerodynamic center,
so if you are off a bit to the back side on you cg
calculations (i.e., the cg is aft of where you think
it is), you can have your hands full in pitch very
quickly. The plane will tend towards instability.
I have experienced this myself. When the instability
is small, the pilot can compensate. If it gets larger,
the pilot cannot.
I wish them all the success with the plane. I got
a chance to sit in a Diana cockpt. I am 6'2', and
weigh about 215 lbs. I fit, but it was very close
all around. A different chute would certainly have
helped. I have flown with Jerry Zieba, the US Dealer,
in his. It climbs and runs very well. And if it had
not handled well, he would have looked much more tired
after some of the 5+ hour days we had last summer at
Hobbs, or the long day we had at Albert Lea.
I am hoping that the information on the one in Australia
is due to some mis-interpretations of flight manual
information causing issues with flight characteristics.
Steve Leonard
the Diana with the Diana 2 as far as wing location.
The leading edge at the wing root was moved forward
from the Diana to the Diana 2. This was most likely
due to the overall shift in the wing planform. On
the Diana, the leading edge is more nearly straight
out, and on the Diana 2, the trailing edge is more
nearly straight out. To keep the pilot position relative
to the aerodynamic center similar, the leading edge
of the wing at the root must be moved forward. They
changed from a slightly forward swept wing to a slightly
aft swept wing. This is very important as the Diana
is very light and the pilot is a significant portion
of the minimum flying weight.
This change would also show up in stability if you
used distances and datum lines from a Diana 1 manual
with a Diana 2, or vice versa. Gliders tend to be
flown with the CG very near the aerodynamic center,
so if you are off a bit to the back side on you cg
calculations (i.e., the cg is aft of where you think
it is), you can have your hands full in pitch very
quickly. The plane will tend towards instability.
I have experienced this myself. When the instability
is small, the pilot can compensate. If it gets larger,
the pilot cannot.
I wish them all the success with the plane. I got
a chance to sit in a Diana cockpt. I am 6'2', and
weigh about 215 lbs. I fit, but it was very close
all around. A different chute would certainly have
helped. I have flown with Jerry Zieba, the US Dealer,
in his. It climbs and runs very well. And if it had
not handled well, he would have looked much more tired
after some of the 5+ hour days we had last summer at
Hobbs, or the long day we had at Albert Lea.
I am hoping that the information on the one in Australia
is due to some mis-interpretations of flight manual
information causing issues with flight characteristics.
Steve Leonard