Polars from Standard Cirrus Flight and Service Manual

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Flight Test Evaluation (Dick Johnson)

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Polars of Eight (Paul Bikle)

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Comments by George Moffat

Two Standard Cirrus gliders were delivered to George Moffat from the factory. These were #17 (N3247, 1970) and #218 (D-0960, 1972). In his book Winning on the Wind (1974) George evaluated the various gliders of that period based on his own experience. He called the Standard Cirrus the "most interesting of the three new types in the standard class in 1969." These also included the Standard Libelle and the ASW-15. It had "by far the roomiest cockpit...excellent visibility forward and to the sides" and the "controls are well arranged." He noted that in the early models the "stick and tow release are a bit too far forward for tall pilots." Overall, he rated it as "the nicest ship to fly then" (of 56 types in his logbook). "It seemed to seek out the center of thermals by itself. The ailerons are particularly light and pleasant, having a precision that gives the pilot an immediate sense of mastery. The yaw stability makes string centering almost automatic. Climb performance seemed excellent in tests against the big Cirrus, the greater maneuverability of the small ship at least making up for the lower rate of sink of the 18-meter version."

In 1972, around s/n 175, an additional .75 degrees of washout was added to the wing for a total twist of 1.5 degrees. According to George, this small change did much more than tame the hot landing characteristics of the early model, as Klaus Holighaus had intended. It "distinctly enhanced performance." Apparently it made the new ship climb "much better" and it gave it a "much faster rate of roll" ("slightly over three seconds" compared to "a touch under four"). Indicated stall speed was reduced from 36 kts to 33 kts. George went on to say "early impressions that I was climbing well soon became convictions that I could go up through anything." Flying these ships at Vrsac, he and Ben Green "grew used to outclimbing all comers." In addition glide performance was improved at speeds up to 85 kts. Finally, as Klaus had intended, the new ship had a slower safe approach speed with "much shorter and safe landings."

Comments by J. Laude

In response to a query from Torben Kristensen (#641), J. Laude wrote:

Dear Mr. Kristensen,

Since about S/N 175, early in 1972, we twisted the outer end of the wings - 1,5°.
This improved the flying characteristics at lower speeds, with more stability in curves, specially during thermaling.
A measurable negative influence in performance at higher speeds could not be observed.
At this time it was the only significant modification.

With kind regards
Flugzeugbau GmbH.
J. Laude