kinsell wrote on 1/17/2021 8:54 AM:
On 1/14/21 2:11 PM, Eric Greenwell wrote:
Moshe Braner wrote on 1/14/2021 11:39 AM:
On 1/14/2021 1:43 PM, John Galloway wrote:
...

Another huge advantage, is they don't have that all-flying tail, which
was quickly designed out of the Nimbus line, for good reason.

The late models DG100G, LS1F and Grob built Std Cirruses have conventional tailplanes.
Earlier variants of those 3, and the ASW 15 have all flying tailplanes.


OK, but what is so bad about the all-flying tail?* I know some models had a reputation for
no "feel" in the pitch control.* Others less so. Is it the all-flying tail, or some details
of its design?* Where the hinge is placed along the chord of that tail would make a big
difference, no?* And spring trim added to the system would make it behave better when
hands-off?

For example, Dick Johnson was regularly flying a Nimbus 2 IIRC, when he did the flight test
of the original Janus (both with all-flying tails). *He commented that "The well-balanced,
all-movable horizontal tail (on the Janus) provided good longitudinal stability at all
speeds and was a great improvement over the smaller poorly balanced Nimbus and Std. Cirrus
tails. It did, however, cause the longitudinal control to be fairly sensitive to control
stick position."

My Ka6e and Std Cirrus both had all-flying tails. Based on those gliders and comments from
other pilots in different gliders, I'd say "did cause the longitudinal control to be fairly
sensitive to control stick position" is what's wrong with all-flying tails, especially at
high speeds. Over 75 knots, I held the Std Cirrus stick in both hands, ditto for the Ka6e at
some slower speed I don't remember. I very much liked both those gliders, but it was a deep
pleasure to leave those gliders for the H301 - so steady at high speeds.


Having logged 1200 hrs in a Ka6Cr, I must say it never occurred to me to ever use both hands on
the stick at higher speed.* Such a sweet flying glider.* Maybe because it had the conventional
tail, unlike the E model?

No "maybe" about it: that's the primary difference between the two Ka6 gliders. The Ka6e was
pure all-flying tail, no auto-trim tab. What made it tolerable is there was rarely a reason to
fly very fast, and it was lovely at lower speeds. Terminal velocity spoilers, too!

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
- "A Guide to Self-Launching Sailplane Operation"
https://sites.google.com/site/motorg...ad-the-guide-1